The evolutionary potential of an insect invader under climate change

Although the impacts of climate change and invasive species are typically
studied in isolation, they likely interact to reduce the viability of
plant and animal populations. Indeed, invasive species, by definition,
have succeeded in areas outside of their native range and may therefore
have higher adaptive capacity relative to native species. Nevertheless,
the genetic architecture of the thermal niche, which sets a limit to the
potential for populations to evolve rapidly under climate change, has
never been measured in an invasive species in its introduced range. Here,
we estimate the genetic architecture of thermal performance in the
harlequin beetle (Harmonia axyridis), a Central Asian species that has
invaded four continents. We measured thermal performance curves in more
than 400 third‐generation offspring from a paternal half‐sib breeding
experiment and analyzed the genetic variance–covariance matrix. We show
that while the critical thermal limits in this species have an additive
genetic basis, most components of the thermal performance curve have low
heritability. Moreover, we found evidence that genetic correlations may
constrain the evolution of beetles under climate change. Our results
suggest that some invasive species may have limited evolutionary capacity
under climate change, despite their initial success in colonizing novel
environments.