Bombus terrestris Linnaeus, 1758

Bumble bees may also have an impact on native bees by spreading exotic parasites and diseases which could severely damage native bee populations. In New Zealand it was found that parasites and diseases were not spread interspecifically4, but this has not been investigated in Tasmania. Indeed, it is not known which bumble bee parasites, if any, colonized Tasmania with their hosts. Donovan 4 reports that several bumble bee parasites and diseases are present in New Zealand, probably introduced with the original imported queens, and so it is likely that these were also transferred into Tasmania with the original bumble bees and these may regulate population growth. (Stout, & Goulson, 2000)

Hybridization is threatening the natural genetic diversity of B. terrestris (Widmer et al., 1998) and is also a risk to non-native bees as some of their hybrids can become established, as in Chile (Ruz and Herrera, 2001) and Japan (Matsumura et al., 2004). CABI, Acesso em 18/06/2021)

The use of non-native bumble bee species is a major ecological concern (Velthuis and van Doorn, 2006). Introduced pollinators could change the local flora, e.g., by increasing the pollination rate of exotic weeds, and threaten native pollinators by increasing competition (Goulson, 2003a,b). These concerns are reinforced by results showing that even the introduction of non-native subspecies, such as Bombus terrestris sassaricus from Southern Europe to Western Europe, could lead to the displacement of native bees (Ings et al., 2005a). CABI impactos ambientais

This study documents the extent and speed of invasion of two introduced bumble bee species in southern Argentina, showing that the most recent invader to arrive in the Patagonia region, B terrestris, has rapidly become the most abundant and widespread species, partly replacing not only the native B dahlbomii but also B ruderatus, the previously introduced species. The speed of B dahlbomii’s decline throughout much of its range is noteworthy (Figure 2); this process began, at least in the Challhuaco Valley, with the introduction of B ruderatus and was later enhanced by the arrival of B terrestris. Two years after the detection of B terrestris in northern Patagonia, B dahlbomii had completely disappeared from the Challhuaco Valley (Morales et al. 2013)

... in areas where B ruderatus has not invaded, the demise of B dahlbomii appears to be directly linked to B terrestris’ thriving. Because this very invasive species has reached extremely high local abundances (Figure 2), has larger colonies, is characterized by a longer colony cycle than B dahlbomii (WebPanel 2), and seems to be a generalist forager (Montalva et al. 2011), exploitation competition cannot be dismissed. However, circumstantial evidence implies a potential role of a novel pathogen co-introduced by B terrestris. A recent investigation of bumble bees collected in northern Patagonia, including the Challhuaco Valley, revealed that B terrestris specimens harbor the deleterious pathogen Apicystis bombi, which seems to spread to B dahlbomii and B ruderatus populations (Arbetman et al. 2013 and references therein). The replacement of B dahlbomii by B terrestris in a large portion of its range may therefore be interpreted as a result of the interplay between resource competition and possible pathogen spillover; additional research is necessary to ascertain all the possible causal factors of decline.(Morales et al. 2013)