Bee Quest

by Dave Goulson

  What, you may be wondering, about the humble beaver? Beavers are a native species, and they pose no direct threat to livestock or man.fn6 They used to be found all over Europe, but were hunted for their fur and became extinct in Britain in the sixteenth century and in much of Europe by the nineteenth century. In most of Europe they are now protected, and through natural colonisations and no less than twenty-four deliberate reintroductions they are now found once again in much of their former range, though more patchily distributed than before. Evidence that they are overwhelmingly beneficial to ecosystems is clear – by building their lodges, damming streams and excavating water channels they create much new habitat, increasing the diversity of plants, birds, fish and amphibians. In the USA, the total weight of all the creatures living in beaver ponds is up to five times greater than in the undammed sections. On top of this they are a huge hit with tourists. Why on earth would we not want them back in the UK?

  Depressingly, even the reintroduction of this benign, charming rodent was met with much opposition in the UK, and until very recently the UK was more or less the only European country left that did not have beavers. Our National Farmers’ Union is strongly opposed to them; in response to a planned release, their spokesman said: ‘I haven’t seen any evidence that they’ll contribute anything to the ecosystem. The history as far as introducing mammals in particular is not a particularly good one. We’ve seen the grey squirrel, rabbits and even mink so in reality there isn’t much evidence to suggest they do any good at all.’fn7

  It is hard not to feel embarrassed on behalf of the poor fool who said this. Aside from demonstrating a complete lack of knowledge or simply stubborn denial of the abundant evidence that beavers do greatly benefit ecosystems, he goes on to draw ridiculous parallels with three non-native species. Nobody denies that alien species such as mink can cause devastation, but the beaver is, of course, a native animal. The only reason they aren’t here is because we shot them all and turned them into snuggly hats. As well as the NFU, there was also resistance from sporting estates in Scotland who feared that beaver activities might upset the salmon, despite all the studies elsewhere showing that fish overwhelmingly benefit from the activities of beavers.

  Despite the knee-jerk opposition, the argument for a reintroduction eventually won the day, and a small release of sixteen animals took place in 2009 in Knapdale in Argyll, western Scotland. At roughly the same time beavers also appeared as a result of illegal releases in Tayside in the east of Scotland, and in the River Otter in south Devon. The official release was not without its teething problems – some animals were illegally shot by disgruntled locals, and one – a prime candidate for the beaver equivalent of a ‘Darwin Award’ – felled a tree, which toppled and killed it. Nevertheless, by 2014, fourteen young had been born in the wild, and over 30,000 people had visited Knapdale to see the beavers and their constructions. The release was acclaimed as a great success, and perhaps has helped to persuade authorities in England to allow the Devon beaver population to remain. This has now become an official reintroduction programme, with formal monitoring by the Devon Wildlife Trust. At the last count there were at least twelve animals, including one young wild-bred kit born in the summer of 2015. Knepp almost certainly has enough freshwater habitat along with plenty of young trees for them to gnaw and fell, and it would be fantastic to see how their activities help to shape the landscape. Charlie has hopes that this might one day become a reality.

  After a day at Knepp, appetite whetted, I was keen to find an excuse to return. Luckily, just such an excuse soon presented itself. Charlie and the team at Knepp are very keen to find out more about what wildlife they have, and how it is changing over time. They’ve had quite a number of surveys, for example of the plants, birds and butterflies, but no one had surveyed the bees, and Charlie asked me if I’d be willing to do it. It was too good an opportunity to miss – the chance to wander around Knepp once a month through the spring and summer was irresistible. I’m pretty good at identifying bumblebees – it would be embarrassing if I were not after all these years of studying them – but I’m far from fully competent in the identification of some of our smaller, solitary bee species and so I asked my PhD student Tom Wood if he’d like to come along. Tom is a classic obsessive entomologist – although I guess you might be thinking about pots and kettles at this point. His PhD is on looking at how effective wildflower strips on farms are at increasing bumblebee populations, so he spends all his working days studying bees. At weekends, he goes looking for bees – in particular the rarer solitary species. His holidays are spent in southern Europe looking for more bees. Come his birthday, he requests that his presents be obscure books on bees, rare and expensive tomes with gripping titles such as A Key to the Halictidae of South-western Moldavia.fn8 You might, quite reasonably, have gained the impression that I am a bee fanatic – but next to Tom my interest seems almost casual, a take-it-or-leave-it, amateurish kind of hobby. Tom is the real deal, perhaps one of the last of a dying breed; just the man I needed if I was to do a thorough job of discovering all the bees at Knepp.

  So it was that in the middle of April 2015 we began our bee survey. Penny Green, the Knepp ecologist, joined us, keen to learn more about bees. It was a slightly overcast, chilly day, and we did not get off to a great start. In early spring there are not too many flowers at Knepp – much of the turf is short at this time of year, grazed down over the winter by the animals, and there were few flowers save the blackthorn hedges and scrub which were in full, dazzling bloom. Unfortunately, blackthorn isn’t very popular with bees, so we struggled to find many of them, just a handful of queens of common species such as buff-tails and red-tails.

  Perhaps more exciting were the other creatures we saw. Penny had scattered pieces of old tin around the estate, which did look untidy and are of course rather unnatural, but they provide a great way to monitor reptile populations. Snakes and lizards tend to gather beneath them, particularly on cool days in spring, for the tin absorbs heat and allows them to warm up. Under the very first tin I lifted was a knot of slow-worms, ranging in colour from dark brown to silver to fawn, a knot that untangled itself as the animals glided slowly away in silent panic at my intrusion. The next tin had more slow-worms, and a goodly sized grass snake, perhaps three feet long. The next, close to the scrape where Charlie and I had watched the pigs wallow, had a couple of common frogs and both a smooth and a great crested newt. I could have spent the rest of the day on a herpetological adventure turning over bits of tin, but this not being a prime way to find bees I thought I’d better focus on the job in hand.

  Near the scrape was a stand of young sallows in full bloom, and it was here that we found most of the bees. Sallow blossom is an absolute favourite with bees, the yellow powder-puff flowers of the male trees producing both pollen and nectar, the more drab green flowers of the females producing just abundant nectar. Given that there are rather few other common flowers in bloom in April, these trees are almost certainly a mainstay of the diets of many queen bumblebees, as well as some of our solitary bee species. It is just as well that sallows are doing so well at Knepp. Queens of several of the common bumblebees were there, mainly early and buff-tailed bumblebees, plus a few early workers.

  There are some small areas of ancient woodland at Knepp, and it occurred to me that this could provide a good place to find bees. It was just about time for the bluebells to be in flower, and in a good patch of bluebells one can usually find a few bumblebee queens foraging. Bluebell woods are an iconic British habitat – although bluebells have a wide distribution, nowhere else do they occur at such high density as in Britain, where they form swathes of blue in mid to late April, before the leaves of the trees above burst out and shade them for the rest of the year. I headed over to a stand of large oaks to see what was beneath them, but instead of bees or bluebells I found pigs. Three sows and innumerable piglets were lying in a dusty heap amidst a scene of devastation. The woodland floor had been thoroughly rootled. Charlie was later
to tell me that pigs love to eat bluebell bulbs, and so for them a bluebell wood means one thing – meal time. On the Continent, woodland flora is more mixed and diverse, but perhaps not as spectacularly beautiful. A few bluebells remained, blooming amongst the mounds of earth, but most had gone. Wood anemone, wild daffodils and primroses were creeping in instead, and I guess they will spread over time.

  This raises an interesting question. Are our beautiful bluebell woods an artificial habitat, only possible in Britain because our overzealous hunting of wild boar accidentally exterminated the bluebell’s biggest enemy? Are those of us that would like to see wild boar living across the UK in the wild,fn9 as they still do in almost all of Europe, willing to pay the price that we may lose many of our bluebell woods? I would say yes, but that of course is just my value judgement, and others will no doubt disagree. There are often no right answers in conservation.

  I snuck up close to the sleeping pigs, camera in hand and snapping away, until suddenly they detected my presence and exploded in a cloud of dust, grunts and squeals. It was hard to know how to react to such huge animals at such close quarters, and I was momentarily aware of just how much bigger the sows were than me. Were these wild animals or domestic ones? I wasn’t quite sure, and a pulse of adrenalin surged through me. Of course, once the pigs got over their surprise they were fine, and the adults settled back to their slumber, while the inquisitive piglets crept up to me to have their portraits taken.

  I realised once again that I had digressed from the mission to find bees, so I left the pigs to it, and went in search of Tom and Penny. In the meantime, Tom had been busy searching for solitary bees, most of which are rather small and difficult to identify without a lot of practice. They don’t even have a satisfactory name as a group, for although they are usually referred to as solitary bees some are not in fact solitary. Tom prefers the technically accurate ‘non-corbiculate’ bees, the corbicula being the proper name for the pollen basket possessed by bumblebees and honeybees but not by these other species, yet this is an abstruse term that would mean nothing to most people. Perhaps the term ‘forgotten bees’ is best, for these obscure creatures are little studied by scientists and almost entirely unknown to most of us. Yet what we do know about them suggests that they are important in pollinating crops and wildflowers, and that they have fascinating, complex and highly variable life histories.

  Many of these forgotten bees tend to nest in aggregations, clusters of sometimes hundreds or even thousands of burrows in the ground, each marked by a small conical volcano of excavated earth. In most species, each female has her own burrow (though how she remembers which is hers is a bit of a mystery), single-handedly stocking it with pollen and sealing her eggs inside, where they develop without further attention. A few of these ‘solitary’ bees are truly social, with the queen founding a nest and then rearing a batch of workers who then help her to rear a batch of males and new queens – in other words their life cycle is very similar to that of bumblebees. When I finally caught up with Tom he had found a nesting aggregation of one such species, the less than snappily named sharp-shouldered furrow bee,fn10 or Lasioglossum malachurum, a greyish bee just six millimetres long. The nests were scattered along the bare, packed clay of a vehicle track. Males were patrolling busily backwards and forwards above the nest entrances, hoping to mate, while the females came and went, bringing back pollen loads and doing their best to avoid the attentions of the amorous males.

  Instead of looking for bumblebees on the blackthorn, which had proved to be pretty unproductive, I started scanning bare patches of earth for bee nests. In no time at all we’d caught specimens of no less than ten different species of bee, most of them members of a genus called Andrena, mostly smallish bees, often with shiny dark abdomens and commonly known as mining bees. Globally, there are no less than 1,300 known species of mining bee alone, most of them very easily overlooked. Some were rather handsome – such as the orange-tailed mining bee, Andrena haemorrhoa, which has a fox-red thorax and bottom, and Andrena fulva, one of the few solitary bees that is eye-catching enough to have long been accorded a common name: the tawny mining bee. When I was a child we had an aggregation of these large, rust-coloured bees nesting in our lawn, and I loved to peer down into their holes and see the females staring back up at me. We also found a little nomad bee, Nomada flavoguttata, a minute, almost hairless, reddish bee that is a ‘cleptoparasite’ – it specialises in nipping in to the Andrena nests when the mother is away and laying its own eggs on the pollen stores therein. Nomad bees are very like cuckoos – their eggs hatch fast, and the very first thing the newly hatched nomad bee grub does is to kill the egg or grub of the host. The young nomad larvae are equipped with large, sickle-shaped mandibles expressly for this purpose. Once the host’s offspring has been dispatched, the nomad grub can consume the pollen store at its leisure. As it grows and moults, it loses the murderous mandibles, which are of no help in consuming pollen. This might seem a pretty underhand strategy, but clearly crime pays because there are about 850 species of nomad bee known in the world, each adapted to a different host.

  Over the next few months, on our successive visits, it was fascinating to see how the vegetation changed through the season. In early spring, the turf had been close-cropped, leaving few flowers. Over the winter the plants would have been able to grow little, and so were grazed right down by the cows, deer and horses. If that had remained the case through the spring and summer, as I had suspected it might, then we would have found few bees. What I hadn’t reckoned on was the fairly obvious point that plant growth accelerates through the season, while the number of animals remains more or less the same. By late May the meadows were a sea of creeping buttercup, sprinkled with patches of blue speedwell with purple ground ivy spreading in the shadier spots and the first bramble blossoms appearing in the thickets. By July, the open areas were knee-deep in white clover, the tiny mauve blossom of smooth tare, with clumps of red clover and bird’s-foot trefoil. Grazers love to eat clover, but there is clearly far more of it than they can consume, and so it gets to flower. In August, the common fleabane takes over, producing yellow daisy-like flowers on grey-green, woolly stems. This plant is unpalatable to grazers, and has become very common in much of the pasture at Knepp. Charlie might have been tempted to control it, because it reduces the fodder available for the livestock, but of course that would be contrary to the philosophy of what he is doing. If fleabane runs amok, then so be it. My guess is that some balance will soon be restored, as types of insects that are able to eat fleabane arrive and take advantage of the abundant food source. Time will tell.

  Through the year we clocked up a list of ten bumblebee species, none of them particularly rare. Much more exciting in many ways were the other bees, of which we found forty-two different types by the end of the summer, including many more mining bees and a few more types of nomad bee, plus yellow-faced bees, sweat bees, mason bees and more. Some are very scarce bees on a national scale. Perhaps most thrilling of all was finding another cleptoparasite, the rough-backed blood bee (Sphecodes scabricollis), which is exceedingly rare across Europe and in the UK is listed as a ‘Red Data Book’ species, making it a high priority for conservation. Blood bees differ from nomad bees in that the adult female enters the host nest and kills the host’s offspring herself before laying her own egg, rather than leaving her newborn offspring to carry out the dirty deed. This particular species is rather tiny, at just six millimetres long, black with a bright red band around its abdomen, and it specialises in attacking the nests of the flamboyantly named bull-headed furrow bee (Lasioglossum zonulum).

  Of course I am sure that we missed many more. Searching for creatures which may be just five millimetres long in a 3,500-acre estate, it is reasonable to assume that one won’t find them all. We also don’t know which ones were here before the rewilding began. In an ideal world, Charlie would have had the entire estate subject to a thorough inventory of its wildlife while it was still a regular farm, and then we coul
d see how it was changing over time, but he had neither the time nor the resources. At least we will be able to see how it changes into the future – which new species arrive, and which ones disappear. It will be fascinating to watch. Perhaps some of the rarer bumblebees will eventually arrive. I suspect that the flora will become steadily more diverse as time goes on – it may take many decades for some species to get here. What is certain is that the flora and fauna of Knepp will change over time, following natural processes.

  It is interesting that humans are so averse to change, so keen to maintain the status quo. Charlie’s project had met with a lot of resistance at the outset – some locals felt that it was immoral to abandon farmland, that it was a farmer’s duty to keep the land neat, tidy and productive. Of course this is a dubious contention; we may have got used to modern, large fields containing neat monocultures but they are a relatively new phenomenon. One hundred years ago, before mechanisation and the advent of chemical herbicides, farms would have been much messier, a patchwork of small fields separated by dense hedges, some fields with crops and colourful arable weeds, some left fallow with yet more weeds, some kept for hay, others grazed by livestock. Four thousand years ago it was probably mostly forest. Four million years ago it was forest or perhaps something savannah-like, roamed by elephants. Who is to say what the land should look like? But humans instinctively resist change, and want to hang on to whatever they are used to, however humdrum.

  Early on in the project, one particular family, who live in a cottage surrounded on three sides by the new wilderness, started complaining that they were being kept awake at night by birds singing. A little investigation revealed that the racket was due to a medium-sized, rather shy brown bird that had taken up residence in a nearby thicket – a nightingale. Knepp had previously had no nightingales, but it now supports 2 per cent of the UK population, with about 140 breeding pairs. Nightingales like to nest a foot or two above the ground in dense, spreading thickets, and as the abandoned hedges at Knepp spread sideways they have come to provide perfect habitat. The males arrive back from their over-wintering grounds in Africa in late April, and they find a good nesting site and then sing to call down the females as they fly north. Since nightingales migrate mostly at night, that is when the males sing, serenading the females as they pass over in the dark, hoping to lure one down. Their song is of course famously beautiful, a complex mix of liquid trills and warblesfn11 – presumably because female nightingales are pretty hard to impress, and hence the males must sing their hearts out to stand any chance of wooing one. So, imagine the hardship suffered by Charlie’s neighbours, having to listen to the awful din of nightingales every night – one’s heart bleeds. Encouragingly, the story ended well. These folk now know what the noise is, and eventually came to appreciate it, even to love it, and have realised how privileged they are. As I said, we humans can be oddly resistant to change, no matter how benign.