Author(s): John K Leiser, Murray Itzkowitz
We examined the breeding behavior of the endangered Comanche Springs pupfish ( Cyprinodon elegans ) during 3 separate breeding seasons in a pool of springwater originating in Phantom Cave, near Balmorhea State P ark, Texas, in relation to behaviors reported for the species in swift-flowing canals (Itzkowitz 1969). In the quiet pool, unlike in swift water, the breeding system was characterized by 3 different male mating tactics: territorial defense, satel- lite positioning, and sneak spawning. Although the breeding strategies adopted by the males were conditional, mating tactics generally reflected male size. Territorial residents were the largest, satellites were medium-sized, and sneakers were the smallest adult males observed in the population. Territorial males traversed the least amount of area, defending com- pact territories, while satellites and sneakers covered more area in attempts to spawn. Although preferred territories in swift water centered on algal mats, territorial residents in quiet water seemed to prefer territories around large rocks. Males defending rocks had higher reproductive successes than males occupying other substrate types. The flexibility of the males’ tactics was exhibited during one year of study when large males appeared to be absent from the population. During that year, medium-sized males switched from the satellite to territorial tactic, while small males remained sneakers.