It’s almost impossible to imagine a world without chocolate.
I am a passionate chocolate lover and an entomologist who studies cocoa pollination. Crop sustainability now appears to depend on small fly pollinators of some species.
thousand flowers
Chocolate is extracted from the seeds of the cocoa tree Theobroma cacao L., literally means “food of the gods”. This plant originated in the western Amazon region of South America, and in many parts of Central and South America he has been cultivated for over 3,000 years. Today it is grown in equatorial regions around the world, including western Africa and some tropical regions of Asia.
These flowers are small, only 0.5 inch (1 to 2 cm) in diameter. The flowers usually grow in clusters directly from the trunk or large branches of the tree.
Each flower requires pollination to successfully produce a roughly football-sized fruit containing 30-60 seeds that can be processed to make chocolate.
It may sound simple, but in reality, successful cocoa pollination is problematic in many areas. Only about 10% to 20% of the flowers produced by cocoa trees are successfully pollinated. The remaining up to 90% receive no pollen at all. Or they don’t receive enough pollen to produce fruit.
Scientists don’t fully understand cocoa pollination, which is surprising given that more than 50 million people worldwide currently depend on chocolate for their livelihoods.
small fly big job
Insects involved in pollinating cacao’s tiny flowers are themselves tiny in order to access the flower’s reproductive structures. Ceratopogonidae Family and Gallmidge from beetle family The family is one of the most important known cocoa pollinators in the world.
The majority of cacao trees are self-incompatible, meaning they are unable to pollinate themselves. It must be attached to the female part of the flower of another tree.
Cacao flowers are also short-lived, usually receiving pollen for only a day or two. A flower that has not received enough pollen will die within 36 hours of opening.
There is evidence that improving midge habitat increases fruit yields. Therefore, in some cocoa-growing regions, current agricultural practices include developing and maintaining suitable ground habitat within and near cocoa orchards to increase the number of pollinating midges. .
a lingering mystery
Successful artificial or hand pollination, which can more than double yields, indicates that cocoa trees can produce far more pods than they do today.
One can’t help but wonder, why aren’t midges doing a better job of pollinating cocoa flowers? They are more likely to be passive rather than active pollinators of cacao because they can obtain sugars from other plant sources. Scientists also wonder if they can fly significant distances among trees in the wild.
All this begs the question: Are there better insects designed for this job? If so, where have they gone?
Most studies linking midges and cocoa pollination have been conducted in orchards, but the biology of wild cocoa pollination has been largely unstudied.
One exception is a study that examined both cultivated and wild cocoa in Bolivia. They found that chironomids make up only 2% of all insects that visit wild birds. Other flies and small bees were more common there.
These results are intriguing and raise the possibility that one or more unknown insects are the primary pollinators of wild cocoa. Only additional studies of wild cacao may reveal whether this is the case.
