Natural control of arthropods, with special reference to ants (Formicidae), by fungi in the tropical high forest of Ghana.
In connexion with studies of insect pests and vectors of disease in Cocoa plantations, an investigation was made of the fungus pathogens of ants and other arthropods at two sites in each of three forest types (a transitional forest between moist semi-deciduous and evergreen forest, and two moist semi-deciduous forest types) in E. Ghana, during 1972. Data are tabulated for ant and arthropod hosts and their associated fungi, and for monthly totals of diseased arthropods (excluding ants) collected from the different sites. Arthropod populations increased as the forest types became more depleted or disturbed. The incidence of disease was highest in undisturbed forest with heavy shade and little seasonal variation, while in secondary or depleted forest the numbers of diseased arthropods were low during most of the year, with an increase in the occurrence of epizootic fungus species during the very wet months. Ants were susceptible to fungus attack; coccids were also commonly infected in all the habitats studied and so, to a smaller extent, were species of Diptera and Araneida. It is suggested that pathogenic fungi may be important factors in the natural control of arthropod populations in humid tropical forests. [Cf. FA 35, 4903]