Introduced Honeybees (Apis mellifera) Reduce Pollination Success without Affecting the Floral Resource Taken by Native Pollinators

Abstract

Detrimental effects of introduced honeybees (Apis mellifera L.) on native plant pollination have been predicted based on their observed deterrence or expulsion of native pollinators or their depletion of floral resources. Here, a case is reported in which floral visitation by the introduced honeybee affects male fitness and probably fruit and seed production of a tropical tree without affecting the resource sought by the native pollinator. Clusia arrudae is a dioecious species and is pollinated by individuals of Eufriesea nigrohirta that visit its flowers to collect resin. Male flowers, however, are also visited by individuals of A. mellifera, which remove ca 99 percent of their pollen grains. When E. nigrohirta leaves flowers previously visited by A. mellifera, they carry on their bodies less than 0.1 percent of the pollen grains carried by bees leaving flowers not visited by the honeybee. This may explain why the frequency of A. mellifera at male flowers is negatively correlated with the number of seeds produced by female flowers. This novel situation may affect other plants offering alternative rewards for pollinators, such as resins, oils, and aromatic compounds. RESUMO A polinização de espécies nativas de plantas pode ser prejudicada em decorrȩncia das visitas da abelha introduzida Apis mellifera. Isto tern sido previsto com base em registros de situaço̧es em que esta abelha impede o acesso de polinizadores nativos ou os expulsa das flores e também pelo fato dela exaurir os recursos florais. Clusia arrudaeé polinizada por Eufriesea nigrohirta que busca resina em suas flores. Apis mellifera visita as flores masculinas de Clusia arrudae e remove cerca de 99 percento dos grãos do pólen da flor visitada. Quando E. nigrohirta visita flores já visitadas por A. mellifera, ela carrega em seu corpo menos de 0.1 percent dos grãos de pólen carregados por abelhas que visitam flores ainda não visitadas por A. mellifera. Isto pode explicar porque a freqüȩncia de A. mellifera em flores masculinas é negativa‐mente correlacionada com a quantidade de sememes produzidas por flores femininas. Esta é uma situação que ainda não havia sido registrada e que pode afetar outras plantas que oferecem recursos alternatives para o polinizador, como resinas, óleos, e compostos aromáticos.

Bees (Hymenoptera: Apoidea) and flowers in natural forest patches of southern Pantanal

“…This overlap in flower visitation has been reported in areas of Cerrado in the State São Paulo (Pedro & Camargo 1991), and to a lesser extent in arid areas in northeastern Brazil (Zanella & Martins 2003). Plenty of studies show evidences that Apis mellifera affects the reproductive success of different plant species (Gross & Mackay 1998, Hansen et al 2002, Carmo et al 2004) as well as the diversity and abundance of communities of native bees through resource competition (Roubik 1980, 2009, Roubik & Villanueva-Gutiérrez 2009.…”

Reproductive biology of Protium spruceanum (Burseraceae), a dominant dioecious tree in vegetation corridors in Southeastern Brazil

“…Two of the most observed visitors of dense inflorescences of P. spruceanum are Apis mellifera and Trigona sp., and the opportunistic behavior of such family (Apidae) has been reported in many habitats and associated with plant density and clusters (Ramalho 1990). Thought exotic honeybees can be important competitors of native pollinators (Carmo et al 2004), sometimes they have neutral or even beneficial effects on the pollination of native plants (Gross 2001, Dick et al 2003, Suzuki 2003, because of their high density, social organization and propensity for agricultural landscapes (Dick et al 2003). High temperatures around midday could result in high insect activity, as observed in this study, and this could lead to high visiting rates (Arroyo et al 1985).…”

Diversidade de abelhas visitantes das flores de Citrus em pomares de laranjeira e tangerineira

“…mellifera é uma espécie exótica no Brasil, que compete com as espécies nativas na exploração dos recursos florais, sendo predominante na estrutura de diferentes comunidades já estudadas (AGUIAR; MARTINS, 2002;BIESMEIJER;SLAA, 2006;CARMO et al, 2004;GAMITO;MALERBO-SOUZA, 2006. Outras espécies sociais, como Trigona spinipes e Tetragonisca angustula, foram consideradas dominantes neste estudo, mas a contribuição delas no percentual total de abelhas coletadas é baixa (aproximadamente 22% na laranjeira e na tangerineira).…”