Furry, plump, boldly patterned, tricky to tell apart, bumblebees have been called “pandas of the insect world.” The Himalayas, fittingly, are the Amazon of Bombus (“Buzzer”) diversity. Alaska representatives of the bumblebee genus—22, with 9 on the North Slope and 17 in Denali—then must be polar bears.
They lie nine months in torpor, chambered like bullets on south-facing slopes where snow melts earlier in spring. Glycerol, the bee’s antifreeze, keeps water in their cells from congealing. By mid-May, as soon as Arctic willows blossom, pregnant queens brave subzero weather, even blizzards. Elsewhere, they busy themselves under a full moon. “To bees, time is honey,” punned Bernd Heinrich, the author of Bumblebee Economics. With daylight returned and summers beyond the Brooks Range brief, these most northerly social insects—among the few insects that thermo-regulate—forage 24/7.
Invertebrate workaholics weaving livelihoods from floral candescence, they commute for miles on half-hour trips, faster than charging honeybees and galloping horses, before flies and mosquitoes can travel. They siphon nectar and collect up to 80 percent of their weight in pollen from early-blooming pink louseworts, yolk-eyed dryas, and later, monkshood and lemony poppies. The gold-dusted bruisers are the primary fertilizers of 80 threatened arctic plants, and their imbibing at willow catkins and berry bushes ripples through moose and grizzly populations. Denali promotes them as its “sixth furbearer” joining the park’s flashy “Big Five.” Brush advancing in longer, hotter summers will affect high-elevation bees there and in other alpine regions.
A bumblebee in the far north
Circumpolar Bombus polaris thrives farther north than all but one parasitic “cuckoo” species. Its larger, velvet-coated body, stocky as a bulldog’s, retains heat well. Internal flight muscles twitch over 100 times per second, raising its temperature to 95 degrees, similar to a human’s. The black-and-orange-banded dynamos weigh a tenth of a jellybean, which makes their output even more impressive. On sunny days, queens and their female cohorts bask in the open, engines idling. Resting in reflective poppies, “shivering” rapidly—pumping hidden beefcake lats and pecs—they generate extra warmth. “Cold-blooded insect” is a misnomer, really, for Bombus polaris. The Museum of the North entomologist Derek Sikes compares their caloric needs to our culture’s octane consumption: “As long as we have lots of energy, we’re going to burn it like hell until it’s all gone. That’s what they do.” Their fuel, of course, is renewable—high-sugar nectar and pollen stoking amped-up metabolisms.
Hunting pollen
Like Rimsky-Korsakov’s concert piece, offhand bee watching suggests whimsical motion, not beelines but nautical tacking or manic meandering drunks. In truth, Bombus are rather efficient if hyper navigators. They and their apian cousins don’t see red but do ultraviolet, “bee’s purple.” Zooming about, they identify flowers five times quicker than we can from moving cars. Multi-faceted, compound eyes zero in on mellifluous targets, attracted by pigment contrasts and sheens outside our perceptual range. Padded feet stamp pheromone tracks onto recently plundered chalices, scents signaling fellow gleaners to skedaddle without delay.
Moistened forelegs groom pollen buzzed loose into “baskets” on females’ hind legs, which feeds two summer broods. Nectar and millions of granules bulge these saddlebags with more protein than moose meat or salmon would.
Queen and colony
Right after she resurrected from snowy ground, the queen claimed a vacant vole, lemming, or bunting cubby. She fretted fur, feather, moss, or old leaves into a nest slightly smaller than a baseball. She installed clumps of pollen-ball larva food and wax nectar cups for days too cold for sorties. A circulatory system shunting the equivalent of blood from the thorax to her abdomen warmed her ovaries. The process jump-started the production of eggs fertilized by sperm stored inside her since fall. Pressing her belly bird-style to eggs laid in June, she incubates those, beating wings between forays, maintaining the nest’s temperature until 20 milky-white grubs hatch. These pupate into adults, small, sterile, female grunts that enlarge the dirt palace, tax the surrounding vegetation, and tend the second, late-summer clutch: royalty-in-waiting and drones, males whose sole job is the casting forward of genes, that sniff out non-kin, perfumed, airborne queens.
Peaking, the colony, a village to a beehive’s metropolis, numbers 50 to several hundred individuals. The murmuring ebbs as winter descends. The dowager dies with her progeny, except for inseminated females. Normally, only one survives from each arctic lineage to renew the cycle.
Coups d’état rattle the miniature realm—“reginacide” by stinger and mandible. Bombus hyperboreus or, on the North Slope, Bombus fernaldae, invade a household, kill its head, and implant their own offspring to be pampered by foreign serfs. The mooching assassins are slackers in other ways too. Providing neither shelter nor nourishment, they hibernate until their unwary hosts’ housewarming. The queen is dead! Long live the queen! they’d hum if they were royalists. Fit for Shakespearian drama, the usurpers’ reign, like the shuttling of a polaris and her retinue, is but a brief candle.
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