December 9, 2023

I am now beginning to believe that the cacao tree wasn’t designed to be modified by us humans anyway or changed into something edible. Highly susceptible to disease and less productive than its potential, requiring constant attention and care. Who even considered creating a viable food product from this thorny plant?

With all that said (we all adore the cacao tree because of the way you look), It’s difficult to imagine how chocolate can be so easily and readily accessible when it’s so difficult for the cacao tree to thrive and produce healthy fruit. The battle doesn’t begin with the fruits; it goes on all the way to the level of the flower.

Cacao flowers

“The number of flowers that are pollinated is way lower than the maximum number of fruits a cacao tree can produce.”

Suppose you hear about cacao’s imminent threat of disappearing. In that case, this is one of the factors (together with the aging of cacao plants, the absence of young cacao farmers, the ridiculously low price, deforestation, etc.). However, let’s look at this issue starting from the basics. How does a cacao flower even pollinate?

How Cacao Pollination Works

It is hermaphrodite. It has a female component (where the eggs are) as well as a male portion (the structure that makes pollen). Pollination aims to make the pollen go to the ovule. Since both are in the same bloom, the process ought to be fairly straightforward, do you think? Nope! It’s the cacao tree we’re talking about. It’s not that simple.

It is an auto-incompatible one. What is this? The cacao flowers that are on the same tree won’t be pollinated by one another and only through flowers that come from different trees. Cross-pollinating is the most effective method (cacao flowers that get pollen from the same tree won’t produce fruit). Since cacao trees are on their feet, they require some “vehicle” to take the pollen from tree A and place it in the female parts of the tree B or reverse the process. However, it’s not enough for wind as this pollen can be too dense, sticky, and viscous to be carried through the air. Therefore, cacao flowers depend on insects flying around to accomplish the task. What’s the deal to you?

The process of cacao pollination carried out by flying insects could be very easy and simple (it occurs every day with the most commonly used flowers). Still, for a major issue fact: cacao flowers are tiny, incredible, and incredibly small and can range between 1 and 2 inches (or between 2.5 and five centimeters). In addition, the structure of its reproduction is complex, concealed, and difficult to access. This means that the cacao flower will only take in equally tiny and invisible insects. This means that only a few types of insects are suitable to pollinate cacao.

The Best Insects for Cacao Pollination

They’re too big to be able to get into a cacao flower. If they do manage to collect pollen at all, they’re taking it away for themselves. There are bees spotted around cacao flowers, but that does not mean that they are helping by pollinating. In reality, many insects come to the cacao blossom (hard to resist, even for the human eye). However, they’re not necessarily working directly with cacao’s reproduction system.

To get into the flower’s reproductive structure and allow for a reasonable quantity of pollen, insects must:

in the right dimension (smaller than 2 mm),

hairy (so that pollen sticks on their body),

is suitable for environments where cacao can thrive (very moist).

So, who are the top cacao pollinators?

Biting midge in the cacao plant. Photo Credit: Mark Moffett, photographer for National Geographic

The biting midges of the Ceratopogonidae family, as well as (to a lesser extent) gall midges of the Cecidomyiidae family, are among the best-recognized cacao pollinators around the world. Fun fact: Female midges go to cacao flowers more often than males, thus being the primary pollinators. However, even when the perfect pollinators are in the area, there are a few issues.

“The crop’s sustainability currently appears to depend on several species of tiny fly pollinators, who are frankly struggling to get the job done.”

They are surrounded by a stunning range of flowers that offer them pollen, not just cacao flowers. So cacao flowers, which are already pollinated by a small percentage of all insects, are “competing” with other flowers to draw attention and actions from midges.

Midges are amazing to get inside the cacao flower and enter the reproductive system of the cacao flower. However, they’re also limited to the number of seeds they transport. To allow a tiny flower to grow into a football-sized fruit, between 100 and 250 grams of pollen is needed, while a single midge is able to transport around thirty grains of pollen at one time.

Since cacao trees are self-incompatible, midges must move from tree to tree and travel for longer distances in comparison to just moving between flowers on the same plant or even on the ground.

Are you beginning to realize the difficulties here and how amazing cacao pollination can be? But there is a chance and the potential for improvement!

Two major strategies can be employed to boost the rate of pollination of cacao blossoms:

The best conditions are created that allow midges to thrive and multiply.

How Agroforestry Helps Improve Cacao Pollination Rates

If we offer these frogs the most comfortable environment to reside in, They will want to stay there, become involved, and reproduce. In creating the most welcoming habitat for them, they’ll be pollinating cacao flowers.

It happens that the best habitat for these insects is with the most favorable conditions for cacao trees to thrive in shady, damp, humid, semi-aquatic, or moist soil with other animals and plants with lots of decaying organic matter available to feed on (leaf litter cocoa pod husks rotting fruit from the shade tree). Midges are attracted to this area because it is the best place to lay eggs and allow their larvae to grow. It’s only under these conditions of agroforestry that cacao trees, as well as the midges, thrive in a wonderful exchange of value with each other. The best of biodiversity! However, this does not happen in monocultures. In areas with no shade, very little organic matter, less fertile soil, and the heavy application of pesticides, pollinators are in an unfriendly environment to reproduce, which reduces the number of cacao flowers that they can pollinate.

An approach to increase cacao pollination is through hand pollination.

Hand Pollination OF CACAO FLOWERS

It is definitely a laborious and meticulous technique; hand pollination aims to transfer pollen from the male portion of the flower into the female. The process must be performed by hand due to the small dimensions of the cacao flowers as well as because the female part is tucked away inside the flower. The pollinators must use the most precise tools like forceps or tweezers to get the task accomplished.

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