Ecology, functional morphology, behaviour, and feeding in coral- and sponge-boring species of Upogebia (Crustacea: Decapoda: Thalassinidea)

Abstract

Species of Upogebia, commonly found as infaunal bioturbators of soft sediments in marine coastal environments, have been discovered inhabiting burrows in coral and siliceous demosponges on tropical reefs. Upogebia operculata is experimentally demonstrated to actively bore into the calcium carbonate skeleton of the coral Porites astreoides. An undescribed species of Upogebia burrows into the sponge Agelas sceptrum. Morphological and behavioural adaptations to these habitats are more striking in the coral-boring species, including the development of probable boring glands and an unusually shaped tail fan. Feeding and, as far as is known, life history are similar to those of the better-known mud-burrowing species. Neither species appears to gain any nutritional benefit from its host; appendage morphology, feeding behaviour, and gut contents are consistent with a suspension-feeding mode of life.