Global drivers of historical true fruit fly (Diptera: Tephritidae) invasions

Abstract

Given the high costs associated with fruit fly (Tephritidae) invasions, there is a need to better understand and predict the risks of future invasions. We assembled a global database of historical Tephritidae invasions with the objective to identify biological and socioeconomic drivers that explain invasions. We investigate the tendencies of certain species to invade and the characteristics of regions that make them more prone to invasions. Our database documented the occurrence (presence/absence) and status (native/non-native) of individual Tephritidae species in each country in the world. Values of several socioeconomic and environmental variables were also assembled and considered as explanatory variables. A generalized linear mixed-effects model framework was used to evaluate the utility of these variables for predicting the country-level occurrence of each species outside of its native range. A total of 44 species were identified as having been accidentally introduced. Most species of invading Tephritidae have established in five or fewer countries. The number of invasions has rapidly increased since the 1950s. Climatic similarity between native and invaded countries and gross domestic product of the invaded country significantly increased the incidence of invasion, whereas distance to the native range had a negative effect on the probability that a given country would be invaded. Our analysis revealed that both economic and biological factors explain patterns of historical Tephritid invasions. Despite the rising efforts to prevent new invasions, additional species may continue to invade, and many currently established species will likely continue to expand their ranges into new areas.