If you’ve ever followed a bumblebee in its foraging, you might conclude by its lazy, almost drunken behaviour that it hasn’t a care in the world.
But it should. Bumblebee populations, along with those of many other native pollinators are declining. Across North America and in Europe, these important plant and crop pollinators – bees, wasps, butterflies and moths as well as hummingbirds and bats -- have all been recorded in lower numbers. In Alberta, the overall trend is one of concern. Of the roughly two dozen species of bumblebee in the province, several are in decline
. Alberta’s honeybees are not suffering the same extent of loss as their Ontario, US and European cousins, nevertheless, with 2014 winter losses at 18.5%
, it is still greater than the 15% accepted maximum. The status of many other pollinators is less certain and the fact that the historic distribution for many species is unknown suggests that declines may have gone entirely unnoticed until very recently.
The recent genome sequencing of two species of bumblebee
might help protect the iconic bumble of one of our most important pollinators. A study published in Genome Biology presented the sequenced genomes for a common European and a common eastern North American bumblebee species, providing the beginnings of understanding of the basic biology of bees and how they respond to their environment. It was accompanied by a second paper that found a genetic difference in immune response between female and male bumblebee, which was significantly higher in the female bees and surmised to be due to the females’ requirement to build and sustain colonies rather than simply reproduce.
Also published in late April were two papers in Nature that looked at the much-maligned class of pesticides called neonicotinoids, or neonics, which have been under scrutiny for their possible contribution to honeybee colony collapse for several years. The first study
, conducted in Sweden, outlined some surprising results that appears to redeem neonics in one instance, but damn it in another. This study found that honeybees were not adversely affected by neonics, but bumblebees and other wild pollinators were: the colonies of wild pollinators located alongside fields treated with neonics declined by half and were found to be unable to grow and reproduce.
More troubling still were results from the second, unrelated study
in Ireland, which found that bumblebees actually prefer the nectar from plants that had been treated with neonics. It seems the bees may be unsuspecting agents of their own demise.
Of course, it’s generally understood now that many factors contribute to weakness and decline of a pollinator species including habitat loss, parasites, disease, monoculture, severe weather events and pesticides. We do know a great deal more about the health of honeybees, for which much more extensive research has been conducted in the past decade. Apiculturists and university-based research have been using genetics and breeding programs
in efforts to improve bees’ resistance to pests such as the Varroa destructor mite as well as other diseases. In time, this work could hopefully be applied to diseases that have spilled over from honeybees to bumblebees
and other pollinator species.
Even with a healthy honeybee population, further declines in wild pollinators are a major concern for canola, alfalfa and other crop farmers. In the US, this concern prompted the creation of a National Strategy to Promote the Health of Honey Bees and Other Pollinators
, which was announced in mid-May. According to this and similar Canadian guidelines, habitat preservation and regeneration will be key pillars to the survival of wild pollinators, alongside continued research and breeding efforts.