Notes on the behaviour of the portunid crab Charybdis longicollis Leene parasitized by the rhizocephalan Heterosaccus dollfusi Boschma

Abstract

A significant portion of the population of Charybdis longicollis (Decapoda: Portunidae) along the Mediterranean coast of Israel is parasitized by the rhizocephalan Heterosaccus dollfusi. The behaviour of the parasitized crabs, in different stages of infection, is examined and compared with the behaviour of nonparasitized crabs. Locomotion, rest, body-, egg- and parasite-grooming, digging and burying, courtship and mating are described qualitatively and analysed quantitatively under standardized conditions. Behaviour patterns of parasitized crabs lacking externae, either immature or scarred, were similar to those of nonparasitized crabs. The presence of externae was observed to modify digging and to inhibit burying behaviour. The presence of externae induces an imitation of egg-grooming behaviour pattern in both males and females. Externae-bearing crabs engaged in parasite-grooming more intensely than ovigerous crabs in egg-grooming.

Keywords :

• Charybdis
• Heterosaccus
• Rhizocephala
• parasitism
• behaviour