Cerambycidae and other Coleoptera Associated with Branches Girdled byOncideres sagaDalman (Coleoptera: Cerambycidae: Lamiinae: Onciderini)

Abstract

Species of Oncideres Serville, often referred to as twig girdlers, girdle tree branches prior to oviposition to promote larval development. The behavior creates a unique niche that is utilized by other beetle species. The objective of this study was to compare emergence of insects from branches girdled by Oncideres saga Dalman in an intercropping system and a monoculture of Acacia mangium Willd. in the Atlantic Rainforest of Minas Gerais, Brazil. Twenty-four Coleoptera species emerged from the branches: 17 Cerambycidae; three Cleridae; and one individual each from Cantharidae, Cucujidae, Elateridae, and Trogossitidae. Although branches from the intercropping system yielded more individuals, branches from the monoculture had higher species richness, including almost all of the cerambycid species and all of the potential predators. The use of girdled twigs may confer a reproductive advantage to subsequent cerambycid colonists, which are probably attracted to the volatiles released by the girdled branch. Beetles belonging to other families may prey on the Cerambycidae dwelling inside the branches. Potential predators may be ecologically important, contributing to the natural biological control of O. saga. Collecting and burning the infested branches is the technique most extensively used to control the twig girdlers. However, this also destroys beneficial organisms as well as the subsequent colonists that depend upon these branches.