by Dave Goulson
Joe’s PhD was on the ecology of Hebridean bumblebees. We hoped that with Quinn’s help, he would be able to find dozens of rare bumblebee nests. The Hebrides are one of the last strongholds of the great yellow bumblebee, Britain’s rarest species, and only a handful of nests of this species had ever been found. Before heading off to the Hebrides, Joe put Quinn through his paces; in exchange for a pint, he persuaded a friend to bury small samples of nest material from a range of bumblebee species. It was important that Joe didn’t do this himself as he might have then subconsciously helped Quinn to find the samples. The bits of bee nest were placed in perforated plastic pots so that the smell could escape. Empty ‘control’ pots were also buried. In these trials Quinn worked fantastically – he found every pot containing bee nest, showing no interest at all in the control pots. It looked as if we might have finally cracked it.
So it was that Joe and Quinn spent the summer of 2006 on the lovely island of Tiree in the Inner Hebrides, living in a camper van and searching for rare bumblebee nests. Tiree is a lovely little island, with superb shell-sand beaches, lots of flowers, and heaps of interesting bees. Although it was hard to argue with his choice of field site on academic grounds, I always suspected that Joe chose Tiree in part because it has some great surfing breaks. In their summer of searching, Joe and Quinn found twenty-five nests of the moss carder bumblebee and four of the great yellow. This was pretty good, and revealed some interesting things. Joe and Quinn discovered that these bees often nest very close together; they don’t seem to mind if the entrance to another nest is just a few feet away from their own. Great yellow bumblebees, it seems, love to nest in old rabbit burrows, and the majority of bumblebee nests that Joe and Quinn found were either in sand dunes or on the sandy ‘machair’ inland from the dunes.16 Yet although this sounds impressive, the truth is that Joe and Quinn were only averaging one bumblebee nest every couple of days, whereas I’d been naively hoping that they might find dozens a day. This said, I had little idea how many nests there were on Tiree for Quinn to sniff out, so I didn’t know whether to be pleased or disappointed.
By this stage the bumblebee season was also drawing to a close, and Joe had to keep Quinn trained over the winter when there are no wild bumblebee nests to find. Moreover, a sniffer dog needs constant practice, so every day Joe had to thaw out bits of frozen bumblebee nest, bury them, and get Quinn to find them. In the early spring of 2007 Quinn and Joe then returned to the Defence Animals Centre for an update on their training. Declared fit for operation, they were unleashed once more on to unsuspecting bumblebee nests, this time in Hertfordshire, as part of a big project designed to find out how fields of oilseed rape and beans affect bumblebee nests. Most arable crops are of no interest to bees (think cereal fields, vast flowerless wastelands from a bee’s perspective), but rape and beans are both popular with bees and benefit from bumblebee pollination. You might therefore assume that having huge fields of flowers must be good for bees, but these crops flower for only a few weeks and the debate is whether such a brief glut of food is a good or a bad thing. So the plan was for Joe and Quinn to find us bumblebee nests near fields of flowering crops, and a similar number away from them, and then to monitor how they all fared through the season.
Quinn found Hertfordshire hard going. We already knew from Juliet’s nest survey that most bumblebee nests in arable farmland were likely to be in thick hedges and woodland edges, and compared to the open machair and sand dunes of Tiree, Quinn couldn’t easily get into these to sniff about. We began to suspect that many of the nests we sought might be in bramble thickets and at the bottoms of the hedgerows where the vegetation was too impenetrable for Quinn. Whatever the reason, he found far fewer nests than we had hoped. Even worse, the nests he did find were all soon dug up by badgers. The plan was to go back to each nest every week and count the bee traffic coming and going to give us some idea of how big each nest was. Sadly, the dozen or so that Quinn managed to find were all dug up by badgers within the following week. It was almost as if the badgers were following Quinn’s scent, or perhaps both Quinn and the badgers were finding the smelliest nests. Maybe the disturbance of Quinn trampling around near the nests made them easier to find, but whatever the reason, this was pretty disastrous for the project. We had no nests left to follow and see what effects flowering crops had on them.
Disillusioned by the lack of success, Joe now decided that bumblebee research was not for him and announced that he was going to retrain as a teacher. I couldn’t really blame him – when a project isn’t going as planned it can be enormously frustrating. In any case an academic career is uncertain and poorly paid, and there aren’t anywhere near enough jobs for most PhD students to be able to stay in research once they finish. The trouble was that Joe and Quinn were an inseparable team, and although we had paid the DAC to train Quinn I didn’t think that I could ask Joe to hand him over when he left. And so it was that we found ourselves once more without a sniffer dog. Quinn’s early successes on Tiree were sufficiently promising that it seemed a terrible shame to give up on this idea. On the other hand, we didn’t have anyone willing and able to take on the full-time task of becoming the handler of a new dog, even if we had one.
It was around this time that I first met Steph O’Connor. Steph had applied to study for a PhD with me, and although she didn’t make my initial shortlist she subsequently rang me up and begged for an interview. Impressed by her enthusiasm, I thought I’d give her a chance. Ben Darvill was on the interview panel, and his favourite question is to ask the candidates whether they have ever found themselves in a particularly challenging or stressful situation, and if so, how they coped. The candidate who eventually got the PhD, Nicky Redpath, had described how she and a friend had been held at gunpoint whilst on holiday in Kashmir, and had somehow talked their way out of it. Exciting stuff, but nowhere near as bizarre and amusing as Steph, who described how she had come across an advert on the Internet from a Swedish man who wanted a girl willing to dress up in Viking costume and help him stage historical re-enactments. When Steph volunteered and went to stay in his house, however, she soon found that his main interest was in getting her out of her traditional Viking dress. Instead of returning to Britain, and demonstrating a typically cavalier attitude to personal safety and common sense, Steph stole his dog – which he wasn’t looking after properly – and went to live somewhere in the woods, in a tent, with the dog and two young English guys who professed to be Nazis. Steph recounted this tale (which went on further, but I will spare her blushes) in her rather posh voice and with a beaming smile, and I and the rest of the panel were aching with laughter by the end of it. Of course this didn’t necessarily make Steph the ideal person for a PhD, but it certainly made her interview memorable. And so it was that when, a few weeks later, I found myself with some money to employ a temporary research technician, I couldn’t resist offering the job to Steph.
Soon after she started work it became apparent that Steph would be a perfect handler for a new sniffer dog. If ever there is some kind of global catastrophe, Steph will undoubtedly be among the survivors. Her idea of a perfect weekend is to go rabbiting with her three pet ferrets, or out in the woods shooting pigeons, or making home-made wine out of unpromising root vegetables. On one occasion she came in to work with a packed lunch of squirrel casserole; at the time her skinning skills were not great and she had to spit out clumps of fur as she ate. She assures me that the casseroles have improved.
When I asked the Defence Animals Centre if they could train up a second bumblebee sniffer dog, to be handled by Steph, the Leverhulme Trust kindly agreed to provide funding for three years, thereby assuring her salary. This time the DAC found a suitable dog swiftly, a springer spaniel named Toby. Once he was ready, Steph went down to Melton Mowbray to learn how to handle him, and by the spring of 2008 the two were ready for action. Steph was keener on publicity than Joe had been, so we put out a press release and she and Toby ended up appearing on BBC breakfast television and on The One Show
. Toby quickly became something of a minor celebrity, and had many invitations to visit schools. His sniffing abilities are quite phenomenal, and he gives a great demonstration for kids. If he is making an appearance in a school, we post them a few strands of moss from a bumblebee nest in advance and ask them to hide them somewhere in the school grounds. To the kids’ delight, Toby dashes around excitedly, invariably finding the nest material within minutes.
Frustratingly, however, and just like Quinn, Toby is nowhere near as good at finding real, live, wild bumblebee nests as he is at locating the bits of nest that we hide. Although he finds some, he scampers right past others. We suspected at first that freezing might slightly change their scent, and to overcome this, Steph retrained him using fresh nest material. When this didn’t seem to help, we wondered whether nests of different bee species might smell different, so that Toby would learn only to find nests of whatever species he had recently been trained to find. In fact, however, he finds nests of a range of species. Our latest theory is that perhaps real nests containing live bees smell different from bits of empty nest, but it is difficult to use nests with real bees in them when training Toby as the bees quickly fly away. At the time of writing we are trying to analyse the chemical constituents in the hope that this might help us to understand why Toby can smell out some nests but seems unable to detect (or perhaps chooses to ignore) others.
Steph has also compared Toby’s nest-finding abilities to those of human volunteers. Juliet Osborne’s approach of asking volunteers to stare at a fixed area of ground for twenty minutes does seem to work, but the majority of the time there is no nest in the area being surveyed, so it is pretty boring. An alternative tactic is to allow human volunteers to roam free when searching, which is more fun. To compare them to Toby, Steph asked dozens of volunteers from Stirling University to search the woodland on campus for bumblebee nests. Each person did one twenty-minute ‘fixed search’ (staring at a randomly allocated patch of ground), and one twenty-minute search where they could walk wherever they liked. Steph shadowed them as they went, and she also searched the woodland with Toby. Tragic as it is to report, it turned out that, despite his army training and sensitive nose, Toby is no better than a novice human volunteer in terms of the average number of nests he can find in twenty minutes. In a fixed search, volunteers had roughly a one in nine chance of seeing a bumblebee nest. When allowed to wander about, they had on average a one in four chance of locating one. Toby’s rate was also one nest per four twenty-minute search periods. Experienced bee researchers fared no better than novices (I was one of the volunteers, and to my frustration I found nothing).
This is not particularly good news for Toby and the future of sniffer dogs in bumblebee research. Given that a dog requires months of costly training, then a full-time handler, and needs constant practice with bits of buried nest over the winter, he needs to be substantially better than a human to justify the daily tin of Pedigree Chum. If we cannot find a way to improve his skills, then Toby may soon be putting on his slippers and lighting up a pipe.
Ironically, Steph herself has become very good at spotting bumblebee nests. When shadowing the volunteers she spotted many nests that they did not, and often when working with Toby she finds the nests before he does. After two and a half years of searching, she has become something close to the finely honed bumblebee nest-finding machine that we had hoped Toby would be. Between the two of them they have managed to track down over 100 bumblebee nests in the last two years, and Steph has been studying them in detail to find out what their main natural enemies are. It may be that there is no magical answer to locating nests beyond persistence, a quality that she has displayed in spades.
CHAPTER NINE
Bee Wars
Is this wretched demi-bee,
Half-asleep upon my knee,
Some freak from a menagerie?
No! It’s Eric the half a bee!
Monty Python, 1972
Bumblebees are surely among the most gentle and friendly of insects. When visiting flowers in the garden they are placid and simply fly away if disturbed by a human or another bee. Unlike wasps or honeybees, most bumblebees don’t even seem to mind very much if you poke around their nest, stinging only as an absolute last resort. Moreover, they are highly social creatures, with the daughters working together with their mother to look after their young and to gather food. Philosophers and writers from Aristotle and Plato to Shakespeare and Marx have used bee societies as a model example against which humans are regarded as comparing poorly. After all, what could be more harmonious than a sisterhood of celibate bees devoting themselves to helping their aged mother and their younger sisters? Yet this apparently altruistic and idyllic nunnery is not what it seems, for within the shadowy confines of the nest violent fights do occur, and cannibalism, infanticide and murder are rife.
To explain this dark side, it is first essential to look into why bees are normally so sociable, and this is a little complicated. In most creatures, parents look after their offspring because their offspring carry their genes into the next generation. Parents that leave lots of offspring behind pass on many genes, so any gene which makes a parent good at producing and rearing offspring will become more and more common in successive generations. Self-evidently, the genes of parents that leave few offspring will quickly disappear. This is the basis of evolution by natural selection (of course you do not need to know or understand this to be a good parent). Some evolutionary biologists even argue that we are simply vehicles manufactured by our genes as mechanisms to help them multiply – a somewhat disconcerting thought.
At the risk of this sounding a little like a textbook, I need to explain a bit about genes and inheritance. These two words strike fear into the hearts of biology undergraduates, for they associate them with fiendishly complex exam questions such as, ‘Calculate the probability that the child of a left-handed colour-blind woman from Cardiff married to a one-legged Glaswegian with sickle-cell anaemia will have brown eyes and a limp.’ I will keep this as simple as possible and there is no exam at the end. Genes are carried in chains (called chromosomes), contained within the nucleus of almost every cell in our body. Most animals, including ourselves and female bees, are diploid, meaning that we have two copies of each chromosome, and hence two copies of each gene. In humans, we happen to have twenty-three pairs of chromosomes. Female bumblebees have between twelve and nineteen pairs, depending on the species. Oddly enough, adder’s-tongue fern holds the record at over 1,200 pairs, although why this rather nondescript little plant needs so many is unknown. These chromosome chains contain all the information needed to build a fully functioning human, bee or fern, a bit like a vast instruction manual.
Each gene can be seen as a recipe – they provide the information required to build a particular protein needed in the body. It is handy that we have two copies of each gene, for some are duds – the recipe contains a mistake, and so does not work. For example, roughly one in twenty-five Caucasians has a mistake in the gene which provides the recipe for a protein with the snappy name of cystic fibrosis transmembrane conductance regulator, or CFTCR. So long as we also have a good copy of this gene, we are fine. If by chance we have two duff copies, we have cystic fibrosis.
When we produce offspring, we pass to them one of each pair of chromosomes, and hence one copy of each gene, good or bad; they obtain the other copy from their other parent. To do this, we have a special type of cell division (known as meiosis), which takes place in our gonads whereby normal, diploid cells divide to produce gametes – sperm or eggs – which are haploid, meaning they have just one copy of each of the twenty-three chromosomes. During sexual reproduction, gametes from each parent fuse to produce a diploid cell, a zygote, which then divides and grows to produce a new organism. It follows from this process that each of your offspring carries 50 per cent of your genes (the remaining 50 per cent coming from their other parent). In evolutionary terms, your genes have broken even if you have two children, for on average each of
your genes will have been passed on once. More than two children, and your genes might consider that they have done well for themselves. Fewer than two, and your genes might rightfully be disappointed in your performance.
In humans, one of the pairs of chromosomes determines sex; the sex chromosome comes in two types, X and Y. Your mother had two X chromosomes. Your father had an X and a Y, and your sex depends solely on whether he passed on to you his X chromosome or his Y chromosome. Under this common genetic system, you are not only 50 per cent related to your offspring, but you are also 50 per cent related to your parents and to your siblings. By extrapolation, you are 25 per cent related to your grandchildren, grandparents, aunts, uncles, nephews and nieces, and so on. The same applies to most animals, but not to bees. In bees, it is much more complicated.
Bees belong to the Hymenoptera, a huge and very successful insect group that also contains ants and wasps. It is not by coincidence that the Hymenoptera includes most of the known social insects. It is because of their rather weird genetics. In bees, sex is determined by a single gene. If an individual has two different copies of this gene, it is female. If it has two identical copies, or just one copy, it is male. Female bees, like us, have two copies of each chromosome. Male bees, typically, have just one. To produce a son, a female bee has just to lay an unfertilised egg; the haploid gamete develops into a healthy son. Sons have no father (male bees are bastards). To produce a daughter, she fertilises her egg using sperm from a male; in bumblebees this sperm had been stored inside the queen since the previous summer. So long as the copy of the sex-determining gene in the sperm is different from each of the two different copies held by the mother, then these diploid offspring will all be female. In a normal, healthy bee population there are dozens (perhaps hundreds) of different versions of this gene, so it is unlikely that the gene of the father will match either of the versions held by the mother.
