Female-extended control over their reproductive investment: the role of early mating interactions on oocyte maturation in the terrestrial crustacean Armadillidium vulgare (Latreille, 1804)

In the terrestrial crustacean Armadillidium vulgare, the prolonged presence of males along with females is known to boost female reproductive physiology, and the so-called 'male-effect' was best characterized by a significant shortening of the pre-parturial intermoult (PPI) during which oocyte maturation spontaneously takes place. Continuous presence of a male over that period can speed up vitellogenesis and the moulting cycle, so to reduce female PPI by 15-20 days (shortening of 30-40%, in comparison to females reared with other females or in isolation, respectively). In the last investigation on the subject, we revealed that sexual interactions may start much sooner than previously thought in this species, and suggested that the observed 'male-effect' may likely result from early mating stimulations. Here we tested the specific effect of controlled mating interactions (one or two mating events at different times) on female PPI. We revealed that male presence for the time (about 2 h) that allowed a single mating to occur was enough to reduce the female intermoult by about 10 days (shortening of 19%, in comparison to females reared in similar conditions but in the absence of a mating interaction). Moreover, results indicate that the earlier and longer the copulations, the stronger the 'male-effect'. Altogether, the data support the conclusion that A. vulgare females are adjust their reproductive physiology according to the presence/absence and the intensity of male mating stimuli. We place the findings in a broader ecological context, revise the so far prevailing view on the 'male-effect', and stress its possible significance in relation to the occurrence of feminising bacteria in this and other terrestrial isopod species.