Meeting Abstract

P3.29  Wednesday, Jan. 6  Differing foraging responses by bees to the invasive thistle species Centaurea solstitialis L. in native (Greece) and non-native (USA) island ecosystems BARTHELL, John F.*; CLEMENT, Meredith L.; GIANNONI , Manuel A. ; LIU , Lucy ; PRESKY , Miyeon E. ; REDD , JeAnna R. ; RICCI , Paige R. ; STEVISON , Blake K. ; FREEMAN, Brett; PETANIDOU, Theodora; HRANITZ, John M.; WELLS, Harrington; University of Central Oklahoma ; University of Central Oklahoma ; University of Puerto Rico; University of North Carolina, Chapel Hill; SUNY College at Oneonta; University of Central Oklahoma ; Bloomsburg University of Pennsylvania; Oklahoma State University; University of Central Oklahoma; University of the Aegean; Bloomsburg University of Pennsylvania; University of Tulsa jbarthell@uco.edu

The honey bee (Apis mellifera L.) is among the most successful of terrestrial, multicellular invaders on the planet. As mutualists, honey bees also promote non-native plant species, including the noxious weed yellow star-thistle (Centaurea solstitialis L.), an invasive plant species that is common in the western USA. Honey bees and yellow star-thistle have not been studied from a biogeographic perspective as a means to understand their role as biological invaders. We have now done so in two island ecosystems: 1) the Northeast Aegean Island, Lesvos (Greece), where these species are native, and 2) Santa Cruz Island, Californa (USA), where honey bees and yellow star-thistle have been co-invasive species. We report herein on studies of foraging patterns of honey bees and solitary bees on Lesvos with reference to parallel studies on Santa Cruz Island (SCI). Our results show that yellow star-thistle is generally less attractive to honey bees on Lesvos relative to SCI, especially when in proximity to the competing flowering plant species Vitex agnus castus L. As shown in pairwise studies at these locales, yellow star-thistle is very effective in drawing bees from native plants in California but not so with honey bees in its native range in Greece. Our results therefore suggest that yellow star-thistle more effectively increased its range in California in the presence of honey bees and in the absence of natural enemies.