Sperm displacement ability in the damselfly Calopteryx haemorrhoidalis asturica Ocharan: no effect of male age, territorial status, copulation duration and syn-copulatory behaviour (Zygoptera: Calopterygidae)

During copulation and before sperm transfer, odon. 3 6 are able to manipulate rival sperm stored in the $ sperm storage organs (usually the bursa copulatrix and spermathecae). 3 3 of the territorial C. h. asturica use 2 mechanisms for this. Bursal sperm is removed physically whilst spermathecal sperm is displaced via aedeagal stimulation (through a series of abdominal flexions) of the $ sensory system that controls spermathecal sperm ejection. Most bursal sperm is removed but there is individual variation in spermathecal sperm displacement Previous results have found that this variation is related to aedeagal width. In this paper 4 variables that may also explain variation in spermathecal sperm displacement ability are investigated: 3 age and status (territorial and nonterritorial), duration of the sperm displacement stage and the number of aedeagal stimulatory flexions. Variation in the ability to displace spermathecal sperm, however, was not related to these variables. This suggests that variation in this ability is reliant only on 3 genitalic attributes, aedeagal width. These results are briefly discussed in terms of current theory of sexual selection as the process propelling genitalic evolution.