Pre-dawn. The dark lump at the bottom of the bed that is Wally and the red LED on the face of the clock announcing it is 5:27 am are about all I can see. Light is a relative thing. Though scientists, who measure light in precise angstroms and lumens, would argue this. Today is the Winter Solstice. The earth, tilted askew, is moving paradoxically closer to the sun even as longer nights are at their peak. An owl calls, breaking the silence, followed by another in the same cadence but a higher pitch. Sliding silently out from under the covers, feet finding slippers, I see the moon hanging in the sky, casting shadows of tree trunks and limbs across the grass.
Nothing is stirring.
At the bathroom sink, I turn on the tiny night light to brush my teeth, then pad softly to my desk to retrieve my notebook. My dog is at the top of the stairs by now, luxuriating in a down-dog stretch. I push my big toe forward until I find the top step then start down in near-darkness. The light on the coffee maker shines bright blue; I open the refrigerator to retrieve my coffee and a white light glares at me. Squinting, I know how bees must feel when I open their hive on a bright sunny day.
There’s a time when it seems to get darker before it gets lighter as the moon sinks below the tree line. This fringe of darkness lingers in the woods beyond the yard. Then, shades of rose and peach color the sky over the pond, and the sun winks above the horizon.
I think about how much light is a part of my life and how much light is not a part of a honey bee’s life. It’s dark inside the hive and it stays that way 24 hours a day. Though bees venture out daily in search of food and water most of the year, using the sun as their compass for foraging and finding home again and again, colder temperatures keep them clustered in darkness for weeks at a time. Under normal circumstances, the queen is destined to darkness always, traveling the honeycomb by feel and pheromone, as she deposits eggs and accepts the solicitations of her workers. Imagine living in darkness like this. Many years ago, I visited some old caverns. Deep down inside, the guide shut off his flashlight for a moment, sending us all into a velvety dark blackness. Zero angstroms, zero lumens. He told us that humans go blind in darkness like this in as little as 7 days, and most certainly would go mad as well. Since I have yet to see any blind, deranged bees stumbling around, I’m certain that their physiology is different from ours.
Humans see light within a specific spectrum, which is called the visible spectrum, measured in nanometers (nm). This is a misnomer, or at least rather humancentric, because the visible spectrum is different for many animals. Humans see in the range of about 700 nm to 400 nm. If you visualize the colors of the rainbow, red is at the 700 nm end and violet is at the 400 nm end. These numbers represent the length of a light wave. Red light has a longer wavelength; violet has a shorter wavelength. Remember the old fashioned phone cords? Picture one stretched out, its spirals elongated. That’s red. Now picture the cord dangling loosely from a phone on its cradle, a tight spiral. That’s violet.
There are longer and shorter wavelengths of light beyond each end of this human visible spectrum. Beyond the red end lie the longer wavelengths of infrared, microwave, and radio waves. Beyond the violet lie ultraviolet, x-ray and gamma rays, in even tighter curls of that phone cord. Bees don’t have x-ray vision, but they can see ultraviolet rays, so their visible spectrum lies in a different range than ours does. Everything is shifted towards the violet end of the spectrum and beyond into the ultraviolet. Bees actually have the hardest time seeing red, especially if it blends into the background. The blossoms of a Rudbeckia, what many of us know as a Brown-eyed Susan, with its happy yellow petals and suede-brown centers, are often visited by pollinators, honeybees included. But though we see yellow and brown, a honeybee sees them quite differently. To a honeybee the flower petals are a deep magenta at the edges with darker purple streaks leading into the center, almost like a runway. And if you’re a bee coming in for a landing, you’ll follow this runway to the center of the flower where the nectar and pollen are. Flower petals, for all their beauty, are merely directional signals.
Bees see ultraviolet as a separate color, something we cannot do without sophisticated instruments, and even then, it is only something we can approximate. But ultraviolet light is as important to them as being able to distinguish a red light from a green light on a traffic signal is to us. On overcast days, if you notice a decrease in foraging, chalk it up to the lack of ultraviolet light.
As humans, we depend on our sense of sight probably more than any of our other senses. We are the exception to the animal rule, along with most birds. Many other animals depend more on their sense of smell, hearing and touch. There are days when I let my dog have it his way on our walks and this means that he meanders in a serpentine, in fits and starts. He reads the ground and the air with his nose, and learns what animals have traversed our route the night before. Unless it is very strong, like skunk musk or a pile of fresh coyote scat, I am oblivious to these smells. Dogs can also sense emotions and a number of health conditions in the pheromones released by other animals, including humans. There have been accounts of dogs predicting an epileptic seizure or detecting a cancerous lump in a human and these have been attributed to specific pheromones released under those conditions.
Bees also depend on pheromones to guide them, especially inside the hive. The queen releases pheromones to establish her reign and health status. Worker bees release pheromones to coordinate activities at certain times of the year. Workers that have found a particularly abundant supply of pollen and nectar will enter the hive and perform a waggle dance, emitting pheromones as to where this place is. Touch is important in this dance too, since other foraging workers will touch the dancing bees to “get directions.” It’s dark in there; they certainly can’t see. It’s no wonder they’re agitated when I open the hive, especially when I dig down deep. Light floods the honeycomb, scents from outside waft in and around the frames, diluting the pheromones circulating in the hive that make it smell like home. They become disoriented, especially the queen, by this flood of light.
But even though light isn’t the primary sense they use, it is still important to them. They respond to the change of seasons as measured by the amount of daylight more than by temperatures. In these days of shorter daylight, today being the shortest of them all, honey bee colonies look quiet from the outside. There is activity inside, wings beating in that cluster to generate warmth, the queen cozy in the center. Pheromones, if not light, circulate, saying all is well.