Resumo. ABSTRACTThe insect fauna knowledge of forest ecosystems have their importance in relation to damage caused bytheir different segments. The bioecology of theOncideres cervina(Coleoptera: Cerambycidae) inOcoteapuberula(Lauraceae) was studied in the central region of Rio Grande do Sul state, Brazil. In 49 cut twigswere analyzed the cutoff frequency, the diameter of cut twigs and sections, twig length, posture incisionsfrequency, adult emergence, exit orifice size, length and volume of the larvae gallery of this species. Thecut twigs period extends from February to March and this species is fit as thick cutter twigs. The incisionsposture number is variable, but the highest concentration is found on sections 20 to 40 cm from the cut, withan average value of 11 incisions. Two hundred adults emerged from 27 twigs, with the most emergent onthe first half of December. In order to complete its development, this species requires less wood volume ifcompared to other twig girdlers species.