I think technically summer has already started (not that you would notice with all the rain we’ve been having!). So, apologies for the lateness of this article.
Way back at the end of March, I was thrilled to see my first bumblebee of the year, a buff-tailed queen, whilst strolling through Princes Street Gardens on a very dull and overcast day. These are the largest of our bumblebees and often the first species to emerge from hibernation. I tried and failed to get a photo as this queen wasn’t in the mood for a photo shoot. Which is understandable really. Spring is a particularly busy time of year for bumblebees. Not only do the queens have to find nectar to renew their depleted energy reserves but they also have to find a suitable nesting site within which to establish their colony. To that end you will often see queens flying very low to the ground in a zig-zag pattern. They stop now and then to investigate some dark spot for its summer letting potential! Most bumblebee species nest on or in the ground and will take over old mouse holes or occupy your compost bin.
Urban parks and gardens play an important role in the conservation of our declining bumblebees. Of the 24 species found in Britain, only six are considered common. 7 species are BAP species (Biodiversity Action Plan) which means the government are obliged to carry out specific conservation measures to ensure their future. Habitat loss is the main reason for their catastrophic declines as over 97% of our wildflower meadows have been lost over the last 70 years. For bumblebees to thrive they need a continual supply of nectar and pollen from early in the Spring, February/March to late Autumn, September/October. It is therefore very important to plant areas with a great mixture of flowering trees and shrubs, which will flower at different times in succession throughout these seasons.
As you can well imagine the Royal Botanic Gardens in Edinburgh is a great place for bumblebee spotting. I’ve managed two visits this season, in May and June and have seen all but one of the six common species. The Garden bumblebee is proving elusive. During my last visit I even found an entrance to a white-tailed bumblebee nest, in the ground near the top of the waterfall! Often nests are really hard to find and this was only the second one for me. It was lovely to observe the constant traffic in and out of workers with full pollen baskets dropping off supplies and others leaving once more on yet another foraging trip.
Now that I am working for the Bumblebee Conservation Trust I am learning so much about these fascinating insects. I had never heard of nectar robbing until recently and just last week I saw it in practice while walking into town, somewhere near East London Street. Bumblebee species differ in the length of their tongues, so in theory only those species with long tongues can access the nectar inside long-tubed flowers. But the Buff-tailed bumblebee, a short-tongued species, has a pair of jaws, which it uses to snip a hole at the base of such long-tubed flowers to gain access to the sweet nectar within! This beautiful flowering shrub, pictured above, was alive with bumblebees but the poor flowers were nearly falling apart with all the nectar robbing going on. Buff-tails weren’t the only perpetrators. A smaller species, the Early bumblebee, was an accessory to the crime. They don’t have jaws with which to make holes but they take advantage of those already made and get a sweet reward once the nectar has been replenished.
Who knew that such a tiny brain could contain such deviousness!