Winter moth (Operophtera brumata) adaptation to climate change: Embryonic response to temperature

Climate change influences the seasonal timing of many organisms, but at different rates such that mismatches can occur between trophic levels. Increased winter temperatures caused winter moth egg hatching to advance, leading to a mismatch in timing between winter moth caterpillars and their food source young oak leaves. In response, winter moth egg development has genetically adapted to climate change. Eggs now need higher temperatures to complete development at a given time compared to 10 years ago, leading to a better match with oak bud burst.
To investigate how and when temperature influences embryonic development, an experiment was carried out. The aim of the experiment is two-fold, to determine (1) which stages of winter moth embryonic development can be distinguished, and (2) the effect of temperature in- or decreases on developmental rate in these different stages of development. In a split-brood design, sub-clutches of eggs were transferred from a baseline temperature of 10 degrees to a colder or warmer temperature for two weeks at different times during development. Before transfer and two weeks after transfer, eggs were fixated and imaged using confocal fluorescence imaging.

Here we present the first glimpses of winter moth embryonic development, a moth with an unusually long development of multiple months, and one of the few species that has been able to rapidly adapt to climate change.