Temperature has an overriding role compared to photoperiod in regulating the seasonal timing of winter moth egg hatching

To accurately predict species’ phenology under climate change, we need to gain a detailed mechanistic understanding of how different environmental cues interact to produce the seasonal timing response. In the winter moth (Operophtera brumata), seasonal timing of egg hatching is strongly affected by ambient temperature and has been under strong climate change-induced selection over the past 25 years. However, it is unclear whether photoperiod received at the egg stage also influences timing of egg hatching. Here, we investigated the relative contribution of photoperiod and temperature in regulating winter moth egg development using two split-brood experiments. We experimentally shifted the photoperiod eggs received by 2-4 weeks compared to the actual calendar date and measured the timing of egg hatching, both at a constant temperature and in combination with two naturally changing temperature treatments – mimicking a cold and a warm year. We found an eight-fold larger effect of temperatu..., We investigated whether photoperiod received at the egg stage influences the seasonal timing of egg hatching in the winter moth, both as a cue on its own and in interaction with temperature. In two split-brood experiments, we determined egg hatching date after giving eggs either an early or late season photoperiod treatment, with naturally changing day lengths shifted 2-4 weeks earlier or later compared to the actual calendar date. Temperature was kept constant in the first experiment, while the second experiment also incorporated two naturally changing temperature treatments – mimicking a cold and a warm year – to investigate the relative contribution of temperature and photoperiod.
Eggs were collected from wild females (31 clutches and 20 clutches, for experiment 1 and 2 respectively), with each clutch of eggs split into sub-clutches and divided over the different photoperiod and photoperiod-temperature treatments. Raw egg hatching data (i.e. 2-3 observations per week of the number of..., , # Temperature has an overriding role compared to photoperiod in regulating the seasonal timing of winter moth egg hatching

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Raw data belonging to the manuscript \"Temperature has an overriding role compared to photoperiod in regulating the seasonal timing of winter moth egg hatching\". We investigated whether photoperiod received at the egg stage influences the seasonal timing of egg hatching in the winter moth, both as a cue on its own and in interaction with temperature. In two split-brood experiments, we determined egg hatching date after giving eggs either an early or late season photoperiod treatment, with naturally changing day lengths shifted 2-4 weeks earlier or later compared to the actual calendar date. Temperature was kept constant in the first experiment, while the second experiment also incorporated two naturally changing temperature treatments – mimicking a cold and a warm year – to investigate the relative contribution of tem...