Influence of weather variables on population dynamics of rice insect pests and their natural enemies: A six year light trap study in Gazipur, Bangladesh

Sustainable rice production in tropical and subtropical agroecosystems, it is essential to know, how climatic variability regulates the dynamics of insect pests and natural enemies. Our study evaluated the monthly and seasonal pattern of key weather variables and their influence on the abundance and interaction of major insect pests and their natural enemies from January 2019 to December 2024 through light trap catch in Gazipur, Bangladesh. Temperature was highest from March to October (maximum:32.87–35.25°C; mean:26.58–30.31°C), peaking during the Aus season, while relative humidity and rainfall were maximum during the monsoon month (June-October). Two peaked abundance of planthoppers, leafhoppers, rice leaf folder, stem borer, caseworm, rice bug and cricket showed in September-November and April-May coinciding mainly in Aman season and rice transitional periods under reproductive phases of rice. The pressure of insect pests was comparatively lower during the Boro season. Natural enemies; spiders, carabid beetles, ladybird beetles, odonates, and staphylinid beetles displayed distinct seasonal and climatic responses, with peaked activity largely synchronized with abundance of insect pests. Correlation analysis disclosed that temperature, rainfall and relative humidity influenced pest and predator populations differently. Temperature positively correlated most of the pests and natural enemies except staphylinid beetles, green mirid bug and spiders. Significant positive correlations among most insect pests and selective predator-prey relationships were revealed, highlighting intricate interactions. These findings, manifested that rice pest dynamics are strongly formed by seasonal climate variability, crop growth, and cropping transitions period, emphasizing the importance of climate-based monitoring and ecologically based integrated pest management strategies under changing climatic scenario thus helps to reduce insecticide use.