Male age and color pattern predict female remating behavior in a polyandrous butterfly

Paola Calderon-Oñate , Mathieu Joron, Owen W. Mcmillan, Catarina Vila-Pouca 

In polyandrous insects, females can mate with multiple males to improve their fitness. A female's decision to remate may be shaped not only by the phenotype of the available male, but also by the attributes of her previous mate. For example, females may become increasingly choosy and ‘trade-up’ male quality with successive matings. In this study, we investigated how male age, size, and wing color pattern affect female multiple mating decisions in Heliconius numata, a butterfly species with remarkable variation in wing coloration within populations. In H. numata, matings between individuals with the same wing coloration (assortative mating) produces fewer viable offspring than matings between individuals with different coloration patterns (disassortative mating). Despite this, we found no evidence that females preferred to remate with males bearing different color patterns, as predicted by the trade-up hypothesis. Instead, females of the two morphs (H. n. bicoloratus and H. n. euphrasius) showed a significant preference for remating with H. n. euphrasius males. In addition, the time between matings depended on the interaction between the morph of their first mate and the morph of the second male. Female remating behavior was influenced by the age of their first mate. Females that initially mated with older males remated sooner. Importantly, we found that remating frequency was globally low in both morphs. Our findings suggest that male wing color pattern and age influence female multiple mating behavior in H. numata, with females adjusting their sequential mating decisions based on traits of prior mates.