Caribbean damselfish with varying territory quality: correlated behaviors but not a syndrome
The behavioral syndrome hypothesis suggests that individuals within a population behave differently due to specific behavioral types and these should be consistent in a variety of contexts. In contrast, for territorial animals that live in stochastic environments, natural selection should favor animals that show behavioral flexibility and can modulate behavior in relation to current territory quality. We examined the territorial behavior of a natural population of male beaugregory damselfish by enhancing territory quality using artificial breeding sites and comparing their behavior to males on lower quality natural sites. When male fish were defending high quality artificial territories, they had higher levels of aggression toward male conspecifics and courtship toward females than when on low quality natural territories. We also found that aggression and courtship behaviors were correlated on natural sites, but not artificial. Behaviors were not correlated when males switched from natural to artificial territories or from artificial to natural territories. These results indicate that males assess their current territories and adjust behaviors accordingly and that courtship and aggression behaviors are not linked within a permanent behavioral syndrome.
Differences in territory quality and subsequent behavioral changes of male beaugregory damselfish, Stegastes leucostictus
When territory quality can vary over time, natural selection should have favored animals with behavioral flexibility in order to modulate the cost of defense in accordance with territory quality. This requires assessment of the territory followed by appropriate types and intensities of behavior. We examined this hypothesis using male beaugregory damselfish by enhancing territory quality using artificial breeding sites and comparing their behavior to males on natural sites. Males on artificial sites reproduce at higher levels than males on natural sites. In Experiment 1, our aim was to determine if a behavioral syndrome existed between courtship and aggressive behaviors across different quality sites. We found that behaviors were correlated on natural sites, but not artificial. When changes in territory quality occurred, courtship and aggression were not correlated and males had high levels of behaviors on high quality (artificial) territories. These results indicate that males assess their current territories and adjust behaviors accordingly. In Experiment 2, the value of reproduction was explored by giving males a choice between courting a female (potential reproduction) or attacking an egg predator (potential loss of eggs). A significant interaction was seen between the territory type and the stimuli: males on natural sites spent more time courting females and less time defending, while males on artificial sites behaved oppositely. Thus, males defending low quality territories invest in courtship while devaluing the relative importance of an egg predator while males defending high quality sites invest more in repelling the egg predator than attracting the female.
Aggression & Courtship Behaviors of Beaugregory Damselfish on Different Quality Territories: Correlated Behaviors, But Not a Syndrome
Personalities, temperaments, or behavioral types have long been the interest of scientists and have been studied in more than 60 species, from ants to zebrafish. The behavioral syndrome hypothesis suggests that individual animals within a population behave differently because of their specific behavioral type or temperament and these behavioral types should be consistent across behaviors or in different situations. In contrast, when animals live within an environment in which territory quality can change over time, natural selection should have favored animals that show behavioral flexibility and modulate the cost of defense of the area in relation to territory quality. This would require assessment of the territory followed by displays of appropriate types and intensities of behavior. We examined the territorial behavior of male beaugregory damselfish by enhancing territory quality using artificial breeding sites and comparing their behavior to males on natural sites. Males on artificial sites reproduce at a higher level than males on natural sites. We found that when male fish were defending high quality artificial territories, they had higher levels of aggression toward male conspecifics and courtship toward females than when on low quality natural territories. We also found that behaviors were correlated on natural sites, but not artificial. Behaviors were not correlated when males switched from natural to artificial territories or from artificial to natural territories. These results indicate that males assess their current territories and adjust behaviors accordingly.
An Examination of Biparental Care by Convict Cichlids: Sex Differences in the Retrieval of Offspring
Parents do not always share offspring care equally and each parent often has a specialized role. The most commonly observed sex-typical roles are defense by males and direct care of the offspring by females. In our study of convict cichlids (*Archocentrus nigrofasciatus*) we examined the behaviors of each parent when non-swimming young were displaced from the nest. Parental care was measured using retrieval of offspring and agonistic behaviors toward potential offspring predators. We found that males were more likely to retrieve young displaced far from the nest, while females retrieved young at closer distances. Additionally, although we found that both parents do attack the potential predator (a conspecific individual), retrieval behaviors did not change for either parent. We also examined retrieval behavior when one parent was removed and found that the remaining male or female parent was able to perform all behaviors associated with parental care. These preliminary studies suggest that while there is plasticity in parental behavior of convict cichlids, when together, parents often assume sex-typical roles.
Does past experience with a male predict female mate choice in the convict cichlid?
In many monogamous species, both sexes compete for mates and demonstrate mate choice. However, the degree to which intrasexual competition limits the choice of the other sex may not be well known. In this study, we monitored the effects of past experience of male-male competition on the mate preference of female convict cichlids, Archocentrus nigrofasciatus. Females were allowed to interact with two size-matched males while they competed until a winner and loser could be determined. Females were then given a choice between a male she had had past experience with and a novel male. Females were placed in two treatment groups and given a choice between a novel male and 1) a male that had successfully competed against another male (winner) or 2) a male that had unsuccessfully competed against another male (loser). Males were isolated from each other in the experimental aquarium so that intrasexual selection after the initial interaction could not affect the females preference. Mate preference was determined by observing a time based preference of the female for a specific male. Over a ten day period, females showed a significant preference for a winner male as compared to a novel male. Females did not show a decreased preference for a loser male over a novel male. This study suggests that positive past experience may impact female mate choice, whereas negative past experience may have little or no affect.