Insect galls of the Tijuca National Park, Rio de Janeiro (RJ, Brazil): richness and characterization

Abstract

The Tijuca National Park comprises the world’s largest urban forest. It has a rich flora, with around 1,550 plant species. For the first time, the insect galls of this area were investigated. We carried out 12 monthly collections from January to December/2009. Samples of host plants were pressed and identified. Galls were photographed and characterized according to their external morphology and number of chambers. Gall-inducing insects and secondary inhabitants were obtained from gall dissecation as well as from rearing in laboratory. Data on origin and geographic distribution of plant species were retrieved from Flora e Funga do Brasil website. We found 72 gall morphotypes on 43 plant species (36 genera, and 23 families). Rubiaceae, Sapindaceae, Salicaeae and Melastomataceae were the botanical families with the highest gall richness. Psychotria cf. bahiensis DC. (Rubiaceae) and Serjania sp. (Sapindaceae) highlighted as super host plant species. Five host plants are endemic to Brazil; they shelters eight gall morphotypes. Due to the high specificity of the gall-inducing insects, we considered them co-endemic, Leaf galls were the most frequent. Gall-inducers were represented mainly by Cecidomyiidae. Galls of Tijuca National Park followed the patterns already known from Brazil, but it richness is relatively low when compared to other areas of the Atlantic forest.