Data from: The influence of ecological and life history factors on ectothermic temperature-size responses: analysis of three Lycaenidae butterflies (Lepidoptera)

Body size has been shown to decrease with increasing temperature in many
species, prompting the suggestion that it is a universal ecological
response. However, species with complex life cycles, such as
holometabolous insects, may have correspondingly complicated
temperature-size responses. Recent research suggests that life history and
ecological traits may be important for determining the direction and
strength of temperature-size responses. Yet, these factors are rarely
included in analyses. Here, we aim to determine if the size of the
bivoltine butterfly, Polyommatus bellargus, and the univoltine
butterflies, Plebejus argus and Polyommatus coridon, change in response to
temperature and whether these responses differ between the sexes, and for
P. bellargus, between generations. Forewing length was measured using
digital specimens from the Natural History Museum, London (NHM), from one
locality in the UK per species. The data were initially compared to annual
and seasonal temperature values, without consideration of life history
factors. Sex and generation of the individuals and mean monthly
temperatures, which cover the growing period for each species, were then
included in analyses. When compared to annual or seasonal temperatures
only, size was not related to temperature for P. bellargus and P. argus,
but there was a negative relationship between size and temperature for P.
coridon. When sex, generation and monthly temperatures were included, male
adult size decreased as temperature increased in the early larval stages,
and increased as temperature increased during the late larval stages.
Results were similar but less consistent for females, while second
generation P. bellargus showed no temperature-size response. In P.
coridon, size decreased as temperature increased during the pupal stage.
These results highlight the importance of including life history factors,
sex and monthly temperature data when studying temperature-size responses
for species with complex life cycles.