Aquatic Entomology

Aquatic Insects

• Insects that spend most of their life cycle in bodies of water

• Coleoptera

• Diptera

• Crane flies, Black flies, Mosquitoes and Midges

• Hemiptera – Water Striders, Giant Water Bugs, Water Boatman

• Odonata – Dragonflies and Damselflies

• Ephemeroptera - Mayflies

• Megaloptera – Alderflies, Fishflies and Dobsonflies

• Plecoptera - Stoneflies

• Tricoptera - Caddisflies

Complete Metamorphic Insects

Eggs – larvae – pupae (aquatic) - Adults (terrestrial)

Incomplete Metamorphic Insects

Eggs – nymph (naiad) (aquatic) -Adults (terrestrial)

Aquatic Systems

• Standing bodies of water

• Lakes, ponds, marshes and swamps

  • Not overly diverse in their environments

  • Relatively low in dissolved Oxygen

  • Little movement to the water

  • Surface can be completely covered by ice

  • Temperature tends to change slowly

  • Organisms are well adapted to these environments

    • But can be susceptible to pollutants and other inputs

Moving bodies of water

• Ditches, creeks, streams, and rivers

  • Much more diverse in their environments

  • Tend to be higher in dissolved Oxygen and more variable

  • Little to great amounts of movement

  • Surface not typically covered by ice

  • Temperature tends to change slowly

  • Organisms are well adapted to these environments

  • But can be susceptible to pollutants and other inputs

• Much more diversity in habitats

  • Standing water vs flowing water

• Riffle/Pool Alternation

  • Rocky area vs Sediment

  • Hi flow vs lower flow rates

  • Spatial heterogeneity in habitats

Why Decomposition not overly well studied in these environments

• Temperatures tend to be lower – reduce decomposition rates

• Internal flora destroy tissues more slowly

• Bloat is delayed

• If body is not weighted down or stuck under some object, it will eventually pop up to the surface

• Bodies can be moved great distances under water by currents

• There is NO “Blow Fly” equivalent in aquatic systems

Caddisfly Larvae

• Live in silken tubes = “case”

• When mature, case is glued to a surface

• After adult emergence, case remains

• Some are mobile, others remain stationary

• Evidence! Requires knowledge of life cycle

Black Fly Life Cycle

• Medically important species of flies

• Biting fly that can vector diseases, but NOT in the U.S.

• Attach to rocks and other items in the stream

The Missing Wife Case Study

• Car found in a river by divers – June 1989

• Northern Michigan

• Car had a body in it

• Authorities were called

• Traced the ownership of the car to a local man

• Man admitted that the car belonged to him

• Said that he and his wife had a fight a couple of weeks before… she took off in his car not to be seen again

• Problem…car did not show major damage, but wife had major head trauma

• Car had numerous midge cases and empty black fly pupal cases

• Sent to entomologist for ID

When Black fly hatch

January

When black fly pupation

March

When black fly adults emerge

May

When Oviposition and egg diapause for black fly

June

When egg hatch for black fly (2nd gen)

November