Cerambicideos associados a melastomataceas : biologia e padrão de utilização das plantas hospedeiras, Serra do Japi, Jundiai-SP

AUTOR(ES)
DATA DE PUBLICAÇÃO

2003

RESUMO

Cerambycidae constitute one of the largest groups of insects, presenting cosmopolitan distribution, being very abundant and diversified in the tropics. Larvae of this beetle are wood borers, utilizing live or dead trunks. This study investigated aspects of the biology of Oncideres humeralis Thoms (Cerambycidae: Lamiinae), especificity cerambieid-host plant, utilization of the diferents species of plants present in the study area and the impact on the population at 000 of their hosts. The field observations were conducted in the Serra do Japi (south-east Brazil), where data on the biology, ecology and behaviour of the species were recorded. Adult O. humeralis occur between December and March, period utilized mainly for reproduction. Thereupon mating, the female begin cutting the branches, which is interrupted to deposit eggs. After this, it continues the cutting, certifing that the utilized brach fall to the ground. It use to chew a small oval hole in the bark of the twig and deposits its eggs below of the bark. The mean oviposition per plant was six and two eggs per oviposition. Eggs hatch between 20 and 25 days after the oviposition. The eggs are laid on twig bifurcations, and are used as an entrance door for the initial larva! stages. This region possess only parenchymatic cells, without lignificated cells. Arriving at the pith region of the main branch, larvae initially feed the inner phloem, but as soon as they grow, they acquire ability to feed the secundary xilem The larva! development time may takw more two years. Camponotus crassus (Formicidae: Formicinae) and Braconidae parasitoids were the most important natural enemies. O. humeralis utilize more intensely Melastomataceae than other plant families. However, only four species were utized as host among the 11 species present in the study area: Leandra scabra DC., Miconia latecrenata (DC) Naudin., M jucunda triana (DC) Naudin. and M sellowiana Naudin. Temnopsis megacephala Germ utilize twigs with smaller diameters not occupied by O. humeralis, being considered a secundary colonizer of M sellowiana. This beetle aet plants with diameters between 1,13 and 6,64 cm (diameter 10 cm above the ground), between 0,99 and 3,0 cm (diameter at height of the cut) and twigs with length between 74 and 340 cm. Two factors influence the choice of the plant or twig to be utilized: diameter and number of secundary twigs. The greater number of the twigs of Melastomataceae girdled by females of O. humerlis (83,_1Ó) were under 1,5 m of ground. 20,7% of the plants of M sellowiana that had twigs with diameters within the size range utilized by o. humeralis was girdled and approximately 44,44% died. Hence, the mortality among plants of the population of M sellowiana suitable of being attackeds is approximately 10,4%. Therefore, O. humeralis affect the populational size of M sellowiana, and this could affect the recruitment of the its host plant

ASSUNTO(S)

plantas hospedeiras japi serra do (sp) biologia

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