Meeting Abstract

72.2  Thursday, Jan. 6  Linking hydrodynamic stimuli and lateral line-mediated feeding behavior in a Lake Malawi cichlid BERGSTROM, MA*; WEBB, JF; University of Rhode Island; University of Rhode Island mbergstrom@my.uri.edu

The mechanosensory lateral line system of fishes is thought to form hydrodynamic images of disturbances to flow immediately around the body and can mediate behaviors including prey detection. Of the four types of lateral line canal systems found among teleost fishes, widened canals, the most taxonomically limited, are found in about ~12 families in benthic marine, mesopelagic, lacustrine, and stream habitats. It has been suggested that widened canals evolved as an adaptation for detection of hydrodynamic disturbances generated by prey. The peacock cichlids, (Aulonocara spp.) of Lake Malawi are thought to use their widened canals for detection of their benthic/infaunal invertebrate prey, but only recently has this been examined experimentally. To address this question, we characterized flow patterns generated by a tethered prey (adult Artemia) using digital particle image velocimetry. We analyzed the ability of A. hansbaenschi to feed on Artemia for 30 minutes under light or dark conditions with an intact or chemically ablated lateral line system (using cobalt [II] chloride) recorded using HD video. Live and a dead (fresh frozen) Artemia were tethered to each of six 4”x4” mesh platforms in a 2×3 grid submerged in the sandy substrate of a large experimental tank. The relationship between stimulus characteristics and several parameters of search and prey detection behaviors were evaluated. We have shown that A. hansbaenschi can localize and capture prey at night, non-visually using its lateral line system; this is not otherwise known among cichlids, and is not well studied among fishes in general. This study provides important insights into the functional and ecological significance of lateral line-mediated feeding behavior in species with widened lateral line canals. Supported by NSF grant IOS-0843307 to JFW.