Sib-mating avoidance Collet 1 Insects and incest : sib-mating tolerance in natural populations of a parasitoid wasp 1

1. Sib-mating avoidance is a pervasive behaviour that likely evolves in species subject to 5 inbreeding depression. Laboratory studies have provided elegant demonstrations of sib6 mating avoidance, but small-scale bioassays often minimize the costs associated with mate 7 finding and choice, which could lead to spurious findings. 8 2. We used the hymenopteran parasitoid wasp Venturia canescens as a model organism, 9 because previous laboratory studies revealed that sib-mating led to a 25% decrease in 10 fertile offspring, and that sib-mating was partially avoided. 11 3. Our study consisted of a mate choice experiment in laboratory cages to determine if kin 12 discrimination occurs in this species. We further performed a field study in which 86 wild13 caught males, 155 wild-caught females and their 226 daughters were genotyped at 14 eighteen microsatellite loci. With these data, we reconstructed the genotype of each 15 female’s mate and estimated the relatedness of each mating pair. 16 4. Mate choice experiments confirmed that females are capable of discriminating kin. Time 17 to mating depended on the frequency of female encounters with related and unrelated 18 males. Contrary to previously published results, however, no sib-mating avoidance was 19 Supprimé: , which 20 Supprimé: that are 21