Inbreeding, inbreeding depression, and infidelity in a cooperatively breeding bird.

摘要: Inbreeding depression plays a major role in shaping mating systems: particular, inbreeding avoidance is often proposed as mechanism explaining extra-pair reproduction socially monogamous species. This suggestion relies on assumptions that are rarely comprehensively tested: present, higher kinship between social partners increases infidelity, and infidelity reduces the frequency of inbreeding. Here, we test these using 26 years data for cooperatively breeding, bird with high female superb fairy-wren (Malurus cyaneus). Although inbred individuals were rare (∼6% offspring), found evidence nestling mass (but not fledgling survival). Mother-son pairings resulted 100% but pair did otherwise predict infidelity. Nevertheless, offspring less likely to be than within-pair offspring. Finally, environment (the number helpers group) affect coefficients or levels. In conclusion, despite some agreement necessary drive apparent scarcity events observed levels seem insufficient explain ubiquitous this system, beyond mother-son avoidance.