Thermal plasticity of gene expression in response to chronic versus acute temperature exposure in Pieris rapae

Understanding how thermal plasticity will contribute to the response of ectothermic species to climate change is an important goal for evolutionary ecology. However, it remains challenging to predict the influence of thermal plasticity on performance because the effect of temperature varies depending on the temporal scale at which it is manipulated. For example, chronic differences in temperature can lead to developmental plasticity in growth rate, while acute temperature exposures can cause an immediate physiological response. Additionally, there can be interactions across timescales, whereby the response to current temperature depends on the individual’s thermal history. While the importance of timescale to thermal plasticity has been demonstrated in many species, we still know little about the groups of genes that respond to temperature on chronic versus acute timescales. This is because many existing RNA-sequencing studies either focus on responses to short, stressful temperature exposures or confound responses to past versus immediate temperature conditions. Our study disentangles the effects of chronic versus acute temperature exposure on gene expression by manipulating both rearing and testing temperature conditions of Pieris rapae larvae. We found little overlap in the differentially expressed (DE) genes and enriched Gene Ontology terms associated with rearing versus testing temperature, demonstrating that different groups of genes respond to chronic versus acute temperature exposures. We also found that the expression of a small group of genes was significantly affected by the interaction of rearing and testing temperature, highlighting how thermal history can influence the gene expression response to immediate temperature conditions.