Reproductive success of nesting male longear sunfish (Lepomis megalotis peltastes)

Summary

Although a few male longear sunfish nest solitarily, most territorial males excavate their nest in dense aggregations. The importance of sexual selection in the evolution of this breeding system was evaluated by 1) examining the influence of certain male and nest characteristics on spawning success and 2) by comparing the success of social and solitary nesters. Among group nesters, females spawned preferentially with males nesting early within a spawning period and occupying central nests. Male size and nest diameter were negatively correlated with nesting day and hence spawning success. However, female discrimination using these traits directly could not be demonstrated. The reproductive success of social and solitary males was compared by counting the larvae in their nests several days after spawning. Successful males (with larvae) were more likely than males without larvae to be encountered later in the breeding season and to nest in small groups or solitarily. Spawning period (of which there were 5 or 6 in a season) was significantly correlated with larval abundance in the nest, while male size was not. Social and solitary males were equally successful, but aggregations may nonetheless result from sexual selection: males unlikely to attract females may nest around more attractive males to steal fertilizations from them. High spawning synchrony may prevent attractive males from renesting elsewhere once other nesters aggregate around them.