Abstracts (first author)
Should males invest more because they are fathers? Or are they fathers because they have invested more? The effect of male allocation in parental and reproductive efforts on paternity
Although it has long been argued that males should adjust their parental behavior in response to female promiscuity level, empirical data does not support a general pattern of males behaviorally decreasing their parental effort in response to decreases in certainty of paternity. Here, we propose an alternative explanation, considering that male parental investment may have, in fact, played a more decisive role modulating paternity level over evolutionary time. In this sense, we predict that males experiencing high costs associated to care have been under stronger selective pressures favoring the evolution of post-copulatory processes that bias paternity towards parental males, in comparison to males that invest little in parental care. Although several game theoretical models evaluated the trade-off between pre-copulatory competition for mates and sperm competition, the additional component of male parental care has been largely neglected. Therefore, focusing in species with male-only care, in which females usually mate multiply and sperm transference is required by males prior to oviposition, we ask how males should allocate energy between mating effort, sperm expenditure and parental care. We extend previous sperm competition models and report the results of new theory investigating specifically: (a) whether the evolutionarily stable sperm allocation pattern can also explain the positive correlation between paternity and paternal effort predicted by classical theory; and (b) how female choice affects male allocation patterns.