Observing Evolution

Can we see evolution in action? The New York Times reports that a group of evolutionary biologists and geneticists from Harvard University is attempting to find the mechanisms that lead to physical changes and learn how those changes affect fitness. They also want to learn how changes make an organism likely to survive and reproduce. These are critical issues for honey bee health. Harvard’s Dr. Hopi Hoekstra explains, “Fitness is the most important concept in biology, but no one ever measures it.” To observe evolution while it occurs, the researchers devised a test of fitness. They built four large enclosures on light-colored, sandy soil to house deer mice. A distance away, they built another four similar enclosures on dark-colored soil. Some of the deer mice, North America’s most populous mammal, have lighter colored fur than typical deer mice. The researchers discovered that the range of colors is dependent upon a single gene that controls pigment-producing cells. Mutations in this gene lead to deer mice with various levels of fur color. Mice that differ greatly in color from their background are easily spotted by predators, quickly changing the population of highly visible mice. The researchers are measuring the fur color shift in deer mice populations. The deer mice study can be viewed at http://www.nytimes.com/2011/08/09/science/09mouse.html.

While people often think of evolution as an extremely gradual process, at times rapid changes occur. This is seen with pathogens becoming antibiotic resistant and honey bee parasitic mites quickly becoming resistant to chemical treatments. Hopefully, we will start seeing honey bee populations evolve that are fit to live in our rapidly changing environment. European honey bees have been in the presence of parasitic Varroa mites for about 150 years. In this time some resistant lines of honey bees survived, and their offspring are now being selected by breeders. Today’s photo shows tickseed coreopsis, a colorful summertime carpet along roadsides and clearings. Coreopsis is a member of the important family of bee plants, the composites, or sunflowers.

--Richard

Beekeepers of the Heartland

Beekeepers gather in local, state, and regional groups to share the latest findings of research into honey bee health and the craft and business of beekeeping. Rita and I joined three hundred interested beekeepers in Cookeville, Tennessee for the Heartland Apicultural Society’s annual conference. All attending this regional meeting are fully aware of the stresses that honey bees are facing and listened intently to presentations involving various areas of honey bee health. The same conditions continue to challenge beekeepers across the Heartland of America: parasitic mites, viruses, Nosema disease, American and European foulbrood, honey bee nutrition, and the effects of chemicals in the bee hive and in the environment. Viruses vectored by Varroa mites, the new strain of Nosema disease, and chemical residues in the beeswax honeycomb combine to make for a deadly combination. Those attending sessions involving honey bee pest management learned that small hive beetles gain control and can easily overwhelm the bee colony when there are several generations of beetles existing in the hive at the same time. We learned that Varroa mites have developed a resistance to each of the legal miticides, and that they have even developed resistance to unlabeled treatments as well. This year’s serious incident of honey bee poisoning in Indiana was caused by insecticide-treated corn seed which contaminated dandelion pollen. Maryland’s apiary inspector brought Klinker the Labrador, a dog trained to detect American foulbrood.

Following four years of news stories about Colony Collapse Disorder there seems to be developing an understanding among the public of the important role that honey bees play through pollination service in providing human, animal, and wildlife food. There is also is a developing understanding among beekeepers of the effect of two decades of fighting deadly parasitic mites by using chemical treatments inside the bee hives. In today’s photo a honey bee visits tickseed coreopsis in bloom in the Arkansas Delta. The bee is collecting pollen from coreopsis, like dandelion, a member of the composite family of plants.

--Richard

Coreopsis in Bloom

Throughout the spring, summer, and fall there is a progression of yellow wildflowers. Coming into bloom now is tickseed coreopsis, a member of the important bee plant family, the composites. Tickseed coreopsis has bright yellow petals surrounding a reddish-brown center. The composites are the sunflowers. The composites are among the largest families of flowering plants, making up one tenth of the world’s plant species. There are 25 thousand composites, including dandelion, chicory, lettuce, and chrysanthemum. They contribute both nectar and pollen to the honey bees. It seems that the honey bees in the Arkansas Delta use coreopsis primarily as a source of pollen. A diverse number of pollen sources are important for good honey bee nutrition. Click on the photo to see the honey bee with pollen covering its legs and hairy body. The bee will rake the pollen from its body, mix it with some honey from her honey gut, and pack it on her pollen baskets on her hind legs. She will then be ready to fly back to her hive.

There will not be another yellow flower in place in great numbers until the coreopsis has completed its colorful showing. Not only have the flowering plants evolved with attracting schemes of color, shape, infrared nectar guides, fragrance, and taste for the pollinators, they also have a time-sharing scheme to help insure their pollination. By not competing with other yellow flowers at this time of year, the coreopsis helps insure its pollination and seed production for next year’s plants. The honey bees and flowering plants have always benefited each other.
--Richard