Does the novel trait influence male success in competition over mates in year 2?
Male collared flycatchers that we found breeding after the treatment in year 2 had successfully passed two episodes of sexual selection. First, these males had regained their territories (i.e., an episode of male-male competition, see Pärt and Qvarnström, 1997, Qvarnström, 1997) and then attracted a female (i.e., an episode of mate choice). To test whether a male’s probability of breeding was influenced by the experimental treatment we performed a multiple logistic regression. The arrival date of males was included in the model because arrival date is likely to influence the intensity of competition over mates. Competition over mates is likely to increase as the number of available breeding sites and unpaired females declines during the course of the season. We found that a male’s probability to breed after treatment was influenced by an interaction between treatment and arrival date (Table 1). To visualize this interaction we divided males into two groups based on their arrival date (
