Fright and Fight: Role of predation and competition on mate search tactics of wild male zebrafish

Mate search tactics and association preferences among organisms in natural habitats can be dynamic and are determined by inherent trait preferences as well as the cost-benefit trade-offs associated with each mating decision. Two of the prime factors regulating mating decisions are the presence of competing conspecifics and predatory threats, both of which have important fitness consequences for the individual. We studied the influence of these two factors separately in mate search tactics and association preferences among zebrafish males. Male zebrafish were presented with a choice of two patches, consisting of different number of females, of which one patch was also associated with a predatory threat. We found that males made a preferential choice for the patch with more number of females only when the numerical difference between choices are starkly different, irrespective of the predatory threat associated with the patch. This points towards the role of numerical cognition in assessing cost-benefit tradeoffs in male zebrafish. We also studied the association preference of males in a multi-choice setup, consisting of four separate mixed-sex groups of zebrafish varying in densities. Our results showed that while test males preferred to visit the male-biased patches more often, they spent more time near female-biased patches or patches with equal sex ratio patches indicating the role of complex interplay of social cues in determining the associative behavior of males to a patch. This study, thus, sheds further light on the interactive roles of social cues and cognitive abilities in mate association patterns in this species.