Mating behavior of the Iranian fiddler crab Austruca iranica Pretzmann, 1971 (Decapoda: Brachyura: Ocypodidae), with an emphasis on the mate choice of burrow-mating

Fiddler crabs exhibit two modes of mating: burrow and surface mating. In burrow mating, males wave and attract mate-searching females for mating inside their burrows, whereas in surface mating males search for and mate with females on the surface. We studied the reproductive behavior of Austruca iranica (Pretzmann, 1971), an Indo-West Pacific species, specifically female-mate choice with regard to the size of both male individuals and their burrows. We also compared the size of male and female burrows in the population. Austruca iranica performed both surface and burrow mating despite the different size of the burrow of the two sexes, within the semi-lunar tide cycles at the study site. There was strong size-assortative mating in burrow mating. Burrow-mating females generally chose larger males and wider burrows and even though chosen and rejected males were not different in burrow length, females sampled males with longer than average burrows. Surface-mating females also possessed burrows that were longer than those of the females in the population and this may have enabled them to mate on the surface and breed alone. Regardless of its similarities to some species that only perform burrow mating; the ecology of A. iranica has made it possible for this species to mate on the surface as well as in male-defended burrows. The choice of large males by burrow mating females may provide benefits to females from both the large male itself (e.g., protection) and his wider burrow (e.g., better incubation temperature).