XVI International Botanical Congess

Morpho-anatomical features of galls induced by Calorileya nigra (Hymenoptera) in roots of Cattleya were studied. Four developmental stages were recognised. The first stage corresponds to the slightly enlargement of the root apex, after the oviposition. The second stage exhibits a globular shape and the root promeristem presents alterations in its activity. The inducers are in larval instar and nutritive tissue is present. The third stage is characterised by the greater size of the gall, which is covered by velamen. The inducers are in pupal or mature instar and nutritive tissue is absent. The fourth stage is characterised by the presence of emergence orifices resulting from the emergence of the adult inducers. The morphogenetic responses leading to the formation of the gall are discussed (CNPq, FAPESP).