Genitalic changes related to oviposition in the terrestrial isopod Armadillidium vulgare (Latreille, 1804)

概要

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Females of the terrestrial isopod Armadillidium vulgare (Latreille, 1804) possess a pair of cuticular genitalia in the oviducts, which are renewed at each non-parturial molt. The genitalia consist of a distal segment surrounding the gonopore, and a cuticular tube lining the lumen of the oviduct. At parturial molt, however, adult females do not produce new genitalia. Their genitalia are only modified. Moreover, egg-carrying females possess new genitalia after each parturial molt. The timing of formation of new genitalia after the parturial molt is still indistinct. The process was investigated morphologically around the time of oviposition. After the parturial molt, females retain only the cuticular tubes of the old genitalia in the oviducts. Several hours after molting and just before oviposition, these cuticular tubes are cast off from the oviducts and a pair of oopores opens on the coxal plate of the fifth perionite. After oviposition, the oopores become gradually unobservable with time. New genitalia are not present in the oviducts until at least 24 hours after the parturial molt. The reconstruction of new genitalia seems to be associated with the disappearance of the oopores.