Conservation Kid's Corner November 2004 Edition by Jim Campbell

AQUATIC

BUGS!!!

What are Aquatic Micro Invertebrates?
Aquatic (water)	Micro (big enough to see with the eye)	Invertebrate (animal without a backbone)

In order to have a clean and healthy river we need aquatic insects. These insects spend the biggest part of their lives under water. These aquatic insects are called Benthic Macro Invertebrates. These bugs are big enough (macro) to be seen with the naked eye. They lack back bones (invertebrate) and live at least part of their lives in or on the bottom of a river, pond, or a wetland.

These aquatic insects are at the bottom of the environmental food chain. So it is important that we monitor their existence.

Biological river monitoring is based on the fact that different aquatic insects react to pollution in different ways. Pollution sensitive aquatic bugs such as mayflies, stone flies, and caddis flies are more susceptible to the effect of physical or chemical changes in a river than other aquatic bugs. These bugs act as indicators of the absence of pollutants.

Aquatic insects are relatively easy to identify. They are abundant and can be easily collected by a seine or net and identified with simple training.


Sowbug	Mayfly

Aquatic insects that go through complete metamorphosis undergo four stages of development: egg, larva, pupa, and adult.

Banded Demoiselle

Caddis fly

Crayfish

Dragon fly

Clams and Snails	Damselfly	Dobsonfly Larva

Pond Skater	Leeches & aquatic worms	Scuds

The life of the dragonfly begins as an egg laid in water. It hatches into a larva that grows by splitting its skin and forming a new, larger skin. There are between 8 and 15 molts over 2 years, depending on the species. During the in-between stages, the insect is referred to as a nymph. Finally, the nymph climbs up a stem into the air, splits its skin a final time, and the adult dragonfly emerges. The main diet of the dragonfly is mosquitoes and other small flies.
Aquatic bugs are continuous indicators of the environmental quality. The composition of the aquatic bug's community in a river reflects that river's physical and chemical condition over time. Aquatic bugs are a critical part of the aquatic food web. They form a vital link in the food chain connecting aquatic plants, algae, and leaf litter to the fish species of the river. The condition of the aquatic bugs community reflects the stability and diversity of the larger aquatic food web.