PARENT SESSION
Contributed Oral Session 42: Invasive Species: Competition
Tuesday, August 9, 8:00 AM - 11:30 AM, Meeting Room 516 D, Level 5, Palais des congrès de Montréal

Engineering enemy-free space: An invasive pest that kills its predators.

Suttle, Kenwyn ¹, ¹ Department of Integrative Biology, Berkeley, CA, USA

ABSTRACT- The biological invasion of the glassy-winged sharpshooter, Homalodisca coagulata, into French Polynesia presents a novel threat to Pacific Island ecosystems. Widely known as an agricultural pest because of its role as a vector of numerous lethal plant diseases, H. coagulata may pose a severe risk to arthropod predators on invaded islands in French Polynesia. Controlled feeding experiments revealed that island spiders can be killed following predation on H. coagulata, apparently by lethal intoxication. This is particularly surprising because H. coagulata is thought to feed exclusively on xylem fluids, which generally lack plant secondary chemicals. In the two spider species tested, approximately half of all individuals that attacked H. coagulata nymphs or adults died. As populations of this insect increase in size and range on invaded islands in French Polynesia, H. coagulata will increasingly encounter these and other arthropod predators, raising the possibility of population-level impacts on susceptible predator species. Field surveys of island spiders across nine sites on H. coagulata-invaded and -uninvaded islands suggest that the insect may already have impacted an endemic spider on at least one island.

Key words: glassy-winged sharpshooter, Homalodisca coagulata, Invasion