Variation in female choice of mates: condition influences selectivity

The occurrence and significance of variation in apparent mate choice within populations are poorly understood. While one possible explanation for variation is that individuals differ in their mate preferences, an alternative possibility is that individuals vary in their mate selectivity or ‘choosiness’: that is, some individuals may be willing to accept less attractive mating partners than are others. This latter possibility is likely to result from bidirectional mate choice and differential mating access of high- versus low-quality mating partners. Here we altered the physical condition of female zebra finches, Taeniopygia guttata castanotis, through modest trimming of their flight feathers to explore the possibility that individuals adjust selectivity in response to their own condition. We compared the selectivity of individuals with clipped versus intact wing feathers. Female finches spent less time associating with attractive males when their wings were clipped than when wings were intact. To ascertain whether their choices were influenced by the behaviour of stimulus males that perceived their altered status, we performed a companion experiment that measured male mate choice of females with clipped versus intact wings; no discrimination against clipped females was found. Collectively, these results indicate that a female's mate selectivity is dynamically adjusted based on her assessment of her own condition or mate-getting ability. Future studies that investigate the relationship between realized and ideal mate preferences are necessary to better understand preference functions and the genetic basis of mate preferences.