Diurnal fluctuations in temperature are ubiquitous in terrestrial environments, and insects and other ectotherms have evolved to tolerate or acclimate to such fluctuations. Few studies have examined whether ectotherms acclimate to diurnal temperature fluctuations, or how natural and domesticated populations differ in their responses to diurnal fluctuations. We examine how diurnally fluctuating temperatures during development affect growth, acclimation and stress responses for two populations of Manduca sexta: a field population that typically experiences wide variation in mean and fluctuations in temperature, and a laboratory population that has been domesticated in nearly constant temperatures for more than 300 generations. Laboratory experiments showed that diurnal fluctuations throughout larval development reduced pupal mass for the lab but not the field population. The differing effects of diurnal fluctuations were greatest at higher mean temperature (30 °C): here diurnal fluctuations reduced pupal mass and increased pupal development time for the lab population, but had little effect for the field population. We also evaluated how mean and fluctuations in temperature during early larval development affected growth rate during the final larval instar as a function of test temperature. At an intermediate (25 °C) mean temperature, both the lab and field population showed a positive acclimation response to diurnal fluctuations, in which subsequent growth rate was significantly higher at most test temperatures. In contrast at higher mean temperature (30 °C), diurnal fluctuations significantly reduced subsequent growth rate at most test temperatures for the lab population, but not for the field population. These results suggest that during domestication in constant temperatures, the lab population has lost the capacity to tolerate or acclimate to high and fluctuating temperatures. Population differences in acclimation capacity in response to temperature fluctuations has not been previously demonstrated, but they may be important for understanding the evolution of reaction norms and performance curves. 

These two datasets for laboratory and field populations of Manduca sexta were collected as part of two experiments:  Experiment 1: Effects of temperature regimes on thermal reaction norms for pupal life history traits; Experiment 2: Effects of temperature regimes on later thermal performance curves for larval growth. See associated paper for details on experimental methods and data processing. A separate dataset for each experiment is provided. Individuals that did not survive to pupation are excluded from dataset 1; individuals that did not achieve positive growth rate during the test trial were excluded from dataset 2 (see the paper).

Each file includes a separate worksheet with a definition and description of each data field.  Missing value are indicated by NA.