Seasonal variations of insect abundance: Correlating growth stage-specific metrics with weather patterns in Rangpur Region, Bangladesh

Abstract

The disclosure of insect occurrences correlating with meteorological data is pivotal in devising effective management strategies for rice fields. The study collected data on harmful and beneficial insects, along with meteorological variables, for three consecutive rice-growing seasons in 2021 and 2022. Month-wise insect distribution were delineated, with prominent species such as green leafhopper, brown planthopper, white-backed planthopper, rice whorl maggot, damselfly, parasitic wasps and green mirid bug observed consistently. Notably, most of the harmful insects were predominantly present during March–July and September–October. The spatial distribution, further segmented based on the rice-growing seasons, revealing the Aus season's preeminence in hosting harmful insects followed by Aman and Boro. The prevalence of most of the harmful insects were in tillering stage. Beneficial insects, displayed their dominance during specific months, growth stage, emphasizing their potential role in controlling harmful species and their prevalence were increased by increased of harmful insects. Furthermore, the study elucidated the correlation between climatic factors and insect abundance, emphasizing the role of temperature, rainfall and relative humidity. Temperature metrics and relative humidity manifested significant associations with several insects both harmful and beneficial species differently. While rainfall notably correlated with rice bug, short-horned grasshoppers, yellow stem borer, and non-significant association with other insects. The study underscored mutual dependencies between predator and prey species, emphasizing the ecological balance within the agricultural ecosystem. This comprehensive analysis indicated the need for integrated pest management strategies, considering both harmful and beneficial insect dynamics, to promote sustainable practices for optimizing rice production in changing climatic scenarios.