Meeting Abstract

S4.9  Wednesday, Jan. 5  The neuroecology of competitor recognition GRETHER, Greg; Univ. of California, Los Angeles ggrether@ucla.edu

Territorial animals must decide whether to respond aggressively to intruders. Some intruders represent a competitive threat while others represent no threat or possible mating opportunities. Failing to evict resource competitors is costly but so is evicting potential mates and non-competitors. Thus, we can expect territorial animals to have well-developed competitor recognition mechanisms. In general, recognition systems involve at least three components: a phenotypic cue upon which recognition is based (e.g., odor, surface protein, color pattern), a recognition function or template, and a motor response (e.g., aggression). In the case of competitor recognition, the relevant phenotypic cues are often secondary sexual traits with age- and/or sex-limited expression. By virtue of common descent, closely related species often have similar phenotypes, and this can lead to confusion (misdirected aggression) when the species come into secondary contact. Competitor recognition errors have important ecological and evolutionary effects. Interspecific aggression may result in competitive exclusion of rare or behaviorally subordinate species, even in the absence of resource competition. Selection against interspecific aggression in zones of sympatry may cause species to diverge from each other in secondary sexual traits and recognition templates. Proximate mechanisms underlying competitor recognition undoubtedly constrain and shape these evolutionary responses, and this will be the main focus of my talk. Little is known about how competitor recognition systems work at the neural level, but some inferences about cue specificity and sensory integration can be drawn from simulated intruder experiments. Ontogenetic experiments have shown that imprinting on local cues is common, which may enable templates to track evolved changes in cues automatically. There are many avenues for further research on the understudied but important question of how animals recognize competitors.