Atlantic rainforest remnant harbors greater biotic diversity but reduced lepidopteran populations compared to a eucalyptus plantation

Abstract

Study of the dynamics and distribution of lepidopteran defoliators is important because some of them are major pests of eucalyptus. More than 3,000,000 ha of eucalyptus are now planted in Brazil even though the genus is not native there. The goal of this study was to document the frequency and constancy indexes of lepidopteran pests of Eucalyptus grandis Hill ex Maiden (Myrtaceae) collected with 5 light traps (replicates) in different habitats. The first and second traps were installed in a eucalyptus plantation at 400 and 200 m, respectively, from the interface with a native vegetation area (Atlantic Rainforest); the third in the interface and the fourth and the fifth in native vegetation at 200 and 400 m, respectively, from the interface zone. The most frequent primary pest species were Stenalcidia grosica Schaus, 1901 (Geometridae) and Thyrinteina leucoceraea Rindge, 1961 (Geometridae) with greater frequencies in the eucalyptus plantation at 400 and 200 m from the interface with the native vegetation. In the native vegetation at 200 m from the interface Oxydia vesulia Cramer, 1779 (Geometridae) (33.33%) was the most frequently collected primary pest species, and in the interface zone, Eupseudosoma involuta Sepp, 1855 (16.27%), and Eupseudosoma aberrans Schaus, 1905 (Arctiidae) (15.22%) were the most frequently collected primary pest species. Native vegetation areas of Atlantic Rainforest are more spatially heterogeneous and abundant in host plant species than eucalypt plantations and the high level of species diversity within native vegetation helps to provide natural biological control of herbivorous insects in nearby areas reforested with eucalyptus species.