Had your morning coffee? Thank a killer bee

Smithsonian scientist shows pollination by exotic honeybees increases coffee crop yields by more than 50 percent

Debunking the widely held belief that the self-pollinating shrub that produces the popular Arabica coffee bean has no use for insects, David W. Roubik of the Smithsonian Tropical Research Institute (STRI) in Panama has demonstrated that pollination – particularly by naturalized, non-native African honeybees – dramatically boosts the yield from shade-grown coffee plants.

The results of Roubik’s research in Panama over the past five years, with comparisons to data from 15 countries in the New World and 15 in the Old World, are reported in tomorrow’s issue of the journal Nature. They emphasize the importance of shade-grown coffee – not only to improve the flavor of the beverage, but also to maintain the habitat for naturalized honeybees and other pollinators.

African honeybees took up residence in western Panama in 1985, according to Roubik; shortly thereafter, they were the major pollinators of coffee growing near forests at 1,500 meters (4,921 feet) above sea level. To test the idea suggested by his first work in 1997 – that maximum yield occurs at young coffee shrubs near forest – Roubik studied 50, two-year-old plants in Panama in 2001, keeping the pollinators away from a control branch on each plant by bagging them with fine mesh. In both studies, he found the flowers visited by pollinators produced significantly heavier, more abundant fruit. Conversely, in several countries where the areas of high-density coffee cultivation have increased two- to five-fold in the last 41 years, coffee yield has decreased by 20- to 50 percent. Roubik concluded that he loss of pollinators clearly is implicated in this decline, which strongly suggests that sustained, aggressive cultivation is detrimental, since it removes their natural habitat.

“You probably don’t realize that part of your daily routine involves bees,” said Roubik, adding, “I say this because, from what I see going on in the Neotropics, the work of two or three dozen wild African honey bees is in every cup of coffee that you drink”