Intraspecific variation in seed dispersal of a Neotropical tree and its relationship to fruit and tree traits.

The distribution of wind-dispersed seeds around a parent tree depends on diaspore and tree traits, as well as wind conditions and surrounding vegetation. This study of a neotropical canopy tree, Platypodium elegans, explored the extent to which parental variation in diaspore and tree traits explained (1) rate of diaspore descent in still air, (2) distributions of diaspores dispersed from a 40-m tower in the forest, and (3) natural diaspore distributions around the parent tree. The geometric mean rate of descent in still air among 20 parents was highly correlated with geometric mean wing loading(1/2) (r = 0.

Seed predation and patterns of fruit production in Asclepias syriaca L.

Seed predation in relation to patterns of pod (and seed) distribution was examined in five samples of the common milkweed (Asclepias syriaca L.), in tests of the "resource-concentration" effect both within- and beween-plants. The proportion of pods in a cluster that were attacked, particularly by the weevil Rhyssomatus lineaticollis, was not consistently related to the number of pods contained in a cluster, the frequency of cluster sizes in a population, or the variance of cluster sizes on a stem.