There’s a recent post over there at Bug Girl’s Blog commenting upon sex duration time in stick insects. As Bug Girl noted, there’s quite some confusion at the starting point (a tweet) as to what may be considered actual mating from pairing duration, and even the numbers don’t seem to match between the sexy factoid and the litterature available source.
In this specific case, _pairing_ is indeed quite long (days if not weeks), while _intercourse_ occurs on much shorter timelines (my experience as a breeder is that it is usually around an hour in most pet species, though some species do it so late at night that you wouldn’t really care if the thing really happens provided you get eggs). So basically, instead of writing something like “Stick insects can have sex for around 1400 hours”, the issue would have been more obvious if the sentence were “Stick insects can have sex throughout their whole adult lifetime, like any sexual species”…
But let’s go back to pairing and sex duration. Sure, it’s risky* to mate, because it exposes you to potential predators in a situation where fleeing is somewhat complex. In fact, breeders would tell that unsticking from a stick insect partner can be quite fast, as they may regularly disturb mating pairs when changing their food.
And just as in many biological situations, there’s probably a tradeoff between risk taken and fitness effects, and there are two ways to increase siring success for a male: increasing copulation time and therefore sperms transferred to a female, or increasing pairing time with your partner (so that you control for other males coming in and messing out your own progeny probabilities). The later option is known as mate guarding (actually, one of the very first posts at Seeds Aside dealt with it).
I guess it’s not been really studied in stick insects, but there’s certainly a good opportunity to test this idea in this group. Indeed, many species can be bred quite easily, and there’s quite a good range for pairing duration, with some species staying as couples for weeks while others would not even be seen mating.
Theoretically, this would also potentially be a male-driven competition process, since females are facultative sexuals and can lay parthenogenetic eggs easily.
*well, for phasmids it’s also tricky —you have to catch up, or down, depending