Herbivoria em Tabebuia ochracea (Bignoniaceae) ao longo de um gradiente sucessional em uma floresta tropical seca.

Abstract

This study aimed to determine the herbivory patterns on the “ipê-amarelo”, Tabebuia ochracea (Cham.) Standl. (Bignoniaceae) in a tropical dry forest in the Parque Estadual da Mata Seca (PEMS), north of Minas Gerais, Brazil. We assessed the diversity of free-feeding herbivore insects (sap-suckers and leaf-chewers), leaf herbivory, leaf nitrogen content, phenolic compounds and spider abundance along the rainy season in three different sucessional stages (early, intermediate and late). The samplings were performed in December, coinciding with the beginning of the rainy season (with fully expanded young leaves), February (middle-aged leaves), and April, in the end of rainy season (old leaves). The samples were performed on 15 trees of T. ochracea per successional stage in each period. Herbivore diversity was higher in the early stage, although higher herbivory rates were found in the intermediate and late stages. This result is probably related to differences in herbivore community composition between habitats and to the better foliage quality in the advanced stages, since the nitrogen content showed positive relation with the enhance in leaf herbivory. The phenolic compounds and the spider abundance did not differ between sucessional stages. The higher herbivore diversity was found in April, due to the increment observed in the early stage. In this stage, the greatest increment in herbivory rates was found from February to April, probably as a consequence of a high incidence of herbivores with tolerance to low nitrogen availability. The intermediate and late stages showed a greater increase in leaf herbivory between December and February, coinciding with the period of higher leaf suitability. As a whole, herbivory and plant quality patterns were similar in the intermediate and late successional stages, and both differed from the early stage.