Pollination services of Africanized honey bees and nativeMelipona beecheiito buzz-pollinated annatto (Bixa orellanaL.) in the neotropics

Abstract

Africanized honey bees (AHBs) are the predominant flower visitors of many plants in the neotropics, although little evidence is available on their efficiency as pollinators on native crops. Annatto (Bixa orellana) is a buzz-pollinated neotropical tree. We compared the pollination service provided by AHBs and native Melipona beecheii (Mb) to annatto in the Yucatan. As a result of the different abilities of both species to sonicate, a prediction of the present study is that AHBs on individual visits would result in less efficient pollinators on this crop. A higher frequency of AHBs on flowers (73.8%) compared with Mb (21.3%) was found. However, AHBs deposited significantly less pollen on the stigma and produced less fruits, with fewer seeds and weight, than Mb. A higher pollination index efficiency was obtained for Mb (0.9) compared with AHBs (0.6). AHBs did not sonicate annatto and gleaned the pollen released after Mb visits, which suggests that they act as commensals of the latter. By acting as commensals, AHBs, despite their high abundance, appear to marginally contribute to the pollination of annatto. Studies conducted under scenarios with a differential abundance of AHBs and efficient sonicating species are necessary to test this hypothesis on annatto and other buzz-pollinated plants in the neotropics.