Parasitism rate differs between herbivore generations in the univoltine, but not bivoltine, range

<p>With climate change, plant-feeding insects might increase their number of annual generations (voltinism). However, to what degree the emergence of a new herbivore generation affects the parasitism rate has not been explored. We performed a field experiment to test whether the parasitism rate differs between the first and the second generation of a specialist leaf miner (<em>Tischeria</em> <em>ekebladella</em>), both in the naturally univoltine and bivoltine parts of the leaf miner's distribution. We found an interactive effect between herbivore generation and geographical range on the parasitism rate. The parasitism rate was higher in the first compared to the second host generation in the part of the range that is naturally univoltine, whereas it did not differ between generations in the bivoltine range. Our experiment highlights that shifts in herbivore voltinism might release top-down control, with major consequences for natural and applied systems.</p>