Morisita Index Analysis Reveals Contrasting Distribution Patterns of Pest Insects in Cocoa Agroforestry Systems: Uniform under Papaya vs. Clumped under Banana Canopies

Abstract

The distribution pattern describes how organisms are distributed within a population. Distribution patterns are divided into three types: clumped, uniform, and random. This study aims to analyse differences in the distribution patterns of pest insect genera between shaded cocoa farms with papaya trees and those with banana trees, and to examine the influence of temperature and humidity on increases in pest insect populations in cocoa farms. The research was conducted from January to March 2025. Various trapping methods used include yellow, pitfall, and light traps, as well as visual observations. The distribution pattern was analysed using the Morisita Index (Id), while the effects of temperature and humidity were tested with simple linear regression. Morisita's analysis shows that the distribution pattern of pest insects is significantly more uniform under papaya shade and more clumped under banana shade. Temperature and humidity do not have a significant effect on population increase.