A Comparative Bayes tactic for mate assessment and choice

Models of mate choice tactics have assumed that females randomly encounter males when collecting information and the information is perfect. Empirical observations of four bird species show that females selectively visit males and repeat visits to males before mating. This suggests that the assumptions of previous models have been too restrictive. An alternative model of information gathering and mate choice, which relaxes the assumptions of random encounters and perfect information, is presented. In this Comparative Bayes model, the decision of when and from whom to collect information is made using Bayesian estimates of each male's quality. Predictions from the model are that: (1) the occurrence of mate assessment will increase as initial uncertainty about the quality of males increases, as the cost of gathering information decreases, and as the signal perceived by the female becomes a better representation of males' actual qualities; (2) the occurrence of repeat visits to males will be highest when signals from males are of medium reliability; and (3) the decision of which male to assess will depend on the estimated qualities of males, prior certainty about each male's quality, the reliability of each male's signal, and the costs of assessment. Simulations compare the fitness outcomes of the Comparative Bayes tactic to other mate choice tactics. The fitness from the Comparative Bayes tactic is significantly higher than from the fixed threshold tactic and than from the best-of-n tactic when the cost of assessment is low.