IIMYC   23581
INSTITUTO DE INVESTIGACIONES MARINAS Y COSTERAS
Unidad Ejecutora - UE
artículos
Título:
CALCIUM LEVELS IN THE VULVAR OPERCULA OF GRAPSOID AND OCYPODOID CRABS (DECAPODA: BRACHYURA)
Autor/es:
SAL MOYANO M. P.; MCLAY C
Revista:
JOURNAL OF CRUSTACEAN BIOLOGY
Editorial:
CRUSTACEAN SOC
Referencias:
Lugar: Lawrence, Kansas, USA; Año: 2016 vol. 36 p. 220 - 228
ISSN:
0278-0372
Resumen:
The derived condition in Brachyura is exhibited whenmating is not linked to moulting (i.e. hard-shell mating). Grapsoid and ocypodid crabshave this type of mating wherein females become receptive and have mobile vulvae covered by operculae without moulting. The mobilityof the operculae has been attributed to a decalcification process although it has never been demonstrated experimentally. We describedthe morphology of the vulvae (operculum and hinge) and measure calcium levels employing X-ray Energy Dispersive Spectroscopy ofthe intermoult immature and mature female of several different species of grapsoid crabs: Austrohelice crassa, Cyclograpsus lavauxi,Hemigrapsus crenulatus, Hemigrapsus sexdentatus (Varunidae), Guinusia chabrus (Plagusiidae), Leptograpsus variegatus (Grapsidae),and the ocypodid Hemiplax hirtipes (Macrophthalmidae). We measured calcium levels during a reproductive cycle in the case of H.sexdentatus. In all the studied species the opercula and hinge had lower calcium levels compared to the adjacent exoskeleton, and the hingeshowed the lowest values of calcium (9.7 and 40.8 weight%, respectively). Immature and adult crabs showed that the distribution of calciumremains the same after the pubertal moult as it was before. Furthermore, in H. sexdentatus, hinge calcium levels do not change during thefemale reproductive cycle when females become receptive. It is suggested that an alternative mechanism, not related to decalcification,could be involved in promoting mobility of the hinge in receptive females of these species. We need to modify our ideas of the processesinvolved in female receptivity in all these crabs with an operculate vulva and hence mate attraction. Answers to these questions are the keyto understanding how the linkage of mating to moulting was broken.