Bumblebees: A Man’s Best Friend?

It was as I was mindlessly scrolling through the internet that something caught my eye which is the basis for my next blog post.

I am the first to admit that flying, stinging things are not my favourite type of insect, but I must say I always felt rather sorry for bees, unlike say wasps.

I’ve always been told that every bee’s approach is an all-or-nothing venture, and so although our relationship got off to a rocky start-after my first memory of bees is one being tangled in my hair, (which, let me tell you, was rather traumatic for a toddler and still would be now)- I don’t mind as much their fuzzy little black and yellow bodies buzzing along, because I now appreciate that they prefer to stay out of your way: to sting you is to condemn themselves to death. This is true of the well-known honeybee, however bumblebees have a slightly different story, as I shall explain later, yet I still prefer them to the furious looking wasps.

Thus, it shocked me a little to find out that the first bumblebee has been announced endangered in the U.S. I mean, it has been made very clear that bees are facing a tough time, but it never quite clicked that the fuzzy little things may not be the sign of summer anymore: may not be present at all.

This post looks at bumblebees and the Rusty Patched Bumblebee’s endangered status.

Introduction

Bumblebees are members of the Bombus genus and now over 250 species of bumblebee are known [1].

They are classed as social insects that form colonies with a single queen, although their colonies are smaller than those of their relatives, the honeybees, as they can grow to as few as 50 individuals in a nest [1].

Bumblebees feed on nectar, like their relatives the honeybees. Bumblebees use their long hairy tongues to lap up the liquid and the proboscis (the elongated appendage from the head of an animal-in insects, this is typically an elongated sucking mouthpart which is usually tubular and flexible) is folded under their head during flight. Bumblebees gather nectar to add to the stores inside the nest and pollen is used to feed their young. They use colour and spatial relationships to identify flowers they use to feed from and some species of bumblebees ‘rob nectar’ by making a hole near the base of the flower to access the nectar without touching the pollen. Overall, they are essential agricultural pollinators and thus there is growing concern about their declining numbers in Europe, North America, and Asia [1].

As I have mentioned before, a honeybee generally dies after stinging a human because the barbs on her sting and the relative elasticity of our skin prevents her from pulling her sting out. Thus, she will either be swatted to death or so much of her sting, poison sac and abdominal contents will be left hanging from the stuck sting if she pulls away that she will fly to death (not a very pleasant death, if I say so myself) [2]. On the other hand, female bumblebees can sting repeatedly without injuring themselves because their stings lack the barbs and so they can pull their sting out of the wound. However, bumblebees are generally not normally aggressive and tend to ignore humans and other animals, although they may sting in defence of their nest or if harmed [1].

Rusty Patched Bumblebee

Recently, the U.S. Fish and Wildlife Service announced that the Bombus affinis -rusty patched bumblebee- is “now balancing precariously on the brink of extinction”, when “just 20 years ago,” it was “so ordinary that it went almost unnoticed as it moved from flower to flower”. The rusty patched bumblebee has experienced a swift and dramatic decline since the late 1990s, a shocking 87% decrease in numbers, leaving small, scattered populations in 13 states and one province in the U.S. [3].

The news should not have been surprising however, as only a few months before, the first ever bees were declared endangered in the U.S. In September of 2016, seven species of Hawaiian bees received protection under the Endangered Species Act [4].

We’ll now take a closer look specifically at the rusty patched bumblebee and its importance to us.

In case you ignored them, all rusty patched bumblebees have entirely black heads, but only the workers and males have a rusty-reddish patch located in the centre of their backs. Like the other bumblebees, this species lives in colonies that include a single queen and female workers, and it is only during late summer that the colony produces males and new queens. The queens can be easily distinguished by their larger size [5].

illustrations-of-rusty-patched-bumble-bee

Fig. 2 Illustrations showing a rusty patched bumblebee queen (left), worker (centre) and male (right). [5]

Rusty patched bumblebees are generally not fussy eaters as they gather pollen and nectar from a variety of flowering plants, although since they emerge in early spring and are one of the last species to go into hibernation, they require a constant diverse supply of flowers blooming from April to September [5].

One of the reasons why the rusty patched bumblebees are flying ever closer the edge of extinction is because the habitat they once occupied is slowly being destroyed. The grasslands and tallgrass prairies of the Upper Midwest and Northeast, which the bumblebees once called home, have now been mainly converted to monoculture farms or developed areas, such as cities and roads, and the grasslands that are left are usually too small and isolated to provide the nesting sites (typically underground and abandoned rodent cavities or clumps of grass), overwintering sites (undisturbed soil) for queens and a large array of flowers to be a long-term solution [5].

Another reason for the bumblebees’ fading face from the earth is intensive farming, as many practices which have been adopted, such as increased use of pesticides, loss of crop diversity and loss of hedgerows with their flower populations and legume pastures, have harmed bumblebees. They are especially vulnerable to pesticides because they can absorb the toxins directly through their exoskeleton as through contaminated nectar and pollen [5] and this causes lethal and sub-lethal effects.

Furthermore, global climate change may also play a crucial card because the increased temperature and precipitation extremes; increased drought, early snow melt and late frost events may lead to more exposure or susceptibility to disease, fewer flowering plants [5]. There may also be fewer places for queens to hibernate and nest [5] which may be the final straw for the rapidly decreasing populations because the entire colony relies on the survival of their queen bee through winter-the only member of the colony which survives the season [3].

The Importance of Saying ‘Mi Casa Es Tu Casa’

Well, we all know the intricacies of ecosystems but the rusty patched bumblebees are in fact major contributors to our own food security. They are essential pollinators of blueberries, cranberries, and clover and almost the only insect pollinators of tomatoes. Overall, bumblebees are more effective pollinators than honey bees for some crops because of their ability to ‘buzz crop’, and this is one of the reasons why the economic value of pollination services by native insects (mainly bees) in the United States is around $3 billion per year [5].

One of the main ways people can help is by creating a more bee-friendly garden. Although this is mainly aimed at people living in areas native to the rusty patched bumblebees, you can very well apply this to your own home as almost everywhere there are issues with increasingly more important pollinators being endangered.

This can be as simple as adding a flowering tree or shrub to your garden, or more specifically to the rusty patched bumblebee, native plants such as lupines, asters, bee balm, native prairie plants and spring ephemerals. Or if you’re not one for gardening, just leave some ‘unmowed, brushy’ areas and tolerate bumble bee nests if you find them. On the other hand, if you are a garden enthusiast, try to keep away from pesticides and chemical fertiliser [5].

However, there is still hope as recently the giant panda has been downgraded from ‘endangered’ to ‘vulnerable’ [6], meaning as long as something is done in an effort to help, it may not all be doom and gloom.

References

[1] https://en.wikipedia.org/wiki/Bumblebee

[2] http://www.bumblebee.org/bodySting.htm

[3] https://www.fws.gov/midwest/news/861.html

[4] http://news.nationalgeographic.com/2017/01/bumblebees-endangered-species-rusty-patched/?utm_source=Facebook&utm_medium=Social&utm_content=link_fb20170110news-bumblebees&utm_campaign=Content&sf50288016=1

[5] https://www.fws.gov/midwest/endangered/insects/rpbb/factsheetrpbb.html

[6] http://www.worldwildlife.org/stories/giant-panda-no-longer-endangered