Host plant traits define the strategies of success to the Cecidomyiidae in a restinga environment

Abstract

Gall structures are special microhabitats for associated inducers and may reflect peculiar environmental pressures, a premise tested in Monteverdia obtusifolia (Mart.) Biral (Celastraceae) and Paullinia weinmanniifolia Mart. (Sapindaceae). These two species host galls induced by Mayteniella distincta Maia, 2001 and Paulliniamyia ampla Maia, 2001, respectively, and are biological indicators of the conservation status of restingas from Southeast Brazil. We analyzed the structural and histochemical traits of these two host plant species and of their associated galls looking for adaptations to the exogenous pressures of the restinga that may favor both plant and the gall inducers survivorship. Both host plants have thick lipophilic cuticles, polyphenols, and proanthocyanidins accumulated in vacuoles and cell walls, and lignification of sclerenchyma cell walls as structural and histochemical traits potentiated in galls. Such traits improve the defensive role against intense solar radiation and low water availability of the restinga. Mayteniella distincta galls have intralaminar development, with partial maintenance of the host tissue organization in the gall lateral portion and tissue homogenization toward the inner tissue compartment, which promotes water accumulation and maintains the leaf photosynthetic potential. Differently, P. ampla galls have extralaminar development, reorganization of the host tissues, and differentiation of laticifers and trichomes, protecting the gall inducers against enemies and extreme environmental conditions. The endogenous traits of each host plant peculiarly maintained or overexpressed in the gall structure reveal two distinct strategies toward the success of the gall inducers under the stressful conditions of the restinga environment.