Michael Singer, camille parmesan

This is a reponse to Kharouba and Wolkovichs (2020) review of consumer-resource phenological synchrony. They provide a valuable review and cogent advocacy for future work. However, they misunderstand and misinterpret examples from plant-insect interactions. Their detailed case study involves phenological synchrony/ asynchrony between spring hatching of Winter Moth eggs and budburst of their oak hosts. Published studies of this and other insect/plant systems are misinterpreted by applying a definition of phenological synchrony as "the situation in which the most energetically demanding period of the consumers life cycle overlaps with the period of resource availability." This definition works well for ornithologists, since parent birds require high caterpillar abundance when their chicks are most demanding. But for Winter Moth the crucial phenological event occurs when larvae are just hatched and least demanding of energy, not most demanding (see below). The important role of phenological synchrony in most insect-plant systems is to fit the life cycle into the available time, not to synchronize peak resource demand with peak availability. The same is true of the Bay Checkerspot butterfly, for which baseline data are available from 1968-71 and 1983-5, showing that a fecundity-mortality tradeoff generated a persistent, adaptive, phenological asynchrony between the insect and its hosts, killing 70-80% of larvae each year.

Kharouba HM, Wolkovich EM. 2020. Disconnects between ecological theory and data in phenological mismatch research. Nat Clim Chang 10: 406-415