Cocoa is especially #pollinated by #Ceratopogonidae midges, particularly the genus #Forcipomyia. However...lots of other insects of similar size may play a role. This could include thrips, gall midges, fruit flies, etc. Gall midges are particularly common on cocoa plantations.

But Forcipomyia respond to the odour of #cocoa flowers, and have hairy bodies that cocoa pollen clings to, so they can carry more grains than many other flower visitors. So it's likely that they're most efficient.