The Janzen–Connell model predicts that common species suffer high seed predation from specialized natural enemies as a function of distance from parent trees, and consequently as a function of conspecific density, whereas the predator satiation hypothesis predicts that seed attack is reduced due to predator satiation at high seed densities. Pre-dispersal predation by insects was studied while seeds are still on parent trees, which represents a frequently overlooked stage in which seed predation occurs.
By quantifying pre-dispersal seed predation from ten Quercus serrata populations over two years according to three insect groups, Xiao et al. found that the overall population trend of negative density-dependent, pre-dispersal seed predation due to predator satiation limited the occurrence of Janzen-Connell effects on individual trees.
Xiao, Z., Mi, X., Holyoak, M., Xie, W., Cao, K., Yang, X., … Krebs, C. J. (2016). Seed–predator satiation and Janzen–Connell effects vary with spatial scales for seed-feeding insects. Annals of Botany, 119(1), 109–116. https://doi.org/10.1093/aob/mcw224