Flight-muscle Changes during Adult Life in a Scolytid Beetle

Abstract

IT has long been known that in ant and termite queens the wings are lost and the flight muscles degenerate after the mating flight. Recently, flight-muscle degeneration has been reported in aphids¹ and mosquitoes², although in the latter group further studies appear to be desirable³. In the Coleoptera, protection of the posterior membranous wings, when at rest, by the tough anterior wings or elytra makes possible utilization of confined habitats, such as burrows of various types, which are unavailable to many other winged insects. Whether or not such protection is related to loss or reduction of wings, the fact remains that in several families of this group flightless species have evolved⁴. Most of these species have membranous wings greatly reduced in size; but small wing muscles and other morphological indications of loss of the ability to fly have been noted in some instances where wings are normal. Certain species are variable with respect to capacity for flight, some individuals being able to fly although others are not. A seasonal change in flight muscles has been noted in a weevil, and evidence suggests that such a change occurs in certain water beetles.