Time constraints related to sexual maturation and prolonged copulation in the female-dimorphic damselfly Ischnura senegalensis


Yuma Takahashi, Graduate School of Life Sciences, Tohoku University, 6-3, Aoba, Aramaki, Aoba, Sendai, Miyagi 980-8578, Japan. Email: takahashi.yum@gmail.com


Time constraints are critical for reproductive success. To understand the spatiotemporal dynamics of morph frequency in the female-dimorphic damselfly Ischnura senegalensis, we compared two different morphs for two important time constraints on female reproductive output, i.e. post-emergence sexual maturation and prolonged copulation. The females of both morphs achieved sexual maturation 4–5 days after emergence, suggesting that the rate of sexual mutation does not result in morph-specific fitness. The copulation durations declined with the time of onset of copulation in both morphs. Consequently, all copulations terminated at approximately 12:00 hours. Because females show foraging and oviposition activity only after copulation, the copulation duration does not result in morph-specific time constraints. These two important time constraints do not account for morph-specific reproductive success and do not affect the evolutionary equilibrium of morph frequency in I. senegalensis.