Meeting Abstract

P2.69  Sunday, Jan. 5 15:30  The use of 3D recording of fast-start escape response to study the evolution of placentation in Poeciliid fish QUICAZAN-RUBIO, EM*; FLEUREN, M; VAN LEEUWEN, JL; POLLUX, BJA; Wageningen University; Wageningen University; Wageningen University; Wageningen University elsa.quicazanrubio@wur.nl

Pregnancy is known to have a negative effect on the locomotor performance of females, exposing livebearing females to a higher risk of predation. It has recently been proposed that the placenta evolved in livebearing fish because it alleviates the costs of pregnancy on female locomotory ability, a hypothesis known as the ‘Locomotory Performance Hypothesis’ (Pollux et al., 2009). We test this hypothesis using the fish family Poeciliidae, where the placenta evolved at least 8 times independently. We will work with two closely related species from the genus Poeciliopsis that differ in the degree of post-fertilization maternal provisioning, yet have the same level of superfetation: the non-placental species Poeciliopsis gracilis and the placental species Poeciliopsis turneri. We will assess changes in the metabolic oxygen requirements using a closed respirometry system, and sustained (aerobic) swimming performance (Ucrit) of females throughout their pregnancy using a newly designed state-of-the art recirculating flow tunnel. The tunnel is designed such that fish will swim in the centre of the tunnel. A camera (topview, 500fps) is used to record tailbeat frequency and amplitude during the swimming trials. We will present some preliminary data on the effects of pregnancy on the oxygen consumption and sustained swimming performance of P. gracilis.