Data from: Male mate guarding in a polyandrous and sexually cannibalistic praying mantid

Sexually cannibalized males incur a significant fitness cost due to the
loss of future mating opportunities and are expected to evolve behaviors
to avoid or compensate for such costs. For example, partially cannibalized
males may exhibit mate guarding, in which they accompany the female to
prevent her from mating with another male. In some species, cannibalized
males prolong the duration of copulation. However, little is known about
the adaptive significance of the mating behavior of sexually cannibalized
males. We hypothesized that mating itself serves a mate guarding function,
and that behavioral change caused by cannibalism enhances the mate
guarding function. We tested these hypotheses using the polyandrous and
sexually cannibalistic praying mantid Tenodera angustipennis, with
decapitation as a model of sexual cannibalism. We compared latencies to
female mating with a rival male among three experimental treatments:
unmated treatment, noncannibalistic mating treatment, and cannibalistic
mating treatment. Mating itself delayed female remating, revealing its
function in mate guarding. Decapitated males exhibited a higher guarding
efficiency against rival males via firmer genital coupling. In addi- tion,
spermatophore attached to the female genital opening also delayed female
remating, revealing an additional function in postmating mate guarding.
Although copulation was prolonged due to decapitation, mating by a rival
male was not delayed compared to noncannibalistic mating, probably because
of weaker postcopulatory guarding. These findings suggest that greater
mate guarding by decapitated males during copulation was offset by
processes after copulation.