Meeting Abstract
Barnacles are sessile suspension feeders whose feeding efficiency and behavior is largely determined by the movement of water through their environment. In low flow environments, where particle capture is difficult, barnacles expend energy to feed actively, while in higher flow environments barnacles may feed passively which is more energetically efficient than active feeding. Many intertidal barnacles have been shown to switch between active and passive feeding modes as water velocities increase, but little is known about epibiotic species which are exposed to variable feeding currents and possibly display different behavior than intertidal species. To better understand the behavior of epibiotic barnacles, the sea turtle commensal Chelonibia testudinaria was raised to adulthood in the laboratory. Lab-reared adults (shell diameter = 12.63 ± 0.08 mm) were then subjected to a wide range of water velocities and their behaviors categorized and quantified with BORIS event logging software. Over the course of observation C. testudinaria displayed only passive feeding behavior, and at lower velocities, instead of switching to active feeding, did not feed at all. This species was most active between 20.63 and 53.59 cm s-1 as identified by logistic regression, a velocity range which correlates well with the average swimming speed of two common host species, loggerhead and green sea turtles, on which C. testudinaria resides. Lack of active feeding in this species may have evolved in concert with its epibiotic habitus, potentially making this species an obligate commensal, reliant on its hosts’ movement to provide flow for particle capture as adults.
