The worldwide importance of honey bees as pollinators in natural habitats

Abstract

The western honey bee () is the most frequent floral visitor of crops worldwide, but quantitative knowledge of its role as a pollinator outside of managed habitats is largely lacking. Here we use a global dataset of 80 published plant-pollinator interaction networks as well as pollinator effectiveness measures from 34 plant species to assess the importance of in natural habitats. is the most frequent floral visitor in natural habitats worldwide, averaging 13% of floral visits across all networks (range 0-85%), with 5% of plant species recorded as being exclusively visited by For 33% of the networks and 49% of plant species, however, visitation was never observed, illustrating that many flowering plant taxa and assemblages remain dependent on non- visitors for pollination. visitation was higher in warmer, less variable climates and on mainland rather than island sites, but did not differ between its native and introduced ranges. With respect to single-visit pollination effectiveness, did not differ from the average non- floral visitor, though it was generally less effective than the most effective non- visitor. Our results argue for a deeper understanding of how , and potential future changes in its range and abundance, shape the ecology, evolution, and conservation of plants, pollinators, and their interactions in natural habitats.

Are native bees and Apis mellifera equally efficient pollinators of the rupestrian grassland daisy Aspilia jolyana (Asteraceae)?

“…Freitas & Paxton 1998;Vicens & Bosch 2000) as well as in native plants (e.g. FumeroCabán & Meléndez-Ackerman 2007;Hung et al 2018). Such studies have shown that A. mellifera can be as good pollinator as native species in both crops and native plants (e.g.…”

“…Such studies have shown that A. mellifera can be as good pollinator as native species in both crops and native plants (e.g. Freitas & Paxton 1998;Rader et al 2009;FumeroCabán & Meléndez-Ackerman 2007;Hung et al 2018). However, A. mellifera is sometimes less effective than native species in commercial crops (e.g.…”

“…In this context, the invasive honeybee, Apis mellifera is often regarded as an ineffective pollinator despite its overwhelming abundance (Hung et al 2018). For instance, A. mellifera can collect nectar while avoiding contact with pollen and may even remove pollen grains from stigmas (Westerkamp 1991;Gross & Mackay 1998;Vicens & Bosch 2000).…”

“…Nevertheless, A. mellifera can still provide sufficient pollination for plants (e.g., Freitas & Paxton 1998;Fumero-Cabán & Meléndez-Ackerman 2007), and there has been a great interest in contrasting the effectiveness of the honeybee with that of other indigenous floral visitors (e.g. Freitas & Paxton 1998;Vicens & Bosch 2000;Rader et al 2009;Hung et al 2018). Finally, assessing the role of invasive and dominant floral visitors such as A. mellifera in plant reproduction can benefit conservation planning and management strategies (e.g.…”

“…We were interested in the role of different floral visitors as pollinators for this plant. Moreover, the role of the invasive honeybee in pollination is rarely assessed with experiments (Hung et al 2018), even though A. mellifera is often a dominant floral visitor in diverse Neotropical communities (Souza et al 2018). Thus, we asked whether invasive Apis mellifera and native bees have different effectiveness as pollinators of a generalist native plant.…”