Folded Wings

Posted by John Blatchford Feb 22, 2007

Many adult insects have wings that are kept extended all the time. This allows them to fly away the moment they are threatened, and to move easily from place to place through the air.

Insects that are specialised for life on the ground (or even under water) need to protect their wings when they are not being used for flying, and this has lead to some interesting developments.

Earwigs provide an extreme example of an adult insect that has developed a long flexible body for easy movement through tight spaces. They have kept very large wings and have solved the problem of protecting them by folding them (as many as 40 times in some species) under small hard wing-cases.

Earwig wings are 'stable' in two configurations - folded and unfolded. The 'folded' state is the 'resting' state, and earwigs need to use their pincers to manipulate them into the 'unfolded' position. Once the earwig has finished flying a simple 'flick' allows the wings to snap back into the case. (Even the wings of dead earwigs will do this.).

Other insects have arrived at similar body plans, but a careful look at the details of wing folding allows us to see that these have come from a different ancestry. Rove Beetles look a bit like earwigs (without the pincers), but their wings - like those of all the beetles - need to be carefully folded up after flight. The 'natural' state is for a beetle's wings to be unfolded in 'flying mode'.

This detail of anatomy allows taxonomists to infer that these two groups of insects (the rove beetles and the earwigs) are not very closely related. They have simply arrived at very similar body-plans by adapting to very similar habitats.

This is a very common phenomenon - look for example at the wings of bats, birds , flying-fish and insects. They share similarities simply because they are all adaptations for flight - not because these creatures are closely related!