Insects Alive! The Food Chain in Spring One sure sign of spring is the appearance if insects, and it's no coincidence that many birds appear soon after. Swallows, bluebirds, warblers, and a host of other birds returning from the tropics eat lots and lots of insects. Some eat flying insects. Others eat crawling insects. Read about spring beginings of both kinds. How are they different? Aquatic Insects Mayfly Nymph Mayfly Adult Dragonflies, damselflies, and mayflies start from eggs laid in water. When they hatch, the young are called nymphs. Nymphs have beautifully complex body shapes, with gills for breathing underwater, and no wings. Some nymphs live underwater for three years or more. As they grow, they periodically shed their outer skin. The last time they do this, they don't pupate. They simply climb out of the water and as their outer skin splits and sheds off, their wings unfold. As adults, their main job is to mate and produce eggs, which will hatch into babies that live in the water for most of their lives. Dragonflies and damselflies live for a whole season or more as adults, snatching up smaller insects with their amazing hinged jaw that literally snaps out to grab things. One lovely aquatic insect, the mayfly, emerges as an adult with no mouth! It never eats even a single meal as an adult. It dies within a few days of emerging, after using all its energy to find a mate. The mayfly family name is Ephemeroptera. (Can you find a word in the dictionary that is related to "Ephemeroptera?" How do you think the Mayfly family got its name?) Many species of aquatic insects emerge very soon after ice-out, as people who've already gotten mosquito bites know! Caterpillars Most people know that a butterfly starts as an egg, hatches out as a larvae (caterpillar), pupates into a chrysalis, and emerges from that as an adult. Many moth and butterfly eggs synchronize their hatching with leaf-out. Leaves sprout out tiny; On oak trees they're called "mouse ears." The new leaves not only look like tiny mouse ears, but they're as soft as them, too. Plants have cell walls that protect the nutritious insides. Many tiny, newly hatched caterpillars would have trouble eating through the cell walls of full-grown tree leaves to get at the nutritious food inside, but right when the leaves emerge, before the cell walls are firm and strong, these tiny caterpillars can munch on them easily. As the leaves grow and get tougher, the caterpillars are growing, too, their jaws becoming stronger. Warblers fuel their migration in part on hatching caterpillars. If they arrive a day or two before leaves have emerged and caterpillars hatched, the warblers stay near water, where the abundance of emerging aquatic insects can sustain them as they wait for their real food supply. But most warblers arrive just as trees are leafing out. Try This! Field Study and Journaling In your field notebook, make 5 columns and label them: Insects on tree leaves; Insects on tree bark; Insects on the ground; Insects in weeds; Insects in the air; Extremely tiny insects. Take your notebook outdoors and spend 30 minutes searching for insects. Whenever you see a new insect, make a tally mark in the corresponding column in your field notebook. Which kinds of insects are you best at finding? What kind of bird's life would you be best adapted for? In your journal, write what your life might be like if you were that kind of bird. for example, what new skills would you need? What skills do you have now that wouldn't help you as this kind of bird? How do birds that require insects insure that there will be enough food for them at their destination when they start their migration? So many different kinds of insects, and so many different kinds of birds to eat them! Learn about several insect-eating birds here: Going Buggy! Insect-eating Birds Copyright 2004 Journey North. All Rights Reserved. Please send all questions, comments, and suggestions to our feedback form