Insect Abundance in Soils Contaminated with Palm Oil Mill and Spent Engine Oil Effluents and Their Relationship to Ambient Microclimate

Abstract

This study investigates the effects of microclimates, specifically temperature and relative humidity, on the abundance of insects in Abakaliki, Ebonyi State, Nigeria. The study divided Ebonyi State University's Presco Campus into two habitat zones, employing quantitative methods like handheld sweep nets and pitfall traps. Six transect walks were conducted along 0.23-kilometer lines, sampling ground-level vegetation twice a week. Twelve pitfall traps with a soap-water solution were deployed in each habitat. Euthanized insects were preserved with ethyl acetate, and data analysis involved descriptive statistics, One-Way ANOVA, and diversity indices to assess species diversity and distribution. Results indicate variations in temperature, relative humidity and insect abundance across different sites, with the Palm Oil Mill Effluent (POME) site exhibiting the highest mean insect abundance (10.79). The relationship between environmental variables and insect abundance reveals a positive correlation with temperature (r = 0.361; P = 0.03) and a negative association with relative humidity (r = -0.0741; P = 0.667). These findings underscore the nuanced interplay between microclimates and insect abundance, emphasizing the importance of context-specific analyses in understanding ecological relationships. The research findings have implications for agriculture, public health, and ecosystem management in Abakaliki and similar regions, highlighting the need for targeted interventions considering the unique microclimatic conditions of the area.