Interactions between a pollinating seed predator and its host plant: the role of environmental context within a population
Article first published online: 22 JUN 2014
© 2014 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd.
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Ecology and Evolution
Volume 4, Issue 14, pages 2901–2912, July 2014
How to Cite
Ecology and Evolution 2014; 4(14):2901–2912
- Issue published online: 21 JUL 2014
- Article first published online: 22 JUN 2014
- Manuscript Accepted: 30 APR 2014
- Manuscript Received: 7 APR 2014
- Mountain Lake Biological Station
- Biology Summer Fellowship
- Darwin Fellowship
- Wylie Dissertation Fellowship
- NSF. Grant Number: DEB-0108285
- Hadena ;
- plant–insect interactions;
Plant–insect interactions often are important for plant reproduction, but the outcome of these interactions may vary with environmental context. Pollinating seed predators have positive and negative effects on host plant reproduction, and the interaction outcome is predicted to vary with density or abundance of the partners. We studied the interaction between Silene stellata, an herbaceous perennial, and Hadena ectypa, its specialized pollinating seed predator. Silene stellata is only facultatively dependent upon H. ectypa for pollination because other nocturnal moth co-pollinators are equally effective at pollen transfer. We hypothesized that for plants without conspecific neighbors, H. ectypa would have higher visitation rates compared to co-pollinators, and the plants would experience lower levels of H. ectypa pollen deposition. We predicted similar oviposition throughout the study site but greater H. ectypa predation in the area without conspecific neighbors compared to plants embedded in a naturally high density area. We found that H. ectypa had consistently higher visitation than moth co-pollinators in all host plant contexts. However, H. ectypa pollinator importance declined in areas with low conspecific density because of reduced pollen deposition, resulting in lower seed set. Conversely, oviposition was similar across the study site independent of host plant density. Greater likelihood of very high fruit predation combined with lower pollination by H. ectypa resulted in reduced S. stellata female reproductive success in areas with low conspecific density. Our results demonstrate local context dependency of the outcomes of pollinating seed predator interactions with conspecific host plant density within a population.