Gall-inducing insects of restinga areas (Atlantic Forest) in Brazil: economic importance

Abstract

Abstract Many gall-inducing insects have been reported as pests in the Old World and North America, although few such examples are known from South America. A list of gall-inducing insects of potential economic importance, with a focus on those of restinga environments, was compiled using Maia (2013a) as starting point and updated with the database “Thompson ISI”, using ‘Insect (title) and gall (topic)’ as keywords. Botanical names were updated using the site “Flora do Brasil, 2020”, while potential economic significance of host plant species was acquired from Santos et al. (2009) and the site “Useful Tropical Plants”. Fifty-eight galling species were associated with 29 economically important plant species of 18 families in Brazilian restingas. The gallers were found to belong to Diptera (Cecidomyiidae and Agromyzidae) and Hemiptera (Eriococcidae and Psyllidae), among which Cecidomyiidae were the most important, with 55 gall-inducing species distributed among 28 genera. Six of the found genera are endemic to the Atlantic Forest and, until now, have been exclusively reported in restingas. About 78% of the gallers have been recorded only in Southeast Brazil and about 64% only in the state of Rio de Janeiro. Most gallers were found to be mainly associated with edible and/or medicinal plant species. Data on natural enemies are scarce with most records having been published at the taxonomic level of family or genus. Natural enemies were found associated with 43 gall-inducing species and included parasitoids, predators and inquilines. The first were the most diverse, being represented by 13 hymenopteran families, but the impacts of all of these guilds on galler populations are poorly known. Although 58 gall-inducing species were identified in the present study, the number of insect galls associated with plants of economic interests in restinga environments is about three times greater, since a total of 186 gall morphotypes have been reported. Nonetheless, many gallers are still undetermined, thus revealing how deficient their taxonomical knowledge remains.