Association Between Temperature, Rainfall, and Insect Population Dynamics

Abstract

Climatic variability has a strong influence on insect populations, as both temperature and precipitation have direct physiological effects on development, reproduction and survival, and indirect effects which are mediated by the availability of host plant, the dynamics of natural enemies, and the quality of the insect habitat. The climatic drivers are directly impacted by global climate change and have been shown to affect insect phenology, geographic range, abundance, and community composition. The study is designed as a quantitative, observational type of research to examine the relationship among temperature, rainfall and insect population dynamics in the four groups of insects (mosaquitoes, butterflies, beetles and aphids) monitored with standardized field transect surveys over a 48 month period (2020-2024) at six sites that are ecologically diverse. Weather data were retrieved from co-located weather stations as well as from regional National Oceanic and Atmospheric Administration (NOAA) data. Using multiple regression and correlation analysis, strong positive relationships were found between temperature and mosquito population indices (r = 0.82, p < 0.001) and between temperature and aphid population indices (r = 0.65, p < 0.001); but, the strongest positive relationships were found between rainfall and butterfly population indices (r = 0.70, p < 0.001) and between vegetation greenness and butterfly population indices (r = 0.78, p < 0.001). The temperature was highly correlated with the locusts (r = 0.88), while the rainfall showed a moderate negative correlation (−0.35), which is in accordance with their preference to live in semi-arid areas. The overall insect abundance index was best predicted by the multiple regression model (R² = 0.714, F = 28.3, p < 0.001). The seasonal analysis showed that the summer months favored high abundances in all groups, and the emergence timing in spring was well correlated with the number of accumulated degree-days. The results are of relevance to vector control, agricultural pest management and biodiversity conservation to accelerate climate change.