The role of non-dipterous insects in the pollination of cocoa in Brazil

Abstract

AbstractField collections in Bahia State, Brazil, of open cocoa flowers from an untreated plantation and one treated with insecticide and fungicide showed that Homoptera, including the cicadellid Xesrocephalus ancorifer Linnavuori, the aphidid Toxoptera aurantii (Boy.), and species of Pseudococcidae and Margarodidae (Coccoidea), constituted 96% of the total number of insects collected. In the untreated area, Wasmannia rochai Ford formed 22% of the ants collected and Brachymyrmex pictus Mayr, Crernatogaster ? parabiotica Forel,Iridomyrmex sp., Pheidole sp. and Solenopsis sp., a further 48%, whereas in the treated area, 47% were C. parabiotica, 14% W. rochai and 9% B. heeri Forel. There was evidence of a mosaic distribution pattern for the ant species. No cocoa pollen was found on any of the insects collected. Total pollination ranged between 7·4 and 8·1 % and effective pollination between 3·7 and 2·8 % in the treated and untreated areas, respectively. Approximately 76% of the pollen masses were stylar, with 38% of the ball type and 54% of the smear type, whereas the 16% stigmatic pollen masses consisted of 63% ball and 29% smear types; 44% of the stigmatic pollinations were effective, compared with only 33 % of the stylar ones. Some quadrats were more attractive to pollinators than others, and there was a significant positive correlation between percentage effective pollination and insolation, probably due to the favourable effect of sunshine on Forcipomyia activity.