The duration of copulation correlates with other aspects of mating behaviour in Orthetrum chrysostigma (Burmeister) (Anisoptera: Libellulidae)

The behaviour of marked individuals of O. chrysostigma was observed at a small stream during 15 days in July, 1982, at Hunter’s Lodge, Kenya. In a 30 m length of stream there were normally 3 resident males. 2 of which held the same territories throughout the study period. Further males visited the stream intermittently, acting as wanderers or as satellites to resident males, and showing much less spatial constancy than residents. Females appeared at the stream at a mean rate of 0.34 per half-hour throughout each 7-hour "day". One territorial male obtained 44% of all observed copulations (total 27), while 37% of the copulations were shared between about 15 satellites and wanderers. Territorial males copulated 9 times as often as nonterritorial males but copulation in the latter lasted up to 17 times longer. The possible significance of long and short copulations for sperm competition is considered.