Postcopulatory sexual selection in tropical odonates

Odonates have been a model group to study sperm competition since the
discovering of their ability to remove sperm from previous matings using the
aedeagus. In a recent review of postcopulatory sexual selection and genital evolution
in this group, it was found that most of the studies so far are restricted to a small
number of species and families from temperate regions of Europe, North America
and Japan. For entire families we have no information at all about the possible
mechanisms of postcopulatory sexual selection, and this is especially true for
families restricted to tropical regions. In this talk, I present preliminary anatomical
evidence of sperm competition and its influence on genital evolution in tropical
families, with special reference to Polythoridae, Protoneuridae, Chlorocyphidae,
Perilestidae, Platystictidae and Megapodagrionidae. My own observations and
a review of the literature on reproductive behaviour in tropical forest odonates
indicates that mating frequencies are extremely low compared to temperate species:
in many species copulations are rarely seen, which suggest that the rendezvous
is far away from watercourses and/or population densities are low. I discuss future
avenues for research and highlights how tropical odonates might contribute to our
understanding of sexual selection.