The invasion of southern South America by imported bumblebees and associated parasites

Abstract

Summary The Palaearctic Bombus ruderatus (in 1982/1983) and Bombus terrestris (1998) have both been introduced into South America (Chile) for pollination purposes. We here report on the results of sampling campaigns in 2004, and 2010-2012 showing that both species have established and massively expanded their range. 2. Bombus terrestris, in particular, has spread by some 200 km year À1 and had reached the Atlantic coast in Argentina by the end of 2011. Both species, and especially B. terrestris, are infected by protozoan parasites that seem to spread along with the imported hosts and spillover to native species. 3. Genetic analyses by polymorphic microsatellite loci suggest that the host population of B. terrestris is genetically diverse, as expected from a large invading founder population, and structured through isolation by distance. Genetically, the populations of the trypanosomatid parasite, Crithidia bombi, sampled in 2004 are less diverse, and distinct from the ones sampled later. Current C. bombi populations are highly heterozygous and also structured through isolation by distance correlating with the genetic distances of B. terrestris, suggesting the latter's expansion to be a main structuring factor for the parasite. 4. Remarkably, wherever B. terrestris spreads, the native Bombus dahlbomii disappears although the reasons remain unclear. Our ecological and genetic data suggest a major invasion event that is currently unfolding in southern South America with disastrous consequences for the native bumblebee species.

Massively Introduced Managed Species and Their Consequences for Plant–Pollinator Interactions

“…Parasite spillover consequences for wild pollinators could be huge and remain largely underestimated (F€ urst et al, 2014), because infections can strongly reduce fitness, survival and even foraging behaviour in wild populations (Graystock et al, 2013b, Garibaldi et al, 2016Meeus et al, 2011). In Patagonia, the spectacular regression of the endemic B. dahlbomii following B. terrestris invasion has been suspected to be caused by pathogen spillover (Morales et al, 2013;Schmid-Hempel et al, 2014). In the United States, Cameron et al (2011) observed a correlation between N. bombi infections and declining populations of eight native bumblebee species.…”

Synergistic effects of floral phytochemicals against a bumble bee parasite

“…Crithidia bombi infects bees in many ecosystems worldwide (Cameron et al., 2011; Schmid‐Hempel, Schmid‐Hempel, Brunner, Seeman, & Allen, 2007), where phytochemical exposure will be complex and varied. The parasite's deleterious effects on infected bees (Brown, Schmid‐Hempel, & Schmid‐Hempel, 2003; Sadd & Barribeau, 2013), including threatened native species (Schmid‐Hempel et al., 2014), indicate its ecological and practical importance (Sadd & Barribeau, 2013). …”

A sting in the spit: widespread cross‐infection of multipleRNAviruses across wild and managed bees

“…2014; Schmid‐Hempel et al . 2014). EIDs are known to be a major threat to the most widely used commercial pollinator, the honeybee ( Apis mellifera ), with the exotic ectoparasitic mite, Varroa destructor , meriting particular attention.…”