Climate Fact: Timing is Everything

In the Netherlands, the time that Winter Moth caterpillars hatch has traditionally corresponded to when their food source, oak tree buds, come out. These caterpillars can only survive two to three days without food, and if they hatch before the oaks bud, they will not survive. The average January through April 15th temperature has increased over the past three decades, while the number of frost days during these months has not. These trends have corresponded to little or no change in the timing of the oak bud burst, but a steady advance to earlier dates in the year of the timing of the winter moth hatching.

(Source: Visser, ME and Holleman, LJM. “Warmer springs disrupt the synchrony of oak and winter moth phenology.” Proc. R. Soc. Lond. B (2001) 268, 289-294.)