Bee Quest

by Dave Goulson

  Aside from the obvious issue that aquifer waters will eventually run out, there are other problems with their use. This underground water contains lots of dissolved salts, absorbed from the surrounding rocks over the millennia. California being a generally warm and sunny place, the water evaporates fast from the soil or from the leaves of the crop, but the salts have nowhere to go and so they are building up in the soil, stressing and eventually killing the crop. Many farmers are aware that their almond crops are showing the early signs of stress, which include sickly, pale leaves lacking chlorophyll, and browning of the leaf edges. There is no easy way to get rid of the salt – heavy rainfall will slowly wash it away, but there has been precious little of that in the last few years.

  If all that isn’t enough to give pause for thought, the depletion of the aquifers is actually causing the Central Valley to sink. According to NASA in 2015, the land is falling by five centimetres a month in some places, and in total has dropped by up to two metres, causing damage to houses, roads, irrigation channels and bridges.

  The vast orchards have other demands besides water. As I’ve already mentioned, the almond farmers ship in honeybees in February and March to pollinate their crops. It requires about 85 per cent of all the commercial honeybee hives in the USA to pollinate them – 1.7 million hives, or about eighty billion individual bees, which are brought in from all over the USA to pollinate the 2.5 trillion almond flowers. For most of these bees, this is but one stop on a long annual migration. After the almonds, they may be taken north to the apple and cherry orchards in Washington State, then east as summer comes to the fields of alfalfa and sunflowers in North and South Dakota, onwards to the pumpkin fields of Pennsylvania in August, and then finally to Florida for the winter. Others follow different routes, taking in squashes in Texas, cranberries in Wisconsin and blueberries in Michigan or Maine. Some of these hives cover 20,000 kilometres per year, but the almond orchards are by far the most lucrative stop for the beekeepers. This is the biggest commercial pollination event on the planet, and beekeepers can charge up to $200 per hive for the two to three weeks of pollination they provide. Just as the levels of the aquifers have gone down, the price of renting honeybee hives has gone up, for they cost just $75 ten years ago. The rise in price has been driven by two factors: an increase in the area of almonds, which has driven up demand, and the problems that commercial beekeepers face in keeping their bees alive, which has pushed down supply. The poor honeybees are stressed from all sides. They have to deal with the dozens of pesticides applied to all of these different crops, cope with outbreaks of foreign diseases and parasites, and put up with a bizarre, monotonous diet consisting entirely of almonds one month, cherries the next, and sunflowers after that. On top of all that they repeatedly spend days on end sealed in their hives and rumbling along on the back of a lorry, which must surely be confusing and stressful. Small wonder that beekeepers in the USA have been struggling to keep enough healthy hives alive to service the demand for almond pollination – Davis scientists have estimated that the average number of bees per hive arriving in the almond orchards has dropped from about 19,000 a few years ago to 12,000 today. Beekeepers are splitting their hives more often to make up for colonies dying, but the end result is that the colonies are getting smaller and weaker.

  It is pretty clear that this whole system is teetering on the edge of collapse. If the drought continues, or honeybee problems get any worse, then Californian agriculture is going to be in big trouble, particularly the almond growers. Of course, one of these problems could be tackled by encouraging wild bees into the almond orchards. Neal’s team have focused mainly on field crops, but incorporating areas of wildflowers or natural vegetation amongst the almond orchards to provide food and nest sites for native bees seems like a wise idea.

  Although almonds are famous for being pollinated by honeybees, there is evidence that the honeybees’ efforts are more effective when wild bees are also present. Claire Brittain, a postdoc working with Neal Williams and Claire Kremen, recently showed that honeybees actually change their behaviour when other bee species are present in the orchards. In almond orchards far from native vegetation, where no other bees occur, the honeybees tend to move very short distances between flowers. In orchards nearer the edge of the Central Valley, where mining bees and other native species often crop up, on average the honeybees move about more, and more frequently fly from row to row amongst the trees. Perhaps the honeybees are trying to avoid competition, so when they smell the odour of a native bee they skip on a bit (I’m guessing on this). You might wonder why it matters how far the honeybees fly – the answer lies in the planting arrangement of the orchards. Farmers tend to alternate rows of different almond varieties, and just as with apples, the different varieties cannot pollinate themselves; they need pollen from a different variety to produce a nut. So only when bees move from row to row do they effectively pollinate. Claire estimated that the wild bees increase yield by 5 per cent or more – not a huge amount, but with almond sales worth five billion dollars, a 5 per cent increase is not to be sniffed at. Of course, if something were to happen to the honeybees, those native bees would suddenly become worth a whole lot more. If I were an almond grower, I’d be making a bit of space for them.

  The landscape was pretty desolate and I hacked northwards, stopping only for a quick coffee in a roadside diner which had the unusual feature of a stuffed grizzly bear that reared up menacingly in the corner, until the Central Valley narrowed and the mountains began to close in from both sides. From here the road began to climb, and Interstate 5 becomes rebranded as the ‘Cascade Wonderland Highway’. It was certainly pretty, with endless rolling conifer forests on both sides, and the snow-capped peak of Mount Shasta, which I had seen from the air just a few days before, looming up in the distance ahead. For much of the approach to Mount Shasta the road follows the Sacramento River, the water rushing southwards in a hurry to irrigate all those almonds in the Central Valley. Just south of the great volcano the road veers westwards, side-stepping the mountain, and passing through the remote and unusually named town of Weed, where I stopped for lunch. The place was memorable only for the ‘Weed like to welcome you’ sign on entry to the town, but nonetheless I was sad to hear that much of it burned down in a wildfire in 2014. After Weed the road wound on through the forests for another hundred kilometres until I hit the Oregon border, and from there it was only another fifteen kilometres or so downhill to Ashland.

  The ancestral home of Franklin’s bumblebee turned out to be an old-fashioned country town with an historic heart of clapboard wooden houses, nestled amongst flower-filled meadows and set off beautifully by the snow-capped mountains to the east. Unfortunately for me a Shakespeare play was being performed in the local open-air theatre, and as a result the hotels in town were full. Ashland has an appealingly arty, hippie feeling, as if someone has picked up a piece of San Francisco and dropped it in rural Oregon. I ended up lodging in an edge-of-town motel, but its lack of charm was more than compensated by the lovely views of the surrounding mountains. I spent the next few days hiking the local area, net in hand, in optimistic search of Franklin’s bumblebees.

  There were a few more hazards than I was used to contending with on bee hunts back home. Dashing about through the under-growth after bees in this area is unwise, as poison oak turned out to be common. Luckily Paul at McLaughlin had pointed out what it looked like, and had warned me that contact with the shiny green oak-like lobed leaves of this shrub can cause the skin to blister into sores that take weeks to heal, so I did my best to avoid it and only ended up with a few minor stings. More intimidatingly to someone from Britain, rattlesnakes turned out to be common along the rocky trails. The first one I came across I heard before I saw – a dry zither, which I foolishly mistook for the call of a cicada, and headed through the scrub to investigate. It was probably a good job that I was moving slowly to avoid any poison oak and so I spotted the fat brown snake before I could blunder too close. It eyed me with th
e fixed, defiant glare that all rattlesnakes have, and rattled its tail at me in warning. At this time of year they are just waking up from hibernation, and so they tend to be sluggish – most I subsequently saw were just poking their triangular heads from their burrows, and the first I noticed of them was the movement when they darted back inside.

  It was a lovely area to explore as spring burst into life, and I felt like a child again as I wandered about, net in one hand and camera in the other, soaking up the sights and sounds. Bobwhite quails were common in early morning – charming, fast-running little creatures with an outlandish floppy crest, resembling someone from a New Romantic pop band of the Eighties. They would explode out of the bushes as I approached and careen along the trail ahead like clockwork toys. Jackrabbits lolloped about more sedately, seemingly weighed down by their comedic, oversized ears. The trees were alive with skirmishing animals, perhaps establishing their summer territories, or perhaps just driven by the surging hormones of spring, so that the forest rang with a cacophony of squawks. The western scrub jays and grey squirrels seemed to have declared war on one another and were engaged in running battles in the canopy, presumably contesting shared food sources, though from what I could see neither side had the weaponry to achieve a convincing victory. Meanwhile, rival gangs of acorn woodpeckers pecked hell out of each other – these are unusual birds in that they live in family groups, sharing the work in looking after a single nest, and storing thousands of acorns for the winter in a ‘granary’, a tree that they drill with a myriad individual acorn-sized holes. The acorns dry and shrink over time, and the birds occupy the long winter months by constantly shifting acorns into more appropriate, tight-fitting holes. Presumably these battles were over the last of their winter stores – on one occasion a pair that were locked in combat fell from a tree and crashed to the forest floor not two paces in front of me. Their feet were entwined, and each seemed intent on pecking the other’s eyes out, so I was relieved when they finally noticed me and shot off in different directions, apparently unharmed.

  Bumblebees were plentiful. There were most of the species I had found with Robbin, plus more that I had not seen before, including the delightfully named fuzzy-horned bumblebee, a shaggy-haired little bee with no discernible horns. Of course I didn’t find any Franklin’s bumblebees, despite catching and inspecting hundreds of different bumblebees, many of them queens fresh from hibernation. After failing to find any Bombus dahlbomii in Argentina, I should not have been surprised, for this was always going to be the longest of long shots, a ghost hunt for a bee that local experts had failed to find for six years. Once I got myself briefly excited, but quickly realised that I had captured a lovely queen of the rather similar ‘obscure bumblebee’.

  After a few days it was time to pack my walking boots and head back south to fly home. I took the scenic route, skirting east into the Cascades and then southwards to the Sierra Nevadas, passing through some truly wonderful scenery though I hardly had time to appreciate it. On my last evening in California I stayed in a shabby little motel on the southern shores of Lake Tahoe, an idyllic, emerald lake perched 2,000 metres up in the sierras on the Nevada border, due east from Sacramento. California’s rich come here to party; the shoreline is a little spoiled by casinos, in one of which Frank Sinatra occasionally used to sing. JFK and Marilyn Monroe are said to have had an affair in a cabin in the woods, though I’d hazard a guess that it was a rather nicer cabin than the one I was staying in. I sat on a rustic bench among the tall firs, and feasted on rye bread, tomatoes and a deliciously tangy local goat’s cheese named Humboldt Fog, though I had my work cut out to repel the bold advances of a gang of chipmunks who had designs on my comestibles. Terrapins slowly hauled themselves out onto rocks along the lake shore to catch the last of the day’s sun. Beyond the lake to the north and east, I could see endless serried rows of snow-capped peaks and forested valleys, fading into the distant haze. The Rocky Mountains cover a vast area, much of it inaccessible, and there are not too many entomologists able to recognise a Franklin’s bumblebee, should they be lucky enough to stumble across one. Perhaps Franklin’s bumblebee now exists only in Robbin’s memory, and as a few pinned specimens in his office at Davis.fn4 Or perhaps not. There could be some left, somewhere out there, in a valley that the disease never reached, or maybe the offspring of a few individuals that just happened to have a little natural resistance. I’m sure that Robbin will continue to diligently search its old haunts until he himself loses his personal battle with extinction. It would be wonderful if he could see just one more.

  CHAPTER SIX

  Ecuador and the Battling Bumblebees

  May your trails be crooked, winding, lonesome, dangerous, leading to the most amazing view. May your mountains rise into and above the clouds.

  Edward Abbey

  Why do students move so slowly? This is a question that has vexed me for many years. Every university building I have ever worked in has possessed long corridors, which in termtimes are choked by gaggles of students ambling along purposelessly. True, some are more than a touch overweight, and this must slow them down, while others are ‘Facetiming’ friends or chatting on their hands-free iPhones, which presumably distracts them from the complex business of placing one foot in front of the other. But even those who aren’t plugged in to the internet or suffering from a surfeit of KFCs often seem to move at an almost imperceptible pace. Perhaps they just have too much time on their hands and we academics are to blame for not giving them more work to do. No matter the cause, I find their trundling irksome as I am generally in a hurry and they provide an endless moving chicane of obstacles to negotiate. This may sound odd, but I often run from place to place, even along the corridors at the university, and almost always when going across campus. I particularly like to run up stairs whenever the opportunity arises, and I find it enormously frustrating when I come up behind a phalanx of large-bottomed students blocking the stairwell. Life is too short for such dawdling.

  Given my impatient and perhaps entirely unreasonable attitude to ambulation, it was particularly humiliating to my foolish macho pride to find myself at the rear, struggling to keep up with a column of students as we wound our way up a steep muddy path high in the Andes in September 2014. The bus had dropped us off at the closest point it could reach, about six kilometres of jungle trail from our destination, and so the thirteen students, two other staff and I were slogging up the slippery path. A team of four mules was carrying our rucksacks and equipment, which had been strapped in improbably large bundles to the sturdy beasts’ backs. Perhaps it was age, or the altitude, or jet lag, but whatever excuse I could think up did little to salvage my injured pride as the last of the students disappeared into the misty forests above me, leaving me panting and sweating far behind as the trail climbed up into the clouds. It turned out that I was just about to go down with food poisoning, the likely result of consuming a large, meat-filled pastry from a roadside stall in Quito the day before; it left me weak as a kitten for the next few days.

  We were here for a two-week residential field course from the University of Sussex, in which the students were to learn about the wonderful biodiversity and ecology of the cloud forest, high-altitude rainforests perched between 1,500 and 4,000 metres up on the precipitous sides of the Andean mountains. These forests are famous for their huge diversity of birds, orchids, butterflies and much more. Ecuador is one of the world’s great biodiversity hotspots, bisected by the spine of the Andes which run roughly north to south. To the east of the mountains, Ecuador encompasses a portion of the steamy Amazon basin, a part as yet affected relatively little by deforestation. The west is more densely populated, with fragments of tropical forests amongst farmland, and palm-fringed beaches that attract tourists looking for an alternative destination to the Caribbean. Far off the coast to the west, the Galapagos Islands are also part of Ecuadorian territory. The Andes themselves support a huge diversity of habitats, from bleak ash-strewn active volcanoes capped with snow to lush green
highland cloud forests and chilly paramo grasslands above the treeline. Although not much larger than Great Britain, Ecuador supports about 10 per cent of all the known species of animal and plant on Earth. The figures are astonishing – 317 mammal species, 460 amphibians and 410 species of reptile (the respective numbers for the UK are 101, seven and six). Of course no one has a clue how many insect species there may be in Ecuador, but the butterfly list so far runs to about 4,500 (compared to about seventy in the UK).

  I sat down for a rest at the side of the track, gasping for breath with sweat trickling down my spine. Clearwing butterflies flitted ghost-like in the shade beneath the forest canopy, their wings largely devoid of coloured scales so that they are transparent aside from a delicate network of dark scales and veins. A long-winged Heliconius butterfly,fn1 black with golden-yellow stripes, soared effortlessly along the path and fluttered around me, perhaps briefly wondering if my red T-shirt was some new exotic flower. I noticed a large web-lined burrow in the bank at the side of the path, from which the front two hairy legs of a sizeable tarantula protruded. Big spiders have always given me the willies, so I decided it was time to move on.

  I eventually climbed above the cloud and emerged at our destination, a wooden lodge perched in a clearing on the top of a mountain at about 1,800 metres in altitude. The views were breathtaking: densely forested peaks rose from a woolly blanket of white cloud that shrouded the valleys far below. Hummingbirds whirred amongst the pretty shrubs around the lodge, exotic birds called from the surrounding forest, and colourful butterflies soared on the thermals.