Identificação e atuação dos galhadores de Gochnatia barrosoae Cabrera (Asteraceae) em área de cerrado stricto sensu

Abstract

The galls are complex structures caused in plants due to the action of various organisms such as viruses, bacteria, fungi, insects and mites nematodes. Among them we can highlight the bugs as the main inducers, obtaining food, physical protection against environmental extremes and against natural enemies. This group of sophisticated herbivores supersede chemical and physical defenses of plants and, with the release of chemical compounds, stimulate the proliferation and differentiation of your meristem tissue. The galls may be present from the roots until the apical end, however are more common in leaves and branches. Due to the fact act as strong drains and compete for assimilated, in most cases the formation of galls have deleterious effects on the host plant. Among the various plant families that presented galls, Asteraceae, is one of the most used for inducers. In cerrado strictu sensu are found numerous examples of species Gochnatia barrosoae Cabrera (Asteraceae) that present globoids hairy, yellow galls and easy viewing. The objective then was check what is the fauna associated with galls of G. barrosoae, as well as the pattern of occurrence of these gall forming insects and the factors that influence on your life cycle. The survey was conducted over a two-year 2012/2013, for each year 100 plants were marked in arbitrary mode, in plants with galls were placed traps including the galls, which allowed the obtaining of insects associated with then. Weather data provided by the Departamento de Engenharia Núcleo de Agrometeorologia e Climatologia (UFLA) were used to assess the influence of climatic factors. The galls of G. barrosoae are induced by Asphondylia sp. (Diptera: Cecidomyiidae), and these are more abundant in the transition from the dry season to the rainy season when the host plant emits new leaves and the temperature is cooler, getting protected in the galls during the summer when rainfall increases. Other insects have also been found, composing the guild of Parasitoids and inquilines. The former were represented solely by Hymenoptera (Eulophidade, Eurytomidae and Torymidae) and the second for Coleoptera, Lepidoptera and Hymenoptera (Formicidae).