Community-wide masting improves predator satiation in North American oaks

Mast seeding, a phenomenon observed in numerous perennial plant species, is highly variable reproduction across years, synchronized among individuals within a population. One major fitness advantage of masting is the reduced seed predation rates, achieved through alternating seed scarcity and abundance that starve and subsequently satiate seed consumers. Proximately, the variability in seed production frequently correlates with weather conditions. Convergent responses among species to weather fluctuations often lead to synchronized masting events across species, which may help with predator satiation, but this hypothesis has rarely been tested. Here, we address this gap by using 23 years of seed production and pre-dispersal seed predation monitoring in three North American oak species ( Quercus rubra , Quercus alba , Quercus montana ). We found that spring and summer weather patterns correlated with masting events in all three species, resulting in intraspecific synchrony levels ranging from 0.21 to 0.38, depending on the species pair. Intraspecific masting synchrony facilitated efficient insect starvation in Q. rubra and Q. alba , while community-wide mast years were necessary for satiation in Q. montana . Our findings present a rare empirical test supporting the hypothesis that intraspecific masting synchrony enhances reproductive efficiency by minimizing seed losses to generalist pre-dispersal seed predators. Improved seed survival via community-wide masting implies that stands with diverse oak species may have improved regeneration potential, suggesting management options for increased seed supply. • Mast seeding is variable reproduction over years, synchronized in populations. • Masting reduces seed predation by alternating seed scarcity and abundance. • Weather impacts seed production, synchronizing masting events across species. • A 23-year study shows intraspecific masting synchrony aids predator satiation. • Stands with diverse oak species may have improved regeneration potential