Behavioral ecology in co-occurring territorial males of the pupfishes, Garmanella pulchra and Cyprinodon artifrons, at reciprocally asymmetric densities in a mangrove floodplain

Two cyprinodontids, Garmanella pulchra and Cyprinodon artifrons, coexist in a small mangrove floodplain on the Yucatan Peninsula, enabling comparison of male territoriality in two species with similar social structure and resource needs. There were two contrasting situations, one where territorial males of G. pulchra were several times more abundant than those of C. artifrons and one where the reverse was true. In both situations, the roughly circular breeding territories were non-overlapping intraspecifically and showed complete overlap interspecifically. Territories of both species were several times smaller in the situation where they were numerically dominant. In that situation, the territories of G. pulchra were about twice as large as those of C. artifrons and males of both species showed higher conspecific aggression, lower heterospecific aggression, more reproductive activity, lower feeding rates, and lower percentages of body fat. In both situations of relative density, the percentage fat content was orders of magnitude greater in C. artifrons than in G. pulchra, potentially reflecting higher rates of territorial male turnover in the latter. Social behavior in the wild, described for the first time for both species, generally conforms to typical cyprinodontid themes for territorial and reproductive behavior. There was no evidence, in G. pulchra, of the courtship dance, nor the overt, male parental care described for Jordanella floridae, a species once considered a congener.