The birds, the bees and everything in between – Part 2

Samantha J. Forbes and Tobin D. Northfield, 2015.

Edited by Dr. Marissa Moses and Dr. Lambert Motilal (Cocoa Research Centre, The UWI St. Augustine Campus) of a Paper presented at the International Fine Cocoa Innovation Centre Conference & Symposium, Trinidad and Tobago, March 23-24, 2015.

The plantations suffer from low yields and when coupled with an observed scarcity of midges, there is a question as whether farms have limited amounts of pollinators.

Ecuador, Brazil, Ghana, Nigeria; these are some of the countries that you may immediately think of as cocoa growers. However, cocoa is a tropical crop and once the climate is just right, cocoa can also be grown in non- traditional countries. Many non-traditional countries are encouraging small acreages that can support burgeoning boutique chocolate manufacture through on-farm processing, or by selling to aligned chocolatiers. Such is the case of the cocoa plantations such as the Daintree Estates in North East Australia (Figure 1).

Cocoa production in Australia is highly mechanised and input dependent. Even so, the plantations suffer from low yields and when coupled with an observed scarcity of midges, there is a question as whether Australian farms have limited amounts of pollinators. In our last post we explored the aspects of pollen ecology in three islands in the Caribbean. In this study, scientists at the James Cook University, Queensland, Australia, conducted experiments to determine if natural pollination success could be enhanced using cocoa husks.

In November of the sample year, a random plot design of 14 plots was generated where husks were added to seven plots while the remaining seven had no husks (Figure 2). All the trees in these plots were stripped of cocoa fruits and in February of the following year, the number of fruits/plot was counted. There was a fivefold increase in the number of fruits/plot in those plots that had added cocoa husks, versus those which had no added substrate which is in congruence with previous studies.

Husk addition therefore correlates with increased pollination, presumably because this creates a suitable habitat for the pollinators of cocoa, as well as encouraging localized midge populations versus immigration from surrounding habitats.

This research work is part of a larger research programme to understand pollination in cocoa which can be accessed here http://onlinelibrary.wiley.com/wol1/doi/10.1002/eap.1491/full

Figure 1. Cocoa producers in Australia are located along the wet tropical coast from the Daintree region to south of Tully and focused around the towns of Mossman and Innisfail.

Figure 1. Cocoa producers in Australia are located along the wet tropical coast from the Daintree region to south of Tully and focused around the towns of Mossman and Innisfail.

Figure 2. A random plot design of 14 plots was generated where husks were added (left) to seven plots while the remaining seven (right) had no husks.

Figure 2. A random plot design of 14 plots was generated where husks were added (left) to seven plots while the remaining seven (right) had no husks.


To read more on these studies we recommend:

  1. H. Brew (1988). Cocoa Pod Husk as a Breeding Substrate for Forcipomyia Midges and Related Species Which Pollinate Cocoa in Ghana. Cocoa Growers Bulletin, 40:40-42. Cocoa husks increase pollination services in Ghana (Brew 1988)
  2. M. Young, (1986). Habitat Differences in Cocoa Tree Flowering, Fruit-Set, and Pollinator Availability in Costa Rica. Journal of Tropical Ecology, 2:163-186.
  3. Adjaloo, Michael, Ben Kwaku Branoh Banful, and William Oduro (2013). Evaluation of Breeding Substrates for Cocoa Pollinator, Forcipomyia spp. and Implications for Yield in a Tropical Cocoa Production American Journal of Plant Sciences, 4: 203-210.
  4. Forbes, Samantha J. and Tobin D. Northfield, (2016). “Increased pollinator habitat enhances cacao fruit set and predator conservation.”¬†Ecological Applications, 27(3): 887-899.
  5. Winder, John A., and Pedrito Silva (1972). Cacao pollination: Microdiptera of cacao plantations and some of their breeding places. Bulletin of Entomological Research, 61: 651-655.