Agro forestry | Community Ecology Lab

Posts from the ‘Agro forestry’ Category

Oct 13

New evidence supporting the role of biting midges as pollinators of cacao

In a new paper lead by Eliza Van de Sande and Sara Vroman we provide new evidence that the principal pollinators of cacao are biting midges of the order Ceratopogonidae. Work in Malaysia and French Guyana illustrates that particularly members of the genus Forcipomyia exhibit pollinating behavior and are regularly caught coverd in pollen. The study re-affirms insights from the 70’s and 80’s that over the years have been eroded as more and more studies have documented other insects visiting cocoa flowers… fueling the believe that the crop has a wider range of pollinators. Upon close inspection most of these visitors in all likelihood do not seem to pollinate and likely play a negligible role. In the paper we try to generate new testable hypotheses and a decision tree that may help to distinguish likely from unlikely pollinators. The question is far from resolved and more detailed observations are needed to distinguish the casual flower visitor from the useful visitor!

https://www.sciencedirect.com/science/article/pii/S143917912600037X?via%3Dihub

The work was covered by The Economist in a recent issue.

https://www.livemint.com/global/the-chocolate-industry-is-built-on-the-labour-of-bloodsucking-midges-11781784002526.html?aiQuickSummary=true

Nov 19

Bromeliads as habitats for cacao pollinators

In a new paper, we report the presence of cacao pollinators in bromeliad plants and identify factors that influence their abundances.

Bromeliads are common plants in the Neotropics. Being epiphytic, they are often incorrectly considered as parasites and removed from agroforestry systems. However, their water-filled leaf axils provide habitats for a diverse group of aquatic organisms, potentially including cacao pollinating dipterans which could be beneficial to local farmers. Thus far, it is unclear how frequently and abundantly potential pollinators occur in bromeliads in cacao plantations. Therefore, we investigated the aquatic fauna in different types of bromeliads in Nicaraguan cacao agroforestry systems. Our main goal was to study the impact of bromeliad morphology and vertical position on aquatic biodiversity with particular attention for larvae of presumed cacao pollinators. Aquatic biodiversity was higher in larger bromeliads and in bromeliads positioned closer to the ground. Particularly invertebrates without flying life stages were deficient in elevated bromeliads suggesting dispersal limitation. Potential cacao pollinators occurred in 66% of the bromeliads and were most abundant in bromeliads with larger tanks that were located higher in the canopy rather than on the plantation floor. We conclude that larvae of cacao pollinators can be common and relatively abundant inhabitants of tank bromeliads in cacao trees, and it is likely that preserving these habitats could boost local pollinator abundances.

The paper is out now in Hydrobiologia