MATING STRATEGIES OF 2 PARASITIC COPEPODS, LERNAEOCERA-BRANCHIALIS (L) (PENNELLIDAE) AND LEPEOPHTHEIRUS-PECTORALIS (MULLER) (CALIGIDAE) ON FLOUNDER - POLYGAMY, SEX-SPECIFIC AGE AT MATURITY AND SEX-RATIO

Laboratory experiments demonstrated the potential for multiple insemination of females of both Lernaeocera branchialis (L.) and Lepeophtheirus pectoralis (Müller). While multiple insemination of females seems to be the rule in L. branchialis, it is probably rarer in L. pectoralis. This difference in female mating strategy may reflect differences in the life history of the two species. Males of both species are able to copulate with several females and survive for up to 75-100 days after maturity. In both species the males reach maturity faster than the females, and the sex ratio of broods equals 1. L. branchialis males seem to have a higher reproductive potential, take a shorter time to develop and have a shorter adult lifespan than males of L. pectoralis under the same environmental conditions. In both species the long lifespan of the males, the sex-specific developmental rates and the sex ratio may lead to an accumulation of sexually active males on the flounder host and thus increased competition for mates. This is particularly relevant in L. branchialis where few males leave their initial host after mating. Males of L. pectoralis have a much stronger tendency and ability to migrate between different host individuals. Males of L. pectoralis copulate with each female only once, and seal the genital openings of the female. The seal may remain on the female for as long as 1 month. Males of L. branchialis, on the other hand, do not seal the genital openings of the female, bust most males transfer several pairs of spermatophores to each female. The two male mating strategies may obstruct insemination of the female by other males, and both may thus reduce sperm competition. © 1990.