A Sting in the Tale (4 page)

The presence of British short-haired bumblebees in New Zealand provided a unique and exciting opportunity to give our beleaguered wildlife a boost, and to act as a flagship for conservation efforts for bees and flowers. Why not bring them back from New Zealand? Could we once again have short-haired bumblebees buzzing across the British landscape?

One obvious obstacle is that we didn't know much about this creature. There was very little in the way of studies of short-haired bumblebees before they went extinct in the UK. There would be no point in bringing them back and then watching them die out again for exactly the reason they died out in the first place. We would need to be certain that there were now enough of the right flowers for them to feed on, but we had scant records as to the flowers they favour.

So it was that in January 2003, I found myself in New Zealand with a friend and colleague, Mick Hanley, in search of the short-haired bumblebee. Mick is a stocky, ginger-haired beer-drinking Black Country lad, who did his PhD on slugs (he prefers to call it ‘seedling herbivory', but a lot of slugs were involved). At the time he was working for me on an ill-fated project to find a means of controlling fly outbreaks on landfill sites, but he is an excellent botanist and shares my enthusiasm for pies, so he made a great travelling companion. Our mission was to find out more about the food plants and habitats of the elusive short-haired bumblebee, to pave the way for an attempt at reintroduction. We needed to know which flowers it favoured for collecting pollen, which for nectar, and what habitats it was found in. Ideally, we wanted to find out where it liked to nest. Once we knew these things, it might be possible to recreate suitable habitat in Britain. Good reasons though these were, the prospect of escaping the northern winter for New Zealand summer sunshine was also attractive.

We set out from Christchurch in a tiny and rather flimsy hire car, heading south-west towards the centre of South Island which was where, we were told, the short-haired bumblebee had its hideaway. New Zealand is a land of marked contrasts. Christchurch sits on the Canterbury Plain, a rather monotonous and absolutely flat stretch of farmland covered in a neat grid of rectangular fields and a scattering of small, pretty but unremarkable towns. As we hurtled along the dead-straight road – Mick has a habit of driving ludicrously fast – ahead and to the right we could see in the distance the snow-capped peaks of Mount Cook National Park. Every few miles we crossed rivers full of snow-melt flowing down from the mountains to the sea, their shingle banks clothed in yellow tree lupins. We stopped for the night in the pleasant market town of Geraldine, and the next day, with me at the wheel, we proceeded at a slightly more leisurely pace along increasingly windy roads as our route started to climb into the foothills of the Mount Cook range. There, the neat arable fields gave way to sprawling sheep ranches and scree-covered hillsides glowing purple with viper's bugloss. According to the old records, we were entering short-haired bumblebee territory. Every few miles we stopped and searched, finding that buff-tailed bumblebees were common everywhere, and ruderal bumblebees almost as abundant. The latter was a real treat as I had only ever seen one small worker before, on Salisbury Plain. At this time of year in New Zealand the ruderal queens were still on the wing; they are absolutely huge, the biggest British species, more like flying mice than bumblebees.
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They are also unusual in that they come in many colours (most bumblebee species are fairly uniform). Some are entirely jet black, others have a range of brown or yellow stripes and white or brownish bottoms. It would be wonderful if they could one day become a common sight in British gardens as they once were.

In part because they are so variable in colour, ruderal bumblebees are quite hard to separate from garden bumblebees – the two species are very closely related. Both are not dissimilar to short-haired bumblebees. As Mick and I spent several hours catching bees and staring at them in an attempt to decide what they were, I couldn't help thinking that the folk who introduced bumblebees to New Zealand could have thought to make life easier for future entomologists by introducing only readily distinguishable species. The accepted technique is to place the bee in a clear plastic tube and then push a ball of tissue paper in so that the bee becomes trapped and cannot move. They don't much like it but it doesn't do them any harm, and you can then get a good look at them. We usually used urine sample tubes – they are cheap and do the job so I always carry a few with me in summer, but it is sometimes a bit embarrassing when a handful of them tumble out of your pocket in a public place, suggesting that you have a serious urological problem. After a lot of staring at slightly squashed bees we decided that we could distinguish between garden and ruderal bumblebees (it is all to do with the shape of the second yellow band on the back of the thorax, if you really want to know). None of them were short-haired bumblebees. According to the books, the latter are supposed to have faint greenish-brown stripes on their abdomens, but no matter how hard we stared we couldn't find anything that matched this description.

On the third day we arrived at the stunningly scenic Lake Tekapo. The lake is filled from glacial meltwater which, due to the tiny fragments of crushed rock suspended within it, is the most striking icy blue. The lake stretches for 20 miles to the foot of Mount Cook whose snow-capped peak reflects beautifully in the chilly waters. The shingle-covered shores of the lake and the surrounding meadows were awash with so many wild flowers – towering mauve spikes of viper's bugloss, dense lush stands of purple and yellow lupins, and luxuriant tussocks of red clover – that this was surely bee heaven. We jumped from the car and excitedly explored the flower patches, catching bees by the dozen. Still no short-haired bumblebees. After a couple of hours of searching I saw a large bee that looked a bit different, feeding on the bugloss. She was big, a queen, but a little smaller than the ruderal queens. She wouldn't keep still, but I was sure that she had some greenish-brown stripes.

Now, I pride myself on my proficiency with a butterfly net. I have been using one for years, and I don't often miss. There is a knack to stalking an insect, then timing the sweep and flicking the end of the net over so that one's prey is trapped in the folded end. I like to think that I have that knack, that if there were an Olympic event for netting insects then I would be a strong contender. Some insects are flightier and faster than others, and each requires a different approach. Bees are actually amongst the easiest of insects to catch because they are focused on the job of visiting flowers and will let you approach very close. Also, once their head is inside a flower they cannot see anything for a moment or two. I usually choose this moment to move close and then wait for them to drop backwards off the flower, at which point they hover briefly while choosing which flower to visit next. A quick sideways swipe and a flick of the wrist and the bee should be safely in the bag. On this occasion I fluffed it. Maybe it was jet lag, but instead of calmly approaching, I leapt forwards to strike like a total novice, lost my footing on the shingle bank and fell head first into the bugloss bush on which she was feeding. Before I could extricate myself she was gone.

Mick had wandered a way off into the shrubs, and when I shouted he ambled over and unhelpfully observed that I was an idiot. We scoured the flower patches for the rest of the day but could find no more.

Rumour had it that the best place to find short-haired bumbles was Twizel (sadly pronounced Twy-zel, not Twi-zel, which is somehow more amusing). It was 20 miles or so beyond Lake Tekapo, so after a night in a pleasant hostelry we drove on. Twizel is a popular base for skiing and is said to be lively in winter but in summer it is a very quiet town, one of those miles-from-anywhere places where it is hard to work out what anyone does for a living. It didn't seem to have anything like as many flowers as Lake Tekapo but we did find some promising patches along the Twizel River bank and the shores of Lake Ruataniwha. Search as we might, however, we could find no short-haired bumblebees. I began to wonder if I hadn't imagined the one at Tekapo. Maybe they had also gone extinct in New Zealand, and our plans for a reintroduction would have to be abandoned.

On our second day in Twizel we were driving through the back lanes of the town looking for more flower patches when we spotted a splash of colour off to our left. On investigation this turned out to be the town rubbish tip, a sprawling area of building rubble with a mountainous pile of broken bottles. Clearly the tip wasn't heavily used – perhaps they had started taking rubbish elsewhere – for lots of weeds had sprung up, including thistles, lupins and yet more viper's bugloss. We thought it would be worth a look and so started working our way through the treacherous terrain, climbing over rusting girders and crumbling piles of concrete, nets in hand. And here it was, on perhaps the least scenic spot in all of New Zealand, that I caught my first short-haired bumblebee. She was a plump worker, the brownish stripes on her abdomen giving her a slightly grubby appearance in flight. If I'm honest, the short-haired bumblebee is not the most beautiful insect in the world. They have, as you might surmise, rather short hair. The females are mostly black with a number of yellowish-brown stripes, sometimes with a greenish tinge, and a scruffy white tail. But after flying 12,000 miles and searching for five days we were thrilled. In fact the Twizel tip turned out to be a short-haired bumblebee hotspot. We saw five more before the day was out. That night we celebrated with a couple of local beers and an especially large pie each.
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We spent the next few weeks searching central South Island for short-haired bumblebees, travelling down to Queenstown in the south and as far as Palmerston on the east coast. They were not common anywhere, but we found quite a few. We mapped wherever we found them, and made notes as to which flowers they visited. To start with we used a GPS to map each bee's position – that was until I accidentally left the GPS on the roof of the car and drove off. We also watched each bee closely to see whether it was collecting pollen or nectar on each flower – nectar they drink with their long tongues, pollen they gather with their hairy legs and store in sticky balls in the pollen baskets on their hind legs. Short-haired bumblebees have long tongues, and so prefer deep flowers. They adore viper's bugloss for nectar, and also sometimes collect its purple pollen. Their favourite pollen source seems to be red clover, still often grown as a ley crop in New Zealand. We also saw them visiting bird's-foot trefoil, St John's wort and thistles, but they seemed to have a pretty narrow diet. Try as we might we could find no nests, although we were struck by the fact that almost every short-haired bumblebee we found was close to a lake, and the shores of all the lakes have stony banks. Twizel tip also has great piles of stones. Perhaps they like to nest under these stones where they would be warmed by the sun.

We took genetic samples to test if they were inbred – a technique which involves snipping a ‘toe' off the bee (not really a toe, strictly speaking the final tarsal segment). As you might imagine, they really don't like this, but experiments on more common bumblebee species have shown that it neither shortens their lifespan nor reduces their ability to gather food for the nest, so although we felt rather mean we were able to console ourselves that we weren't doing any real harm.

By the time we returned home to the UK (with a bag full of little pots containing pickled bumblebee toes), we felt that we had learned quite a bit about the short-haired bumblebee. So far as we could tell, it does not need anything particularly unusual to survive – lots of red clover and viper's bugloss would go a long way and it shouldn't be too difficult to create big patches of these kinds of flowers. A bigger question was how to get the bees back. Going in the other direction, the hibernating queens had been dug from the ground in autumn. The short-haired bumblebee must have been much more common in Kent in the 1880s than it is now in New Zealand because I think you could probably dig all winter long without finding a single one. We could catch queens in December and January in New Zealand as they came out of hibernation, but if we brought them back to the UK at that time of year there would be no flowers and they would die. Nor would it be possible to put them back into hibernation as they would have just woken from an eight-month sleep – they would never survive another six months and then have the energy to build a nest. Clearly some thought needed to be applied if we were ever to get them back living in the wild in Britain …

CHAPTER TWO

The Bumblebee Year

A bee is never as busy as it seems; it's just that it can't buzz any slower.

Kin Hubbard (American humourist)

Until the mid-1800s, so little was known about bumblebees that even the basics of their life history had yet to be described. Charles Darwin was one of the first to study bumblebees, but he had diverse interests ranging from barnacles to worms to coral reefs, and bumblebees could necessarily occupy only a small proportion of his attention. The first person to devote himself wholeheartedly to the study of bumblebees was Frederick William Lambart Sladen, the eldest of twelve children born to Lieutenant Colonel Joseph Sladen, commanding officer of the School of Gunnery at Woolwich. Born in 1876, Frederick spent his childhood at the family home, Ripple Court near Dover in Kent. Victorian Britain had a strong tradition of studies of natural history, particularly among those of ‘independent means', the lucky few who could afford to spend their days skipping through flowery meadows, pinning butterflies and pressing flowers (or at least that is how I imagine it). Schooled at home by private tutors, Sladen seems to have had plenty of time for raking through the fields surrounding his home looking for bumblebee nests, which he dug up and brought home for study. Astonishingly, by the age of sixteen he was the world expert, publishing a short book on bumblebee habits in 1892, and continuing to study them for the next twenty years, culminating in the publication of
The Humble-bee; its life history and how to domesticate it
in 1912. This was the first proper book devoted to bumblebees, and it is still an invaluable guide, containing many fascinating observations, anecdotes and descriptions of the experiments that he carried out in his garden. Species that are today rare or extinct in Britain, such as the short-haired bumblebee, were familiar to Sladen, and his descriptions of the nests of such species remain pretty much all that we know. No one since has come close to matching Sladen's knowledge of the nesting habits of bumblebees. Much of the information that follows in this and subsequent chapters was first discovered by Sladen.
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