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Premise Herbivores directly influence plant reproduction by damaging reproductive tissue which reduces seed production in consumed plants. Consumption of reproductive tissue may also indirectly depress reproduction in unconsumed plants by isolating unconsumed individuals from prospective mates and reducing pollination. However, empirical support for such hypothesized indirect effects remains limited. Methods To investigate potential indirect effects of herbivory on mating opportunities and pollination, we quantified spatial patterns of white-tailed deer (Odocoileus virginianus) herbivory and reproductive outcomes in Lilium philadelphicum (Liliaceae). We mapped 708 flowering plants, monitored deer herbivory, and examined how distance to prospective mates influenced rates of ovule fertilization, a proxy for pollen receipt. Results Most floweringL. philadelphicum plants (83%) failed to produce seed. Deer consumption of flowers prevented seed production in 35% of individuals. The probability of deer herbivory declined with distance to flowering conspecifics. Sixty-five percent of the remaining, unconsumed plants failed to produce seed due to apparent pollen limitation. While ovule fertilization rates declined with multiple predictors quantifying distances to flowering conspecifics, isolation metrics that excluded plants consumed by deer significantly improved predictions of ovule fertilization. Conclusions Our results offer empirical support for the hypothesis that herbivory reduces pollination and seed production in unconsumed plants by altering spatial mating opportunities. This feedback between deer herbivory and distance-dependent pollination contributes to widespread reproductive failure in L. philadelphicum, though the extent to which deer reduce seed production varies with plant isolation. Herbivory may exacerbate pollen limitation in other species by isolating unconsumed plants from prospective mates.
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Data and code: Herbivory exacerbates pollen limitation by isolating unconsumed plants from prospective mates
Beck and Wagenius. Herbivory exacerbates pollen limitation by isolating unconsumed plants from prospective mates. Contains data and R code necessary to replicate figures and analyses presented in the manuscript. This data set includes spatially explicit data on multiple stages of reproduction for N = 708 Lilium philadelphicum individuals. We documented spatial patterns of deer herbivory, capsule formation, and seed set enabling us to test how proximity to prospective mates influences both rates of herbivory and pollination as well as interactions between herbivory and pollination. We found rates of both deer herbivory and seed set increase when conspecific flowering plants are nearby. However, proximity to unconsumed neighbors better predicts variation in seed set than measures of proximity that include both consumed and unconsumed individuals revealing that deer exacerbate pollen limitation by increasing the distance to prospective mates. This finding reveals how herbivores can indirectly depress reproduction by altering the spatial distribution of prospective mates. This data set will be made publicly accessible as soon as the associated manuscript is accepted.
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- PAR ID:
- 10492284
- Publisher / Repository:
- figshare
- Date Published:
- Edition / Version:
- 1
- Subject(s) / Keyword(s):
- Population ecology
- Format(s):
- Medium: X Size: 129375 Bytes
- Size(s):
- 129375 Bytes
- Sponsoring Org:
- National Science Foundation
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