Latitude-associated evolution and drivers of thermal response curves in body stoichiometry

1. Trait-based studies are needed to understand the plastic and genetic responses of organisms to warming. A neglected organismal trait is elemental composition, despite its potential to cascade into effects on the ecosystem level.
2. Warming is predicted to shape elemental composition through shifts in storage molecules associated with responses in growth, body size, and metabolic rate. Our goals were to quantify thermal response patterns in body composition, and to obtain insights in their underlying drivers and their evolution across latitudes.
3. We reconstructed the thermal response curves (TRCs) for body elemental composition [C(carbon), N(nitrogen), and the C:N ratio] of damselfly larvae from high- and low-latitude populations. Additionally, we quantified the TRCs for survival, growth and development rates and body size to assess local thermal adaptation, as well as the TRCs for metabolic rate and key macromolecules (proteins, fat, sugars, and cuticular melanin and chitin) as t...