# Identification of Female Sex Pheromone of a Plant Bug, Polymerus pekinensis Reuter (Hemiptera: Miridae)

## TL;DR

Researchers identified octyl acetate as a female sex pheromone for the plant bug Polymerus pekinensis, which can be used to attract males for pest monitoring.

## Contribution

The study identifies octyl acetate as a female sex pheromone and reveals its effectiveness in attracting male P. pekinensis for pest control.

## Key findings

- Octyl acetate (OA) is produced in higher amounts by females and strongly attracts male P. pekinensis.
- Adding decyl acetate (DA) to lures significantly reduces their attractiveness to males.
- OA-based lures offer a sustainable method for monitoring and managing P. pekinensis.

## Abstract

Plant bugs’ locating of mates mainly relies on peculiar chemical signals known as sex pheromones, which can be utilized to develop environmentally friendly pest control methods. This study investigated the sex pheromones of Polymerus pekinensis, a phytophagous insect of alfalfa crops in East Asia. By analyzing chemical extracts from both male and female insects, we identified two antenna-active compounds: octyl acetate (OA) and decyl acetate (DA). Females produced higher amounts of OA, while males produced greater quantities of DA. Field experiments demonstrated that lures loaded with solely OA strongly attracted male P. pekinensis, making it a valuable tool for monitoring this pest. However, the addition of DA in larger amounts significantly decreased the attractivity of lures. Our findings offer new strategies for monitoring and managing these insects in a manner that does not harm non-target insects.

Insect sex pheromones have been widely used in integrated pest control due to their efficiency, non-toxicity, specificity, and environmental sustainability. They are considered a key component of green pest management techniques. Polymerus pekinensis is a phytophagous plant bug on alfalfa (Medicago sativa L.) in East Asia. This study used gas chromatography–electroantennogram detection (GC–EAD) and gas chromatography–mass spectrometry (GC–MS) to analyze the whole-body extracts from male and female P. pekinensis. Octyl acetate (OA) and decyl acetate (DA) elicited the antennal response of males and were identified as the predominant components of female and male extracts, respectively. Subsequent field trials demonstrated that OA (>8 mg per lure) showed the strongest attraction to conspecific males. However, when DA was added in a lure (≥2 mg), a significant decline in captures occurred. These findings provide new insights into the understanding of sex pheromones in Miridae and benefit the development of sustainable management of P. pekinensis.