Aquatic insect Ecosystem

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72% Water + 28% landEntomologists


Insects in Aquatic Ecosystem K .Elango

what is Aquatic insects ???

Why do we care ???

Habitat of Aquatic insects ???

Adoptions of aquatic insects ???

Uses of aquatic insects???

Just listen this seminar

One million known insect species, there are over 8000 species that fall into the macro invertebrate category

All living organisms in aquatic environments fall into one of three categories:

Plankton - Drifters Nekton - Free-swimmers Benthos - bottom dwellersAquatic Ecosystem

(Danks , 2002)

Truly aquatic insects are those that spend some part of their life-cycle closely associated with water, either living beneath the surface or skimming along on top of the water

The immature stages are truly aquatic while the adult is a winged terrestrial form.

(Subhashini et al ., 2008)

Aquatic insects

Why do we care ??? Major component of the aquatic food chain Indicators of aquatic health Affect human health Role in forensic investigationBusiness partner

Aquatic Insect Orders1. Collembola* 2. Ephemeroptera ** 3. Odonota**4. Plecoptera** 5. Hemiptera6. Megaloptera 7. Neuroptera*8. Trichoptera**9. Lepidoptera* 10. Coleoptera11. Hymenoptera*12. Diptera

* ---- Minor aquatic order with only a few aquatic species ** ---- Entirely aquatic orders


12 orders ,150 Families ,8600 Species

1 mm21 cmSmall & Larger Aquatic insectsMegaloptera Hymenoptera

Ephemeroptera - May fly 21 families with 676 species Eggs Nymph Adult Naiads often with abdominal gills Maxillary and labial gills 3 styli on naiads and adults Nymph (Predacious) Adult ( Not feed) Upto 45 instars


All odonates are predators as both nymphs and adults Eggs nymphadult Up to 20 instars Predacious No external gills Longer body on damselflies (wings up) Dragonflies (wings down) Odonata Dragon fly, Damsel fly 9 families with 407 species

NymphAdultAdultNymphDamsel flyDragon fly

Plecoptera Stone flies 9 families and 626 species Mostly temperate regions Closed tracheal system with anal gills Need high oxygen, good environmental indicators. Upto 10-33 instars Water purity indicator


Hemiptera Back swimmers, Water Boatmen, water bugs , water strider, water scorpions

Diving or at surface Adults and naiads both aquatic. Highly modified legs. Generally wings still functional as adults, can disperse between waterways.

Aquatic bugs

Coleoptera Diving beetles, Whirligig beetles, Scavenger beetles

Egg larva pupa adult Larva very different from adult Adults have hard case on body that does not overlap Adults have chewing mouthparts Larva undeveloped eyes, sometimes have tusks

Aquatic beetles

Coleoptera( Subramanian and Sivaramakrishnan, 2007 )

Diptera Mosquito , Meniscus midges, chironomids 29 families and 3,500 species

Larvae are maggot like or worm like Very diverse in aquatic ecosystem Anal spiracles breathing at surface upto 5 instars

Diptera( Subramanian and Sivaramakrishnan, 2007 )

Trichoptera Caddisflies 21 families and 1,400 species

Caddisflies are related to Lepidoptera and resemble small hairy moths Wings are covered in dense hairs rather than scales Upto 6-7 instars The larvae may be either herbivorous or predatory


Trichoptera ( Subramanian and Sivaramakrishnan, 2007 )

( Subramanian and Sivaramakrishnan, 2007 )

Submerged plantsHabitat of Aquatic insects

Sediment (mud)

Freely in the water

Around rocks

Habitat of Aquatic insectsCollembolaEphemeropteraOdonotaPlecopteraHemipteraTrichopteraColeoptera

DipteraSprings and spring ponds Lakes and Streams Lakes and Streams Streams Lake and Stream MarginsLakes and Streams Lakes and Streams All Aquatic Habitats ( Ronald et al., 2007 )

Structure and Appearance

Lifecycle and Development

Slow season life cycle - Mayflies, Stoneflies, And Caddisflies 2.Fast season life cycle - caddisflies and dragonflies

3.Non seasonal life cycle - Hellgrammites Life cycles for aquatic insects may be very short or very long ( Voshell et al ., 2002 )

Lifecycle and Development

( Hope Batcheller, 2010)

Food sources & Feeding mechanism

ScrapersCollectorsShreddersPredators Food sources - Functional feeding groupsCategorize :

(Reese , 2009)

Scrapers : - special mouthparts that remove algae growing on the surface of rocks or other solid objects Collectors : - acquire small pieces of decaying plant material (detritus)Shredders : - aquatic insects feed on parts of live plants that grow under the water.Feeding mechanismPredators : - feed on other animals that are alive (small vertebrates, such as fish and tadpoles)(Reese , 2009)





The most common way for aquatic insects to breathe effectively underwater is to use oxygen that is dissolved in the water

Immature stages Gills obtaining dissolved oxygen - water

Use the holes in their bodies to get oxygen from the air Respiratory siphon

A few kinds of aquatic insects have their spiracles on the end of a long tube at the end of their abdomen ( water beetle)

Respiration( Reese Voshell , 2009)

2. Snorkel with a breathing tube : - Mosquito larva and water scorpions 3. Scuba tank :- Water beetle and Water Spider 1. Gills : - May fly , Dragon fly , Stone fly , caddish flyRespiratory adoptions

Air = 21% O2 , 78% N2Water = 35% O2 , 64% N2,






Reproduction Only adult insects are capable of reproducing, and most aquatic insects spend their adult stage out of the water

After mating on land, females return to the water to deposity her eggs

Eggs are usually stuck on solid objects under water, but a few kinds deposit the eggs on trees or rocks above the water

( Hodkinson and Jackson , 2005 )


Other aquatic adoptions1. Ripple effect: - Most aquatic insects are sensitive to water ripples to detect predators or prey - own ripples on the water surface and process the returning "echoes" to detect prey

(Hershey et al ., 2008)

2. Double vision - The Whirligig Beetle has eyes divided horizontally to see both under and above water.


(Hershey et al ., 2008)

3.Oars - Many aquatic insects paddle underwater with oar-like legs - Legs are long, flattened and fringed - water beetle and water boatman

(Hershey et al ., 2008)

4. Skates - Aquatic insects skate on the water surface by distributing their body weight over long, thin, waterproof legs.

- They paddle with the middle pair of legs, steer with the hind legs and use the short front legs to attack and hold prey

(Englund , 2007 )

5. Jet skis - The Camphor Beetle also skates on the water surface. - When alarmed, it releases a chemical from its back legs that reduces the water surface tension

1 meter / second

( Choudhary and Ahi , 2015)

5. Suckers

Blephariceridae, commonly known as net-winged midges Found near fast-flowing streams where the larvae live Suckers are sometimes called creeping welts

Immature stagesAdult

( Choudhary and Ahi , 2015)

No water loss from evaporation Less temperature fluctuation Less light for predators to see them with Avoid competition with terrestrial species

Advantages: Water uptake from Osmosis Less oxygen available Moving water Different food sources Pollution Disadvantages:

Aquatic insects and Water quality

Hazardous chemicals, automotive products, pesticides, fertilizers, pet wastes, excessive soil erosion and air pollution all contribute to water pollution.

Mayflies Stoneflies Caddisflies (ETP Group)

Making survey of aquatic insects is called Bio monitoring

(Kaur et al ., 2010)

Role in Food chains

( Baxter et al., 2005 ) Algae Protozoa Small Insects Large aquatic Insects Small fish Large fish

Diseases transmitted by mosquitoes include: - Malaria, dengue, filariasis, chikungunya, yellow fever, Japanese encephalitis, Saint Louis encephalitis, Western equine encephalitis, Eastern equine encephalitis.

- Nearly 700 million people get a mosquito borne illness each year resulting in greater than one million deathsMosquito Vs Human

(Bond et al., 2014)

1. Malaria 2.Kala Azar 3. Dengue 4.Plague 5. Filariasis