Comparative morphology of sensilla on antenna, maxillary palp and labial palp of larvae of Eucryptorrhynchus scrobiculatus (Olivier) and E. brandti (Harold) (Coleoptera: Curculionidae)

Abstract

Yang, Y., Ren, L., Wang, T., Xu, L. and Zong, S. 2017. Comparative morphology of sensilla on antenna, maxillary palp and labial palp of larvae of Eucryptorrhynchus scrobiculatus (Olivier) and E. brandti (Harold) (Coleoptera: Curculionidae). -Acta Zoologica (Stockholm) 98: 400-411.Eucryptorrhynchus scrobiculatus (Olivier) and E. brandti (Harold) are two wood boring pests of Ailanthus altissima (Mill.) Swingle (tree of heaven) and the variety Ailanthus altissima var. Qiantouchun. These beetles attack healthy trees and bore into roots and trunks during the larval stage. We studied the typology, distribution and morphostructure of the sensilla on the antennae, maxillary palps and labial palps of E. scrobiculatus and E. brandti larvae using scanning and transmission electron microscopy. The results showed the following: (i) the antennae of the two weevil larvae had two types of sensilla, sensilla basiconica (S.b.1 and S.b.2) and sensilla twig basiconica (S.tb.1-S.tb.3), with S.tb.4 observed only on the antennae of E. brandti larvae; (ii) the maxillary palps had three types of sensilla, S.b.2, S.tb. (S.tb.2, S.tb.3 and S.tb.5) and digitiform sensilla; (iii) the labial palps had two types of sensilla, S.b.2 and S.tb. (S.tb.2, S.tb.3 and S.tb.5); (iv) the quantity and distribution of sensilla on the antennae, maxillary palps and labial palps remained constant between E. scrobiculatus and E. brandti larvae; and (v) sensilla basiconica had distinct sidewall pores, an apical pore was observed on sensilla twig basiconica, and digitiform sensilla were oval in shape, with a distinct apical pore. Based on the microstructure of the cuticle wall and dendrite, we hypothesized that these sensilla functioned as olfactory, gustatory and hygro-/thermo-receptors, respectively. We discuss the relationships among types of sensilla and the types of damage caused by the larvae inside the host tree to understand olfactory and gustatory receptor mechanisms. The results of this study will provide a firm basis for future electrophysiological studies.Shixiang Zong, Beijing Key Laboratory for Forest Pest Control, Beijing Forestry University,

Comparison and Functional Analysis of Chemosensory Protein Genes From Eucryptorrhynchus scrobiculatus Motschulsky and Eucryptorrhynchus brandti Harold

“…Insect sensilla play important roles in semiochemical detection and perception both in adult and larvae stages (Sato and Touhara, 2009;Liu et al, 2011), and the chemosensory protein genes that express at the sensilla are considered to be related to this process (Sanchez-Gracia et al, 2009). As insect sensilla distribute at different tissues and stages, performing the functions of smell, taste, and touch (Rees, 1970;Hu et al, 2009;Yang et al, 2017), CSP genes that express at these sensilla may be involved in the regulation of insect foraging and oviposition behavior. We screened CSPs-encoding transcripts in different developmental stages using an RNA-seq approach to complete the expression profiles of TRW and TTW CSP genes.…”

Morphologic Characters of the Rostrum in Two Weevils, Eucryptorrhynchus scrobiculatus Motschulsky and E. brandti Harold (Coleoptera: Curculionidae: Cryptorrhychinae)

“…The references for the classification of the sensilla were as follows [ 7 , 22 , 23 , 24 , 25 ]. The mean length and width of the sensillum were measured using ImageJ.…”

Morphological coupling of the distal organ in the Peruvian walking stick (Oreophoetes peruana): Structural and functional aspects

“…These are functional units with one or few sensory neurons, and additional cell types. The sensilla can occur on the cuticle (e.g., Garza et al, 2021; Haberkorn et al, 2019; Ichikawa et al, 2014; Nowińska et al, 2020; Pflüger et al, 1981; Yang et al, 2017; Zhao et al, 2021) or form complex internal organs (Field & Matheson, 1998; Kavlie & Albert, 2013; Nation, 2008).…”