Meeting Abstract

P3.160  Tuesday, Jan. 6  Plasticity of gender-biased behavior in the Julidochromis cichlid WOOD, K.J.**; ZERO, V.H.; RENN, S.C.P.; Reed College; Reed College; Reed College woodk@reed.edu

Most monogamous cichlids exhibit gender-biased social and parental behavior. Conventionally, males are larger and are more aggressive and territorial than females, while females provide the majority of direct parental care. This is the case in the African cichlid Julidochromis transcriptus. However, in the closely related Julidochromis marlieri, females are larger and the more aggressive sex. To determine the socio-environmental influences on this gender-bias reversal, we experimentally manipulated the relative sizes of monogamous pairs in both species. Then, using the freeware program Jwatcher, aggressive behavior was quantified continuously during 10-minute observations using a universal ethogram for all species and sexes. Aggression was measured both towards conspecifics on the other side of a clear divider and towards heterospecifics introduced to the tank. Males were found to be more aggressive overall in J.transcriptus, while females were more aggressive in J.marlieri. However, size-reversed pairs of both species were found to be behaviorally reversed in respect to aggression: female J.transcriptus and male J.marlieri showed more aggression than their mates. This work defines an interesting model with which to address the molecular and hormonal basis of gender-roles and gender-biased behavior. As cichlid fish enter the "post-genomic" era, it becomes possible to address these questions on a genome wide basis.