Morphology and ultrastructure of antennal sensilla of the parasitic wasp Baryscapus dioryctriae (Hymenoptera: Eulophidae)

Abstract

Baryscapus dioryctriae is an endoparasitic wasp in the pupae of many Pyralidae pests, such as Dioryctria mendacella, Ostrinia furnacalis, and Chilo suppressalis. To provide requisite background for our ongoing research on the mechanisms of host location in B. dioryctriae, the morphology, abundance, distribution, and ultrastructure of the antennal sensilla were investigated using scanning and transmission electron microscopy. The geniculate antennae of B. dioryctriae are composed of scape, pedicel, and flagellum. Eight types of sensilla including Böhm sensilla, chaetica, trichodea, basiconic capitate peg, campaniformia, placodea, coeloconica, and sensilla styloconicum with a long hair were identified on both sexes. Sexual dimorphism exists in the antennae of B. dioryctriae. The number of flagellomere in males is over females, and the subtypes and abundance of sensilla are also different between the sexes. Additionally, the possible functions of distinct sensilla were discussed, which varies from olfaction, contact chemoreceptive, mechanoreception to hygro-/thermoreception, especially, the sensilla trichodea and placodea might be involved in olfactory perception in B. dioryctriae. These results provide an essential basis for further study on chemical communication between B. dioryctriae and their hosts, and contribute to the development of B. dioryctriae becoming an effective biocontrol agent against the pests of agriculture and forestry.

The morphology of the sensilla on the antennae, maxillary palps and cerci of Grylloprimevala jilina Zhou & Ren, 2023

“…Insects live in a complex external environment where various physical and chemical stimuli influence and drive a range of life activities, including feeding, courtship, mating, oviposition and evading predators (Kaissling 1971; Chen et al . 2023). The sensilla are the structures that link the external environmental stimuli with the internal perceptual system and are the direct channel for insects to perceive various types of external stimuli (Yu 2007).…”

“…They are responsible for perceiving stimuli that are generated by mechanical external forces (Zhang et al 2015). The BB exist widely in many insect species (Zhang et al 2015;Fu et al 2020;Zhang et al 2021;Chen et al 2023) and are usually located in areas opposite the intersegmental membrane between the head and scape and between the scape and pedicel (Schneider 1964;Fu et al 2020). They are phasic-tonic mechanoreceptors and proprioceptors that are used to perceive the position of the antennae (Schneider 1964;Chen et al 2023).…”

“…The BB exist widely in many insect species (Zhang et al 2015;Fu et al 2020;Zhang et al 2021;Chen et al 2023) and are usually located in areas opposite the intersegmental membrane between the head and scape and between the scape and pedicel (Schneider 1964;Fu et al 2020). They are phasic-tonic mechanoreceptors and proprioceptors that are used to perceive the position of the antennae (Schneider 1964;Chen et al 2023). In a study on C. formosanus, it was suggested that the presence of BB may be responsible for measuring the antennal curved surface and the position of two cuticular elements (Fu et al 2020).…”

“…The ST of Coptotermes formosanus may respond to pheromones in colonies to induce and regulate individual behavioral responses (Fu et al 2020). In Lepidoptera (Keil & Steinbrecht 1984) and Hymenoptera (Pettersson et al 2001;Chen et al 2023), ST was consistently recognized as a class of chemoreceptor that is involved in pheromone perception. However, it has also been suggested that ST may be related to the perception of plant volatiles (Maida et al 2005).…”

“…In most cases, SCa are found in areas where the cuticle undergoes drastic deformation, such as insect antennal segments, wing bases, legs and cerci (Schneider 1964;Dumpert & Gnatzy 1977;Keil 1997). The SCa are proprioceptors of insect behavior, and they detect local deformation of the body and transmit strain through the dendrites of the inferior single sensory neuron, where they convert tension into depolarizing currents (Faucheux 1999;Zill et al 2004;Liang et al 2011;Dickerson et al 2021;Chen et al 2023). Researchers have suggested that the diverse SCa subtypes and distribution patterns may imply a more important role in the perception of antennae in C. formosanus (Fu et al 2020).…”