# Morphology of the Larval Antennae and Mouthparts in Conogethes punctiferalis (Guenée) (Lepidoptera: Crambidae) with Special Reference to Sensilla

## TL;DR

This study examines the structure of larval antennae and mouthparts in the yellow peach moth, revealing details about their sensory structures and potential roles in feeding behavior.

## Contribution

The study provides the first detailed ultrastructural analysis of larval antennae and mouthparts in Conogethes punctiferalis.

## Key findings

- No significant morphological differences were found between first-instar and mature larvae in antennae and mouthparts.
- Six types of sensilla were identified, primarily on the labrum-epipharynx, maxilla, and labial palp.
- The study contributes to understanding the behavioral ecology and potential pest control strategies for C. punctiferalis.

## Abstract

Conogethes punctiferalis is a well-known, highly polyphagous pest that poses a serious threat to agriculture and forestry across numerous countries. As important sensory and feeding organs, the larval antennae and mouthparts of C. punctiferalis have received little research attention to date. In this study, the ultrastructure of the antennae, mouthparts, and associated sensilla of C. punctiferalis larvae was investigated using light and scanning electron microscopy. We conducted a systematic analysis of the characteristics of sensilla and discussed their variation in the context of Lepidoptera phylogeny. The potential functions of these sensilla have also been inferred.

The yellow peach moth, Conogethes punctiferalis, is a destructive polyphagous pest and poses a severe threat to the fruit industry and field crops worldwide with its continuously increasing population and expanding host range in recent years. Despite the severe damage caused by C. punctiferalis larvae, their antennae and mouthparts, equipped with abundant sensilla responsible for feeding behavior, have not been investigated in detail. In our study, the antennae, mouthparts, and associated sensilla of first-instar and mature larvae of C. punctiferalis were examined with light and scanning electron microscopy. Our results revealed no obvious morphological differences between the two instars in the basic composition of the antennae and mouthparts, or in the types, distribution, and numbers of sensilla. The antenna is three-segmented, with no sensilla on the scape, three sensilla basiconica and two sensilla chaetica on the pedicel, and three sensilla basiconica and one sensillum styloconicum on the flagellum. The mouthparts of C. punctiferalis are typically mandibulate and consist of a labrum-epipharynx, paired mandibles, a pair of maxillae, a labium, and a hypopharynx. Six types of sensilla were primarily concentrated on the labrum-epipharynx, maxilla, and labial palp, including sensilla chaetica, sensilla basiconica, sensilla styloconica, sensilla digitiformia, sensilla epipharyngea, and sensilla placodea. We conducted a systematic analysis of the characteristics of sensilla and discussed their variation in the context of Lepidoptera phylogeny. The potential functions of the sensilla have also been inferred. The study could advance our understanding of the behavioral ecology of C. punctiferalis and provide potentially useful information on the development of pest control technologies.