Several species of Ficus present leaf galls and the goal of this research is to study the structural alterations involved in the formation of leaf galls caused by Gynaikothrips ficorum on F. microcarpa, an ornamental plant. The galls of young and mature leaves were separated into two developmental stages based on the presence of lesions on leaf lamina and the degree of leaf folding. Swellings of the lamina were observed in young and mature leaves during gall development which coincided with the areas of cellular hypertrophy and tissue hyperplasia. Swellings were detected in a greater amount and more precociously on young leaves when compared to mature ones. In young leaves, the cecidogenetic responses were quicker and led to further structural differences because younger cells are not completely differentiated. Cell hypertrophy and tissue hyperplasia were striking processes involved in the ontogenesis of the studied gall, similar to other galls induced by thrips. Nevertheless, in spite of the numerous sites of feeding and the wide area of attack, F microcarpa galls can be considered rudimentary, since no new tissue differentiation was observed.
leaf gall; thrips; Ficus microcarpa; Moracecae; anatomy