Not all exotic pollinator introductions are bad: an introduced buzz-pollinating bee Amegilla pulchra (Hymenoptera: Apidae) in Fiji indicates little potential for enhancing the spread of weeds

The Australian buzz pollinating bee Amegilla pulchra (Anthophorini) is now widespread in Fiji and represents a potentially major change to plant-pollinator networks. The introduction of a buzz pollinator into the Fijian ecosystem, which has no native buzz pollinators, may have especially important consequences because many pan-tropical weed species are from the Solanaceae and usually require buzz pollination for effective seed set. We examined floral visitations of three introduced bees, A. pulchra, Apis mellifera, Braunsapis puangensis and one native bee Homalictus fijiensis at 16 sites across Viti Levu, covering a total of 27 plant species and 165 bee-plant interactions. We did not observe any visits by A. pulchra to any solanaceous plants, but it was a frequent visitor to several introduced plants that do not require buzz pollination. Our results contradict recent studies that suggested that A. pulchra may enhance the spread of solanaceous weeds in Fiji. The majority of plants, however, received more visits from exotic bees combined than from the native H. fijiensis and indicate that exotic bees in Fiji may increase weediness of multiple exotic plants. Our results indicate the need to explore pollination networks to understand exotic pollinator influences on the spread of potential weeds.