Data from: The contribution of spontaneous mutations to thermal sensitivity curve variation in Drosophila serrata

Many traits studied in ecology and evolutionary biology change their
expression in response to a continuously varying environmental factor. One
well-studied example are thermal performance curves (TPCs); continuous
reaction norms that describe the relationship between organismal
performance and temperature and are useful for understanding the
trade-offs involved in thermal adaptation. We assayed TPCs for locomotor
activity in a set of 66 spontaneous mutation accumulation lines in the fly
Drosophila serrata. Factor-analytic modeling of the mutational
variance-covariance matrix, M, revealed support for three axes of
mutational variation in males and two in females. These independent axes
of mutational variance corresponded well to the major axes of TPC
variation required for different types of thermal adaptation;
‘faster-slower’ representing changes in performance largely independent of
temperature, and the ‘hotter-colder’ and ‘generalist-specialist’ axes,
representing trade-offs. In contrast to its near-absence from standing
variance in this species, a ‘faster-slower’ axis, accounted for most
mutational variance (75% in males and 66% in females) suggesting selection
may easily fix or remove these types of mutations in outbred populations.
Axes resembling the ‘hotter-colder’ and ‘generalist-specialist’ modes of
variation contributed less mutational variance but nonetheless point to an
appreciable input of new mutations that may contribute to thermal
adaptation.