Cocoa Pollination 

​The cocoa tree (Theobroma cacao L.), a major traded commodity globally, strongly depends on insect pollinators for fruit production (1,2). But there are major knowledge gaps on the pollination ecology of cocoa and its contribution for increasing yields sustainably. ​This is relevant as stakeholders face the challenge of boosting production without further forest conversion.

 As we know that around 5% of flowers are naturally pollinated, and from this proportion less than 10% develop to harvestable fruits (3), the main question arising is: to what level can enhancing pollination services in cocoa help meeting this challenge? 
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Cocoa flowers

The case of Central Sulawesi, Indonesia

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Results of hand pollination experiments in Central Sulawesi (4)
During my PhD studies, I wanted to contribute in closing the knowledge gaps in cocoa pollination. The main findings of my work in Indonesia can be summarized as follow:
  • In contrast to previous assumptions, tiny midges are not the most common pollinators. 
  •  Other dipterans, ants, parasitic wasps may play an important role in pollination.
  • Forest conservation and shade trees help sustaining more pollinators in the farms.  
  • Hand-pollination of 13% flowers in a tree improves yields by 51%, and by 161% if hand pollinating an entire tree (100% flowers).
  • Hand-pollination benefits farmers by improving their income by 69% after considering farm and labor costs. 
Find out more here.

Cross-Continental Cocoa Pollination ​

The Cross-Continental Cocoa Pollination project was developed with the support of international scientists conducting long-term research in cocoa agroforests in the main producing regions of South America, West Africa, and South East Asia. 

This project uses the studies carried out in Indonesia as baseline, with the addition of innovative sampling techniques and ideas, to understand the contribution of cocoa pollination at a global level.

​Current field work covers countries such Brazil, Ghana, Cameroon and Indonesia. 

Main research areas

The contribution of hand pollinations to increase yields
  • Long-term hand pollination effect on tree-energy resources
  • Optimum hand pollination level for maximum yields
  • Tree physiology response to hand pollination
  • Tools to reduce hand pollination time and costs
Landscape and farm management effect on pollinator communities
  • Landscape configuration (e.g. land-use type, forest size, tree diversity, vegetation structure)
  • Farm management (e.g. shade tree diversity, canopy cover, soil litter type, fertilizer and pesticide use) 
  • Tree performance (e.g. flower production, self-in/compatibility, cocoa age) ​
Innovative techniques to monitor insect pollinators
  • Reveal the in/direct role of ants in pollination
  • Plant-pollinator and pollinator-pest interactions
  • Metabarcoding to identify insect pollinators
  • High resolution insect camera-traps using machine learning algorithms
References
(1) Donald, P. F. (2004). Biodiversity impacts of some agricultural commodity production systems. Conservation biology, 18(1), 17-37.
(2) Tscharntke, T., Clough, Y., Bhagwat, S. A., Buchori, D., Faust, H., Hertel, D., ... & Scherber, C. (2011). Multifunctional shade‐tree management in tropical agroforestry landscapes–a review. Journal of Applied Ecology, 48(3), 619-629.
(3)  Toledo-Hernández, M., Wanger, T. C., & Tscharntke, T. (2017). Neglected pollinators: Can enhanced pollination services improve cocoa yields? A review. Agriculture, ecosystems & environment, 247, 137-148.
(4) Toledo-Hernández, M., Tscharntke, T., Tjoa, A., Anshary, A., Cyio, B., & Wanger, T. C. (2020). Hand pollination, not pesticides or fertilizers, increases cocoa yields and farmer income. Agriculture, Ecosystems & Environment, 304, 107160.