Increased pupal temperature has reversible effects on thermal performance and irreversible effects on immune system and fecundity in adult ladybirds

<p><span>The environmental conditions an organism encounters during development vary in their lasting impact on adult phenotypes</span><span>. </span><span>In the context of ongoing climate change, it is particularly relevant to understand how high developmental temperatures can impact adult traits, and whether these effects persist or diminish during adulthood. </span><span>Here, we assessed the effects of pupal temperature (17°C – normal temperature, 26°C – increased temperature, or 35°C – heat wave) on adult <em>Harmonia</em> <em>axyridis</em> thermal stress tolerance, immune function, starvation resistance, and fecundity. </span><span>Temperature during pupation significantly affected all investigated traits in fresh adults. Heat acclimation decreased adult haemocyte concentration, cold tolerance, and total egg production, and had a positive effect on heat tolerance and starvation resistance. The negative effects of heat acclimation on cold tolerance diminished after seven days. In contrast, heat acclimation had a lasting positive effect on adult heat tolerance. Our results provide a broad assessment of the effects of developmental thermal acclimation on <em>H</em>. <em>axyridis</em> adult phenotypes. The relative plasticity of several adult traits after thermal acclimation may be consequential for the future geographic distribution and local performance of various insect species.</span></p>