Data from: Does thermal plasticity align with local adaptation? – An interspecific comparison of wing morphology in sepsid flies

Although genetic and plastic responses are sometimes considered as
unrelated processes, their phenotypic effects may often align because
genetic adaptation is expected to mirror phenotypic plasticity if
adaptive, but run counter to it when maladaptive. The magnitude and
direction of this alignment has further consequences for both the tempo
and mode of adaptation. To better understand the interplay between
phenotypic plasticity and genetic change in mediating adaptive phenotypic
variation to climate variability, we here quantified genetic latitudinal
variation and thermal plasticity in wing loading and wing shape in two
closely related and widespread sepsid flies. Common garden rearing of 16
geographical populations reared across multiple temperatures revealed that
wing loading decreases with latitude in both species. This pattern could
be driven by selection for increased dispersal capacity in the cold.
However, although allometry, sexual dimorphism, thermal plasticity and
latitudinal differentiation in wing shape all show similar patterns in the
two species, the relationship between the plastic and genetic response
differed between them. While latitudinal differentiation (south to north)
mirrored thermal plasticity (hot to cold) in Sepsis punctum, there was no
relationship in Sepsis fulgens. While this suggests that thermal
plasticity may have helped to mediate local adaptation in S. punctum, it
also demonstrates that genetic wing shape differentiation and its relation
to thermal plasticity may be complex and idiosyncratic, even among
ecologically similar and closely related species. Hence, genetic responses
can, but do not necessarily, align with phenotypic plasticity induced by
changing environmental selection pressures.