High nitrogen loading impacts the temperature-size rule and heat tolerance in a nettle-feeding butterfly

Host-plant quality and ambient temperature are key environmental drivers of herbivorous insect performance, affecting growth, development, and survival. While temperature accelerates physiological processes in ectothermic insects, nutrient limitation in host plants can constrain insect herbivore fitness. Yet, few studies have examined how these two factors interact to shape insect herbivore performance. We experimentally quantified the combined effects of host-plant stoichiometry and rearing temperature on the larval growth rate, development time, and adult heat tolerance of the Map butterfly (Araschnia levana L. 1758). Caterpillars were reared on Stinging nettle (Urtica dioica L.) cultivated under three nutrient addition regimes differing in N:P ratios—to alter the nutrient stoichiometry of their host plants—and under two diurnally fluctuating temperature regimes simulating ambient (day-night: 21 °C/12 °C) and elevated (day-night: 24 °C/16 °C) conditions. Both temperature and host-plan..., , # High nitrogen loading impacts the temperature-size rule and heat tolerance in a nettle-feeding butterfly

Dataset DOI: [10.5061/dryad.jsxksn0r1](https://doi.org/10.5061/dryad.jsxksn0r1)

## Description of the data and file structure

During the experiment, caterpillars of *Araschnia levana* were reared on stinging nettle (*Urtica dioica*) leaves, which received three different fertilization treatments, and reared under two different climate conditions. During the run of the experiment, caterpillars were weighed every couple of days, and pupation, as well as emergence day, were recorded. The fresh weight of both pupae and adults was determined.

Once adult butterflies had emerged, adult heat tolerance was determined. After adult butterflies were dried, their total dry weight and abdomen dry weight were determined. 

For the leaves of *U. dioica*, the elemental composition was determined every couple of days and at the end of the experiment, especially focusing on C:N:P ratios.

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