Shade management and seasonal temperature shifts reshape termite feeding dynamics and soil health in cocoa agroforestry systems

Abstract

Termites are major ecosystem engineers, contributing to organic matter recycling and soil health, but they are also increasingly recognized as a major constraint to cocoa production due to their damage to cocoa trees. However, the impact of reducing shade tree density and seasonal temperature shifts on termite assemblages, feeding behavior, and soil health remains unclear. We investigated termite functional diversity, cocoa tree infestation, and soil organic matter decomposition across five cocoa agroforestry systems over two seasons. We showed that shade management towards tree reduction associated with temperature increase significantly increased the number of cocoa trees infested by harmful termites. Cocoa trees in poorly shaded systems were more infested by non-beneficial termite species during dry seasons than those in heavily shaded systems during the same period. Soil-feeding species such as Procubitermes undulans and Anenteotermes humerus apparently shifted from below-ground foraging to attack cocoa branches in dry periods. Shade management towards tree reduction also contributed to reduce decomposition of soil organic matter (Humification score of 2.1 <2.5). This result implies that reducing companion tree density in cocoa agroforestry systems may lead to more beneficial termite species becoming non-beneficial, more termite outbreaks, less soil organic matter and poor soil health. These phenomena could be severe with global increasing temperatures. Proper management of shade trees by keeping a diversity of shade trees is the recommended solution to reduce pest pressure on cocoa trees, improve cocoa soil health and enhance beneficial interactions.