Buckley, Nicholas E. , Avila-Sakar, Germán .
Sex-Specific Resource Allocation: Indirect Costs of Reproduction in the Dioecious Shrub Ilex glabra.
Males and females of a dioecious species differ in resource allocation during reproduction. According to the resource allocation hypothesis, this reproductive dimorphism allows for tradeoffs to exist among functions other than those associated with reproduction such as growth and herbivore defense. However, not all studies on dioecious species have supported this hypothesis. One possible reason for this discrepancy is that resource allocation varies throughout life history and therefore influenced by factors such as current reproductive investment. We have conducted a field study using the dioecious shrub Ilex glabra to determine if there are indirect costs associated with different reproductive allocation and whether costs are influenced by the current reproductive status of the plant. In this species, male plants expend resources on a relatively large floral display relative to the female plant. However, post-flowering female plants may allocate resources towards fruit and seed production at a time when male plants no longer contribute resources towards sexual reproduction. Through partial and full defoliation treatments, herbivory damage assessment, and leaf demography we are testing whether there are tradeoffs between seasonal reproductive allocation, growth, and herbivore defense. Preliminary results indicate no significant difference in leaf size and herbivore damage between males and females at the time of flowering. However, a greater number of leaves per branch were produced by males between flowering and post-flowering periods indicating a difference in growth between genders. These results were not expected as males produce a larger floral display and develop a greater number of leaves at the time of flowering, suggesting that floral production among males is not limiting leaf growth.
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Primary Investigator Web Site
1 - Acadia University, Biology, 24 University Avenue, Wolfville, NS, B4P 2R6, Canada
2 - Mount Saint Vincent University, Biology, Bedford Highway, Halifax, NS, B3M 2J6, Canada
Presentation Type: Poster:Posters for Sections
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM