Protecting the Hive
by Dr. Sarah D. Oktay
Managing Director UMass Boston Nantucket Field Station
Amidst the summer time hoopla here on Nantucket you might have missed a very important holiday which just concluded on Sunday. For the past five years, the U.S. Department of Agriculture has designated the last full week of June as “National Pollinator Week” to draw attention to the critical role pollinators play in our ecosystem and food chain (http://www.pollinator.org/pollinator_week_2011.htm). As I write this article, I am packing up my bee costume for next year after hearing one too many “Blind Melon” comments. It’s pretty easy here on island to get excited about bees. Nantucket is blessed to have a plethora of bees and beekeepers. Whether you are cursing the carpenter bees that are expertly drilling holes into your wooden front door or noticing the many different types of native bees buzzing from flower to flower in the moors, you’ve certainly encountered a bee on Nantucket.
Last week I wrote about mosquitoes and briefly mentioned the danger that a common “safe” mosquito control ingredient, permethrin, can pose for bees. This week, the Nantucket Conservation Foundation (NCF) has honeybees shipped in en masse out at the bogs to pollinate cranberries and make honey. This Plum TV video, www.plumtv.com/videos/nantucket-bees-bogs, shares an interview with NCF Assistant Bog Manager Tom Larrabee about the bee pollination process. So from our cranberry bogs to our marshes and harbors, how we treat and use bees are an intrinsic part of island life. Understanding and protecting them is key for our own survival.
First, some bee basics: A bee is a winged, flower-feeding insect with branched body hairs. These body hairs are designed to help pick up and deliver pollen from flower to flower. Bees are dependent on pollen as a protein source and on flower nectar or oils as an energy source. Adult females collect pollen primarily to feed their larvae. The pollen they inevitably lose in going from flower to flower is important to plants because some pollen lands on the pistils (reproductive structures) of other flowers of the same species, resulting in cross-pollination. Bees are, in fact, the most important pollinating insects, and their interdependence with plants makes them an excellent example of the type of symbiosis known as mutualism, an association between unlike organisms that is beneficial to both parties. They are found on every continent except Antarctica, in every habitat on the planet that contains insect-pollinated flowering plants.
Bees are insects in the order Hymenoptera within the superfamily Apoidea, presently classified by the unranked taxon name Anthophila. The name Hymenoptera is derived from the Greek words "hymen" meaning membrane and "ptera" meaning wings. It is also a reference to Hymeno, the Greek god of marriage. The name is appropriate not only for the membranous nature of the wings, but also for the manner in which they are "joined together as one" by the hamuli. The hamuli are hooks along the leading edge of the hind wings that catch in a fold near the back of the front wings (adult Hymeoptera have two pairs of wings). In flight, both wings operate in unison to form a single aerodynamic surface. As a rule, members of the order Hymenoptera can be regarded as ecological specialists. Most species are rather narrowly adapted to specific habitats and/or specific hosts. Their remarkable success as a taxon probably has more to do with their immense range of behavioral adaptation rather than any physical or biochemical characteristic. The Hymenoptera is the only order besides the Isoptera (termites) to have evolved complex social systems with division of labor. The earliest bees evolved from a wasp-like insect well over 100 million years ago. A piece of amber containing an insect bearing features of modern bees and wasps has been found, and scientists have dated it to be 100 million years old. Fossils of bees closely related to modern bees have been found dating back to over 35 million years ago. In a cave near Valencia, Spain there is a wall painting, which is around 15,000 years old, showing men collecting honey from wild bees.
The best-known bee species is the European honey bee, which, as its name suggests, produces honey, as do a few other types of bee. Human management of this species is known as beekeeping or apiculture. There are three types of bees, queens, workers, and drones. Drones are male bees and they have no stingers. Their sole purpose is to mate with the queen. If the colony is short on food, drones are often kicked out of the hive like unwanted house guests. Workers, which are the smallest bees in the colony, are undeveloped females. A colony can have up to 60,000 workers. The life span of a worker bee depends upon the time of year. Her life expectancy can be as long as 35 days. Workers feed the queen and larvae, guard the hive entrance and help to keep the hive cool by fanning their wings. Worker bees also collect nectar to make honey. In addition, honey bees produce wax comb. The comb is composed of hexagonal cells which have walls that are only 2/1000 inch thick, but support 25 times their own weight.
From one of the most well written sites on bee life out there, Jason Nelson’s “A Voice from the Hive” (http://www.voiceofthehive.com/); “Drones do not gather honey. They do not gather pollen. They do not clean, or care, or do anything other than hang out in the local "Drone Congregation Area." No matter how many hives you have in an area, the drones select a particular area, and gather loosely there to watch for queens on mating flights. It is unknown how it is that drones from one season to the next choose the same congregation area, since none normally survive. Nor is it known how the queen, on her second flight from the hive, knows where the congregation area is.” Nelson goes on to tell the sad story of the drone and the queen he dies for. His description of building the cells in the comb and how the hive changes throughout the year as more drones or workers are needed is thorough and funny. Drones pretty much check out around 11-12 days after their emergence from the cell (for late bloomers as soon as they mate); queens can live for 1-5 years!
North America and Canada are home to approximately 4500 species of bees and world-wide about 20,000 species. The domesticated European honeybee was introduced to North America 400 years ago by colonists at Jamestown and Williamsburg to provide their settlements with honey; few bees native to the continent produced enough honey to make harvesting viable. Since then, the honeybee has spread into every farmable corner of North America. Crops that depend on bees for pollination include: apples, oranges, lemons, and limes, broccoli, onions, blueberries, cherries, cranberries, cucumbers, cantaloupes, carrots, avocados, and almonds.
The Trustees of the Reservation has just received a grant to investigate some of the 300 species of native bees known to flit around Massachusetts on that “other” island. Dr. Paul Goldstein is coordinating the inventory which is being done by both scientists and citizen scientists. One of the methods for collecting and inventorying bees is through the use of “bee bowls.” Bee bowls are traps for bees set up by island scientists at the Nantucket Conservation Foundation to get an idea of the types of bees hanging out on Nantucket. A “bee bowl” is simply a cup or bowl painted in an alluring yellow, blue, or white color and filled with detergent. A bee who is attracted to the cups’ colors (say that 5 times fast) will head for the bowl and not be able to escape the surface tension change caused by the soapy water. These bowl traps capitalize on the attractants that flowers use to lure in pollinators. Many flowers have nectar guides that lead bees to the nectar and pollen. Some are markings like the lines on a pansy, others are ultraviolet patterns that we can't see, but bees can. But visual cues, way more than smell, are responsible for drawing bees in; once they get close, the smell of a flower helps them hone in. Bees are the favorite meal of Merops apiaster, the bee-eater bird. Other common predators are kingbirds, mockingbirds, beewolves (predatory wasps), and dragonflies.
By now everyone has heard the famous shout-out to the hardest working little insect in the world: “For every third bite of food you take, thank a bee or other pollinator” from the book, Forgotten Pollinators (1996) written by Stephen L. Buchmann and Gary Paul Nabhan. The more I think about it, the more I am convinced that bees have become our new canary in a coal mine. In 2006, beekeepers in the U.S. started to notice an alarming drop in bee populations. In a scene reminiscent of an X Files episode, they started to find their “supers” or bee hive containers empty. Panic struck fruit and almond growers as they searched for enough bees to pollinate their crops and the price of bee rentals soared. In the United States alone, more than 25 percent of the managed honey bee population has disappeared since 1990. Beekeepers first sounded the alarm about disappearing bees in the United States in 2006. Seemingly healthy bees were simply abandoning their hives en masse, never to return. Researchers are calling the mass disappearance Colony Collapse Disorder, and they estimate that nearly one-third of all honey bee colonies in the United States have vanished. The number of hives in the United States is now at its lowest point in the past 50 years.
Since 2006, colony collapse disorder has stymied entomologists and ecologist around the world. Theories for the precipitous decline in population include habitat loss that threatens the ability of bees to find enough food to non selective pesticide applications that carry over into hives and break down their communication pathways. Climate change is most likely playing a part by affecting the timing of blooming of various plants that hibernating bees expect to feed on when they emerge. When those plants have already bloomed, the bees have literally missed the bus. Other possible culprits include the aptly named and insidious mite Varroa destructor, which carries a variety of viruses that can wipe out bee colonies. One virus first identified in Israel named the “"Israel acute paralysis virus” has been implicated in a majority of CCD cases. Usually these diseases and other issues such as fungus called Nosema apis and N. ceranae gang up on bees to combine with a variety of factors and make it harder for them to survive. Moving bees around to pollinate crops is thought to increase the transference of diseases and fungi between bee populations and many apiarists are working to isolate their bees from potentially infected bees. We’ll read more below on some more specific theories as to CCD. Bees and the food they pollinate are a multi-billion dollar industry; which means that scientists around the world have been feverishly trying to find out why they are leaving and dying. In a tragic turn of events fit for a Shakespearean play, we’ve managed to poison or starve the very creature that keeps us alive.
On-island beekeepers (or apiarists) include David Berry, Jim Gross, Andy Bennett, and Mickey Rowland among many others. I am fortunate enough to get some delicious honey from at least three or four different beekeepers. Most beekeepers produce (well, the bees produce) seasonal honey which changes with the type of flower being visited and varies in color, thickness, aroma, and taste. David Berry gives excellent courses in basic bee biology and Beekeeping 101 in coordination with Sustainable Nantucket, the Nantucket Community School and the UMass Boston Nantucket Field Station. Jim Gross is one of the several bee experts on island who will come get a bee colony out of your house for you. When colony populations are high, the queen may move part of the colony to new harborage. Bees swarm at this time, usually finding hollow trees to begin their new colony, but they occasionally work their way into building wall voids.
If one takes the time to read the many many different papers out there on CCD, you’ll find that pesticides certainly are implicated in bee mortality and in fact, many pesticides such as Cypermethrin and permethrin are extremely toxic to bees. Cypermethrin is a synthetic pyrethroid used as an insecticide in large-scale commercial agricultural applications as well as in consumer products for domestic purposes and is found in many over the counter pesticide applications like Raid and ant chalk.
Some scientists, such Richard J. Sharpe and Lisa C. Heyden think if the honeybees feed on pyrethrum producing plants, that will reduce the aphids on them; which basically uses the toxicity of natural pyrethrums to attack the insects that can weaken bees. From their abstract: “Industrialized farming relies on bee keepers transporting hives to the vicinity of large areas of mono-crops for crop pollination. Hives are typically moved multiple times per growing season to satisfy the pollination need. A phenomenon wherein colonies of honey bees collapse in large numbers has been threatening crops in North America. Honey bees are hosts to at least two pathogenic mites; Varroa destructor and Acarapis woodi (a tracheal mite). Pyrethrums are a group of flowering plants which include Chrysanthemum coccineum, Chrysanthemum cinerariifolium, Chrysanthemum marschallii, and related species. These plants produce potent insecticides, also named pyrethrums, which are powerful mite toxins. We believe that a honey bee dietary deficiency of pyrethrums and other micro-nutrients from pyrethrum producing plants allows parasitic mites to either kill the honey bees directly or reduce honey bee resistance to other pathogens. Intermittent feeding of honey bees on pyrethrum producing plants might reverse or prevent colony collapse disorder.” Honey bee colony collapse disorder is possibly caused by a dietary pyrethrum deficiency .
Honestly, that sounds a bit crazy to me, but it is certainly thinking outside of the box. This paper “Nutritional stress due to habitat loss may explain recent honeybee colony collapses” by Dhruba Naug with the Department of Biology at Colorado State University talks about the linkage between open space and healthy bee populations and I think argues again for the need and real value open space gives us. From the abstract: “In spite of the tremendous public interest in the recent large honeybee losses attributed to colony collapse disorder, there is still no definitive explanation for the phenomenon. With the hypothesis that nutritional stress due to habitat loss has played an important role in honeybee colony collapse, I analyze the land use data in United States to show that the colony loss suffered by each state is significantly predicted by the extent of its open land relative to its developed land area. I provide further support for this hypothesis by showing that states with the largest areas of open land have a significantly higher honey yield on a per colony basis. I discuss how increasing loss of foraging resources could be synergistically acting with emerging diseases to stress honeybee populations and the importance therefore for preserving natural areas that act as important pollinator habitats.”
Other scientists believe that the most likely recent cause for CCD is a one-two punch delivered by a co-infection of two pathogens, the microsporidia, Nosema apis and N. ceranae and invertebrate iridescent virus. Much like humans who succumb to a heart attack after a series of stresses and a life of not enough exercise and too much junk food, the health of our bees may be stressed by pollutants in the air and water and by an introduction of normal diseases and fungi that overcome the millions of years of safeguards built into hive stability. For more information, read “The Vanishing Bee,” at http://www.nrdc.org/onearth/06sum/bees1.asp. And be happy to see a bee going about its business. Without them, the world would be a much less diverse, and nutritious, place.
