All the insects we chose live in the nymph stage for about a year, then mature to adults. In this adult stage they live long enough to lay their eggs and die which only takes from one hour to a day. But in this year and a day, they are of huge importance to the food chain and the Chena River.
Fish eat the larva and nymphs.
Then the surviving insects that have matured fly up the river, some being eaten by birds. If the river is polluted, then the insects would die and then the fish and birds would not have food. Most of these insects are very sensitive to pollution so if there is a decline in the number of insects in the river, we can use it as a sign that the river's health is in trouble.