Questions about mast-building amphipods and attempts to clarify them

Abstract

The behavioral features of clinging to a self-constructed mast-like structure have been described in eight species belonging to three genera of gammarid amphipods in the family Dulichiidae. The mast is usually composed of mud and amphipod feces and constructed with the aid of ‘amphipod silk’ spun out from the dactyli of pereopods 3 and 4. The major function of masts is believed to be the provision of conditions to optimize suspension-feeding. However, there are many questions about mast-building that remain to be determined, such as the reason for the presence of diatoms within the muddy material of masts and the way by which these amphipods avoid predation. Masts appear to be constructed mainly by adult females and guarded as territory for their reproduction and care of young. Dulichia species may culture benthic diatoms on the mast and provide as the food for adults and juveniles. Examination of the generating process and fiber structure of the amphipod silk threads will be useful for the development of new water-proof fiber materials.