Abundance of Gall Midges on Poulsenia armata (Moraceae): Importance of Host Plant Size and Light Environment in Tropical Rain Forests

We studied the effects of contrasting light environments on the relationship between the host plant size of Poulsenia armata and the abundance of two gall midges in a tropical rain forest in Veracruz, Mexico. The number and density of two gall morphs (i.e., laminar and vein-petiole galls) were positively correlated with plant size only in trees found in the forest but not in gaps. The availability of foliar area of P. armata trees was greater in forest gaps than in the forest. The foliar area was positively correlated with the abundance of laminar galls in trees in forest sites, but not with vein-petiole galls. We concluded that the abundance of two morphs of gall midges on P. armata was associated with host plant size only in the forest trees. Larger plants had more galls than small plants, although this relationship was affected by local light environments.