Con Trung Nong Nghiep - Nguyen Duc Khiem 1

Trng i hc Nng nghip H Ni -Gio trnh Cn trng nng nghip ---------------1

B GIO DC V O TO TRNG I HC NNG NGHIP I

PGS.TS. NGUYN C KHIM (Ch bin)

Gio trnh CN TRNG NNG NGHIP

(DNG CHO I HC, CAO NG CHUYN NGNH CY TRNG)

H NI 2005


PHN M U

Cn trng nng nghip l mn hc v Bo v thc vt nm trong chng trnh o to k s nng nghip v cao ng chuyn ngnh cy trng. Mn hc ny cung cp cho sinh vin nhng kin thc c bn v lp cn trng, v nhng loi cn trng thng gy hi cho sn xut nng nghip, v cc bin php phng chng su hi cy trng nhng khng nh hng xu n mi trng sng v nhng sinh vt c ch ngoi t nhin, khng nh hng xu n sc kho ca con ngi. Cu trc cun gio trnh chia lm 2 phn tng ng vi 2 hc phn l: phn i cng v phn chuyn khoa. Phn i cng trnh by nhng kin thc c bn nht v cn trng lin quan vi hnh thi, gii phu - sinh l, sinh vt, sinh thi v phn loi. Phn chuyn khoa trnh by nhng kin thc v nguyn l v cc bin php phng chng su hi, v su hi ca cc cy trng chnh v bin php phng chng tng loi c th. im mi ca gio trnh ny so vi cc gio trnh xut bn trc y l trong mt quyn gio trnh bao gm c i cng v chuyn khoa, ph hp ging dy vi thi lng ngn (3-4 n v hc trnh). Gio trnh c vit xc tch nhng vn m bo c tnh khoa hc, cp nht cc kin thc mi, ph hp cho sinh vin s dng trong khi hc trng i hc v cng l cm nang gn nh dng sau khi ra trng. Gio trnh c phn cng bin son nh sau: Ch bin: PGS.TS. Nguyn c Khim Phn i cng: - PGS.TS. Nguyn c Khim: cc chng I,II,III,IV,V,VI Phn chuyn khoa: - PGS.TS. Nguyn c Khim: cc chng VII, XI v ph lc - PGS.TS. Nguyn Vn nh: chng VIII - PGS.TS. Nguyn Th Kim Oanh: chng IX - GVC.TS. Trn nh Chin: chng X - GS.TS. Nguyn Vit Tng: chng XI - KS. Nguyn c Tng: phn hnh nh Mt s hnh nh minh ho ca gio trnh c trch t gio trnh cn trng nng nghip (Ch bin H Khc Tn, NXBNN 1981). Do iu kin bin son v trnh nn khng trnh khi nhng thiu st. Chng ti mong nhn c kin ng gp ca cc ng nghip ln xut bn sau s hon chnh hn.

Cc tc gi


Phn A I CNG


Chng I KHI NIM V CN TRNG HC

1. nh ngha mn Cn trng nng nghip Cn trng nng nghip l mn hc cung cp cho sinh vin nhng kin thc c bn v lp cn trng, v nhng loi cn trng c hi cho sn xut nng nghip, v nhng cn trng c ch cn bo v, nhng bin php nhm gim thiu s mt mt do su hi gy ra nhng bo v c a dng sinh vt trong h sinh thi, khng gy nhim nng sn v mi trng sng. 2. V tr phn loi v c im ca lp cn trng Cn trng l ng vt khng xng sng. Lp Cn trng c tn khoa hc l Insecta hay Hexapoda, thuc ngnh Tit tc Arthropoda.

Hnh 1.1. Cu to c th chu chu 1. u; 2. Ngc; 3. Bng; 4. Ru u; 5. Mt kp; 6. Mt n; 7. Ming; 8. Ngc

trc; 9. Ngc gia; 10. Ngc sau; 11. Chn trc; 12. Chn gia; 13. Cnh trc; 14. Cnh sau; 15. Chn sau; 16. L thnh gic; 17. L th; 18. Lng ui; 19. B phn

sinh dc ngoi (theo Frost)

Cn trng c nhng c im chung sau y: - C th chia ra 3 phn r rt l u, ngc v bng (Hnh 1.1). - u c 1 i ru u, ming, 1 i mt kp v 2-3 mt n (mt s loi khng c mt

n). - Ngc c 3 t, mi t c 1 i chn ngc v thi k trng thnh c th c 2 i

cnh. - L sinh dc v l hu mn nm cui bng. - Da lm chc nng ca b xng ngoi (Hnh 1.2). - H hp bng h thng kh qun. - Trong qu trnh sinh trng pht dc c bin thi bn trong v bn ngoi.


Hnh 1.2. So snh b xng trong v b xng ngoi 1. B xng trong ca ng vt c xng sng

2. B xng ngoi ca cn trng (theo Chu Nghiu)

3. Ngun gc tin ho ca lp cn trng V ngun gc ca lp cn trng c nhiu kin khc nhau. Handlirsch cho rng cn trng c xa tin ho t lp tam dip (Trilobita). Cc hc gi Hancea, Carpenter, Crampton cho rng cn trng tin ho t lp gip xc (Crustacea). Cc hc gi Brauer, Packard, Tyllygard v Imms li cho rng cn trng tin ho t lp a tc (Myriapoda). Nh vy, cn trng tin ho t 1 lp no trong ngnh tit tc (Arthropoda), c th l ng vt sng trn cn (Myriapoda), c th sng di nc (Trilobita, Crustacea), t tin ca cn trng u c ming nhai, kiu ming nhai cn trng l nguyn thu nht, t mi bin i thnh cc kiu ming khc, b my tiu ho kiu tiu ho thc n rn l nguyn thu nht, cnh mi xut hin lp cn trng v khng phi t chi ph ca t c th phn ngc bin i thnh. Cn trng c s loi v s c th tng loi nhiu, phn b rng bi v chng c nhng u th hn cc ng vt khc: (1) C th cn trng c bao bc mt lp da c cu to c bit, gip cho chng c th thch nghi vi nhng iu kin khc nghit ca ngoi cnh. (2) Chng c cnh nn c th bay tm kim thc n, tm i giao phi, chn la ni trng v tm ni sinh sng tt nht, c th di c v m rng vng phn b d dng. Do c cnh nn cn trng tin b vt xa t tin ca chng, lm cho chng chim u th trong cnh tranh sinh tn v hnh thnh cc loi mi, khin cho s loi nhiu, chim u th trong sinh qun. (3) C th cn trng b nh, khin cho chng c th n nu mi ni, vi mt lng thc n t i cng hon thnh mt th h v sinh ra th h sau. Nhng nghin cu ho thch cho thy cn trng xut hin trn mt t cch y hn 300 triu nm, tri qua thi k bng h, nhng ng vt c kch thc ln nh khng long b tit chng, cn cn trng li tn ti v pht trin. (4) Cn trng c sc sinh sn ln v vng i ngn, c loi nh rp mui (h Aphididae) vng i ch 5-7 ngy. V vy sc tng mt cao. (5) Cn trng c sc sng v kh nng thch nghi cao vi nhng bin i ca iu kin ngoi cnh, khin cho chng vt xa cc loi khc trong gii ng vt v tnh a dng.

4. Vai tr ca cn trng i vi t nhin v con ngi 4.1. Vi t nhin Cn trng l lp ng vt c s loi nhiu nht. n nay bit khong trn 1,5 triu loi cn trng, chim n 3/4 s loi c ghi nhn ca 60 lp thuc gii ng


vt. S lng c th mi loi cng rt ln. Th d, 1 t kin c tnh 50 vn con, 1 t ong ln khong 8 vn con. V l cn trng c vai tr quan trng s mt trong a dng sinh hc v trong cn bng sinh hc ca mi h sinh thi. Cn trng th phn cho khong 85% s loi thc vt hin hoa kho t (thc vt c hoa v bu nh l ra ngoi). V vy, ngi ta cho rng s pht sinh lp cn trng trn mt t lm xut hin sau nhng thc vt hin hoa kho t. Cn trng l nguyn nhn lm a dng mu sc v hng thm ca cc loi hoa trn tri t. Cn trng n nhng thc n khc nhau c ngun gc thc vt, ng vt, xc cht ng vt, phn ng vt, tn d thc vt, nn mi loi tham gia mt khu trong tun hon vt cht trong t nhin. Chng c coi l i qun v sinh thin nhin mi ni, to mu m cho t, tng tnh bn vng ca h sinh thi. 4.2.Vi con ngi Mt s loi cn trng n thc vt gy hi cho cy trng, nh hng n nng sut, phm cht nng sn, gy tn tht kinh t ng k cho nng dn. Nhng loi ny gi l su hi cy trng. Su hi thng lm gim 5-10% nng sut, sn lng cy trng. Khi chng pht sinh vi s lng ln c th gy thit hi nghim trng, buc ngi nng dn phi phng chng, nn khng nhng lm tn km tin ca m cc thuc tr su cn lm nhim mi trng sng, li d lng cht c trong nng sn v lm mt cn bng sinh hc trong t nhin. nc ta xy ra nhiu dch su hi trong 50 nm qua. Thi k 1961-1970, dch bnh vius la vng li do b ry xanh ui en (Nephotettix spp.) l mi gii truyn bnh xy ra khp cc tnh min bc (nh Lng Sn, Sn Ty, Thi Nguyn, Bc Ninh, Bc Giang, H Giang, Hng Yn, Hi Phng, Thi Bnh, Nam nh, H Nam, Thanh Ho...). Bnh gy hi nghim trng hng chc vn ha. Thi k 1971-1975, dch su nn (Pachydiplosis oryzae) xy ra khp cc tnh ng bng sng Hng (Nam nh, Thi Bnh, Hng Yn, Hi Phng...). Nhng nm 1977-1979, ry nu (Nilaparvata lugens) v ry lng trng (Sogata furcifera) pht sinh cc tnh ng bng sng Cu Long (Long An, Tin Giang, Bn Tre, Cu Long, Hu Giang, ng Thp...) vi mt hng vn con/m2 trn din tch n 200 ngn ha. Nhng nm 1979-1981, su nn (Pachydiplosis oryzae) gy hi n 11 ngn ha cc tnh min trung (Qung Bnh, Qung Tr, Tha Thin, Ph Khnh) vi t l dnh hi 30-50%. Nhng nm 1986-1987, b xt en (Scotinophara lurida) gy hi hng ngn ha la v xun v v ma cc tnh Thanh Ho, Ngh An, H Tnh. Ch tnh trong v xun nm 1986, nng dn cc tnh ny bt bng dng c th s c 200 tn b xt. Dch su cun l nh hi la (Cnaphalocrocis medinalis) xy ra trn phm vi c nc, v nm 2001 pht sinh gy hi 885 ngn ha cc tnh ng bng bc b v min ni pha bc, c v ng xun v v ma, mt hng trm con/m2. Nm 2001 hn 120 ngn ha ng v ma cc tnh ng Nai, B Ra, Vng Tu, Ty Ninh b co co pht sinh thnh dch gy hi nghim trng (Theo bo co ca Cc BVTV, nm 2002). Trn cc cy trng khc cng xy ra cc dch su, khin cho con ngi lun lun phi phng chng. iu, nh ca, g, sch th vin, nng sn sau thu hoch b mi v su mt gy hi. Thit hi do chng gy ra rt ln. Chng c th l nguyn nhn gy v , lm sp nh ca v nhng thm ho khc. Nhiu loi cn trng l k sinh trn ngi v ng vt nui. Chy, rn, b cht, mui, rp ging, rui vng khng nhng ht mu, m cn truyn cc bnh truyn nhim cho ngi v ng vt. S loi c th gy hi hay gy phin toi cho con ngi ch chim khng qu 1%, cn li l v hi hoc l c li cho con ngi. C nhng loi nh tm nh (Bombyx


mori), ong mt (Apis spp.), cnh kin (Laccifer spp.) l vt nui to ra sn phm c gi tr kinh t cao. Sn phm to ra ca hng chc loi cn trng l nguyn liu lm thuc cha bnh. Hng vn loi l k th t nhin ca su hi cy trng, chng gp phn hn ch s lng ca su hi trn ng rung, v chng chnh l bn ca nh nng". Cn trng th phn cho cy trng, gp phn lm cho cy c hoa thm qu ngt. Chng lm v sinh thin nhin, lm sch mi trng sng ca con ngi v lm tng mu m cho t canh tc. Nh vy, cn phi nhn bit loi no gy hi c bin php phng chng, loi no l v hi hoc l c ch bo v v to iu kin cho chng pht trin trn ng rung, lm thay i sinh qun ng rung theo hng c li cho con ngi.

5. Mt s mc lch s nghin cu v cn trng 5.1. Trn th gii Ba ngn nm trc cng nguyn Trung Quc bt u nui tm. Gn 400 nm trc cng nguyn Aristote (ngi Hy Lp) vit v 60 loi cn trng trong tc phm ca mnh. u th k 18 Reaumer (nh t nhin Php) vit 6 tp Hi k v lch s cn trng. Cui th k 18 Pallas (Vin s ngi Nga) nghin cu v vit v thnh phn loi ca cn trng. Vo th k 19, cng vi s pht trin ca cc ngnh khoa hc khc, cn trng hc thc s tr thnh mt khoa hc. C rt nhiu ngi chuyn su v cn trng hc v hng lot cc Hi cn trng c thnh lp cc nc, nh Php nm 1832, Anh nm 1833, Nga nm 1859. Cc hi cn trng gi vai tr ch o pht trin cn trng hc mi nc. T th k 20 cc lnh vc cn trng thc nghim ra i, trong c cn trng nng nghip, cn trng lm nghip. 5.2. Vit Nam - Vo nm 1905 on nghin cu ngi Php cng b 1020 loi cn trng thu thp

c ng Dng, trong c Vit Nam. - T u th k 20 n 1945 c nhiu kt qu nghin cu c cng b lin quan

n cn trng Vit Nam ca cc tc gi: Dupasquier (Cn trng hi ch), Fleutiaux (Mi, xn tc v cn trng hi ma, u ), Joannis (Lepidopteres heteroceres du Tonkin), Trn Th Tng (Les Chrysomelinae du Sud de la Chine et du Nord Tonkin), Salvaza (Faune entomogique de lIndochine), Paulian R. (Scarabaeidae), Lemee A. (Lepidoptera).

- Sau 1945: Nm 1953 thnh lp Phng cn trng thuc Vin trng trt. Nm 1961 thnh lp Cc bo v thc vt. Nm 1966 thnh lp Hi cn trng hc Vit Nam.

CU HI N TP CHNG I 1. V tr phn loi v c im chnh ca lp cn trng l g? 2. Ngun gc tin ho ca lp cn trng v nhng g l u th ca cn trng so

vi t tin ca chng? 3. Vai tr ca cn trng i vi t nhin v vi con ngi nh th no? 4. T nhn thc v vai tr ca cn trng i vi t nhin v vi con ngi, suy

ngh g v vic phun thuc tr su trn ng rung ca nng dn trong nhng nm qua?

5. Nu mt s mc lch s chnh ca vic nghin cu cn trng trn th gii v trong nc.


Chng II HNH THI HC CN TRNG

1. nh ngha Hnh thi hc cn trng nghin cu cu to bn ngoi c th cn trng. Mi cu to ca c th cn trng u c chc nng nht nh, l kt qu ca s bin i rt phc tp v lu di qua chn lc t nhin thch ng vi hon cnh sng v vi c tnh sinh vt hc ca mi loi, ng thi cu to ca cc b phn trong c th c tng quan vi nhau. Nghin cu hnh thi cho ta bit c nguyn nhn hnh thnh nn tng cu to v quan h gia cu to vi phng thc sng. Qua nghin cu hnh thi c th nhn bit nhng c im chung ca tng nhm loi v c im ring ca mi loi gip cho cng tc phn loi. l c s quan trng phn bit cc b, h, ging, loi ca cn trng. V l , khi tm hiu v mt loi cn trng no , bao gi cng bt u t vic nghin cu cc c im hnh thi hc. 2. Cu to khi qut c th cn trng C th cn trng c bao bc bn ngoi bng mt lp da tng i cng. Lp da ny gip cho c th cn trng c hnh th nht nh v l ch bm cho cc h c, nn ngi ta gi da cn trng l b xng ngoi phn bit vi cc ng vt c xng bn trong. C th cn trng c cc vng hp bng cht mng phn ct thnh cc vng rng hn, to nn cc t c th. Nhng vng hp bng cht mng gi l mng gia t. Nh c th c chia t nh vy nn c th c ng d dng. C th cn trng do 18-20 t thi k pht dc phi thai to nn. Mi t thi k phi thai (cn gi l t nguyn thu) c 2 mu li 2 bn gi l mm chi ph. Chng tp hp thnh 3 phn l u, ngc v bng. Cc t phn u kt li vi nhau rt kht, c th thy c vt tch chia t thi k phi thai, cn thi k sau phi thai ch nhn bit qua cc chi ph l 2 ru u, 2 hm trn, 2 hm di, 2 na mi di. V vy, c ngi cho rng u l do 4 t phi thai to nn (Holmgren, Hanstrom, Snodgrass), do 5 t (Schwanvitch), do 6 t (Heymons, Viallanes). Phn ngc ca tt c cc loi u c 3 t. Chng gn kt rt cht vi nhau lm im ta cho cc c quan vn ng l 3 i chn v 1-2 i cnh. Phn bng do 11 t to nn ( giai on trng thnh thng ch thy 6-10 t). Cui bng ca cn trng trng thnh c b phn sinh dc bn ngoi, mt s loi c lng ui, cn cc chi ph khc khng cn na..

3. Cu to chi tit c th cn trng 3.1.Phn u 3.1.1. Cu to c bn ca u

u cn trng c bao bc bng mt v cng, c 4 i chi ph l mt i ru u v ba i chi ph ming, c mt i mt kp v phn ln c 3 mt n. Ru u, mt kp, mt n l c quan cm gic. Ming l c quan thu nhn thc n. V vy, u l trung tm cm gic v thu nhn thc n.

Trn b mt v u c cc ngn. Ngn l ng lm xung ca da to nn, phn lm vo trong c gi l sng ni trong. Cc sng ni ny c bm v tng thm cng ca v u. Cc ngn phn chia v u thnh cc khu v cc mnh, nh khu trn- chn mi, khu cnh-nh u, khu t, khu t sau, khu di m, v c bit mi trn v li cng l mt mnh ca v u to thnh. Trn nh u giai on u trng thy rt r ngn lt xc hnh ch Y ngc. Mi khi u trng lt xc th ngn ny


tch ra c th cn trng chui ra khi lp da c. giai on trng thnh khng nhn thy ngn ny.

Hnh 2.1. Cu to c bn u cn trng A. u nhn mt trc; B. u nhn mt bn; C. u nhn mt sau

1. Ru u; 2. Mt kp; 3. Mt n; 4. Trn; 5. Chn mi; 6. nh u; 7. Sau u; 8. M; 9. Ngn t; 10. t; 11. Khu di m; 12. t sau; 13. Mi trn; 14. Hm trn; 15.

Hm di; 16. Mi di; 17. L s (l chm); (theo Chu Nghiu)

Cn c vo v tr ca ming trn u, chia ra 3 kiu u:

Hnh 2.2. Cc kiu u cn trng A. Kiu u ming di; B. Kiu u ming trc; C. Kiu u ming sau

(theo Trng i hc Nng nghip Hoa Nam) - u ming trc: c ming hng v pha trc u, trc dc ca u song song

vi trc dc c th. Kiu u ny thun li cho nhng loi lao v pha trc tn cng con mi (nh b chn chy Carabidae, b h trng Cicindellidae) v c khot thc vt (nh b u di Curculionidae).

- u ming di: c ming pha di u, trc dc ca u gn thng gc vi trc dc c th. Kiu u ny gp ph bin cc loi n thc vt, theo kiu va b va gm n (nh chu chu, d mn, d di b cnh thng Orthoptera).

- u ming sau: c ming ko di ra pha sau u hng v mt bng, trc dc u cng trc dc thn to thnh gc nhn. Kiu u ny gp cn trng c kiu ming chch ht (nh ve su, b ry, rp mui b cnh u Homoptera v b xt b cnh na Hemiptera).

3.1.2. Cc phn ph ca u a) Ru u Hu ht cc loi cn trng c mt i ru u mc trn chn ru nm v tr gia 2 mt kp. Chc nng chnh ca ru u l c quan khu gic v xc gic. C mt s loi cn trng ru u cn c cc chc nng khc, nh mui c l c quan thnh gic, ning ning Hydrophilus dng ru u bt mi, ban miu c Mylabris dng


Hnh 2.3. Cu to ru cn trng 1. Chn ru; 2. Cung ru; 3. Roi ru

(theo Chu Nghiu)

ru u gi con ci khi giao phi, b bi nga Notonecta dng ru u gi thng bng khi bi v.v... Cu to chung ca ru u gm 3 phn: chn ru (1 t), cung ru (1 t) v roi ru (chia lm nhiu t, rt a dng). Hnh dng v kch thc ru u ca cc loi, ca con c v ca con ci cng mt loi khng ging nhau. Thng ru u con c pht trin hn, c tng din tch b mt tip xc vi khng kh nhiu hn so vi con ci cng loi. V vy, c th da vo c im cu to ru u phn bit cc loi, phn bit con c vi con ci cng mt loi. c im hnh thi ru u c s dng trong phn loi, nn cn phn bit mt s kiu ru u thng gp sau y (Hnh 2.4):

Hnh 2.4. Cc dng ru u 1. Ru hnh si ch (Chu chu Locusta migratoria Linn.); 2. Ru hnh chui ht (Mi th Calotermes sp.); 3. Ru hnh lng cng (Chun chun Anax parthenope Selys); 4. Ru hnh rng ca (Xn tc Prionus insularis Motsch.); 5. Ru hnh li kim (Co co Acrida lata Motsch.); 6. Ru mui ci (Culex fatigas Wied. ); 7. Ru mui c

(Culex fatigas Wied. ); 8. Ru hnh lng chim (Su rm ch Semia cynthia Drury); 9. Ru hnh rng lc (Ptilineurus marmoratus Reitt.); 10. Ru hnh r qut mm


(Halictophagus sp. ); 11. Ru hnh di c (Bm phn trng Pieris rapae Linn.); 12. Ru hnh di trng (Loi Ascalaphus sp.)13. Ru hnh l lp (B hung Holotrichia

sauteri Moser); 14. Ru hnh u gi (Ong mt Apis mellifica Linn.)15. Ru hnh chu (Ve su bm Lycorma delicatula White); 16. Ru rui (Rui xanh Luccia sp.); 17. Ru hnh lng cng (Su non bm Sericenus telamon Donovan); 18. Ru dng si

cong cun (Chrysomphalus dictyospermi Morg.) (theo Chu Nghiu)

- Ru si ch: di, mnh, cc t roi ru hnh ng di gn bng nhau v cng v cui ru cng nh dn. V d, ru u con gin.

- Ru chui ht: cc t roi ru c hnh ht trn ni tip nhau nh chui ht. V d, ru u ca mi th, ca b chn dt.

- Ru rng ca: cc t roi ru hnh tam gic nh v mt pha trng nh rng ca. V d, ru ca con ban miu c, ca om m.

- Ru hnh lng chim (hay rng lc kp): hai bn cc t roi ru ko di trng nh lng chim. V d, ru con ngi c su rm hi ch.

- Ru cu lng: tr 1-2 t gn chn ru, xung quanh cc t khc c nhiu lng di mn, cng v pha cui ru lng cng tha v ngn dn. V d, ru u mui c.

- Ru u gi: t chn ru di cng vi cc t roi ru to thnh hnh cong gp ta u gi. V d, ru u ca ong vng, ca ong mt.

- Ru di c: cc t roi ru pha chn ru hnh ng di, cc t cui phnh to dn ri li tht dn li 3-4 t cui cng. V d, ru u ca bm.

- Ru di trng: cc t cui phnh to r rt nh hnh cu, t cui cng to nht. V d, ru chun chun ru di.

- Ru hnh l lp: mt s t cui phn roi ru pht trin thnh nhng mnh c th xp chng ln nhau v xo ra c. V d, ru u con cnh cam.

- Ru hnh chu: t chn ru v cung ru phnh to nh qu chu. V d, ru u ca ry nu.

- Ru lng cng: ngn, 1-2 t pha chn ru ln hn cc t sau, cc t sau rt nh ta nh mt si lng cng. V d, ru u ca ry xanh, ca ve su, ca chun chun.

- Ru rui: ging nh ru lng cng, nhng trn lng cng c nhng lng mn nh. V d, ru rui nh.

b) Ming

Hnh 2.5. Cu to ming gm nhai A. Mi trn; B. Hm trn; C. Hm di (1. L trong hm; 2. L ngoi hm; 3. Thn

hm; 4. Chn hm; 5. Ru hm di); D. Mi di (1. L gia mi; 2. L ngoi mi; 3. Ru mi di; 4. Cm trc; 5. Cm sau)


(theo Bocanp. Katxcp) Ming cn trng l c quan thu nhn thc n. Thc n ca cc loi rt khc nhau. V vy, cu to ca ming trong lp cn trng rt a dng ph thuc vo thc n ca mi loi. Ming gm nhai l kiu ming nguyn thu nht (Hnh 2.5). Cu to ming gm nhai gm c 5 phn: mi trn, hm trn, hm di, mi di v li. Mi trn c cu to nh mt mnh da che pha trn ming. Hm trn l mt i xng cng nm pha di mi trn. Mi mt hm trn c nh ln mp di cnh v u bng 2 mu. Mt trong ca hm trn c nhng kha nhn dng rng, nhng kha pha ngoi gi l rng cn, nhng kha pha gc hm gi l rng nhai. Hm di l mt i xng nm di hm trn. Mi hm di chia lm 5 phn: t chn hm, t thn hm, l trong hm, l ngoi hm v ru hm di. L trong hm c nhng kha rng nhn c th ct v nghin thc n, l ngoi hm hnh tha khng cng lm v c th c ng c. on gia thn hm c ru hm di. Ru hm di chia 5 t, dng xc nh mi v thc n. Mi di gm cm sau, cm trc, 2 l gia mi, 2 l cnh mi v 2 ru mi di. Mi di che pha di ming, ru mi di cng xc nh mi v thc n. Li l mt mnh xng cng gn vi pha di v u, lm nhim v nho trn thc n. Kiu ming gm nhai gip cn trng gm, cn nhng thc n rn, gy nhng tn thng nhn thy rt r trn cc b phn cy trng nh l b cn thng hoc mt tng mng, thn cy hay hoa qu b c rng hoc b gm nham nh. Cc kiu ming ht l t kiu ming nhai bin i thnh, c c im chung l cc chi ph u ko di thch nghi cho vic ly thc n dng lng nh mu ng vt, dch cy, mt hoa v.v... Loi hnh ming ht chia lm nhiu kiu nh sau: ming gm ht, ming chch ht, ming ht, ming gia ht, ming lim ht v ming ca lim. - Ming gm ht: thng gp cn trng b cnh mng Hymenoptera nh ong mt.

c im c bn ca kiu ming ny l hm trn v mi trn cn gi theo kiu ming nhai; hm di v mi di ko di ra; ru hm di ngn nh. L ngoi hm di ko di thnh hnh li kim c tc dng tch lt cnh hoa khi ht mt. L gia mi ko di thnh vi, pha cui phnh to hnh cu gi l a vi. Khi ly thc n, hm trn, hm di v ru mi di hp li thnh thc qun rng, a vi ly mt hoa, nh s co gin ln xung ca l gia mi m mt hoa c ht vo. Hm trn c tc dng xy dng t.

- Ming chch ht: thng gp rp, b ry, b xt, mui. Loi ming ny c th chch vo m cy ht dch hay chch vo c th ng vt ht mu. c im c bn ca kiu ming ny l cc phn ca ming u ko di, mi di thnh vi c tc dng bo v ming. Xoang ming v cung hng hp li thnh b phn bm ht. Ming chch ht ca b xt, b ry c 4 ngi chm do 2 hm trn v 2 hm di ko di hnh thnh. Mt pha trong mi ngi chm hm di c 2 rnh dc, nn khi hai ngi chm hm di hp li s to ra 1 ng dn thc n v 1 ng dn nc bt. Khi b xt v b ry ht dch cy th trc ht dng 2 ngi chm hm trn thay nhau chc vo ni c thc n, khi thnh l ri mi cm 2 ngi chm hm di cng vo, cn vi th b cp ra sau v nm ngoi. Trc khi ht dch th b xt v b ry tit nc bt bm vo m cy phn gii mt phn thc n, nn lm bin dng m cy ch c vt chch ht. Ming mui c 6 ngi chm do 2 hm trn, 2 hm di, mi trn v li to thnh. Ngi chm t mi trn v li ca mui hp li thnh 1 mng dn nc bt v 1 ng dn thc n.

- Ming ht: thng gp cc loi bm hay ngi b cnh vy. c im c bn ca kiu ming ny l 2 hm di ko di v khi hp li thnh mt vi di, gia to thnh 1 ng dn thc n. Ru mi di pht trin. Cc phn khc u thoi ho ch cn du vt.


- Ming gia ht: thng gp b cnh t Thysanoptera. c im c bn ca kiu ming ny l mi trn, mt phn hm di v mi di to thnh vi, gia vi c li v 3 ngi nhn, trong s 2 ngi do 2 hm di, 1 ngi do hm trn bn tri ko di hnh thnh. Hm trn bn phi thoi ho. ng dn thc n do 2 hm di hnh thnh. Li v l gia mi di hp thnh ng dn nc bt. Khi n, hm trn gia rch biu b cy, 3 ngi co gin ln xung ht dch qua vi.

- Ming lim ht: thng gp rui nh. c im c bn ca kiu ming ny l hm trn v hm di thoi ho. Mi di ko di thnh vi ngn, u mt mi di phnh to thnh 2 a mi (cn gi l a vi) hnh qu thn c tnh n hi, c th dng a vi lim v ht thc n dng lng, nho hoc cc ht rn nh b trn b mt thc n. Mi trn v li hp li to thnh ng dn thc n, trong li c ng tit nc bt.

- Ming ca lim: thng gp rui tru. c im c bn ca kiu ming ny l 2 hm trn v 2 hm di pht trin hot ng theo chiu ngang, ca rch da ng vt cho chy mu a vi lim v ht. on cui mi di phnh to to thnh a vi lim v ht cht lng. Mi trn v li to thnh ng dn thc n, trong li c ng dn nc bt.

- Ming u trng nhng loi cn trng bin thi khng hon ton th ging nh ming ca trng thnh (v d, b cnh thng Orthoptera, b cnh na Hemiptera, b cnh u Homoptera). Ming ca u trng nhng loi bin thi hon ton thng khc vi ca trng thnh khi hai pha ny khai thc ngun thc n khc nhau (v d, ming con bm, ming con rui v u trng ca chng hon ton khc nhau). Trong s nhng kiu ming c trng ca u trng nh vy c kiu ming ca u trng b cnh vy (nh ming con tm), v ca u trng b hai cnh (nh ming con gii). Ming u trng b cnh vy thuc kiu ming nhai. i hm trn pht trin dng cn thc n rn, cn hm di, li v mi di hp li thnh mnh tng hp, cui mnh tng hp c mt nm nhn li ln l ng nh t. Ming gii ch cn mt i mc ming do hm trn bin ho thnh khuy v ht thc n, cn cc phn khc u khng cn na.

3.2.Phn ngc 3.2.1. Cu to c bn phn ngc Cn trng c ba t ngc c gi l t ngc trc, t ngc gia v t ngc sau, gn cht vi nhau. Mi t ngc do 4 mnh l mnh lng, mnh bng v 2 mnh bn gn cht vi nhau to nn. Mi t ngc c mt i chn c tn tng ng l chn trc, chn gia v chn sau. Giai on trng thnh nu c 2 i cnh: i cnh trc t ngc gia, i cnh sau t ngc sau. Nu ch c mt i cnh nh rui, mui th i cnh sau thoi ho v bin i thnh mt cu to hnh chu lm nhim v gi thng bng khi bay. V vy, ngc l trung tm vn ng ca c th cn trng. 3.2.2. Cc phn ph ca ngc a) Chn ngc


Hnh 2.6. Cu to chn cn trng 1. t chu; 2. t chuyn; 3. t i; 4. t chy; 5. Bn chn; 6. Mng chn

Ba i chn ngc c ngun gc t mm chi ph ca 3 t nguyn thu. Mi chn ngc cu to t 5 phn: chu, chuyn, i, chy, bn chn (Hnh 2.6). Chn kiu ca con gin gi l chn b, l kiu chn nguyn thu nht. Bn chn chia ra 3-5 t, cui bn chn thng c 2 mng, gia 2 mng c m bn chn. m bn chn c cc gic ht gip cho cn trng bm c vo cc b mt nhn. Mp ngoi t chy thng c nhiu gai, cui t chy c th c ca (l cu to dng gai nhng c ng c). S t bn chn ca 3 i chn ngc c th khng bng nhau nn ngi ta thng dng khi nim cng thc bn chn phn bit cc loi, v d 3-3-3, 3-4-4, 4-5-5, 5-5-5 v.v..., trong con s u ch s t bn chn ca i chn trc, con s th 2 ch s t bn chn ca i chn th 2, con s th 3 ch s t bn chn ca i chn th 3. thch nghi vi iu kin sng v hon thnh nhng chc nng khc nhau, cc loi cn trng c chn rt a dng, nh kiu chn b (chn con gin), chn nhy (chn sau ca chu chu), chn bt mi (chn trc ca b nga), chn ly phn (chn sau ca ong mt), chn o bi (chn trc ca d di), chn bi li (chn ning ning), chn kp leo (chn con chy, con rn)...(Hnh 2.7).

Hnh 2.7. Cc kiu chn cn trng 1. Chn b (Chn Hnh trng); 2. Chn nhy (Chn sau Chu chu); 3. Chn bt mi (Chn trc B nga; 4. Chn o bi (Chn trc D di); 5. Chn bi (Chn sau

Ning ning); 6. Chn bm ht (Chn trc Ning ning); 7. Chn ly phn (Chn sau Ong mt).

(theo Chu Nghiu)

b) Cnh


Cn trng l ng vt khng xng sng duy nht c cnh. Cnh ca cn trng c hnh thnh do da hai bn mnh lng ca t ngc gia v ca t ngc sau pht trin ko di ra, nn c 2 lp mng t 2 tng biu b. Gia 2 lp mng c cc ng rng gi l gn cnh hay mch cnh. Cc mch cnh c tc dng lm cho cnh c cng cn thit bay, l ni c thn kinh phn b, ng thi mu v khng kh lu thng bn trong. Cnh thng c

Hnh 2.8. S cu to cnh cn trng 1. Mp trc cnh; 2. Mp ngoi cnh; 3. Mp sau cnh; 4. Gc vai; 5. Gc nh; 6.

Gc mng; 7. Np gp mng; 8. Np gp ui; 9. Np gp gc; 10. Np gp nch; 11. Khu chnh cnh; 12. Khu mng; 13. Khu ui; 14. Khu nch

(theo Snodgrass) hnh dng tam gic, c 3 cnh v 3 gc. Cnh pha trc gi l mp trc, cnh pha ngoi gi l mp ngoi, cnh v pha sau gi l mp sau. Gc to thnh bi mp trc v mp sau gi l gc vai, gc to thnh gia mp trc v mp ngoi gi l gc nh, gc to thnh gia mp ngoi v mp sau gi l gc mng. thch nghi cho vic bay ln v gp cnh, trn cnh c mt s ng np gp chia mt cnh thnh 4 khu (khu nch, khu chnh, khu mng, khu ui) (Hnh 2.8). Cc mch cnh dc v ngang trn cnh cn trng u c t tn, nh: mch dc mp (C), mch dc mp ph (Sc), mch dc chy (R), mch dc gia (M), mch dc khuu (Cu), mch dc mng (A), mch dc ui (J); mch ngang mp (h), mch ngang chy (r), mch ngang chy chung (s), mch ngang chy gia (r-m), mch ngang gia (m), mch ngang gia khuu (m-cu) (Hnh 2.9). Trn cnh cn trng c th quan st thy cc bung cnh. Bung cnh l cc do cc mch dc, mch ngang v mp cnh to nn. H thng mch cnh rt khc nhau gia cc loi, nn l mt ch tiu c s dng trong phn loi cn trng. hai i cnh hot ng nhp nhng, mt s loi cn c cu to c bit l cc dy gai mc cnh v gai ci.

Hnh 2.9. S mch cnh gi thit theo Comstock-Needham (theo Ross)


thch nghi vi iu kin sng khc nhau, mc pht trin v cht cnh ca cn trng c rt nhiu thay i. C nhiu cn trng thuc lp ph c cnh (Pterygota) nhng cnh hon ton tiu bin, v d, cn trng thuc b n lng (Mallophaga), b rn (Anoplura), b b cht (Siphonaptera), v mt s loi cc b khc, trong c b cnh thng (Orthoptera), b cnh t (Thysanoptera), b cnh cng (Coleoptera), b cnh vy (Lepidoptera), b hai cnh (Diptera) l cc b c nhiu loi su hi cy trng. C nhng loi con c c cnh cn con ci khng c cnh (nh mt s loi rp sp b cnh u Homoptera). Loi hnh khng sinh sn ca cc loi kin khng c cnh. Mt s khc c cnh ngn nh thng gp b cnh thng, b cnh da, b gin, b cnh cng, b cnh u. Phn ln cnh ca cn trng l cht mng mng, trong sut nh cnh con ong, nn gi l cnh mng. Nhng cnh ca nhiu loi thay i v cht. Cnh trc ca cn trng thuc b cnh cng bng cht sng, khng c mch cnh, c tc dng bo v cnh sau v gi thng bng khi bay, c gi l cnh cng. Cnh ca cc loi b xt b cnh na c mt na pha gc vai ho cng, na pha ngoi mm, mch cnh n gin, c gi l cnh na. Cnh trc ca con chu chu v ca con gin gn ging cht da nn c gi l cnh da. Cnh ca con bm, con ngi bng cht mng c ph y vy nn c gi l cnh vy (Hnh 2.10).

Hnh 2.10. Cc loi cnh ca cn trng 1. Cnh da; 2. Cnh mng; 3. Cnh na cng; 4. Cnh cng

(theo Chu Nghiu)

3.3.Phn bng 3.3.1. Cu to c bn phn bng

Hnh 2.11. Cu to phn bng cn trng I-X. t bng t 1-10; XI. Phin trn hu mn; XI. Phin bn hu mn (tc mnh

lng v mnh bng ca t 11); 1. Lng ui; 2. Hu mn; 3. L qup m c; 4. Phin di sinh dc; 5. Dng c; 6. Bao v gc dng c; 7. L bn dng c; 8-9. Mng


trng; 10-12. Phin trng trn, gia v di; 13. L sinh dc.

(theo Chu Nghiu)

Phn bng do 11 t to nn, nhng giai on trng thnh thng ch thy 6-10 t. Mi t c th phn bng ch c mt mnh lng, mt mnh bng v 2 bn l phn mng n hi. Do mnh lng pht trin thnh vng cung ko di xung pha di cho nn phn mng hai bn c th thng b che khut. Cc t bng ni vi nhau nh mt mng gia t tng i rng v n hi, mp trc ca mi t lng vo mp sau ca t trc . Nh c phn mng hai bn bng v mng gia cc t nn bng c th phng ln, xp xung, ko di ra, thu ngn li v dao ng v mi pha d dng, ph hp vi s hot ng ca cc b my bn trong c th. Cui bng ca cn trng trng thnh c b phn sinh dc bn ngoi, mt s loi c lng ui, cn cc chi ph khc u khng cn na. 3.3.2. Cc phn ph ca bng cn trng trng thnh + Lng ui: l chi ph ca t bng cui cng. Hnh dng khc nhau gia cc loi. V d, dng si di chia t ( ph du, nhy sch), dng phin chia t ( gin), dng mu ( chu chu), dng km ( b Cnh da Dermaptera). + Phn ph sinh dc: l b phn sinh dc ngoi. B phn sinh dc ngoi ca con c gm c dng c v qup m c. Dng c dng a tinh trng vo c th con ci, cn qup m c dng gi cht b phn sinh dc ngoi ca con ci (m c) giao phi. Dng c l vt ko di ra ngoi ca da t mng gia t pha sau ca t bng th 9, cn qup m c phn ln l do gai li ca t bng th 9 to thnh. Cng c loi qup m c do lng ui bin ho thnh (nh chun chun). B phn sinh dc ngoi ca con ci l b phn trng. B phn trng thng do chi ph ca t bng th 8 v th 9 to thnh, c dng mng hoc ng, nn c gi l ng trng (hay mng trng). Khng phi tt c cc loi u c ng trng nh vy. Cn trng b cnh cng, b cnh vy, b hai cnh c b phn trng do mt s t bng cui cng cu to nn. Nhng t cui bng ny thng tng i cng, lng vo nhau v c th co dui rt mnh phng trng ra ngoi. 3.3.3. Cc phn ph bng u trng - Chn bng: u trng b cnh vy c 5 i chn cc t bng th 3,4,5,6 v 10.

u trng ca ong n l (Tenthredinidae) c th c n 11 i chn phn bng. Chn bng ca u trng b cnh vy ch c 3 t: t chu ph, t chu v t bn. Trn t bn c nhng dy mc cu gi l mc mng.

- Cc cu to khc (mang kh qun, mu li..): u trng b ph du (Ephemerida), b cnh rng (Megaloptera) c mang kh qun hai bn cc t bng 1-7 hoc 1-8. u trng tm du (Bombycidae) v ngi tri (Sphingidae) c mu li dng gai hay sng t bng th 8.

3.4. Da ca cn trng 3.4.1. Chc nng Da cn trng l b xng ngoi gi cho c th c hnh dng nht nh, l ch cho c bm vo, ngn nga s bc hi nc trong c th cn trng, bo v cho cc c quan bn trong trnh c nhng tn thng c gii, s xm nhp ca vi sinh vt v cc cht c hi. Trn da c nhiu c quan cm gic nn cng l ni thu nhn cc kch thch bn ngoi vo c th cn trng.


3.4.2. Cu to Da cn trng do tng phi ngoi hnh thnh. Mt phn da lm vo bn trong to nn rut trc, rut sau, kh qun, b phn sinh dc ngoi v nhiu th tuyn khc nhau. Da cn trng chia ra 3 lp: lp biu b, lp t bo ni b v lp mng y (Hnh 2.12).

Hnh 2.12. Cu to da cn trng a. Biu b trong vi nhiu lp mng; b. Biu b ngoi; c. Biu b trn; d. Lng cng; e. ng ng trong da; f. ng ng dn ca tuyn ni b; g. Mng y; h. T bo ni b;

i. T bo lng; k. T bo mng nguyn thy; l. T bo mu; m. T bo mu bm mng y; n. T bo tuyn trong lp ni b

(Theo Wigglesworth) a) Biu b: Biu b l lp ngoi cng ca c th cn trng, c hnh thnh bi cc cht tit ra ca ni b, khng c cu to t bo. dy ca biu b khc nhau tu thuc vo loi. Tui u trng cng ln da cng dy, nhng da ca trng thnh c khi mng hn da u trng. Mt s loi cn trng khi sng iu kin sinh thi khc nhau cu to biu b ca chng c thay i. V d, su non b cnh vy khi qua ng khc khi khng qua ng. dy bin ng t di 1 n 0,3mm. Biu b chia ra 3 lp l: biu b trn (Epicuticula), biu b ngoi (Exocuticula) v biu b trong (Endocuticula). Biu b trn cu to ch yu t lipit, protein bin tnh v khng c cht kitin. Biu b trn ch chim 1-7% dy ca biu b, nhng c cu to phc tp v thng chia lm 4 tng c chc nng khc nhau: tng ngoi cng l tng men, tip n l tng sp, tng polifenon v tng cuticulin. Tng cuticulin c cu to bi lipo-protit, chng chu c axit v dung mi hu c; tng polifenon c tc dng dnh ni tng cuticulin vi tng sp; tng sp dy 0,1-0,3, c tc dng lm cho nc v cc cht ho tan trong nc khng thm qua, ng thi gi nc cho c th cn trng. Biu b ngoi cu to t kitin, sclerotin v vi. Biu b trong cu to t kitin v actropodin. Kitin l mt polyxacarit c nit do vi trm n v (-1,4N-acetyl-gluosamine) kt thnh, vi cng thc (C8H13NO5)n. Kitin th rn, khng mu, khng tan trong nc, cn, te, axt long, kim long v mt s dung mi hu c khc. nhit di 1600C kitin khng b NaOH v KOH phn gii, nhng c th ho tan trong axt v c m c v thu phn


thnh glucosamin, axt axetic v polyxacarit. Kitin khng b men tiu ho ca ng vt c v phn gii, nhng b men tiu ho ca mt s cn trng, ca c sn v vi khun Bacillus chitinivorus phn gii. Hm lng kitin trong da cn trng khong 33%. Actropodin l mt protein tan trong nc, cn sclerotin l mt protein khng tan trong nc. Hm lng ca hai loi prptein ny chim trn 50% trng lng biu b. Qu trnh hnh thnh sclerotin bt u t tiroxin qua cc bc nh sau: tiroxin dopa polyfenon octoquinon; octoquinon + actropodin sclerotin. Da cn trng khi mi lt xc thng mm v tng biu b ngoi cha hnh thnh. Qu trnh hnh thnh biu b ngoi ch yu l qu trnh actropodin chuyn ho thnh sclerotin. Tng biu b ngoi ca cn trng mnh mm tng i mng. Ch mng ni gia khp ca cn trng c biu b ngoi khng pht trin hoc thiu nn c th hot ng gp khc v co dui. Quyt nh tnh co gin v un khc ca da cn trng ch yu do cht kitin v actropodin. Da cn trng cng do sclerotin v cc phn t kitin kt hp to thnh mt mng li vng chc. Biu b khng thm nh c lp sp. Lp men cng c chc nng bo v lp sp v ch c hnh thnh sau khi cn trng lt xc. b) Lp t bo ni b: Ni b l mt lp t bo n, gia cc t bo c xen k mt s t bo c chc nng c bit nh t bo hnh thnh lng, t bo hnh thnh cc tuyn trn da. T bo ni b l mt t chc sng rt quan trng. Chng tit ra cc cht to thnh lp biu b mi, tit ra dch tiu ho lp biu b c v hp th tr li cc cht tiu ho to ra lp biu b mi, c kh nng hn gn cc vt thng. Mt khc, mt s t bo ni b c th phn ho to thnh c quan cm gic v cc tuyn trn da. c) Lp mng y: Mng y l mt mng mng dnh st di y lp t bo ni b. Mng y khng c cu to t bo. Pha di mng y phn b cc ngn dy thn kinh. 3.4.3. Cc vt ph ca da v cc tuyn - Vt ph ngoi da: c th c to thnh t biu b nn khng c cu to t bo

(nh cc sng ni, mu li, lng nh trn cnh), c th c to thnh bi mt hoc nhiu t bo ni b (nh gai, ca, lng cng, lng c, lng cm gic).

- Tuyn trn da: Cc tuyn phn b ri rc trn da v tit ra nhng cht c tc dng khc nhau. Mt s loi thng gp nh tuyn sp, tuyn c, tuyn hi, tuyn lt xc, tuyn nc bt, tuyn t ( su non b cnh vy v b cnh lng).

3.4.4. Mu sc da cn trng Da cn trng c mu sc rt a dng, to nn do 3 loi mu sc c bn l: mu sc ho hc, mu sc vt l v mu sc hn hp ca hai loi ny. + Mu sc ho hc do cc sc t to nn. Cc sc t c th ly t bn ngoi qua thc n (nh clorofin, caroten, antoxin, flavones, v cht chuyn ho t clorofin nh hemoglobin). Mt s mu sc thy cn trng nhng khng c trong thc n ca chng, nh mu trng v mu en, li l t cc cht chuyn ho trong c th cn trng. Th d, mu trng l sc t c cht purinin c sn sinh t axit uric tch t li, mu en c sc t en melanin to nn bi tc ng ca men tiroxinaza ln tiroxin. + Mu sc vt l to nn do b mt da c cc cu to c bit (nh c tng sp mng, cc ngn li lm, cc lng, vy ), khi nh sng mt tri chiu vo th c hin tng khc x, ri phn x to nn mu sc khc nhau. Mu sc vt l rt bn vng, khng b mt mu khi x l bng cc cht ho hc, un si hoc sau khi cht. Mu sc c th cn trng c th b thay i di nh hng ca cc yu t ngoi cnh, nh thc n, nhit , m, nh sng. Cng mt loi su nhng n cc cy


khc nhau c th c mu sc khc nhau, nui cn trng nhit cng cao hoc m cng thp th mu cng nht, nui trong iu kin nh sng c bc sng khc nhau th mu sc c th khc nhau do nh sng tc ng ln c th kch thch tuyn bn cung hng (tuyn hu) tit ra cht lm thay i mu sc.

CU HI N TP CHNG II

1. V sao phi nghin cu hnh thi hc cn trng? 2. Trnh by cu to khi qut c th cn trng. 3. Cu to c bn ca u v cc kiu u lp cn trng nh th no? 4. Trnh by cu to chung ca ru u v cc kiu ru u thng gp. 5. Trnh by cu to kiu ming gm nhai v nhng bin i nhng kiu ming

ht. 6. Ming ca u trng c g khc vi ming ca cn trng trng thnh khng?

V sao? 7. Cu to phn ngc ca cn trng nh th no lm trung tm vn ng? 8. Trnh by cu to chung ca chn ngc v cc kiu chn thng gp. 9. Trnh by cu to ca cnh cn trng v cc loi cnh thng gp. 10. Cu to phn bng ca cn trng nh th no lm trung tm trao i cht v

thu nhn thc n? 11. Cc phn ph ca bng giai on trng thnh v giai on u trng khc

nhau g khng? 12. Trnh by v chc nng ca da cn trng, v cu to ca da v ca cc phn

ph da cn trng. 13. Trnh by cc loi mu sc ca da cn trng v ngha ca n i vi kh nng

t v ca cn trng.


Chng III GII PHU SINH L CN TRNG

1. nh ngha Gii phu- Sinh l nghin cu v cu to v hot ng ca cc b my bn trong c th cn trng. nghin cu c thun li, ngi ta nghin cu ring tng b my, tng c quan, mc d hot ng ca c th mang tnh thng nht hon chnh. Cc t bo chuyn ho cng loi tp hp li thnh t chc m. Mt s m tp hp thnh c quan (th d: mt, hch thn kinh, thc qun, kh qun). Mt s c quan c cng mt chc nng tp hp li thnh b my (th d: cc c quan th cm, no, cc hch thn kinh, cc dy thn kinh tp hp thnh b my thn kinh). Ton b cc b my hp nht thnh c th. Ngi ta phn bit 8 b my c chc nng ring bit l: nng , chuyn vn, tiu ho, h hp, bi tit, tun hon, thn kinh v sinh dc. Da ca cn trng lm nhim v ca b my nng , tng ng vi b xng ca ng vt c xng sng, nn ngi ta gi da l b xng ngoi ca cn trng. H c lm nhim v ca b my chuyn vn. Chc nng ca cc b my cn li nh ca cc ng vt khc. Da ca cn trng c cp khi nghin cu cu to bn ngoi ca c th trong chng Hnh thi hc. Cc b my cn li c nghin cu chi tit trong chng Gii phu Sinh l cn trng. 2. Xoang c th v v tr cc c quan bn trong

Hnh 3.1. V tr cc b my bn trong c th cn trng 1. Li; 2. Ming; 3. No; 4. u; 5. ng tiu ha (rut); 6. Mch mu lng (tun hon); 7. B my sinh dc (non so); 8. Hu mn; 9. L sinh dc; 10. ng Malpighi

(bi tit); 11. Chui thn kinh bng; 12. Tuyn nc bt; 13. Mi di. (theo Qun Ch Ha v.v.)

Xoang c th l khoang do v c th to thnh (Hnh 3.1). V c th bao gm da v cc c bm vo da (gi l c v). Xoang c th cha mu, th m v cc b my bn trong. C hai vch mng dc c th (gi l mng ngn lng v mng ngn bng) chia xoang c th thnh 3 xoang nh, gi l xoang mu lng, xoang mu quanh rut v xoang mu bng. Mt s cn trng ch c mng ngn bng (b cnh vy, cnh mng, chun chun). H thng kh qun ca b my h hp bao gm cc ng dn kh xuyn qua cc mng ngn chui vo cc ni quan nn khp cc xoang. Mch mu nm


xoang mu lng. Chui hch thn kinh ln nm xoang mu bng. B my tiu ho, bi tit, sinh dc nm xoang quanh ru

3. Cu to v hot ng ca cc b my bn trong c th cn trng 3.1. H c C ca cn trng thuc loi c vn, l loi chuyn ho cao, m bo cho tnh cht nhanh v phc tp ca cc c ng. S lng c thay i tu theo loi v tu theo giai on pht dc. su non b cnh vy c khong 2000 c. Cc c ca cn trng phn thnh 2 nhm: nhm c v v nhm c ni quan. Vi c v, thng mt u bm vo mt mu c nh trn da, u kia gn vo c quan vn ng bng mt si rt nh gi l tonofibrin. C ca cn trng co v gin nhanh. Th d, ong v rui c th p cnh 250-300 ln trong mt giy. Vi mt xung ng kch thch th c c th p ng li bng nhiu ln co c. l hin tng p ng kp. Lc tuyt i ca c cn trng rt ln. V vy cn trng c th mang c nhng vt c trng lng hn c th chng hng chc ln (15-25 ln), c nhiu loi c th nhy cao v di gp hng trm ln chiu di c th chng. 3.2. B my tiu ho B my tiu ho ca cn trng lm nhim v tiu ho thc n ly t bn ngoi vo. Qu trnh tiu ho bao gm cc khu: thu nhn thc n ngoi vo, phn gii thc n nh cc men tiu ho, hp th cc cht dinh dng v thi phn ra ngoi. Nhng vic ny do ng tiu ho v cc tuyn tiu ho thc hin.

a) Cu to B my tiu ho ca cn trng, cn gi l ng tiu ho, bt u t ming v kt thc hu mn. ng tiu ho chia lm 3 phn: rut trc, rut gia v rut sau. Ranh gii rut trc v rut gia l van Cacdia. Ranh gii rut gia v rut sau l van Pilo. Cc van Cacdia v Pilo ngn khng cho thc n i ngc chiu v iu ho s vn chuyn thc n trong rut (Hnh 3.2).

Hnh 3.2. Cu to b my tiu ha A. Mt bn; B. Mt lng


1. Hu; 2. Ming; 3. Thc qun; 4. Ti cha thc n (Diu); 5. Tuyn nc bt; 6. D dy c; 7. Manh trng; 8. Rut gia; 9. ng Malpighi; 10. Rut thng; 11. Rut non;

12. Rut gi; 13. Hu mn. (Theo Lu Ngc T)

+ Rut trc: Rut trc gm hu, thc qun, diu v d dy c. Hu v thc qun dn thc n vo diu. Diu l phn phnh to ca thc qun cha thc n cha tiu ho. D dy c l mt ti c vch c dy v c nhiu g kitin cng lm nhim v nghin nt thc n. + Rut gia: Rut gia c dng ti phnh to hoc dng ng ngon ngoo. Pha u rut gia c khi thng vi mt s ti nh gi l manh trng tng b mt lm vic ca rut gia v trong manh trng c th c tr cc vi sinh vt cng sinh. Nhim v ca rut gia l tiu ho thc n nh cc men tiu ho, hp th cc cht cn thit v y cc cht khng hp th c vo rut sau thi ra ngoi. Xen ln trong cc t bo vch rut c cc t bo tit cc dch tiu ho. Cc t bo tit lun lun c sn sinh trong vch rut thay th nhng t bo tit b tiu hao. cc loi cn trng n thc n rn c mng kitin mng dng li bo v cho vch rut khng b cc mnh cng ca thc n lm thng tn. + Rut sau: Rut sau c bao ph kitin pha trong v chia ra: rut non, rut gi, rut thng. u rut sau (gip van Pilo) c cc ng Malpighi ca b my bi tit vo. Rut sau khng lm nhim v tiu ho m ch thu hi nc trong phn trc khi thi ra ngoi. b) Hot ng tiu ho Thc n qua ming c cc hm nghin nh. mt s loi thc n tip tc c nghin nt trong d dy c. rut gia cc cht protein, gluxit v lipit c thu phn nh nhm men tiu ho cacbohydraza, proteaza v lipaza. Sn phm thu phn t gluxit l cc ng n, t protein l cc axit min, t lipit l glyxerin v cc axit bo. Qu trnh hp th theo sau qu trnh tiu ho. Nh hin tng thu phn ca qu trnh tiu ho m trong rut gia bao gi cng to nn mt mi trng c cc axt amin, cc ng n, cc axt bo x phng ho v glyxerin nng cao, lm chng thm thu qua vch rut vo c th, do cc thc n thu phn c hp th. Nc, mui, cc nguyn t vi lng, cc vitamin trong thc n rt cn thit cho c th cn trng. Nhu cu v hm lng nc trong thc n ca cc loi rt khc nhau. Phn ln yu cu hm lng nc trn 12%, nhng cng c loi chu c hm lng nc thp, th d, mt Tribolium l 6%, bm Ephestia l 1%. c) Nhng bin i ca b my tiu ho Mt cu to c bit l bung lc ca cn trng b cnh u Homoptera. Bung lc l bin i ca ng tiu ho do hai phn bnh thng xa nhau li dnh vo nhau. Rut gia ca cc loi ny chia lm ba on. on 1 v 2 dng ti ni tip ngay sau thc qun (v diu v d dy c thoi ho), on 3 dng ng mnh vng tr li v dnh vo on 1, thng gn cht vo nh c m lin kt to thnh bung lc (filter chamber). Thc n vt qua bung lc i vo on u rut sau dng ng mnh, ri vo rut thng. Cc ng malpighi hin ra hoc bung lc, hoc qu mt cht. Cn trng b cnh u Homoptera sng trn cy v ht mt lng ln nha cy. Bung lc cho nc ca dch cy thm trc tip t on trc ca rut gia vo rut sau, lm c c dch cy, thun li cho vic tiu ho dch cy on sau rut gia. Cht lng tha i qua hu mn l sng mt (honeydew). V sng mt thng cha mt lng ln cacbohydrat v axit amin, nn c cht nghi ng v chc nng chnh xc ca bung lc.


i vi cc loi n thc n qu kh (nh cc loi mt) th c cu to m rut thng hp thu ti a nc trong phn trc khi thi ra ngoi. pH trong rut ca cc loi cn trng rt khc nhau. Th d, ca ong mt l 5,6- 6,3; ca u trng b hung l 7,4 -7,5; ca su rm l trn 8. pH trong rut nh hng rt nhiu n mc hp th cc thuc tr su c tnh axit hay tnh kim, ch phm BT t bo t Bacillus thuringiensis ch pht huy tc dng khi pH rut ln hn 7. Thc n ca cc loi v ca cc pha pht dc cng loi c th khc nhau. V vy h men trong rut cn trng cng khng ging nhau v thnh phn v hm lng. 3.3. B my h hp B my h hp c chc nng cung cp oxy cho c th v thi kh CO2 sn sinh ra trong qu trnh trao i cht ca c th ra ngoi. a) Cu to B my h hp ca cn trng l mt h thng ng kh qun bt u t cc l th hai bn c th, c ni vi nhau bng cc kh qun dc v ngang, phn nhnh n cc vi kh qun cc t bo ca c th (Hnh 3.3).

Hnh 3.3. S n gin h thng kh qun cn trng 1. Ru u; 2. No; 3. Chui thn kinh bng; 4, 7. L th; 5. Kh qun dc bn; 6. Kh

qun l th; 8. Kh qun bng (theo Kolbe)

Kh qun c ngun gc t tng phi ngoi. Mt trong ca kh qun l mng kitin c nhng g xon m bo cho kh qun khng b bp trong qu trnh cn trng vn ng. Hai l th mi t c ni vi 2 kh qun dc hai bn c th gi l kh qun dc bn, t v tr kh qun chia 3 nhnh: mt nhnh i v pha lng phn b vo mch mu lng v cc c lng; mt nhnh i v pha bng phn b vo thn kinh v cc c bng; mt nhnh i vo gia phn b quanh ng tiu ho, b my sinh dc v th m. Ngoi ra cn c kh qun dc lng, dc bng v dc rut. Cc kh qun ny


thng vi kh qun dc bn bng nhng nhnh ngang. Kh qun phn nhnh nh n tn t bo, gi l vi kh qun. Vi kh qun khng c g kitin xon c nh kh qun. Cc l th phn b hai bn sn dc thn v phn b theo t. Thng thng cn trng c 10 i l th ( t ngc gia, t ngc sau v 8 t bng u tin). Tuy vy s l th c th t hn nhiu, c loi ch c 1 i t bng sau cng, hoc t ngc trc. Cng c loi hon ton khng c l th. L th ca cn trng bc thp (Apterygota) hnh trn v khng c b phn ng m, cn cn trng c cnh (Pterygota) l th c b phn ng m theo yu cu ca c th. b) Hot ng h hp kh qun h hp theo 2 c ch: khuch tn v thng kh qua l th. Khuch tn c thc hin do chnh lch nng kh CO2 v oxi gia bn trong c th v bn ngoi. Thng kh c thc hin do cn trng ch ng c ng lm thay i th tch ca bng bm ht khng kh qua l th. vi kh qun h hp theo c ch thay i lng dch trong vi kh qun (Wiggleswort W.B.,1953). Trong qu trnh trao i cht, trong c th cn trng sn sinh ra CO2, axit hu c v cc sn phm trao i khc, do lm tng p sut thm thu ca m v mu, to nn mt mi trng u trng. Dch t vi kh qun khuch tn vo t bo m v v tr ca n c thay th bng khng kh kh qun a n. Khng kh giu oxi lm gim p sut thm thu ca t bo nn dch t m li vo trong vi kh qun v dn khng kh ra ngoi. Sau chu trnh c lp li. Thnh phn khng kh, nhit , trng thi sinh l ca c th nh hng n h hp. Nng kh CO2 trong khng kh cng cao, nng oxi cng thp, hay nhit cng cao th l th cng phi m nhiu v nhanh. Th nhng, nu hm lng CO2 vt qu 25% hay nhit ln trn 540C th cn trng b hn m v ngng h hp. a s cn trng h hp bng kh qun, nhng mt s cn trng c kch thc nh (Apterygota), mt s u trng ca cn trng ni k sinh v cc loi khng c l th li h hp qua da. Mt s u trng ong ni k sinh c th mc h thng kh qun ca mnh vo h thng kh qun ca k ch h hp nh, hoc c thng da k ch th l th ra ngoi. Mt s loi khng c l th sng trong nc h hp theo kiu khng kh lt qua cc phn li ca c th c mang cc nhnh kh qun bt u gi l mang kh qun. 3.4. B my tun hon B my tun hon c chc nng lm cho mu lu thng trong c th. Chc nng ca cn trng c thc hin nh mch mu lng. a) Cu to Mu ca cn trng trn ngp khp xoang c th khong gia cc c quan. Ch c mt phn mu c lu thng trong mch mu lng (mt mch c nht nm xoang mu lng v c treo bi nhng si c vo vch lng). V vy, l mt h tun hon h. Mch mu lng chia lm 2 phn: phn trc l mt ng di gi l ng mch, phn sau gm nhiu phng co bp c nn gi l cc phng tim. Cc phng tim ni tip nhau, c van ngn cch v hng v pha trc. Mi phng tim c 2 l tim (Osti) 2 bn v c van hng vo trong. Di cc phng tim c nhng b c hnh tam gic gi l c cnh (Hnh 3.4).

b) Hot ng ca b my tun hon


Khi mt phng tim n ra (tm trng) mu qua cc l tim chui vo trong phng. Khi mt phng tim co li (tm thu) p sut mu lm m van pha trc v ng cc van sau mu dn v pha trc. Cc phng tim hot ng cng tn sut nhng lch pha, lm mu trong chui phng tim chuyn dn t sau v trc, dn vo ng mch, ri vo xoang u. Do p sut mu phn u cao nn mu chy v pha sau trong xoang mu bng v xoang quanh rut. S ln co bp ca phng tim ph thuc vo loi, vo trng thi sinh l ca cn trng v vo iu kin mi trng, t 15-150 ln/pht. Mu n c tng c quan ring bit nh ru u, mt nh c s h tr ca bu co bp tng ni, n chn l nh hot ng ca cc mng ngn chn.

Hnh 3.4. S tun hon mu cn trng A. Cc b phn ca b my tun hon; B. Mt ct ngang phn ngc; C. Mt ct ngang phn

bng 1. L tim; 2. Bung tim; 3. C co bp tim; 4. C quan h tr p nhp cnh trc v cnh sau; 5. ng mch ch; 6. C quan h tr p nhp ru u; 7. Vch ngn chi ph; 8. Chui thn kinh bng; 9. Mng ngn bng; 10. Xoang mu bng; 11. Xoang

quanh rut; 12. Xoang mu lng (theo Wigglesworth)

Mu cn trng c chc nng vn chuyn cc cht dinh dng i khp c th, a cc cht b trong c th n cc c quan bi tit thi ra ngoi. Mu cha cc hoc mn c vai tr quan trng trong s iu chnh cc qu trnh sinh l. Mu cn trng c chc nng bo v v min dch. Ngoi ra mu cn trng c chc nng to nn p sut cn thit c th u trng tuy mm nhng vn gi c hnh dng nht nh, cnh v vi c th dui ra, cn trng c th lt xc. Do c th cn trng nh b, nn nhit sinh ra do hot ng ca cc c quan, ca cc phn ng oxi ho lun b tiu hao rt ln bi s to nhit v truyn nhit. Tng quan gia sn nhit v tiu nhit lun thay i, nn thn nhit ca cn trng khng n nh. Nhit c th cn trng ph thuc vo nhit mi trng. Khi cn trng hot ng mnh, nh vy cnh khi bay, th nhit c th c th c nng ln


cao hn nhit mi trng 30-400C, nhng khi dng bay nhit c th li h xung ngang nhit mi trng.

3.5. B my bi tit B my bi tit ca cn trng c chc nng thi ra ngoi hoc vo trong c th nhng cht sn sinh ra trong qu trnh trao i cht. Nhng cht bi tit ra ngoi ch yu l cc hp cht c cha nit sn sinh ra do oxy ha protein, ng thi thi ra ngoi nhng cht tha trong c th nh axit oxalic, axit photphoric, cc ion Ca++ v Na+. a) Cu to B my bi tit ca cn trng ch yu l cc ng malpighi, th m v cc t bo a nhn gi l t bo thn nm xung quanh mch mu lng. ng malpighi l ng c mt u gn vo on chuyn tip gia rut gia v rut sau, mt u kn l lng trong xoang mu quanh rut. S lng ng malpighi thay i tu loi, th d, b xt c 4 ng, cnh cng c 4-6 ng, cnh vy c 6 ng, chun chun c 30-200 ng. Rp v mt s cn trng Apterygota khng c ng malpighi. b) C ch hot ng bi tit Trong mu ca cn trng lun c qu trnh kt hp gia mui KHCO3 v NaHCO3 vi axit uric to ra cc mui urat- kali, urat- natri v H2O. Nhng sn phm ny c u ng malpighi hp th v chuyn dn v pha cui ng ni gn vo rut. Trong qu trnh , cc mui urat- kali, urat- natri v H2O kt hp vi CO2 trong ng to ra axit uric, mui KHCO3 v NaHCO3. Nhng mui ny d tan trong nc, c cc t bo cui ng hp th ri chuyn vo xoang mu thc hin li chu trnh c. Axit uric rt kh ho tan, tch ng li, ri c chuyn vo rut sau v thi ra ngoi theo phn. Nh vy, cc mui KHCO3, NaHCO3 v nc khng mt i, m ch ng vai tr trung gian vn chuyn axit uric t xoang mu vo ng malpighi. Th m ngoi chc nng d tr cht dinh dng cn tch lu cc cht b di dng tinh th, sau chuyn cho ng malpighi hoc loi b khi lt xc ho nhng. Cc t bo thn c kh nng hp th cc cht NH3, Protein v dip lc. 3.6. B my thn kinh B my thn kinh ca cn trng c chc nng iu ho hot ng ca mi c quan trong c th cc hot ng hng theo mt mc ch thng nht, lm cho c th l mt khi thng nht hon chnh, phn ng hp l mi tn hiu ca mi trng bn ngoi, m bo cho s tn ti ca c th. Nh vy, vai tr ca b my thn kinh l vai tr ch huy mi hot ng sng trong c th cn trng. a) Cu to B my thn kinh ca cn trng c cu to phc tp v chia thnh: thn kinh trung ng (TKTW), thn kinh ngoi vi (TKNV) v thn kinh giao cm (TKGC) (Hnh 3.5). n v c s ca h thn kinh l t bo thn kinh, c gi l thn kinh nguyn (neuron). Thn kinh nguyn (TKN) c hai loi phn li: mt loi ngn v phn nhiu nhnh nh r cy, mt loi di v ch phn nhnh cui. Loi ngn gi l nhnh ph, loi di gi l nhnh chnh. Mi TKN c nhiu nhnh ph v ch c mt nhnh chnh. Cc nhnh ny dn truyn cc kch thch v hnh thnh cc dy thn kinh. C 3 loi thn kinh nguyn: cm gic, vn ng v lin h. TKN cm gic nm ngoi TKTW v l thnh phn ca c quan nhn cm. Cc kch thch t bn ngoi


c TKN cm gic tip nhn ri truyn ti TKTW. TKN vn ng nm TKTW nhng nhnh chnh ca n ko di v tn cng cc c quan p ng. C quan p ng l c quan c c (th d chn, cnh) hoc c kh nng p ng li kch thch bng mt hnh thc khc (th d bi tit). TKN lin h nm trong cc trung tm v c chc nng truyn cc kch thch t TKN ny n TKN khc. S dn truyn xung ng t TKN ny n TKN kia thc hin cc Sinapse. Cc TKN tp trung li to thnh cc hch thn kinh hoc cc dy thn kinh.

Hnh 3.5. H thn kinh cn trng 1. Nhn pha mt bng; 2. Nhn pha mt lng (phn u)

ant. Ru u; Ao. ng mch; Call. Tuyn th (allata) cnh hu; Ccar. Tuyn th (Cacdiaca) cnh tim; Ccen. Th trung ng; Cpel. Th t bo thn kinh; Deut. Trung khu ru u; Gocc. Hch thn kinh chm; Grr. Hch thn kinh trn; Gn. Hch thn

kinh bng; Gs. Hch thn kinh di hu; Gven. Hch thn kinh ti cha thc n (diu); Nant. Dy thn kinh ru u; Nar. Dy thn kinh cnh; Npc. Dy thn kinh chn; Nr. Dy thn kinh ngc chiu; Nsim. Dy thn kinh giao cm; Oc. Mt kp; Oes. Cung

hng (hu); Ocer. No trc; Prot. No gia; Trit. No sau (theo Weber)

Cc h thn kinh: + Thn kinh trung ng: TKTW c tnh phn t. l mt chui hch kp ni vi nhau bng nhng nhnh ngang. V nguyn l th mi t c 2 hch lin h vi cc dy thn kinh ngoi bin. TKTW chia lm 2 phn (phn u v phn bng). (1) Phn u gm mt hch trn hu rt ln (chia ra no trc, no gia, no sau) v mt hch di hu. Hai hch ny c dy ni vi nhau to thnh mt vng quanh hu. (2) Phn bng


gm chui hch thn kinh bng. nhng cn trng nguyn thu c 3 i hch ngc v 8 i hch bng. Trong qu trnh tin ho, cc hch ca cc t bng sau c khuynh hng dn v kt hp vi hch cc t trc, v vy cn trng tin ho cao nh rui, b hung c s lng hch thn kinh bng t hn. +Thn kinh ngoi vi: TKNV bao gm cc TKN cm gic (xc gic, v gic, khu gic, thnh gic, th gic) c cc u mt nm ri rc khp c th. TKNV cn bao gm cc dy thn kinh xut pht t cc hch TKTW v TKGC. Nh c TKNV m TKTW v TKGC mi lin h c vi cc c quan. +Thn kinh giao cm: TKGC cn gi l thn kinh thc vt, iu ho hot ng ca ni quan v h c. TKGC c 3 phn (phn ming-d dy, phn bng v phn ui). (1) Phn ming-d dy gm hch trn, hch d dy v dy thn kinh phn hi ni 2 hch vi nhau. (2) Phn bng l mt dy thn kinh dng si mnh nm gia cc dy dc ca chui hch thn kinh bng, mi t mc ra 2 nhnh. (3) Phn ui lin h vi hch cui ca chui thn kinh bng. b) Hot ng thn kinh Cung phn x l ng dn truyn ca kch thch t c quan nhn cm n trung tm, ri t trung tm n c quan p ng. Xung ng thn kinh c dn truyn theo dy thn kinh vi tc 5m/giy. Hng phn c bn cht in-ho hc v thc hin qua s bin i in th thn kinh nguyn v dy thn kinh. Thn kinh nguyn hng phn tit ra cht axetincolin. Cht ny truyn qua synapse ti TKN bn cnh, nh thng tin c truyn t TKN ny n TKN khc. hng phn c truyn i bnh thng cn kh nhanh lng axetincolin ti synapse. Cht Colin-esterasa c TKN nhn thng tin tit ra s thu phn axetincolin thnh colin v axit axetic m bo vic km hm sau khi hng phn. Hot ng thn kinh cn trng c th hin hnh vi. Mi hot ng sng ca cn trng c gi l hnh vi. Hnh vi khng ch quyt nh bi kch thch bn ngoi m cn ph thuc vo trng thi sinh l ca c th cn trng. Hnh vi bao gm cc phn x khng iu kin v cc phn x c iu kin, trong phn x khng iu kin l ch yu. Phn x khng iu kin c tnh cht bm sinh, c truyn t i ny sang i khc. Phn x c iu kin c hnh thnh trong qu trnh sng ca tng c th, khng di truyn v d mt. Xu tnh v bn nng l hnh vi c quan tm nhiu cn trng. Xu tnh ca cn trng l chuyn ng hng ti ngun kch thch (xu tnh dng), hoc trnh xa ngun kch thch (xu tnh m) mt cch khng kim ch c cho d b cht. Th d, con thiu thn(trng thnh su c thn la) bay vo ng la. y l phn x khng iu kin, kch thch t bn ngoi v thc hin c tnh cng bc. Ngi ta li dng xu tnh ca cn trng vi nh sng, mu sc, mi v bng cch to ra cc by thu bt hoc xua ui cn trng nhm hn ch thit hi chng gy ra cho ma mng. Bn nng l hnh vi phc tp c ngha rt ln trong i sng ca c th v ca loi. V d, bn nng lm t ca ong, bn nng lm kn trc khi ho nhng ca su non b cnh vy, bn nng lm cc t su, bn nng tm k ch trng k sinh v.v l mt chui nhng phn x khng iu kin xy ra theo mt trnh t nht nh, phn x trc l tin cho phn x sau, nhng phn x u tin l do nhng kch thch bn trong (nh trng thi sinh l i, thun thc v sinh dc, thiu mt s cht cn thit ).

c) Cc c quan th cm cn trng


C quan th cm (cn gi l c quan cm gic) gip cho cn trng nhn bit cc kch thch t mi trng bn ngoi phn ng li cho ph hp. Tu theo tnh cht ca cc kch thch , ngi ta phn bit cc loi sau y: (1) C quan th cm c hc (=xc gic); (2) C quan th cm m thanh (=thnh gic); (3) C quan th cm ho hc (khu gic v v gic); (4) C quan th cm m v nhit ; (5) C quan th cm nh sng (=th gic). Cu to v phn b ca cc c quan ny trn c th ca cn trng rt khc nhau tu thuc vo loi. + C quan th cm c hc: bao gm rt nhiu lng cm gic nm ri rc khp b mt c th. Mi lng cm gic gn vi mt t bo thn kinh cm gic (gi l Sensil). Khi lng cm gic tip xc vi vt rn hoc tc ng ca dng nc, cm gic c truyn n t bo cm gic, gy nn hng phn truyn v trung ng thn kinh. + C quan th cm m thanh (=c quan thnh gic): nhiu cn trng c c quan thnh gic thu nhn cc m thanh do cc c th cng loi pht ra (ting ve su ku, ting chu chu c mp cnh, v.v... l cc tn hiu gii tnh) v thu nhn cc m thanh khc bo hiu c k th hay c con vt mi. V tr phn b ca c quan thnh gic khc nhau cc loi. Th d, ca mui (h Culicidae) nm ru u, ca chu chu (h Acrididae) nm hai bn t bng th nht, ca st snh (h Tettigonidae) v d mn (h Gryllidae) t chy chn trc, ca gin lng ui, ca u trng b cnh vy trn mt c th, ca trng thnh b cnh vy v b xt nhng ch khc nhau (hoc ngc, hoc bng, hoc gc cnh). Tn s m thanh cn trng thu nhn c tu thuc vo loi, c th t 8 rung ng/giy n 40.000 rung ng /giy. + C quan th cm ho hc: bao gm c quan th cm mi (thu nhn kch thch di dng kh =khu gic) v c quan nhn cm v (thu nhn kch thch di dng th dch =v gic). (1)C quan th cm mi l cc t bo thn kinh cm gic ho hc thng phn b ru u. con c nhiu hn con ci. Cn trng c kh nng nhn bit cc cht ho hc vi nng rt thp trong khng kh, nn chng pht hin c mi cy k ch t xa bay n n v trng, con c pht hin c feromon do con ci tit ra vi nng cc thp v bay n giao phi (vi mt s loi bm xa hng km).V vy, thu bt cn trng ngi ta dng cc by mi thc n hay by feromon gii tnh rt c hiu qu. (2) C quan th cm v ca cn trng thng nhn cm c cc v ch yu l ngt, chua, ng, mn. C quan v gic ca cn trng thng nm xung quanh ming, ca ong v bm cn bn chn. + C quan th cm m v nhit : thng phn b ri rc ru u, ru hm di, cc t bn chn. + C quan th cm nh sng (=th gic): Cn trng c 2 loi mt l mt kp v mt n. (1) Hai mt kp chim mt phn ln u. Mt kp cu to t hng trm n hng ngn mt nh (ommatidium). Mi mt nh c cu to ring bit (gm gic mc, thu tinh th, tr th gic, t bo vng mc, t bo sc t vng mc, si thn kinh lin h vi dy thn kinh i t mt n thu th gic v no). Mi mt nh nhn thy mt im nh sng. Hnh nh mt kp thu c l ghp tt c cc im nh sng ca cc mt nh, v vy l kiu "ghp hnh". Cc mt nh phn b trn mt b mt li cu, nn quang trng ca mt kp rng. Tr th gic ca 2 mt nh cnh nhau vn to mt gc , nn mt vt gn c th ri vo th trng ca nhiu mt nh, nhng khi xa c th ch ri vo th trng ca 1-2 mt nh, nn cn trng thng "cn th". Loi nhn thy xa nht l rui tru, cng ch nhn thy n tru chy cch chng 50m. Mt kp ca loi hot ng ban m khc ca loi hot ng ban ngy ch phn nhn cm khng lin vi thu tinh th nn ngoi tia sng i thng vo tr th gic cn nhn c cc tia sng xin t cc mt nh bn cnh, to nn mt nh r trong iu kin nh sng yu ban m. Nh mt kp cn trng phn bit c hnh dng, mu sc, chuyn ng, khong cch v nh sng phn cc. (2) Mt n khc mt kp l thn kinh ca n


khng xut pht t thu th gic ca no, m t phn gia ca no trc. Mi mt n ch c mt thu tinh th bng cutin. V tr mt n thng gia 2 mt kp, trn hoc nh u. C loi khng c mt n (nh h b xt m Miridae, h b xt li Tingidae, h b xt Pyrrhocoridae). Chc nng ca mt n gip cn trng iu ho chuyn ng bay ng hng v kch thch mt kp tng cng phn ng quang ng. u trng thng c mt 2 bn u, gi l mt bn (Stem). Cu to ca Stem gn ging mt n. Khi ho trng thnh Stem thoi ho v thay vo l mt kp.

3.7. B ny sinh dc B my sinh dc ca cn trng c chc nng to ra trng v tinh trng sn sinh ra th h sau. Tuyt i a s cn trng n tnh, ngha l mi c th ch mang tnh ci (sn sinh ra trng) hoc tnh c (sn sinh ra tinh trng). Mt s rt t loi trong mt c th c c tnh c v tnh ci. V vy, cn phn bit b my sinh dc c v b my sinh dc ci. + B my sinh dc c (Hnh 3.6) gm: 2 tinh hon, 2 ng dn tinh, 1 ng phng tinh, cc tuyn ph sinh dc c, dng c v l sinh dc. Mi tinh hon c nhiu ng tinh. Cui mi ng dn tinh c ch phnh to ra to thnh ti cha tinh tch tr tinh trng khi cha giao phi vi con ci.

Hnh 3.6. S cu to b my sinh dc trong ca con c 1. Tinh hon; 2. ng dn tinh; 3. Ti cha tinh; 4. Tuyn ph sinh dc; 5. ng phng

tinh; 6. Thn dng c (theo Snodgrass)

+ B my sinh dc ci (Hnh 3.7) gm: 2 bung trng, 2 ng dn trng, 1 ng phng trng, m o (hay xoang sinh dc), ti ct tinh (d tr tinh trng sau khi nhn t con


c lc giao phi), cc tuyn ph sinh dc ci (tit cc cht nui tinh trng trong ti ct tinh, bao bc qu trng v bc trng, dnh trng vo gi th) v l sinh dc ci. Phn ph sinh dc ngoi ca con ci l ng trng (cn gi l mng trng). Mi bung trng c nhiu ng trng (th d rp c 2, mi cha c n 2500). C 3 loi ng trng: (1) ng trng chia lm nhiu ngn, mi ngn pht trin thnh 1 qu v khng nui trng (th d b cnh thng, b dn); (2) ng trng bn trong c 2 loi t bo xen k nhau l t bo trng v t bo nui trng (th d b cnh vy, b 2 cnh, b cnh mng); (3) ng trng c t bo trng cui ng, cn t bo nui trng ngn ng. T bo nui trng chuyn dinh dng n t bo trng nh cc si nguyn sinh (th d b cnh cng, b cnh na).

Nh vy, v cu to b my sinh dc ca con c v ca con ci c mt s khc bit l: Con c c 2 ti cha tinh cui 2 ng dn tinh v 2 tuyn ph sinh dc ngay vo cui ng dn tinh. con ci ch c 1 ti ct tinh cng cc tuyn ph sinh dc vo xoang sinh dc (hay m o) l phn tng ng vi on cui ng phng tinh ca con c.

Hnh 3.7.S cu to b my sinh dc ca con ci 1. Dy treo; 2. Bung trng; 3- 4. ng dn trng; 5. ng phng trng; 6. Xoang sinh

dc; 7. Ti ct tinh ; 8. Tuyn ti ct tinh; 9. Tuyn ph sinh dc (theo Snodgrass)


CU HI N TP CHNG III

1. Gii phu Sinh l cn trng nghin cu nhng g? lm g? 2. Trnh by v xoang c th v v tr cc c quan bn trong c th cn trng. 3. Trnh by v h c ca cn trng. 4. Trnh by v cu to, hot ng v nhng bin i thch nghi ca b my tiu

ho cn trng. 5. Trnh by v cu to, hot ng v nhng bin i thch nghi ca b my h

hp cn trng. 6. Trnh by v cu to v hot ng ca b my tun hon cn trng, v chc

nng ca mu cn trng. 7. Trnh by v cu to v hot ng ca b my bi tit cn trng. 8. Trnh by v cu to v hot ng ca b my thn kinh cn trng. 9. Trnh by v cc c quan th cm (=c quan cm gic) ca cn trng. 10. Trnh by v b my sinh dc ca cn trng.


Chng IV SINH VT HC CN TRNG

1. nh ngha Sinh vt hc nghin cu v sinh sn, sinh trng pht dc v cc tp tnh sinh sng ca cn trng. Nghin cu v sinh sn ca cn trng cho ta bit c phng thc mt loi cn trng to ra cc th h k tip nhau. Nghin cu v sinh trng pht dc bit c ch v c im ca cc qu trnh din ra t giai on trng n khi cht ca tng c th cn trng. Nghin cu v tp tnh sinh sng bit cn trng tn ti nh th no trong t nhin. Vic nghin cu ny v cng quan trng, v mun phng chng mt loi c hi, hay s dng mt loi c ch th khng th khng hiu bit cn k i sng ca n 2. Phng thc sinh sn ca cn trng Khng mt lp ng vt no c nhiu phng thc sinh sn nh lp cn trng. Cc phng thc sinh sn a dng cho php cn trng tn ti, pht trin, tr thnh mt lp ng vt v cng phong ph v loi v c s lng c th ln. Tt c cc phng thc sinh sn u hng ti vic to ra hu th nhiu v an ton cnh tranh sinh tn trong t nhin. Nguy c con chu ca mt loi cn trng b cht do k th t nhin hay do cc iu kin sinh thi khc cng ln, th loi phi c phng thc to ra con chu cng nhiu by nhiu. mn t th phi c phng thc sinh sn an ton. Mt loi c th c hai ba phng thc sinh sn tranh th tng s lng trong nhng iu kin sinh thi c th. Nghin cu phng thc sinh sn ca mt loi su hi bit kh nng tng s lng ca n, t ra bin php phng nga, nhm hn ch ti a thit hi do chng gy ra cho ma mng v sn phm sau thu hoch. Phng thc sinh sn ph bin nht ca cn trng l phng thc sinh sn hu tnh. l phng thc trng c kt hp vi tinh trng (sau khi c th c v c th ci giao phi) hnh thnh qu trng c th tinh, ri ra ngoi tip tc pht trin thnh mt c th mi. Phng thc ny c u im c bn l c th con c mang ngun gen ca c b v m nn c sc sng cao, c kh nng thch nghi vi iu kin sng tt nht. Mt trng hp rt him lp cn trng l trong mt c th c th to ra ng thi c tinh trng v trng, c th nh vy gi l c th lng tnh (99% s c th loi rp sp Icerya purchasi M. l lng tnh, ch 1% l c th tnh c). Trng v tinh trng ca mi c th lng tnh c th th tinh hnh thnh hp t, do c kh nng tng s lng nhanh, ng thi c th tnh c c th giao phi vi c th lng tnh trng th tinh hnh thnh hp t, con c mang ngun gen ca 2 c th b m nn c sc sng cao. y cng vn l sinh sn hu tnh. Mt s loi cn trng c phng thc sinh sn n tnh, l trng hp trng khng th tinh vn tip tc pht trin to ra mt c th bnh thng. u th ca phng thc sinh sn n tnh l tng s lng rt nhanh, mt c th ci ri vo ni ring bit vn sinh sn bnh thng. Nhc im ca phng thc sinh sn ny l con ch mang ngun gen ca m. Chnh v vy, cn trng thy c hin tng sinh sn n tnh theo chu k (xen k sinh sn n tnh vi sinh sn hu tnh nh rp mui vng n i), hoc sinh sn n tnh ch do ngu nhin. Ong cha, kin cha sau khi giao phi vn ra mt s trng khng c th tinh do thiu tinh trng, hoc ngay c chu chu bay, tm v nhiu loi cnh vy khc l nhng loi thng thng c giao phi c ci, nhng khng qua giao phi hoc trng khng th tinh c ra ngu nhin vn pht dc cho mt c th mi.


cn trng c phng thc sinh sn thi k u trng. Trng thi k u trng chn v khng cn qua th tinh n ra u trng con, ri u trng con pht dc trong c th u trng m, c nui dng bng cht dinh dng trong c th m, khi hon thnh giai on pht dc th c thng c th m chui ra ngoi v tip tc phng thc sinh sn ca m. C ngi gi y l phng thc sinh sn gi man. Thc cht y l phng thc sinh sn n tnh c thc hin giai on u trng. Sau mt s th h li tr li sinh sn hu tnh bng cch u trng ho nhng, nhng ho trng thnh c v trng thnh ci, ri giao phi, th tinh hnh thnh c th mi. Vic xen k phng thc sinh sn thi k u trng vi phng thc sinh sn hu tnh l cng c sc sng ca loi sau mt s th h sinh sn n tnh. Hin tng sinh sn nhiu phi thng gp cn trng k sinh bn trong thuc b cnh mng Hymenoptera (nh cc h Braconidae, Ichneumonidae, Proctotrupidae, Chalcidae). l hin tng t mt qu trng phn chia to thnh nhiu c th mi (c th t 2 n 2000 c th). Hin tng thai sinh c mt s loi cn trng, nh rui Melophagus ovinus. y l hin tng trng n thnh u trng trong c th m v c nui dng bng cc cht dinh dng tuyn ph sinh dc ca m. u trng khi ra th y sc v nhanh chng ha nhng. Cn trng thng trng, nhng cng nhiu loi ra con, nh cc h Aphididae, Tachinidae, mt s loi h Muscidae v mt s loi cc b Thysanoptera, Coleoptera. Sinh sn kiu trng c kh nng to c nhiu con, nhng t an ton v nhiu loi k th t nhin ca cn trng n trng hoc k sinh trng. Phng thc ra con tuy c s lng con t, nhng an ton hn cho th h sau.

3. Trng v pht dc phi thai: 3.1. Cu to trng Trng l mt t bo ln. Ngoi cng l v trng cng v khng thm nc bo v. Mt trong v trng l mng lng . Mng lng bao bc cht t bo v nhn trng. Cht t bo chia lm 2 phn: phn xung quanh l cht quanh trng (tng ng lng trng trng chim), phn gia l lng . Nhn trng chnh gia lng . Trn v trng c mt vi l trng tinh trng chui vo th tinh cho trng. Kch thc mi qu trng khc nhau tu loi cn trng, thng nh di 0,1mm, nhng mt s loi c trng di hn 10mm, nh trng st snh Saga di 11mm, trng ong Sylo copavalga di 15mm. Hnh dng qu trng ca cc loi cn trng rt khc nhau. Trng c ri rc tng qu hoc thnh tng c hnh dng v c vt che ph khc nhau (Hnh 4.1).

3.2. Pht dc phi thai Trng ca cn trng thuc loi c nhiu lng , nn pht dc phi thai tin hnh theo phng thc phn chia b mt. Nhn trng chia thnh nhiu hch t bo. Cc hch t bo di chuyn t gia trng ra xung quanh nhp vo t bo cht thnh mt lp t bo lin tc kn ht mng trng to thnh nhau phi. T nhau phi, pht dc phi thai tip tc c thc hin qua cc bc: (1) hnh thnh di phi, (2) di phi phn chia ra cc tng phi (ngoi, trong, gia) v hnh thnh ng tiu ho, (3) di phi chia t v hnh thnh cc chi ph, (4) hnh thnh v mt i mng phi, (5) tr phi, (6) hnh thnh cc c quan, b my. Pht dc phi thai l qu trnh phc tp, thi gian di hay ngn ph thuc vo iu kin nhit mi trng. Vo ma ng, khi nhit thp di ngng pht dc ca mi loi th trng trng thi ngng pht dc (Diapause). Qu trng c th tinh


c kh nng chu nhit thp tt hn qu trng khng c th tinh, nn vng n i rp mui (h Aphididae) vo cui ma thu giao phi trng c th tinh v qu trng qua ng n ra rp ci vo ma xun tip theo, sau chng lin tc sinh sn n tnh v ra con, n cui ma thu li giao phi trng qua ng.

Hnh 4.1. Mt s dng trng ca cn trng 1. Trng mui vng nhit i (Aedes albopictus Sk.); 2.Trng mui (Culex fatigans

Wied.); 3.Trng mui (Anopheles sinensis Wied.); 4.Trng rui hi la mch (Sitodiplosis mosellana Ghm.); 5.Trng rui k sinh rut nga (Gastrophilus

intestinalis De Geer); 6.Trng b xt m (Lygus pratensis Linn.); 7.Trng rp ging (Cimex lectularius L.); 8.Trng b xt mp vng (Pierodorus lituratus Fabr.); 9.Trng

b xt (Rhaphigaster nubulosa Poda); 10.Trng ve su ln (Cicadella viridis L.); 11.Trng ve (Graptopsaltria colorata Stal); 12.Trng Lycorma delicatula White; 13.Trng ry ma (Perkinsiella saccharicida Kark.); 14.Trng chun chun bng

(Chrysomphalus dictyospermi Morg.); 15.Trng st snh (Tettigometra sp.); 16.Trng ry bt phn (Aleurodes sp.); 17.Trng su o xanh (Naranga aenescens Moore);

18.Trng su xanh (Heliothes obsoleta Hubner); 19.Trng Rondotia menciana Moore; 20.Trng bm phn trng (Pieris rapae L.); 21.Trng ngi mch (Sitotroga

cerealella Oliver); 22. Trng su loang (Earias cupreoviridis Walker); 23. Trng b ra (Rhaphidopalpia chinensis Weise); 24.Trng b ra 28 chm (Epilachna 28-


maculata Motsck.); 25.Trng chun chun c (Chrysopa sp.); 26.Trng b que (Bacillus sp.); 27.Trng chu chu Phyllum ciccifolium Linn.

4. c im sinh vt hc giai on u trng 4.1. Trng n Sau khi hon thnh giai on pht dc phi thai, u trng ph v v qu trng chui ra ngoi. Hin tng gi l trng n. 4.2. u trng lt xc, sinh trng v pht dc u trng ca cn trng n ln ln, tng v kch thc v khi lng c th. Hin tng gi l sinh trng. Trong qu trnh sinh trng b my sinh sn chn mi dn v tin n vic chuyn sang giai on lm chc nng sinh sn. Hin tng gi l pht dc. c im ni bt ca giai on u trng l s lt xc. Sau mt thi gian u trng n v ln ln n mt mc nht nh th lt b lp biu b da c qu nh tip tc ln ln. Lt xc nh vy gi l lt xc sinh trng. Sau mi ln lt xc sinh trng u trng thm mt tui. Nu u trng lt xc sinh trng n ln, th s tui ca n l n+1. S ln lt xc sinh trng ca u trng cc loi cn trng rt khc nhau, th d b cnh na (Hemiptera) 5 ln, b cnh vy (Lepidoptera) 2-9 ln, b ph du (Ephemerida) trn 20 ln. Khi nhit mi trng tng cao gn gii hn ti a, c loi tng, c loi gim s ln lt xc sinh trng. Khi thc n khng cng thng lm tng s ln lt xc sinh trng. Ln u trng lt xc chuyn t giai on u trng sang giai on nhng nhm bin thi hon ton (Holometabola) v sang giai on trng thnh nhm bin thi khng hon ton (Hemimetabola) gi l lt xc bin thi. Lt xc l mt qu trnh rt phc tp, c iu tit bi hoc mn Juvenile v hoc mn Ecdysone. Hoc mn Juvenile gi l hoc mn sinh trng, c tit ra bi th tuyn cnh hu (Corpora allata) nm di no thu. Hoc mn Ecdysone gi l hoc mn bin thi (c cng thc ho hc C27H44O6), c tit ra bi tuyn ngc trc (Prothoracic glands) nm mt bng t ngc trc. Hai hoc mn ny lun tn ti trong mu, nhng hm lng Juvenin u trng tui nh chim u th, xc tin sinh trng v lt xc sinh trng. Ngc li, hm lng Ecdysone u trng tui cng ln cng nhiu v chim u th cui giai on u trng, lm cho u trng dng sinh trng v lt xc bin thi. 4.3. Bin thi cn trng T giai on trng cho n lc trng thnh, c th cn trng tri qua nhng thay i rt phc tp v hnh thi bn ngoi v cc c quan bn trong. Hin tng thay i gi l bin thi (Metamorphose). C 2 kiu bin thi chnh l bin thi hon ton (Holometamorphose) v bin thi khng hon ton (Hemimetamorphose). Qu trnh pht dc nhng loi bin thi hon ton tri qua 4 giai on: trng u trng nhng trng thnh (Hnh 4.2). nhng loi bin thi khng hon ton ch c 3 giai on: trng u trng trng thnh (Hnh 4.3). nhng loi bin thi hon ton, cu to c th u trng hon ton khc c th trng thnh, nn giai on nhng chnh l giai on trung gian trong qu trnh bin ho t u trng n trng thnh. Trong s cc b c nhiu su hi cy trng, cc b: cnh vy (Lepidoptera), cnh cng (Coleoptera), hai cnh (Diptera) thuc nhm bin thi hon ton; cc b: cnh thng (Orthoptera), cnh na (Hemiptera), cnh u (Homoptera) thuc nhm bin thi khng hon ton.


Hnh 4.2. Bin thi hon ton cn trng Bm phng Papilio xuthus Linn.

1. Trng; 2. Su non tui nh; 3. Su non tui ln; 4. Nhng; 5. Trng thnh

Hnh 4.3. Bin thi khng hon ton cn trng A. Trng; B-G. Chu chu non tui 1-6; H. Chu chu trng thnh


4.4. Cc dng u trng Mt trong nhng c im ca nhm bin thi hon ton l u trng c nhiu dng (Hnh 4.4). Ngi ta chia ra cc dng chnh sau y: - Dng c chn nguyn thu: chn cha pht trin hon chnh, mi ch l cc u li.

Th d, h ong Platygasteridae b cnh mng. - Dng c nhiu chn: ngoi 3 i chn ngc cn c chn mt s t bng. Th

d, b cnh vy (Lepidoptera) v h ong n l (Tenthredinidae) b cnh mng. - Dng c t chn: ch c 3 i chn ngc. Th d, h chn chy (Carabidae) b

cnh cng. - Dng khng c chn: hon ton khng c chn. Trong chia ra 3 loi l:

o Dng c u r: c u cng v khng tht vo ngc. Th d, h xn tc (Cerambycidae) v h vi voi (Curculionidae) b cnh cng.

o Dng c u r va: u ch ho cng pha trc v tht vo trong ngc Th d, h mui ln (Tipulidae) b hai cnh.

o Dng c u khng r: u thoi ho ch cn du vt v hon ton tht vo trong ngc. Th d, cc loi rui b hai cnh (Diptera).

4.5. Hot ng sng ca u trng Giai on u trng l giai on n ln ln, pht dc v tin n ho trng thnh. V vy u trng ca nhiu loi cn trng gy hi nghim trng cho cy trng. Phng thc gy hi ca chng khc nhau tu thuc vo cu to ming. Cn trng kiu ming nhai c th cn t, c khot tt c cc b phn thn, l, hoa, qu, r, thn ngm, c trn cy. Cn trng kiu ming chch ht gy hi lm cy kh ho, vng a, bin mu, ci cc. Cc c t v nc bt ca cn trng chch ht cn lm cy pht trin d hnh, hnh thnh bu su. Ngi ta c th nhn bit c loi gy hi cho cy trng da vo du vt gy hi ca chng trn ng rung, t quyt nh bin php phng chng chng. u trng nhiu loi c tp tnh nh t cun l, dt l lm t bo v c th, nh loi su cun l la (Cnaphalocrocis medinalis). Hu ht chng c tp tnh gi cht, t ri ln trnh k th khi gp nguy him. u trng cc loi c trong thn cy thng c sn l trng thnh chui ra ngay trc khi ho nhng. u trng nhiu loi c tp tnh sng tp th nh su chm hi ch (Andraca bipunctata), di chuyn theo n nh su cn gi la (Mythimna separata). Rt nhiu loi c u trng tui nh nh t treo l lng nh gi pht tn, nh su c thn la hai chm (Tryporyza incertulas) v su c thn ng (Ostrinia furnacalis). C loi ban ngy chui xung t v ban m mi ln mt t gy hi cho cy trng, nh su xm (Agrotis ypsilon). Nhiu loi c trong l hay trong qu n, nhng li xung t ho nhng, nh rui c qu (Bactrocera dorsalis) v rui c l (Liriomyza sativae). u trng thng tm ni kn o, tm nhng v tr c tc dng bo v t nhin, nh t dt kn ho nhng bn trong. Hot ng sng ca u trng cc loi cn trng rt a dng. phng chng chng c hiu qu cn phi nghin cu t m tp tnh sng ca tng loi v c cp cc chng sau.


Hnh 4.4. Cc kiu su non ca cn trng 1.Su non c thn ng (Pyrausta nubilalis Hubner); 2.Su non tm nh (Bombyx mori

L.); 3.Su non bm phng (Papilio machaon L.); 4.Su non ong hi la mch (Dolerus tritici Chu); 5. Su non rui hi la mch (Sitodiplosis mosellana Gehin); 6. Su non mui (Culex sp.); 7.Su non rui k sinh rut nga (Gastrophilus intestinalis

De Geer); 8.Su non rui nh (Musca sp.); 9.Su non b h khoai lang (Cylas formicarius Fabr.); 10.Su non b hung (Holotrichia sauteri Moser); 11.Su non h

trng (Pleonomus canaliculatus Faiderm.); 12.Su non mt u (Bruchus pisorum L.)

5. c im sinh vt hc giai on nhng C 3 loi hnh nhng l: nhng trn, nhng mng v nhng bc (Hnh 4.5). - Nhng trn c cc chi ph v cnh khng dnh st vo c th. Th d, nhng b

cnh mng (Hymenoptera) v b cnh cng (Coleoptera). - Nhng mng c cc chi ph v cnh dnh st vo c th v c bao bc bng mt

lp mng c th nhn thy cc chi ph bn trong. Th d, nhng b cnh vy (Lepidoptera).


- Nhng bc c v cng bc bn ngoi nhng. V cng ny l do lp biu b ca u trng tui cui cng khi ho nhng khng lt b i m hnh thnh. Th d, nhng cc loi rui b hai cnh (Diptera).

Hnh 4.5. Cc kiu nhng cn trng A. Nhng trn (Nhng xn tc); B. Nhng bc (Nhng rui); C. Nhng mng (Nhng

ngi) (theo Tuyt Triu Lng)

Giai on nhng l giai on din ra s ph v cc t chc ca c th u trng v xy dng li cc t chc cho ph hp vi giai on trng thnh. Qu trnh ny din ra theo tng bc sau y: u tin cc t chc mt sc sng, tip n cc t chc hon chnh b phn gii thnh tng on phin, cui cng phn gii ton b. Mm ca cc t chc c quan (l nhng nhm t bo c sn trong c th u trng) dn dn pht trin thnh c quan tng ng ca giai on trng thnh. S bin ho xy ra c bn ngoi v bn trong. Mc bin ho tu thuc vo loi cn trng. b cnh cng (Coleoptera), t bo ni b ca v c th u trng chuyn ho thnh t bo ni b da ca trng thnh, nh vy t bo ni b da ca Coleoptera c bn khng c s bin ho. Nhng b cnh mng (Hymenoptera) v b hai cnh (Diptera), trong qu trnh bin thi t bo ni b da dn dn b ph v, ng thi mt s mm c quan cha phn ho khng ngng tng trng v phn ho hnh thnh c quan tng ng ca cn trng trng thnh. Th d, con gii khng c chn ngc, nhng mm chn ca rui c n su trong c th gii cho n lc ho nhng mi lt ra ngoi. Mc bin ho ca cc c quan, b my bn trong mc khc nhau. Lp t bo ni b, b my tiu ho, cc tuyn v mt s h c hon ton xy dng li. Cc ng malpighi, th m v mt phn h c khc b phn gii rt t. H thn kinh, mch mu lng v i b phn h thng kh qun khng b phn gii. nhng cn trng bin thi hon ton cp thp, cc c quan ca u trng ch cn bin ho rt t thnh c quan tng ng ca trng thnh.

6. c im sinh vt hc giai on trng thnh 6.1. Ho trng thnh Hin tng cn trng t u trng tui cui cng (ca loi bin thi khng hon ton) hoc t nhng (ca loi bin thi hon ton) lt b lp xc bin thnh trng thnh gi l ho trng thnh. Lc ho trng thnh, cn trng c ng c th v chn lm ngn dc gia lng nt ra, chn v mt s b phn khc cng c ng nt. T


nhng ch nt cn trng chui ra khi v nhng. Sau , cn trng ht nhiu khng kh, nc v co gin h c mu chy vo cnh, vo cc chi ph, ri da cng dn, cnh v cc chi ph dui ra hon chnh. T cn trng mi b hoc bay c. i vi nhng loi ho nhng trong thn cy, di t hay trong kn t th u trng chun b sn li thot ra ngoi cho trng thnh. i vi nhng loi nhng nm trong kn bng t hoc bng cht cng th con nhng c cch thc khc nhau ph v v kn chui ra ngoi trc khi ho trng thnh. Thi im ho trng thnh trong ngy cng tu thuc tng loi, loi trnh c nhiu ri ro nht lc mi ho trng thnh, v khi c th cn mm yu nn khng ln trnh c k th. 6.2. Tnh n thm v trng thnh v sinh dc Sau khi ho trng thnh, ch mt s loi cn trng c b my sinh dc chn mi nn trng thnh khng cn n thm cng tin hnh ngay c cc hot ng sinh sn, nh tm i giao phi, tm ni trng v trng. Th d, trng thnh su c thn 2 chm (Tryporyza incertulas), ngi tm du (Bombyx mori), ngi su rm (h Lymantridae), ph du (b Ephemerida) giao phi v trng ngay sau khi ho trng thnh. i vi phn ln cc loi cn trng khc, sau khi ho trng thnh b my sinh dc cn cha chn mi hoc ch mi mt phn rt t trng v tinh trng chn nn trng thnh ca chng phi tip tc n tch lu cht dinh dng cho n khi hon ton trng thnh v sinh dc. S tip tc n ca trng thnh nh vy gi l tnh n thm. Trng thnh nhiu loi n thm xen k vi hot ng sinh sn nn lng trng nhiu v thi gian trng ko di. Th d, trng thnh b h khoai lang (Cylas formicarius) n thm xen k vi hot ng sinh sn ko di 3-4 thng. Nhng loi su nh vy gy hi cho cy trng c giai on u trng v giai on trng thnh. 6.3. Giao phi, th tinh, trng Giao phi l qu trnh con ci tip nhn tinh trng ca con c phng vo xoang sinh dc hoc vo ti ct tinh ca con ci. S ln giao phi tu thuc vo loi cn trng. C loi c i ch giao phi mt ln nh ong mt (Apis spp.) v mt s loi thuc b cnh vy (Lepidoptera), c loi giao phi nhiu ln, c loi sinh sn n tnh nn khng giao phi. Th tinh l qu trnh tinh trng chui vo trng qua l trng kt hp vi trng to ra hp t. V sau khi giao phi, tinh trng c con ci d tr trong ti ct tinh s dng dn nn s th tinh xy ra khng ng thi vi s giao phi, ong mt c th sau hng thng n hng nm. Cn trng trng ngay sau khi trng c th tinh, nhng cng c loi trng pht dc n lc sp n hoc n ra con ri mi ra ngoi. Cn trng c tp tnh chn ni trng thch hp v c cch trng khc nhau tu loi. V tr trng ca cc loi su hi l iu rt c ch trong khi iu tra cn trng trn ng rung.

7. Cc c im sinh vt hc khc ca cn trng 7.1. Cc bin php t v Cn trng l thc n ca nhiu loi ng vt, trong c cc loi cn trng bt mi. Trong qu trnh thch nghi sinh tn trong t nhin hnh thnh chng cc bin php v kh nng t v. Cn trng c th chin u vi k th bng rng sc, bng chn c gai nhn, bng ngi chm c nc c v.v Chng c th lm k th khng gim tip cn v cc lng c, v tuyn hi v cc hnh thc do nt khc nhau. Th d, nc c ca ong v kin, tuyn hi ca b xt, ting n hu mn do tit ra cht lng bc hi nhanh ca ging Brachinus (h Carabidae b cnh cng) u c tc dng chin u v do nt k th. Mt s loi trong c th c cht c cao c th lm


cht loi no s dng n lm thc n th li c mu sc c bit d pht hin t xa k sn mi nhn bit m trnh xa chng. Cn trng cn c kh nng gi dng l cy hay cnh kh k th khng pht hin c. Mt s loi cn c hnh dng v mu sc rt ging mt loi cn trng c kh nng t v tch cc k th khng dm tn cng. Th d, rui n rp rt ging ong mt. l hin tng gi dng ngu trang rt c hiu qu trong vic bo v trc k th t nhin. Cn trng cn c tp tnh gi cht. Khi gp nguy him, nhiu loi cn trng co chn hoc cun trn gi cht v ri xung t nm yn trong thi gian lu, k sn mi b i ni khc. Bin php t v tch cc v gi dng ngu trang gip cho cn trng tn ti trong u tranh sinh tn khc lit ca th gii ng vt. 7.2. c tnh sng tp th Mt s loi nh ong, kin, mi sng tp th hng vn con trong mt t, c s phn cng nhim v ca cc thnh vin trong t cht ch v chng khng th sng tch ri nhau c. Mt s loi khc nh su cn gi, chun chun, bm c tp qun tp trung v bay xa thnh n. Su non su keo (Spodoptera mauritia), su cn gi (Mythimna separata), su khoang (Spodoptera litura), su sa (Agrius convolvuli) khi pht sinh vi s lng ln thng di chuyn thnh n t rung ny sang rung khc ph hi. Su chm hi ch (Andraca bipunctata) tui nh thng xon xt vi nhau hng chc con bm trn mt cnh ch, n lc sp ho nhng mi phn tn. Chu chu n (Locusta migratoria, Schistocera gregaria, Dociostraurus maroccanus) khi mt thp sng n c (gi l pha Solitaria), khi mt cao th chuyn sang pha sng n (gi l pha Gregaria) v bay thnh tng n c chiu rng 100-800m v di 15-20km. Cc n chu chu bay nh vy thng thy Chu Phi. Hnh vi ca i sng tp th c hnh thnh trong qu trnh cc c th cng loi gn gi nhau, cc c quan nhn cm (th gic, xc gic, khu gic) b kch thch to nn cc phn x c iu kin v cc c th thy cn thit phi da vo nhau, dn n c nhng bin i v sinh l nht nh, ri tr thnh mt tp th sng theo n. 7.3. Hin tng ngng pht dc (Diapause) Hng nm vo lc nhit thp di nhit khi im pht dc hoc qu cao, kh hn th cn trng c hin tng ngng pht dc (Diapause). trng thi ngng pht dc, cn trng nm bt ng ti v tr c chun b trc, khng n, qu trnh trao i cht trong c th ngng li hoc ch mc rt thp. Hin tng ny nu xy ra trong ma ng c gi l qua ng, nu xy ra trong ma h c gi l qua h. Giai on ngng pht dc c th l trng, u trng, nhng v trng thnh tu tng loi. Cng mt loi nhng cc khu vc a l khc nhau c th ngng pht dc cc giai on khc nhau. l mt biu hin ca s thch nghi ca cn trng vi mi trng sng. Cn phn bit ngng pht dc (Diapause) vi hn m (Coma) * Hn m (Coma) l trng thi (tat) mt chc nng quan h ( thc, linh ng, nhn cm) vi s bo tn cuc sng thc vt (h hp, tun hon). Hn m xy ra khi b tc ng t ngt do iu kin bt li nh nhit cao, nhit thp, thiu oxy, b ng c ho cht. l trng thi m c th cha kp chun b nhng iu kin sinh l i ph vi hon cnh xu. Nu tc ng ca yu t xu qu mnh v ko di th cn trng c th cht. Ngng pht dc (Diapause) l giai on (priode) ngng hot ng hay pht trin khng c bin thi. Trc thi k ngng pht dc c th chun b y v


sinh l (nh tch ly lipit v gluxit, lng nc t do gim v t l nc kt hp trong dch t bo tng, cng h hp gim). n thi k ngng pht dc th mi s sinh trng pht dc ngng li, mc trao i cht gim thp. Cn trng khi ngng pht dc c th chu ng c iu kin ngoi cnh bt li trong thi gian rt di (t nhiu thng n nhiu nm).

C 2 kiu ngng pht dc: ngng pht dc t do (Diapause facultative) v ngng pht dc bt buc (Diapause obligatoire). + Ngng pht dc t do xy ra c tnh cht chu k do s bin i chu k ca thi tit. Khi nhit thp th cn trng chuyn dn vo trng thi ngng pht dc, n lc nhit tr li bnh thng th c th li khi phc nhng hot ng sng bnh thng. Nh vy, ngng pht dc t do din ra t do theo hon cnh. + Ngng pht dc bt buc l mt c tnh ni ti ca cn trng mang tnh di truyn v tng i bn vng. Khi vo ngng pht dc bt buc th d hon cnh t nhin tr li thch hp cho hot ng sng, trng thi ngng pht dc vn tip tc mt thi gian nht nh mi chm dt. Nh vy, thi im bt u v thi im kt thc ngng pht dc bt buc khng t do theo bin i ca iu kin bn ngoi, m bt buc theo yu t ni ti trong c th cn trng. C ch sinh l ca ngng pht dc lin quan vi hot ng ca h ni tit. Khi u trng v nhng chun b ngng pht dc th tuyn ngc trc (Prothoracic glands) hot ng di tc ng kch thch ca cht c no tit ra ngng tit hormon Ecdysone. Hm lng hormon Juvenile (do tuyn cnh hu Corpora allata tit ra) cng thp nht giai on ngng pht dc. S ngng pht dc ca trng thnh lin quan trc tip vi vic ngng tit cht kch thch sinh dc ca tuyn bn hu. S ngng pht dc ca trng (phi thai ngng pht dc) li lin quan vi cht kch thch c hch thn kinh di hu tit ra c th cn trng m. Hot ng ca hch ny cng chu s chi phi ca no. Cc yu t nh hng n ngng pht dc bao gm: nh sng, nhit , m, thc n v.v, trong nh sng v nhit tc ng r nht. Thi gian chiu sng ngn (tng ng vi ma ng) dn n ngng pht dc. Ngc li, thi gian chiu sng di (tng ng vi ma h) c ch ngng pht dc. Tc ng ca nh sng n ngng pht dc ch th hin trong phm vi nhit nht nh. Nhit cao c th c ch ngng pht dc, nhit thp dn n ngng pht dc. Quan h thc n vi ngng pht dc khng r. Tuy vy, c mt s loi khi cht lng thc n km cng i vo ngng pht dc. Th d, su non su hi ng Diatraea lineolata khi n thn cy ng kh thng xy ra ngng pht dc. Ngng pht dc chi phi chu k sng ca cn trng trong nm. V vy, nghin cu hin tng ngng pht dc ca cc loi su hi cy trng l rt cn thit nm c din bin ca cc la su trn ng rung. 7.4. Hin tng nhiu hnh ca cn trng Hnh thi bn ngoi ca con c v con ci ca cng mt loi c s khc nhau th hin qua cu to phn ph sinh dc bn ngoi, qua ru u v mu sc. Kch thc c th con ci thng ln hn ca con c. Nhiu loi con c c cnh, cn con ci khng c cnh, th d, mt s rp sp h Coccidae, su kn h Psychidae, om m h Lampiridae.

(*) Coma (gr. Kma: sommeil profond): tat caractris par la perte des fonctions de relation (conscience, mobilit, sensibilit) avec conservation de la vie vgtative (respiration, circulation). Diapause: Priode d arrt dans l activit ou dveloppement sans metamorphose. [Larousse,1981]


Trong mt loi c th c nhiu loi hnh c mu sc v kch thc khc nhau, chng thng pht sinh vo cc ma khc nhau trong nm, hoc phn b cc vng a l khc nhau. Th d, bm phng (h Papilionidae b cnh vy) c nhiu loi hnh c mu sc khc nhau. iu ny d gy s nhm ln khi nhn dng loi cn trng thu bt ngoi t nhin. Hin tng nhiu hnh th hin r rt nhng cn trng sng c tnh x hi nh ong, kin, mi. Trong t mi c mi cha, mi th, mi lnh, mi c. Trong t kin c kin cha, kin th, kin lnh, kin c. Trong t ong c ong cha, ong th v ong c. Mi loi hnh ny c nhim v ring trong i sng chung ca c t.

7.5. Chu k sng Trong qu trnh sinh trng pht dc v sinh sn cn trng hnh thnh nn nhng chu k ca cc giai on pht trin. Nhng khi nim cn quan tm l i, vng i v la su. i l khong thi gian tnh t lc mt qu trng hoc mt c th cn trng c m sinh ra cho n lc c th cn trng cht gi sinh l. Vng i l khong thi gian tnh t lc mt qu trng hoc mt c th cn trng c m sinh ra cho n lc c th bt u sinh sn. Thi gian ca mt vng i bng tng s thi gian sinh trng pht dc ca cc giai on: trng (nu cn trng m trng), u trng, nhng (nu c) v trng thnh bt u . Nh vy, i vi loi ra con th khng tnh giai on trng, i vi loi bin thi khng hon ton th khng c giai on nhng. i v vng i l khi nim ca tng c th. Trong t nhin, mi loi cn trng thng pht sinh c tnh chu k ca mt tp th. nm c quy lut pht sinh trong nm ca mt loi su hi ngi ta dng khi nim la. La l khong thi gian tnh cho mt tp th su trn ng rung, k t lc c th u tin c sinh ra cho n lc c th cui cng ca tp th cht. Nh vy, thi gian hon thnh mt la di hn i ca tng c th; i ca mi c th di hn vng i ca chnh n. S la trong mt nm tu thuc vo loi su v tu vng a l. Th d, su c thn la 2 chm (Tryporyza incertulas) min bc Vit Nam c 6-7 la, pha bc Trung Quc ch c 3 la. Trn ng rung, la ny cha kt thc th la sau bt u, nn c hin tng g

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