Meeting Abstract

P1.148  Tuesday, Jan. 4  Leptin modulates mate choice permissiveness in the Plains spadefoot toad (Spea bombifrons) GARCIA, NW*; BURMEISTER, SS; PFENNIG, KS; University of North Carolina, Chapel Hill; University of North Carolina, Chapel Hill; University of North Carolina, Chapel Hill

In mammals, leptin has an important role in lipid homeostasis and is expressed almost exclusively by their fat cells. However, in amphibians and fish, leptin is expressed in a number of tissue types including heart, brain, liver, ovary, testis, and fat. Initial studies in amphibians have demonstrated some homologous functions for leptin (e.g., satiety), but the divergent tissue expression pattern in non-mammals suggests the hormone may be involved in a number of other physiological and behavioral processes that have not yet been investigated. To determine if leptin modulates mate choice behavior we manipulated leptin levels in the Plains spadefoot toad (Spea bombifrons) and measured mate preferences in 2-choice phonotaxis tests. In S. bombifrons, female mate preferences are influenced by body condition: poor condition females are more likely to prefer heterospecific mates than are good condition females. Because mammalian leptin is involved in signaling healthy condition via fat stores, we initially hypothesized that enhanced leptin would increase preference for conspecifics in poor condition females. Rather than enhance preference for conspecifics, however, exogenous leptin decreased preferences for conspecifics by causing the females to be random in their preference for conspecifics versus heterospecifics. In addition, leptin reduced the latency to choose a mate, suggesting that females became less choosy in the leptin treatment. Together these results suggest that anuran leptin increases permissiveness in mate choice. Because gonadal development is known to increases permissiveness in other species and anuran gonads express leptin, we hypothesize that leptin acts as a signal of egg maturity (i.e., readiness to mate), and influences mate preferences by heightening a female’s motivation to mate.