Meeting Abstract

P2.136  Wednesday, Jan. 5  Nectar Levels of a Highly Invasive Flowering Plant Species Correlate with Pollinator Size within Island Ecosystems in America and Eurasia BARTHELL, J.F.*; REDD, J.R.; CLEMENT, M.L.; HRANITZ, J.M.; PETANIDOU, T.; WELLS, H.; Univ. Central Oklahoma; Univ. Central Oklahoma; Univ. Central Oklahoma; Bloomsburg Univ. Pennsylvania; Univ. Aegean; Univ. Tulsa jbarthell@uco.edu

Nectar is a key reward for pollinators that visit flowering plants, and the role of nectar in attracting pollinators may be especially important in understanding the ecological mechanisms that underlie terrestrial plant invasions. Indeed, the average nectar volume available to pollinators among flowers at a given time (standing crop) is thought to direct the foraging behavior of pollinators such as bees. In the current study, we tested for a relationship between body size of bee pollinators and nectar standing crop levels in flowering plant populations. Our findings show significant differences in bee size (estimated by head capsule width) between experimental plots of the highly invasive plant species yellow star-thistle, Centaurea solstitialis. On average, larger bees showed a preference for plots with a higher standing crop. This difference was consistent between plots even when controlling for the effects of collector bias and the geographic locales (islands) where the plant is a native and a non-native species: Lesvos (Greece) and Santa Cruz Island (USA), respectively. Taxonomic diversity of bee species sampled among study plots demonstrate a bias by honey bees (Apis mellifera) toward high nectar standing crop, and other large-bodied species in the family Apidae showed the same preference. These results contribute to our understanding of how high nectar-producing invasive plant species, such as C. solstitialis, attract non-native pollinators to increase their reproductive success.