Evolution in species and climate change
Predicting the consequences of rapid environmental change due to human activity on biodiversity is a critical global issue, but data is lacking on how quickly populations will evolve to escape extinction. Such evolution is especially important to specialist organisms that depend on other species as hosts or prey. The EU-funded CLIMADAPT (Testing the limits and potential of evolution in response to climate change) project studied the Brown Argus (Aricia agestis) butterfly. The species has experienced rapid expansion of its range in the UK, and is one of the few known to have adapted to climate change by shifting the use of its host plant. This ability makes A. agestis an important species for investigating how genetic variation underpins ecologically important traits in the field. It is particularly useful for studying host plant preference and fecundity, and range expansion in the face of an altered climate. CLIMADAPT researchers studied host plant preferences and the fecundity of individual females in experiments in garden conditions. They then analysed genetic variations within and among nine populations from both the established and new parts of A. agestis’ range. Results indicated that individual females from a single population may differ in their host plant preferences. The data also revealed significantly reduced levels of such within-population variation for preferences in newly established populations. This evolutionary shift and the associated reduction of variation may also limit future evolution in newly established populations living at the edge of their range. The phenotypic data on female host plant preferences under common garden conditions also provided a unique data set for testing phenotype-genotype associations using genome-wide sequence variation. Researchers individually sequenced large numbers of butterflies from each of the nine populations for high density genome-wide genetic loci (RADseq). The data was then used to investigate the genetic basis of host plant preferences and fecundity and test for adaptive differentiation in these traits together with range expansion. The integration of the large phenotypic and genetic datasets generated by CLIMADAPT will enable theoretical models of adaptation to be tested. It will also help to make useful predictions of how species and ecological communities may respond to man-made environmental change through evolutionary responses in their biotic interactions.
Keywords
CLIMADAPT, evolution, Aricia agestis, climate change, genetic variation, fecundity, genome-wide sequence variation, adaptive radiation
