Inbreeding and outcrossing in Yucca whipplei: consequences for the reproductive success of plant and pollinator

Unlike most pollinators, yucca moths are active pollinators of their host p lants. Females lay their eggs in the flowers they pollinate, and their larv ae feed solely on the resulting seeds. Previous evidence suggests that the yucca moth Tegeticula maculata avoids self-pollinating their host Yucca whi pplei. Other yucca moths may self-pollinate more frequently. When pollinati ng, yucca moths are also reported to fly large distances between plants, by passing neighbouring plants in the process. We experimentally verify the su ggestion of Pellmyr et al. that yucca is more likely to retain fruits from self-pollination if overall fruit set is low. Thus, selection on moths to a void self-pollinating should be density dependent. We found no evidence tha t mating with close neighbours resulted in inbreeding depression, thus the moth's long-distance flights between plants are yet to be explained.