Dixwell Critters

We found many different types of critters. The diversity of critters indicates that this site has better water quality. We were hoping to find a hellgrammite, since we had found some in this location last year. Hellgrammites require excellent water quality. We never found one here this year, but don't worry, we will check farther up the river.

 

Damselflies

This group of bugs is one of the largest in the world. When they become adults they are beautiful. They feed on mosquitoes. Adults have territories that they defend aggressively. They are known to be vicious predators. Occasionally, numbers of adults join in mass flights for large distances. It is not understood why they do this. The larvae exist underneath rocks. They are carnivorous (meat eaters) and cannibalistic (eat their own kind) and they are attracted to their prey by movement.

 

Caddisflies

The word "caddis" refers to their habit of constructing nets or cases. Caddis flies make their houses out of, bark, or rocks found on the bottom of the river. When they grow up, they are moth-like insects. They are one of the most important food sources for fish. This is a drawing of a caddisfly that made its home out of bark. It's called a case maker. The case makers can increase the amount of oxygen to their body by undulating their abdomen inside the case. The case makers have to come out of their cases and grab their food, but the net spinners make a net, so that when the water goes by, it catches its food and then every once and a while they check their net for their food.

 

 Stoneflies

Stoneflies are close relatives to a cockroach. They are restricted to living in highly oxygenated water. They can be found throughout the year. Once they become adult, they only live from a few days to five weeks. Stoneflies are herbivores. Males attract females by drumming on a rock. Our class found a stonefly that was white. We put him in our tank and he was doing this very weird movement. He was trying to find a female. Females only mate once in a lifetime, but males mate over and over. Our stonefly finally developed his colors. Unfortunately, we didn't catch him a female yet.

 

 Mayflies

You can tell a mayfly from stonefly, because mayflies have three tails rather than two. They are very primitive insects. Adults usually have a short life span, often less then a month. Trout love to eat them. As it moves out of the larval stage it is especially vulnerable because it takes a few minutes for its wings to work. Sometimes males swarm to attract females. Females then fly through the swarm and are grabbed by the male. They need a good supply of dissolved oxygen, although there are a few species that can survive with low amounts.

 

Pronggills Mayflies

These type of mayfly have gills on the side of their abdomens.