Abstract
Climate change and biological invasions pose one of the greatest threats to biodiversity. Most analyses of the potential biological impacts have focused on changes in mean temperature, but changes in thermal variance may also impact native and invasive organisms, although differentially. We assessed the combined effects of the mean and the variance of temperature on the expression of heat shock protein (hsp90) in adults of the invasive fruit fly Drosophila melanogaster and the native Drosophila gaucha in Mediterranean habitats of central Chile. We observed that, under these experimental conditions, hsp90 mRNA expression was higher in the invasive species but absent in the native one. Apparently, the biogeographic origin and niche conservatisms are playing a role in the heat shock response of these species under different putative scenarios of climate change. We suggest that in order to develop more realistic predictions about the biological impact of climate change and biological invasions, one must consider the interactions between the mean and variance of climatic variables, as well as the evolutionary original conditions of the native and invasive species.
Highlights
The question about what makes an exotic organism a successful invader has been central in the fields of applied ecology and environmental protection the last decades (Kolar and Lodge, 2001; Seastedt, 2009)
We address the following questions: (1) Does the expression of transcripts encoding for hsp90 vary across mean temperature and thermal variance treatments? (2) Does the expression of transcripts encoding for hsp90 vary between native and invasive species? and (3) How does putative climate change interact with the biogeographic origin of native and invasive species in the expression of hsp90 mRNA?
In spite of the well-known role of climate change on biodiversity (Burroughs, 2007; Angilletta, 2009; Chown et al, 2010), the range of thermal conditions in time and space, its variability and how invasive and Statistical analysis of gene expression values was carried out using the REST 2008 program (Relative Expression Software Tool V 2.0.7; Corbett Research; Pfaffl et al, 2002)
Summary
The question about what makes an exotic organism a successful invader has been central in the fields of applied ecology and environmental protection the last decades (Kolar and Lodge, 2001; Seastedt, 2009). At individual level the search of traits that predict the invasive potential of a species spans from reproductive potential and foraging habits to environmental tolerances (Sol et al, 2012; Bates et al, 2013; Capellini et al, 2015) It is in the later where thermal physiology provides the conceptual framework needed to explain the success—failure pattern of exotic species over the thermal landscape. How it has been previously described (Helmuth et al, 2010; Bozinovic et al, 2011a,b; Estay et al, 2014), insights about the suitability of a thermal landscape for a given species should make reference to average values, and to the intrinsic variability of Ectotherms in Variable Thermal Landscapes perceived temperatures (Bozinovic et al, 2016a,b). This is a key point at predicting future changes due to climate change, where theoretical (Katz et al, 2005) and empirical approaches (Easterling et al, 2000) indicate that global warming impacts the mean temperatures, and the magnitude of dial and seasonal variation in temperature (Vazquez et al, 2016)
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