Abstract

Acanthephyra pelagica is a deep-sea pelagic shrimp with a global distribution. Mating has never been observed in this species as its pelagic lifestyle makes direct observations difficult. Multiple paternity has been reported for many other crustaceans, although not for deep-sea shrimp species like A. pelagica. Here we used four polymorphic microsatellite loci to test for multiple paternity. We genotyped the mother and a maximum of 63 of her brooded embryos in 19 ovigerous females, all of which exhibited evidence of multiple paternity; the frequency of multiple paternity is thus deemed to be close to 100 % in this species. The number of males contributing to each brood varied between 2 and 4 with evidence of pronounced reproductive skew suggesting the potential importance of mating order, different sperm contribution, the existence of pre-copulatory female choice, or post-copulatory sperm competition or selection. Our results with respect to multiple paternity, together with the size patterns, suggest a pure-search mating system. Our findings on the mating system of A. pelagica contribute to a better understanding of the reproductive behavior of this species.