Contrasting Metatrochal Behavior of Mollusc and Annelid Larvae and the Regulation of Feeding While Swimming.

Contrasting Metatrochal Behavior of Mollusc and Annelid Larvae and the Regulation of Feeding While Swimming. Biol Bull. 2019 Apr;236(2):130-143 Authors: Strathmann RR, Brante A, Oyarzun FX Abstract Molluscan veliger larvae and some annelid larvae capture particulate food between a preoral prototrochal band of long cilia that create a current for both swimming and feeding and a postoral metatrochal band of shorter cilia that beat toward the prototroch. Larvae encountering satiating or noxious particles must somehow swim without capturing particles or else reject large numbers of captured particles. Because high rates of particle capture are inferred to depend on the beat of both ciliary bands, arrest of the metatroch could be one way to swim while reducing captures. Larvae in eight families of annelids arrest metatrochal cilia frequently during prototrochal beat, often over a large part of the metatrochal band and with the arrested cilia aligned near the beginning of the effective stroke. In contrast, metatrochs of veligers of gastropods and bivalves rarely arrested while the prototroch beat, and those arrests were more localized and variable in position. This difference in metatrochal arrest was unexpected under hypotheses of either a single origin of this feeding mechanism or multiple origins within each phylum. Although different in metatrochal arrests, larvae of both phyla can separate swimming from feeding while both prototroch a...
Source: The Biological Bulletin - Category: Biology Authors: Tags: Biol Bull Source Type: research