Nest site selection in a terrestrial breeding frog: interrelationships between nest moisture, pH and male advertisement
© 2020 The Association for the Study of Animal Behaviour In resource defence mating systems where males control nest sites, complex interrelationships between nest characteristics and nest advertisement are likely to influence female mate choice. Surprisingly, however, we know little about the influence of such relationships on female mating decisions. In terrestrial-breeding oviparous species, one character likely to have a major influence on female nest site selection is nest moisture. In addition to influencing the susceptibility of eggs to desiccation, nest moisture also stands to influence nest pH and offspring fitness, as well as the hydration state of resident males, and their potential to advertise. Together, such interrelationships could strongly influence female mating decisions. The aim of this study was to use a long-term field study combined with a multivariate approach to investigate the combined influence of nest moisture, nest pH and male acoustic advertisement on female nest site selection in a wild population of red-backed toadlets, Pseudophryne coriacea. We found that females deposited more eggs in wetter and less acidic nests, and that these variables were positively correlated. Moreover, nest moisture and pH in combination were positively related to the calling potential of resident males, and nests that were advertised more often received more eggs. These results suggest that nest site selection in red-backed toadlets is influenced by a complex interplay between covarying nest characteristics that together influence male sexual signalling and nest advertisement. More broadly our findings highlight the potential for nesting behaviour to be mechanistically intertwined with mate choice.