The spatial dynamics of diversity in Centridini bees: the abundance of oil-producing flowers as a measure of habitat quality

Abstract

It is assumed that oil bees in the tribe Centridini and oil flowers in the family Malpighiaceae have a conservative evolutionary association, and it is postulated that they also have a tight ecological relationship. Here, we test the hypothesis that variations in the availability of Malpighiaceae flowers affect the abundance and richness of centridine bees. We measured oil availability and sampled bees on oil flowers of Byrsonima sericea DC. (Malpighiaceae) in 12 localities (habitats), along the Northeastern Brazilian Atlantic coast. The availability of floral oil was strongly correlated with richness and abundance of centridine bees. In contrast, no significant correlation was observed between abundance and richness of centridine bees after excluding the effect of oil abundance. We proposed that the asymmetry of density dependence is determining the observed pattern of regional diversity for centridine bees.