Data from: Investigating yellow dung fly body size evolution in the field: response to climate change?

Uncovering genetic responses to selection in wild populations typically
requires tracking individuals over generations and use of animal models.
Our group monitored the body size of one Swiss Yellow Dung Fly
(Scathophaga stercoraria; Diptera: Scathophagidae) field population over
15 years, including intermittent common garden rearing in the laboratory
to assess body size with minimized environmental and maximized genetic
variation. Contrary to expectations based on repeated heritability and
phenotypic selection assessments over the years (reported elsewhere),
field body sizes declined by >10% and common-garden laboratory
sizes by >5% from 1993 – 2009. Our results confirm the
temperature-size rule (smaller when warmer) and, albeit entirely
correlational, could be mediated by climate change, as over this period
mean temperature at the site increased by 0.5°C, although alternative
systematic environmental changes cannot be entirely excluded. Monitoring
genetic responses to selection in wild invertebrate populations is thus
possible, though indirect, and wild populations may evolve in directions
not consistent with strongly positive directional selection favoring large
body size.