Predicted decrease in global climate suitability masks regional complexity of invasive fruit fly species response to climate change

Abstract

Climate change affects the rate of insect invasions as well as the abundance, distribution and impacts of such invasions on a global scale. Among the principal analytical approaches to predicting and understanding future impacts of biological invasions are Species Distribution Models (SDMs), typically in the form of correlative Ecological Niche Models (ENMs). An underlying assumption of ENMs is that speciesenvironment relationships remain preserved during extrapolations in space and time, although this is widely criticised. The semi-mechanistic modelling platform, CLIMEX, employs a top-down approach using species ecophysiological traits and is able to avoid some of the issues of extrapolation, making it highly applicable to investigating biological invasions in the context of climate change. The tephritid fruit flies (Diptera: Tephritidae) comprise some of the most successful invasive species and serious economic pests around the world. Here we project 12 tephritid species CLIMEX models into future climate scenarios to examine overall patterns of climate suitability and forecast potential distributional changes for this group. We further compare the aggregate response of the group against species-specific responses. We then consider additional drivers of biological invasions to examine how invasion potential is influenced by climate, fruit production and trade indices. Considering the group of tephritid species examined here, climate change is predicted to decrease global climate suitability and to shift the cumulative distribution poleward. However, when examining species-level patterns, the predominant directionality of range shifts for 11 of the 12 species is eastward.Most notably, management will need to consider regional changes in fruit fly species invasion potential where high fruit production, trade indices and predicted distributions of these flies overlap.

Diamondback Moth, Plutella xylostella (L.) in Southern Africa: Research Trends, Challenges and Insights on Sustainable Management Options

“…However, temperature may differentially affect organisms, such that different insect pests (hosts) and their associated natural enemies may develop at different rates and thus affect host-prey/parasitoids synchronisation [26,33,50,51]. Extreme temperatures eliminate natural enemies that are susceptible to very high/low temperatures, whereas divergence from thermal preferences also disrupts the temporal and spatial synchronization of host/parasitoid phenologies, resulting in a high risk of challenging pest (host) outbreaks [34,35]. An increase in atmospheric carbon dioxide levels associated with global climate change may also reduce the efficacy of biological control agents against DBM by precluding or reducing the production of plants' secondary metabolites, which are necessary for the recruitment of natural enemies as part of the plants' natural defence mechanisms [52,53].…”

“…With a record of 0.5 • C regional temperature increase, [9,35,45,46] predicts a projected increase in temperature of 3-4 • C by 2080, reduced rainfall, and increased degree days, aridity index, and evapotranspiration gradients. These factors will increase stress on already debilitating horticultural ecosystems, especially pest management, through changed pest dynamics, spatio-temporal distribution and increased pressure.…”

“…Therefore, comparative abiotic stress tolerance studies will not only enable the determination of whether it is the host or the parasitoid that is at high risk of extinction due to the impact of climate change, but will also be necessary to improve parasitoid field fitness for future release programs. Insect thermal biology and the ability to predict the impact of climate change on insect species are some of the most noble research findings of our time, yet adequate utilisation of this knowledge to improve pest management is still lacking, especially in Africa [35,55]. In the case of DBM, IPM systems need to have climate-resilient parasitoids capable of absorbing the 'shock' associated with the environmental changes due to global warming as a critical component of a broader climate-resilient IPM-FFS pest management systems approach [26,55].…”

First report of tomato leaf miner, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), in Botswana

“…Furthermore, climate is changing [2], and in consequence, impact on the rate of biological invasions, insect distribution, abundance and impacts of such invasions on a global scale [3]. In Africa, the risk and rate of invasion has dramatically increased [1], with destructive insect pests like Chilo partellus Swinhoe [4], Prostephanus truncatus (Horn) [5], Phenacoccus manihoti Matile-Ferrero [6] and Bactrocera dorsalis (Hendel) [7] invading the continent over the past decades.…”

Drivers, impacts, mechanisms and adaptation in insect invasions

“…To address this, Gibert et al (2016) examined Drosophila species as model organisms for understanding rapid evolutionary adaptation during insect invasions. To better understand how invasive species may be influenced in future, and whether any common responses could occur, Hill et al (2016) report on how climate change may shape future invasions of tephritid fruit flies. They show that general patterns of geographic distribution responses hide species-specific complexity.…”