Do all insects have wings?
Do all insects have wings? This question came up while I was at the University of Georgia Campus in Costa Rica this past February. We were enjoying a morning of "Insectorama!" which began, of course, with a discussion of "What is an Insect?". We started by making a list of basic identifying characteristics. All insects have an exo-skeleton along with the other creatures, such as arachnids and crustaceans, who also belong to the phylum Arthropoda. Translated from the Greek, arthropoda means jointed foot or leg. So add another identifying characteristic: all insects have jointed legs and, identifier number three, all insects have six of them. All insects have three main body parts: head, thorax and abdomen. Then we talked about wings: all insects have wings. But wait, no they don’t. Juvenile insect forms (nymphs and larvae) do not have wings. Then perhaps all adult insects have wings. But wait, they don’t either. Almost all do, but there are exceptions and in the short time I’ve been exploring insects, I’ve already come across two. And believe me they looked very peculiar when I first saw them. Truthfully, I wasn't sure what was so odd about them, until I stopped to carefully observe and notice that these insects didn't have wings.
Booneacris glacialis Pondicherry National Wildlife Refuge, New Hampshire August 2013
When I found this grasshopper, I was taken with it's flightless body. The fully visible, slender, jointed abdomen appeared graceful, beautiful in texture and color. I posted the photograph on BugGuide.net and quite reliably received an identification. (The people who oversee this website are terrific—very generous in sharing knowledge.) This is a female Booneacris glacialis -- a species of wingless grasshopper. Take another close look and notice she is missing something that she should have: she's missing two back legs. “Likely something like a bird or mouse grabbed the two legs, but only got the legs, while the hopper escaped. Could have happened during the last molt too. Sometimes a leg will get pulled completely off as the insect pulls out of the old skin, basically it gets stuck and won't come out. Could have been a curious young human too - they do that sort of thing sometimes.” explained the man who provided the insect's identity.
I came upon this flightless insect, also in New Hampshire, in August of 2012. I confess I was drawn in closer because I felt sorry for it: what a sad, heavy body I thought, and it moved so slowly I thought for sure it suffered from a poor self-image. When I downloaded the photograph I was able to find an identification. This is a species of oil beetle, and it is flightless. It doesn’t have the characteristic hard shell elytra that, on winged beetles, cover the entire abdomen protecting the flight wings underneath. Instead, it has a pair of shortened elytra – look closely and you can see one of them from the side. The beetle has no real use for them as there are no flight wings to protect.
I thought I'd close with a few favorite pictures of those flightless juveniles I mentioned at the beginning.
I love this juvenile grasshopper -- a flightless nymph. I don't know what stage it is in or what species it belongs to.
Caterpillars, the larvae of butterflies and moths, are probably the most well-known and, for many people, the most favored of all flightless juvenile insects. This is the larva of a black swallowtail caterpillar. I believe it is a 4th instar. One more stage to go before it pupates.
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