Asymmetric reproductive interference between specialist and generalist predatory ladybirds
Article first published online: 26 APR 2012
© 2012 The Authors. Journal of Animal Ecology © 2012 British Ecological Society
Journal of Animal Ecology
Volume 81, Issue 5, pages 1077–1085, September 2012
How to Cite
Noriyuki, S., Osawa, N. and Nishida, T. (2012), Asymmetric reproductive interference between specialist and generalist predatory ladybirds. Journal of Animal Ecology, 81: 1077–1085. doi: 10.1111/j.1365-2656.2012.01984.x
- Issue published online: 7 AUG 2012
- Article first published online: 26 APR 2012
- Received 4 October 2011; accepted 22 February 2012 Handling Editor: Stewart Plaistow
- host specialization;
- interspecific competition;
- mating preference;
- species coexistence;
- species recognition
1. Closely related species often differ greatly in the quality and breadth of resources exploited, but the actual mechanisms causing these differences are poorly understood. Because in the laboratory specialized species often survive and perform as well or better on host species that are never utilized in nature, negative ecological interactions restricting host range must exist. Here, we focused on reproductive interference, which has been theoretically predicted to drive niche separation between closely related species with overlapping mating signals.
2. We examined the interspecific sexual interactions in relation to ecological specialization and generalization in two sibling ladybird species, Harmonia yedoensis and Harmonia axyridis. Harmonia yedoensis is a specialist predator that preys only on pine aphids, which are highly elusive prey for ladybird hatchlings, whereas H. axyridis is a generalist predator with a broad prey and habitat range.
3. We experimentally showed that conspecific sperm fertilized the vast majority of eggs regardless of mating order (i.e. conspecific sperm precedence) when a female of H. yedoensis or H. axyridis mated with both a conspecific and a heterospecific male. Moreover, we demonstrated that mating opportunities of H. yedoensis females strongly decreased as heterospecific density increased relative to conspecific density. In contrast, in H. axyridis, female mating success was high regardless of conspecific or heterospecific density.
4. Our results suggest that the generalist H. axyridis should be dominant to the specialist H. yedoensis in terms of reproductive interference. Our results support the hypothesis that asymmetric reproductive interference from the dominant species may force the non-dominant species to become a specialist predator that exclusively utilizes less preferred prey in nature.