The roles of male size and female eavesdropping in divorce in the monogamous convict cichlid (Archocentrus nigrofasciatus, Cichlidae)

In this experiment we examined the roles of male size and female eavesdropping in divorce using the serially monogamous convict cichlid (Archocentrus nigrofasciatus) by testing predictions based upon the better option hypothesis of divorce. We tested the role of male size by exposing females to males that were 20-25% larger than their current mate or males that were similar size to their current mate. Female convict cichlids prefer larger males, therefore we predicted that the frequency of divorce would be higher when the alternate mate was larger than the current mate. We also examined the role of eavesdropping as a mechanism of female assessment of relative male quality. Females were either permitted to eavesdrop (males physically interacted) or females were unable to eavesdrop (males prevented from interacting). We predicted that female eavesdropping would result in greater frequency of divorce. We found that females chose divorce most often (50% ending in divorce) in the treatment where the alternate male was larger than the current mate and eavesdropping was permitted, whereas females never chose divorce in the treatment where the alternate male was similar in size to the current mate and the female was not permitted to eavesdrop. Although it had a mild effect, male size difference alone did not significantly increase divorce. When size difference was coupled with eavesdropping, however, females did significantly increase their divorce rates.