Ontogenetic changes in the external anatomy of the parasitic castrator crab Calyptraeotheres garthi: implications for the timing of host colonization and sexual behaviour

OCAMPO EMILIANO; SPIVAK EDUARDO; BAEZA ANTONIO; LUPPI TOMAS

BIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY

WILEY-BLACKWELL PUBLISHING, INC

Lugar: Londres; Año: 2016

0024-4066

Pea-crabs are symbiotic crustaceans that live in association with a diverse array of macro-invertebrate hosts.Some pea-crabs exhibit an unusual and incompletely known post-larval cycle characterized by the alternation offree-life and symbiotic forms. We analyzed post-larval morphology, the allometry of various body parts, andsexual dimorphism in Calyptraeotheres garthi, an endosymbiotic pea-crab infesting the brooding chamber oflimpets in the southwestern Atlantic. In C. garthi, the smallest invasive crab moults into a male or female prehardstage, which is immediately followed by a hard stage. Then, hard-stage females, but not hard-stage males,pass through four post-hard stages before attaining a fifth terminal stage. The invasive and hard stages exhibitmorphological traits (plumose natatory setae on the legs, compressed body shape, and moderate or strongcarapace hardness) that likely permit them to swim efficiency while outside of hosts and entering and/or leavinghost individuals. In contrast, pre- and post-hard crabs are well endowed for an endosymbiotic lifestyle featuring asoft and rounded carapace, and slender appendages. The allometry of selected traits suggests that males attainsexual maturity during the hard stage and likely roam among host individuals in search of mating opportunities.It remains unclear at which moment females become sexually active and whether hard females abandon hostindividuals in search of sexual partners.