Female spadefoot toads compromise on mate quality to ensure conspecific matings

When high-quality conspecifics resemble heterospecifics, females may be una ble to engage effectively in both species recognition (identification of co nspecifics) and mate-quality recognition (identification of high-quality ma tes). Consequently, females that engage primarily in mate-quality recogniti on may risk heterospecific matings, and females that engage primarily in sp ecies recognition may risk mating with low-quality mates. I examined the ev olutionary consequences of this conflict between species and mate-quality r ecognition in spadefoot toads, Spea multiplicata. I compared mate preferenc es and the fitness consequences of these preferences in spadefoot toad popu lations that did and did nor overlap with congeners. In non-overlapping pop ulations, S. multiplicata females preferred an extreme call character resem bling that of heterospecifics, and they had more eggs fertilized. In overla pping populations, S. multiplicata females preferred those call characteris tics that were closest to the norm for their population, and they did not r eceive the benefit of enhanced fertilization success. Thus, S. multiplicata females appear to trade off species and mate-quality recognition, such tha t those cooccurring with heterospecifics forgo the benefits of high-quality matings to ensure conspecific matings. These results suggest that the inte raction between species and mate-quality recognition may influence mate cho ice decisions in important and nonintuitive ways.