# Bat Community Response to Insect Abundance in Relation to Rice Phenology in Peninsular Malaysia

## TL;DR

This study shows how bat activity in Malaysian rice fields is linked to insect abundance and weather, highlighting their role in natural pest control.

## Contribution

The study provides new insights into bat-insect interactions in Malaysian rice fields and their seasonal dynamics.

## Key findings

- Bat activity peaks when insect populations are highest, indicating a direct response to food availability.
- Temperature and rainfall have a stronger influence on bat activity than insect abundance alone.
- Rhinolophus pusillus is the most common bat species, while Chilo polychrysus and Nilaparvata lugens dominate insect pests in dry and wet seasons, respectively.

## Abstract

Bats are among the most important natural pest controllers in agricultural landscapes. By feeding on insects, they help reduce pest populations that can damage crops and lower yields. Despite their importance, studies on how bats interact with insect populations in Malaysian rice fields are still scarce. In this study, we explored the diversity and activity of bats in relation to insect abundance at Gunung Keriang, Kedah, across different rice-growing seasons. Using harp traps, mist nets and light traps, we recorded 27 bat species and 11 insect orders. The most common bat was Rhinolophus pusillus, while Chilo polychrysus (stem borer) and Nilaparvata lugens (brown planthopper) were the dominant insect pests during the dry and wet seasons, respectively. Bat activity was highest during the same periods when insect activity peaked, suggesting that bats respond to nightly food availability. However, their activity was more strongly influenced by temperature and rainfall than by insect abundance alone. These findings highlight the essential ecological role of bats in naturally regulating pest populations. Encouraging bat-friendly farming practices such as reducing pesticide use and conserving roosting habitats can support sustainable rice production and strengthen ecosystem balance in agricultural areas.

Bats provide essential ecosystem services, particularly in regulating insect populations within agricultural landscapes. However, research on bat–insect interactions in Malaysian rice fields remains limited. This study examined bat diversity and insect abundance in the rice field area of Gunung Keriang, Kedah, using two harp traps, two mist nets and a light trap at three selected sites. A total of 2499 bats representing 27 species were captured, alongside 161,539 insects from 11 orders. Rhinolophus pusillus was the dominant bat species across all seasons. During the dry season, Chilo polychrysus (stem borer) was the dominant insect pest, whereas Nilaparvata lugens (brown planthopper) prevailed during the wet season. Insects from the order Coleoptera, dominant in the dry season, are likely consumed by larger bat species with stronger bite forces. Bat foraging activity peaked concurrently with insect emergence, corresponding to periods of high food availability. Statistical analysis revealed significant associations between bat activity, temperature, and rainfall, but not insect abundance. These findings underscore the ecological importance of bats as natural pest regulators in rice field ecosystems and highlight their potential role in promoting sustainable, ecosystem-based agricultural management.