Tube-building behavior in Grandidierella, and two species of Cerapus

Abstract

Individuals of Grandidierella bonnieroides and Cerapus sp. R commence tube formation by enrolling themselves in a blanket of detritus and gluing together clumps of the material with strands of silk in a few minutes. The initial tubes are very ragged. G. bonnieroides then expands the initial tube by simply dragging in more detritus. In contrast, Cerapus sp. R. commences building an architectured tube outward from the ragged initial tube using very fine detritus collected either by grasping nearby benthic material or by filter feeding particles from the water column. The diameter of the nearly circular architectured tube is tailored very exactly to the height of the body for which we propose a formula. The more advanced Cerapus sp. K skips the initial phase of blanket-tube formation and only makes short architectured tubes as long as the body, carries these about in a fashion analogous to hermit crabs, and attaches them temporarily to epfloral-faunal substrates well above the sediment surface; therefore, no detritus masses are available to Cerapus sp. K. Tube-building in amphipods is roughly classified into 12 kinds having many subdivisions. Advancement of, or specialization in tube building, lacks apparent correlation with morphological advancement or systematic and evolutionary deployment.