Rates And Prevalences Of Predispersal Seed Predation On Plant Communities Across A Latitudinal Gradient

Predispersal seed predation occurs whenever the seeds of a plant are consumed or otherwise killed before the fruit containing them is dispersed from the parent plant. Throughout the literature, there are many studies that focus on the interactions between one or a few predator species with one or two plant prey species. However, there are currently no studies that attempt to investigate the effects of predispersal seed predation on a community scale or across a latitudinal gradient. I hypothesized that certain predation patterns would lead to a stabilizing effect (diversity maintaining effect) on the plant diversity of a community. Four study sites were used for this research: Rector, Pennsylvania; Aguadilla, Puerto Rico; Oxapampa, Peru; and Bariloche, Argentina. At each of these sites I investigated whether the rates of predispersal seed predation differed between plant species of varying relative abundance, whether plants within larger patches of conspecifics experienced higher rates of predispersal seed predation, and if this form of predation increases in incidence or prevalence as one approaches the equator. My results show that predispersal seed predation rates increase as absolute latitude decreases, even with multiple plant genera being sampled across different latitudes, and was the only studied variable to be statistically significant. Host-specificity between insect predators and plant species is the norm and makes generalizing across communities difficult. Additional research must be done to further elucidate the potentially subtle ways that insect predispersal seed predators have on plant communities. Especially in the tropics, predispersal seed predation pressure on plant fecundity adds further importance to the negative density-dependent and diversity-stabilizing effects that birds and other dispersers have on plant communities.