Greetings

I am sorry if I posted inaccurate information about which crops are
better pollinated by bumblebees than honey bees. I am sure this varies
from region to region and from year to year, but never mind. The
point, however,  was to refute the statement that wild bees are not in
decline. There is so much evidence of this, that the statement is
utter nonsense. But I was attempting to cite recent work on the
subject. Too bad our author is not up to speed on commercial
pollination; she did a thorough job of tracking the bees though.

> Bumblebees (Bombus spp.) have been declining rapidly in many temperate regions of the Old World. Despite their ecological and economic importance as pollinators, North American bumblebees have not been extensively surveyed and their conservation status is largely unknown. Bombus affinis in particular was found to have declined drastically in abundance not only in southern Ontario but throughout its native range. The loss of any bumblebee species may result in cascading impacts on native fauna and flora and reduce agricultural production.

> Pathogen spillover has been implicated in the significant declines of many animals but is a poorly understood threat for pollinators. The use of commercial bumblebees with a high prevalence of parasites for greenhouse pollination has been shown to cause pathogen spillover into populations of wild bumblebees foraging nearby. Although the effects of certain parasites on species native to eastern North America have been found to be mostly sublethal, studies have been performed only on the common species B. impatiens. Parasites found in commercial colonies have been found in species other than B. impatiens but the extent of their lethal and sublethal effects in other Bombus species remains unknown. Nonetheless, the increased use of bumblebees in greenhouse operations in recent decades has been implicated in the decline of members of the subgenus Bombus, including B. affinis and B. terricola.

> Another recent change in North America possibly implicated in the observed bumblebee declines is the extensive use of novel pesticides. In particular, one group of persistent pesticides (the neonicotinoids) has been shown to be highly toxic to bees and has been implicated in bee declines in various regions in Europe. Its use in North America began in the early 1990s, before members of the subgenus Bombus were noted to be in decline, and thus this group of pesticides may be a substantial threat. The neonicotinoids are now a commonly used systemic insecticide in many regions of eastern North America for crop and turf pest control. A member of this group (Imidacloprid) is non-lethal to bumblebees when used as directed; however, studies of its effects on bumblebees only tested one species, B. impatiens, as the representative for species in eastern North America. The lethal and sub-lethal effects of this group of pesticides urgently need to be determined for other North American bee species to understand their potential impact on pollinator decline.


" Evidence for decline in eastern North American bumblebees"
by Sheila R. Colla  and Laurence Packer
in Biodiversity and Conservation Volume 17, Number 6 / June, 2008

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