Data from: Thermal plasticity in protective wing pigmentation is modulated by genotype and food availability in an insect model of seasonal polyphenism

Phenotypic variation in natural populations results from complex
interactions between organisms and their changing environments. The
environment shapes both phenotypic frequencies (during adaptation) and
organismal phenotypes (through phenotypic plasticity). Developmental
plasticity, in particular, refers to the phenomenon whereby an organism’s
phenotype depends on the environmental conditions during development. It
can match phenotype to ecological conditions and help organisms to cope
with environmental heterogeneity, including differences between
alternating seasons. Experimental studies of developmental plasticity
often focus on the impact of individual environmental cues and do not take
explicit account of genetic variation. In contrast, natural environments
are complex, comprising multiple variables with combined effects that are
poorly understood and may vary among genotypes. We investigated the
effects of multifactorial environments on the development of the
seasonally plastic eyespots of Bicyclus anynana butterflies. Eyespot size
depends on developmental temperature and is involved in alternative
seasonal strategies for predator avoidance. In nature, both temperature
and food availability undergo seasonal fluctuations. However, our
understanding of how thermal plasticity in eyespot size varies in response
to food availability and across genotypes remains limited. To address
this, we investigated the combined effects of temperature (T; two levels:
20°C and 27°C) and food availability (N; two levels: control and limited)
during development. We examined their impact on wing and eyespot size in
adult males and females from multiple genotypes (G; 28 families). We found
evidence of thermal and nutritional plasticity and
temperature-by-nutrition interactions (significant TxN) on the size of
eyespots in both sexes. Food limitation resulted in relatively smaller
eyespots and tempered the effects of temperature. Additionally, we found
differences among families for thermal plasticity (significant GxT
effects), but not for nutritional plasticity (non-significant GxN effects)
nor for the combined effects of temperature and food limitation
(non-significant GxTxN effects). Our results reveal the context dependence
of thermal plasticity, with the slope of thermal reaction norms varying
across genotypes and across nutritional environments. We discuss these
results in light of the ecological significance of pigmentation and the
value of considering thermal plasticity in studies of the biological
impact of climate change.