Anticipatory reproduction and population growth in seed predators

Mast seeding, the intermittent, synchronous production of large seed crops by a population of
plants, is a well-known example of resource pulses that create lagged responses in successive
trophic levels of ecological communities. These lags arise because seed predators are thought
capable of increasing reproduction and population size only after the resource pulse is available for
consumption. The resulting satiation of predators is a widely cited explanation for the evolution
of masting. Our study shows that both American and Eurasian tree squirrels anticipate resource
pulses and increase reproductive output before a masting event, thereby increasing population size
in synchrony with the resource pulse and eliminating the population lag thought to be universal in
resource pulse systems.