Morphometric analysis of antennae of three female Brachymeria species (Hymenoptera: Chalcididae), parasitoids from the oil palm bagworm, Metisa plana Walker (Lepidoptera: Psychidae)
摘要
Brachymeria species are solitary parasitoids, which use antennae to search for their hosts. In order to investigate the morphological aspects related to the host searching behaviour, the antennal sensilla of female Brachymeria carinata Joseph, Narendran & Joy, 1970, Brachymeria lugubris Walker, 1871 and Brachymeria lasus Walker, 1841 were examined using scanning electron microscopy. The results showed that the geniculate antennae of the three female Brachymeria species have nine flagellomeres, with differences in length among species. In this study, various types of antennal sensilla were found including: trichoid (six subtypes), chaetic (three subtypes), basiconic, placoid, and cylindrical sensilla. All these sensilla were identified on the antennae of these three species, except trichoid sensilla subtype 6 which is absent on B. lugubris, whilst chaetic sensilla subtype 1, was only present on B. lugubris. The chaetic sensilla subtype 3, placoid sensilla, and trichoid sensilla subtype 2 are the most abundant sensilla on these three Brachymeria species. A cylindrical sensilla with papillae structure on the tip of the sensilla is found in these three species. The density of sensilla covering the flagellomeres is different among species. The possible functions of the different antennal sensilla, based on their external morphology, are discussed.