Male Spawning-Partner Preference in an Arena-Breeding Teleost Cyprinodon macularius californiensis Girard (Atherinomorpha: Cyprinodontidae)

Abstract

In a free-choice situation, both large (38.0-40.0 mm) and small (30.0-33.0 mm) male Cyprinodon macularius californiensis courted and spawned with larger females significantly more than with equal-sized or smaller females. Equal-sized females initially elicited high levels of courtship from large males but were ignored thereafter. Smaller and equal-sized females elicited high levels of aggressive behavior from males of both size classes, while larger females were not chased at all. In view of the log-linear relationship between length and fecundity in teleost fishes with an indeterminate growth pattern, the preferences shown in courting ripe females can be explained as a means of maximizing payoff in the number of zygotes fertilized by a given male per effort expended in courtship. The pattern of aggressive behavior that emerges is explained most parsimoniously in terms of an adaptation that maximizes the survival of eggs already present in a male''s territory.