Observations on the Ultrastructure of Antennal Sensilla of Adult Glenea cantor (Cerambycidae: Lamiinae)

Abstract

The external morphology and distribution of antennal sensilla of Glenea cantor Fabricius were studied with scanning electron microscopy. The antennae of G. cantor were observed to be filiform, consisting of scape, pedicel, and flagellum (nine flagellomeres). Four distinct types of sensory receptors were observed, including sensilla chaetica, sensilla trichodea, sensilla basiconica, and Böhm bristles. Three morphological subtypes of sensilla chaetica were found on the antennae, and sensilla trichodea were also categorized into three morphological subtypes. Sensilla basiconica was grouped into two morphological subtypes that were found on subsegments F2-F9 of the flagellum, and Böhm bristles were only found at the intersegmental joints between the scape and the head and between the scape and the pedicel. The antennae of male and female adults were similar in shape, length, and diameter. However, the length, diameter, distribution, and number of each of the four distinct types of sensilla on the males were significantly different from those on females. The types, lengths, diameters, numbers, and distributions of these sensilla were described, and their possible functions were also discussed. The results indicated that the base and end of an antennal segment have a similar sensillum density, but the middle section sensor density is significantly greater, especially for olfactory and gustatory sensilla, possibly because the joints are more involved in mechanical sensing. The density of sensors is closely related to its sensing function; so, future studies on the biology of olfaction and sexual communication in G. cantor will be facilitated by these observations.

First description and comparison of the morphological and ultramicro characteristics of the antennal sensilla of two fir longhorn beetles

“…In the past half century, the antennal scanning electron microscopy of insects has been well-researched [ 23 – 25 ]. As phytophagous insects, Cerambycidae are economically important pests of forest, street trees and fruit trees [ 34 ]. Therefore, antenna scanning electron microscopy of cerambycid beetles has gained much recent research attention [ 26 – 28 ].…”

“…The main reported functions for sensilla chaetica and Böhm bristles show a mechanical function [ 26 , 34 , 35 ]. Meanwhile, some research also have shown that several subtypes of sensilla chaetica have an olfactory function [ 34 ], such as SCh II & IV in A . asiaticus and C .…”

Evaluation of Reference Genes in Glenea cantor (Fabricius) by Using qRT-PCR

“…In May 2019, the G. cantor larvae were originally collected from Qingxiu Mountain (22°47′ N, 108°23′ E) in Nanning City, Guangxi Province, China by cutting down damaged kapok branches. The branches were kept in cages for adult eclosion, and then the insects were reared, as introduced previously [ 3 ]. The insects were reared with ventilation under 25 ± 1 °C, 75 ± 5% relative humidity (RH), and a photoperiod of 14:10 [L:D] h.…”

“…For example, in 2005, this pest killed over 10% of the trees in a B. ceiba plantation in Nanning, Guangxi Province, China [ 1 ]. In 2018, B. ceiba was discovered as a new important host plant for long-horned beetles in Nanning, Guangxi Province [ 3 ]. In severe cases, it often causes the kapok trees to die continuously, which seriously affects the results of urban greening and landscaping.…”

“…The peak period for G. cantor is from March to July, and the larvae mainly hibernate in the affected branches during their fourth instar [ 4 , 5 ]. Biological studies of G. cantor have mainly focused on the biological characteristics [ 3 , 4 , 5 , 6 ], behavior habits [ 2 , 7 , 8 , 9 ], prevention and control [ 1 ], artificial breeding method [ 9 , 10 ], and mitochondrial genome [ 11 ]. As a result, G. cantor is a good reproductive behavior model in the regulatory mechanism, as a polygamous long-horned beetle and R-strategist.…”