Foraging strategies of two dominant native ant species associated with Toxoptera aurantii (Hemiptera, Aphididae) on cocoa trees in Centre Region of Cameroon

Mutualism between ants and Hemiptera is well known on specific plant species. Cocoa is a tree-crop with a high economic value and harbour many ant-tending hemipteran species causing damage on shade trees. Herein, we examined the foraging strategies including frequency of ant activity, palpation and honeydew collection patterns used by local ants Myrmicaria opaciventris and Pheidole megacephala associated with Toxoptera aurantii. Field investigations were conducted from january to december 2022 in five locations in Centre Cameroon. At each location, one plot (0.25 ha) containing cocoa trees were monthly selected. Within each plot, only plants showing association between the target local ants and T. aurantii were investigated for our experiment. The overall number of local ants attending hempiterans was counted, and the palpation and honeydew collection duration were determinate following three time bands (8 a.m to 10 a.m; 12 a.m to 2 p.m; 4 p.m to 6 p.m). A total of 20,189 workers (13,015 individuals of M. opaciventris and 7,174 individuals of P. megacephala ) was recorded associated with T. aurantii . Myrmicaria opaciventris foraged twice than P. megacephala at different time bands. In both ants, the highest number of workers was recorded between 8 a.m to 10 a.m and the lowest between 12 a.m to 2 p.m. All ants foraging on cocoa trees did not participate in palpation and honeydew collection activities. foraging strategies used by M. opaciventris appear more efficient and detrimental to cocoa growing. There is an urgent need to develop control strategies to reduce their populations and preserve cocoa-agrosystems.