Insects evolved flight as plants grew taller

Insects developed wings before any other animals so they could keep up with the growing height of land plants, a new study suggests.

The discovery, by an international team of researchers, comes from a massive new analysis of insect genes which has provided the clearest picture yet of how and when insects evolved.

The research is published today in the journal Science.

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The fact that insect developed wings in the same hundred million years that taller plants grew is not strong evidence of a causal relationship. It is a reasonable speculation but the researcher and the author of this article have not sufficiently flagged that it is speculation. There would be no way to test that causal relationship genetically.

Wouldn’t building a ladder be easier

• Wouldn’t building a ladder be easier

Moths don’t get stuck in baths…

Basically, this study is about firming up the timing of wing-development using genetic analysis.

Insects are not typically well preserved in the fossil record. The earliest winged insect fossils date to 320 million years ago but it has been considered that there may have been earlier winged species that have not yet been found in the sparse fossil record. The range in which wings could have developed has been pegged at 390 to 320 million years ago.

The results of this genetic study indicate a date early in that period.

That’s the news.

It’s sort of weird that very many insects exist in both winged and wingless varieties. I’m thinking in particular ants and aphids, but it’s worthwhile to remember that the same also applies to locusts who start out as wingless hoppers, and to butterflies, moths, cicadas, flies and beetles that all have wingless larval stages. In every one of those cases, I suspect, the winged stage is relatively short-lived and is associated with sex.

AFAIK, nobody knows for sure which part of prehistoric insect anatomy the wings developed from.

> The results of this genetic study indicate a date early in that period.

That makes sense. Although in public perception evolution tends to lead from the less complicated to the more complicated, I’ve noticed in about 10% of cases this is not so, that in about 10% of cases evolution leads to forms that appear morphologically considerably simpler then their predecessors.

Applying this to insects, it seems a fair guess that wings developed very early and in some orders were later lost. The study seems to assume that bristletails and silverfish never had wings, which is a fair enough assumption, but they may have had wings that were later lost.