Evaluating bee (Hymenoptera: Apoidea) diversity using malaise traps in coffee landscapes of Costa Rica

Authors: NGO, HIEN - York University; GIBBS, JASON - Michigan State University; Griswold, Terry; PACKER, LAURENCE - York University

Submitted to: The Canadian Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/1/2012
Publication Date: 5/21/2013
Citation: Ngo, H., Gibbs, J., Griswold, T.L., Packer, L. 2013. Evaluating bee (Hymenoptera: Apoidea) diversity using malaise traps in coffee landscapes of Costa Rica. The Canadian Entomologist. 145:435-453.

Interpretive Summary: Coffee production benefits from pollination services provided by bees. Without bees there is still some production but quality of fruit is reduced and yield is lower. There are two main ways in which coffee is produced, with shade trees and unshaded. Since bees are important to coffee production we asked whether shaded or unshaded coffee had more bees and if they differed in the kinds of bees. Unshaded coffee farms had significantly higher numbers of bee species than shaded and, during coffee bloom, more than nonagricultural sites. Unshaded farms had much higher diversity and abundance of small ground-nesting sweat bees (Lasioglossum) than unshaded farms. These bees, which were not previously known to be common in coffee, accounted for almost half of bees in unshaded coffee farms. Further studies are needed to determine if they are important pollinators of coffee.

Technical Abstract: Even though Arabica coffee (Coffea arabica Linnaeus, Rubiaceae) can self-pollinate, bees are important pollinators, without which there is lower fruit quality and yield. We studied bee diversity in coffee agroecosystems in Costa Rica during two coffee flowering seasons (2005 and 2006). Malaise traps were used as a passive sampling method to collect bees during coffee blooms. We collected 1012 bee individuals from three different site types: nonagricultural fields and shaded and unshaded coffee farms. Unshaded coffee farms had significantly higher species richness (S) and number of bee individuals (n) than did the shaded coffee farms and nonagricultural sites. Overall bee diversity did not differ among site types but evenness (J0) was significantly lower in unshaded coffee farms. Using a more detailed community analysis, there was a significant association between functional groups and habitat type with more species and individuals of small-bodied ground-nesting bees (Lasioglossum (Dialictus) Robertson) associated with unshaded coffee farms. A large proportion (49%) of bees collected were of this subgenus, which was never before reported as common in coffee agroecosystems. Further studies should establish whether Dialictus is important in coffee pollination. We propose strategies involving conservation of native bees through simple habitat management for small-scale coffee farms that may improve crop quality and quantity.