# Antennal Sensilla Morphology and Flagellomere Addition in Nymphs and Adults of Hierodula patellifera Serville, 1839 (Mantodea: Mantidae)

## TL;DR

This study examines the antennae structure and development in Hierodula patellifera mantises, focusing on sensilla types and growth patterns from nymphs to adults.

## Contribution

The paper provides a detailed classification of antennal sensilla and describes the developmental changes in antennae structure across nymphal stages and sexes.

## Key findings

- Seven types and four subtypes of sensilla were identified in nymphs and adults of H. patellifera.
- The adult flagellum is divided into six parts based on sensilla distribution and morphology.
- Males have larger flagellomeres and more grooved peg sensilla compared to females starting from the 7th instar.

## Abstract

To better understand the morphology of the antennae of mantids, the types of antennal sensilla and their distributional features on the antennae of each instar nymph and adult of Hierodula patellifera Serville, 1839 (Mantodea: Mantidae) were investigated. The antennal morphology of nymphs and adults was similar and consisted of the scape, pedicel, and flagellum. Seven types and four subtypes of sensilla were identified in nymphs and adults. Based on the external morphology and distributional features of the sensilla, we proposed to divide the adult flagellum into six parts. Among the different instar nymphs and adults, the most obvious individual growth of antennae occurred from the 5th- to 6th-instar nymphs; sexual dimorphism in antennal length, width, and sensilla distribution becomes evident from the 7th instar, and compared to adult females, the adult males have larger flagellomeres and a large number of grooved peg sensilla. We observed that the antennae of H. patellifera develop with the addition of new flagellomeres at their proximal and secondary division sites.

Hierodula patellifera Serville is a predatory insect widely distributed in Asia. To better understand the morphology of the antennae of mantids, the antennal morphology, structure, and distribution of sensilla in nymphs and adults of H. patellifera were analyzed using scanning electron microscopy. The antennal morphology of nymphs and adults was similar and consisted of the scape, pedicel, and flagellum. Seven types and four subtypes of sensilla were identified (sensilla trichodea: StI, StII; sensilla basiconica: Sb; sensilla chaetica: Sc; sensilla coelocapitula: Sco; sensilla campaniformia: ScaI, ScaII; grooved peg sensilla: Sgp; Böhm’s bristle: Bb), and an undefined cuticular structure was observed in nymphs. Based on the external morphology and distributional features of the sensilla, we proposed to divide the adult flagellum into six parts. Furthermore, the length of the antennae gradually increased with the growth of instars, and the most obvious individual growth of antennae occurred from the 5th- to 6th-instar nymphs; sexual dimorphism in antennal length width, and sensilla distribution becomes evident from the 7th instar, and compared to adult females, the adult males presented larger flagellomeres and a large number of grooved peg sensilla. We found that mantid antennae develop through the addition of new flagellomeres at their proximal and secondary division sections, and the similarities and differences were compared with other insects.