Insect galls of the xeric vegetation of Ilha do Cabo Frio (Arraial do Cabo, RJ, Brazil)

Abstract

The xeric vegetation of Ilha do Cabo Frio (Arraial do Cabo, RJ) was investigated for insect galls, in May, June and August of 2012, totalizing 24 hours of field work. Forty-five morphotypes of insect galls were found on 29 species of host plant (25 genera and 18 families). Asteraceae and Myrtaceae were the most galled plant families. Leaves were the most galled plant organ, with ca. 62% of the total, followed by stems (ca. 22%). Globoid and fusiform galls were the most frequent with about 29% and 24%, respectively. The majority was glabrous (ca. 91%), and one-chambered (ca. 84%). Gallers of 30 morphotypes were determined. They belong to Diptera (Cecidomyiidae), and Lepidoptera. The former was the most frequent. Larvae of Muscomorpha (Diptera) (probably inquilines) were found in a single gall morphotype; parasitoids (Hymenoptera) in seven (ca. 15% of the total), and predators (pseudoscorpion) in a single one. As there is no previous data of insect galls of Ilha do Cabo Frio, all records presented here are new. The geographic distribution of nine species of gall midges (Diptera, Cecidomyiidae) is widened. For the first time, eleven plant species are recorded as host of galling insects, and 24 gall morphotypes are described.