No trade-off between the size and timing of emergence in the damselfly, Calopteryx virgo L.

Many species of insects have been reported to show seasonally declining siz e at emergence. This has been explained as an adaptive response to time con straint between size and age at maturity (emergence). We studied seasonal v ariation in the size of damselfly Calopteryx virgo L. in six different cree ks in central Finland. The length of hind wings was measured for 942 males and 285 females covering the flying period from mid June to mid August. The length of the hind wings of damselflies did not decrease towards the end o f flying period in any river or either sex. In light of this study, seasona l reduction of body size is not a general phenomenon among odonates contrar y to common understanding.