When bio is not green: the impacts of bumblebee translocation and invasion on native ecosystems

Abstract

Adequate pollination is fundamental to optimize reproduction and yield of most flowering plants, including many staple food crops. Plants depending on insect pollination rely heavily on many wild species of solitary and social bees, and declines or absence of bees often hampers crop productivity, prompting supplementation of pollination services with managed bees. Though honeybees are the most widely deployed managed pollinators, many high-value crops are pollinated more efficiently by bumblebees (Bombus spp.), prompting domestication and commercial rearing of several species. This led to a blooming international trade that translocated species outside their native range, where they escaped management and invaded the ecosystems around their deployment sites. Here, we briefly review the history of bumblebee invasions and their main impacts on invaded ecosystems, and close by discussing alternatives to the use of commercially reared bumblebees to enhance crop pollination. As evidence of widespread negative effects on local ecosystems of bumblebee invasions builds up, bumblebee trade adds to the list of examples of "biological" strategies devised to solve agricultural problems that ended up being far from the "green," eco-friendly solutions they were expected to be.

Different bees as vectors for entomovectoring with enhanced pollination and crop protection control: current practices, use cases and critical view on transport

“…The increasing commercialisation and the associated anthropogenic movement of commercial pollinators in and outside their natural ranges can have an impact on native bee species [31]. Moreover, commercial agricultural populations can impact local bee fauna through several mechanisms [32]. For example, they are said to spread harmful pathogens to native wild bee populations.…”

“…As such, the invasive species can replace the native species through competitive exclusion [33]. Competition for both floral resources and nesting sites can have negative effects on the local bee fauna [32]. Finally, interspecific mating between invasive and native bumblebee species can have a detrimental impact on the native bee species [32].…”

“…The native bumblebee species Bombus dahlbomii is a more efficient pollinator for Alstroemeria aurea, for example, in terms of pollen quantity and quality deposited per flower visit. Owing to a shift towards Bombus terrestris and Bombus ruderatus, Alstroemeria aurea could suffer from a reduced fruit set and/ or quality [32].…”

“…In 1880, Bombus terrestris was introduced into New Zealand for the pollination of red clover, and, merely five years later, populations were found in the wild. Subsequently, the pollinator expanded its territory at a rate of approximately 90 km/year, becoming the main pollinating bumblebee [32]. Bombus ruderatus, which was introduced around the same period, became ubiquitous as well, although in some areas the Bombus ruderatus population has declined, especially after the Bombus terrestris introduction [32].…”

“…Subsequently, the pollinator expanded its territory at a rate of approximately 90 km/year, becoming the main pollinating bumblebee [32]. Bombus ruderatus, which was introduced around the same period, became ubiquitous as well, although in some areas the Bombus ruderatus population has declined, especially after the Bombus terrestris introduction [32]. International companies such as Biobest and BVT should therefore pay attention to the local situation.…”