The relative costs and benefits of territorial defense and the two conditional male mating tactics in the Comanche Springs pupfish ( Cyprinodon elegans )

• Published in: Acta ethologica 2002-09, Vol.5 (1), p.65-72
• Main Authors: Leiser, John, Itzkowitz, Murray
• Format: Article
• Language: English
• Subjects: Aggressive behavior; Animal behavior; Animal populations; Animal reproduction; Breeding seasons; Fish; Reproduction; Spawning
• ISSN: 0873-9749; 1437-9546
• DOI: 10.1007/s10211-002-0066-1

We examined the aggressive costs and reproductive benefits of territorial defense and its alternatives in a population of the Comanche Springs pupfish (Cyprinodon elegans). The breeding system was characterized by three different male mating tactics: territorial defense, satellite positioning, and sneak spawning. The mating tactic adopted by males reflected the males' sizes. Territorial residents were the largest, satellites were medium-sized, and sneakers were the smallest adult males observed. Consistent with the hypothesis that primary mating tactics are relatively high-cost, high-benefit strategies, we found that territorial males engaged in a number of aggressive encounters but had higher reproductive successes than any other males. However, our observations did not support the premise that conditionally breeding males engage in relatively low-benefit, low-cost tactics. Medium satellites and small sneakers acquired fewer spawns than did territorial males, but both satellites and sneakers were involved in as much aggression as territorials. That is, the data supported the prediction that satellite or sneaker males with the inability to compete for territories would attempt to accrue some reproductive opportunities in the presence of territorial males despite the high costs of spending time on the breeding grounds. Adopting conditional tactics appeared to allow satellites and sneakers to make the best of a bad situation. During a subsequent breeding season, large males were absent from the population, and medium-sized males established territories. The aggressive behavior exhibited by medium residents was similar to the previous year, but these males did not acquire higher reproductive successes than medium satellites had. The implications of switching tactics and the influence of operational sex ratios on the costs and benefits of the male tactics are briefly addressed. [PUBLICATION ABSTRACT]