Exploring male spatial placement strategies in a biologically plausible mating task

The strategies employed by animals to choose mates can have significant consequences for individual fitness and also profoundly influence evolutionary processes. Female choice of mates has been a research focus, but males can also influence outcomes in many situations. We have developed an agent-based model to explore how internal and external variables may interact in treefrogs to alter the mating task and the ultimate quality of mates that both males and females find. In this paper, we investigate specifically strategies males may use to place themselves in the landscape and the effectiveness of those strategies in attracting females. Our simulated swamp environment contained stationary calling male treefrog agents, wandering male agents (searching for territories near other males), and female treefrog agents (searching for calling male mates). Wanderers and females used one of two possible search strategies to find males to mate with or settle by: a closest-above-a-minimum-threshold (min-threshold) strategy or a best-of-closest-S (best-of-n) strategy. We found that the mean quality of mated pairs is highest when both males and females use the best-of-n strategy, despite using it for different purposes. When the initial proportion of wanderers in the population is high, females see significant benefits in male mate quality when they are using the min-threshold strategy, compared to when the proportion is low. As well, the number of agents that mate at all falls sharply when male agents are using the min-threshold strategy with many initial wanderers. Thus, we find a complex interaction between individual internal variables (strategy choice) and external variables (behavior of conspecifics) that can lead to exciting new empirical studies on treefrogs in nature.