Male influence on the ovarian development of the crustacean parasite Bopyrina abbreviata (Isopoda, Bopyridae)

Abstract

The presence of a male in a population of terrestrial isopods can accelerate the onset of female reproduction, a feature that has been suggested also to occur in bopyrid isopods. This paper aims to estimate the influence of the male presence on the ovarian maturation of Bopyrina abbreviata. Females of B. abbreviata of different sizes were collected at Términos lagoon, Campeche, Mexico. The organisms were morphometrically classified as immature or mature, the male presence or absence at female's marsupium was recorded, and the degree of ovarian development was determined histologically. The internal organization of B. abbreviata agrees with that described for bopyrids and isopods in general. The ovarian cells originate from a dorsal lamina germinal layer that extends horizontally. The ovarian development of lone and paired immature females was classified as incipient and medium, respectively. In mature females it was classified as advanced, in the paired females and in the one lone mature female studied. The lone mature female differed from paired mature females only in the presence of reabsorption process in some oocytes located closer to the ventral wall of the ovary. Morphology variations between lone and paired females suggests that the presence of a cryptoniscus larva or a male between the female's pleopods stimulates the onset of reproduction and accelerates the ovarian development of B. abbreviata.