- Author: Kathy Keatley Garvey
Pity the poor worker bee.
In the spring/summer months, she lives only four to six weeks and then she dies. Bee scientists say she basically works herself to death.
For the first half of her short life, she works inside the hive, tending to the brood, feeding the queen and drones, processing the food, building and repairing the nest, and completing other responsibilities, all in total darkness. In the second half of her life, she leaves the hive, emerging from the total darkness to the bright light. Weather permitting, she'll forage every day for food, propolis or water for the colony.
You've probably noticed these older foragers, with tattered wings, scarred bodies and hairless thoraxes, foraging among the flowers. Those tattered wings could be the result of predators that missed: spiders, dragonflies, grasshoppers, dogs, birds and the like.
Worker bees do not fly well with flawed wings and they're even more susceptible to those crafty jumping spiders lurking in the flowers.
So it's interesting to read the recently published research by scientists at the Arizona State University and the Norwegian University of Life Sciences, research that shows that older honey bees experience reverse brain aging when they return to working inside the hive.
Writing in the journal, Experimental Gerontology, the researchers related that they tricked the older, foraging bees into returning to the hive to perform the social tasks of the younger bees.
In an ASU news release: Gro Amdam, an associate professor in ASU’s School of Life Sciences, said: “We knew from previous research that when bees stay in the nest and take care of larvae--the bee babies--they remain mentally competent for as long as we observe them. However, after a period of nursing, bees fly out gathering food and begin aging very quickly. After just two weeks, foraging bees have worn wings, hairless bodies, and more importantly, lose brain function--basically measured as the ability to learn new things. We wanted to find out if there was plasticity in this aging pattern so we asked the question, What would happen if we asked the foraging bees to take care of larval babies again?"
Well, they found that the older bees that returned to the hive seemed to recover their ability to learn, and that the protein in the bee brains changed for the better.
"When comparing the brains of the bees that improved relative to those that did not, two proteins noticeably changed," the news release said. "They found Prx6, a protein also found in humans that can help protect against dementia--including diseases such as Alzheimer’s--and they discovered a second and documented 'chaperone' protein that protects other proteins from being damaged when brain or other tissues are exposed to cell-level stress."
In some respects, you could almost say that stay-at-home moms are better off than the work-outside-the-home moms, but (1) worker bees are not moms, and (2) both are working. The queen lays the eggs, as many as 2000 eggs a day during peak season. The worker bees are females, but their ovaries are tiny and normally non-functional, says Norm Gary, emeritus professor of entomology at UC Davis in his book, Honey Bee Hobbyist: The Care and Keeping of Bees.
Still, we can imagine that this fascinating bee science research could lead to another tool to investigate dementia in elderly humans.
- Author: Kathy Keatley Garvey
The "honey bee reproductive ground plan" hypothesis that originated two dec
Page, emeritus professor of entomology at UC Davis and now founding director of the School of Life Sciences at Arizona State University, and his collaborator Gro Amdam, are featured in the Oct. 23rd edition of Science, a publication of the American Association for the Advancement of Science.
Writing in the behavior ecology section in an article headlined, "Sex and Social Structure," journalist Elizabeth Pennisi related that the scientists' research "has shown that reproductive traits help shape a honey bee worker's role in life and that ovaries are active players in the process-even if they play little role in reproduction in worker bees."
The specialized tasks "have their basis in what Amdam and Page call a reproductive ground plan," she wrote. Their work has provided a framework and tools to study division of labor, which now "converges on two genes that may explain both ovary size and behavior."
Page and Amdam, an associate professor in the School of Life Sciences and Norwegian University of Life Sciences, believe that genes and hormones likely control social roles as well as longevity.
Their research centers on the role of the ovary in honey bee colonies, and how the worker bees partition the labor of the colony with duties that include rearing young bees, constructing the nest, foraging for pollen and nectar, and processing the food.
Page, a pioneer in the field of evolutionary genetics and social behavior of bees, has long marveled at how highly social bees are. Worker bees, or infertile females, instinctively divide up their roles to run the hive, freeing the queen to lay eggs.
The worker bees serve as nurse maids, nannies, royal attendants, architects, builders, foragers, guards and undertakers.
But why are some colonies high-pollen collectors and hoarders, while others aren't?
His research on high and low pollen hoarding strains that began two decades led to the "reproductive ground plan" hypothesis. Page continues to keep his specialized bee stock, managed by bee breeder-geneticist M. Kim Fondrk, at UC Davis.
This is exciting research.
As Page told us: "The reproductive ground plan research is integrating developmental biology into insect sociobiology. It is completing the synthesis by looking for the signatures of levels of selection above the organism, at the level of the genes, physiology, and embryogenesis. It is substantiating the superorganism."
UC Davis is the hub for the development and maintenance of the high and low pollen hoarding strains of bees "that have been fundamental in testing the reproductive ground plan hypothesis and understanding how selection on colonies affects different levels of biological organization from genes to societies," he said.
Page, who received his doctorate in entomology from UC Davis, retired from UC Davis in 2004 to develop the School of Life Sciences in the College of Liberal Arts and Sciences at Arizona State University.
Page and Amdam are the co-principal investigators on a federally funded project directed by UC Davis entomology professor James R. Carey. Carey directs the Biodemographic Determinants of Lifespan, a National Institutes of Health/National Institute of Aging-funded program involving scientists from UC Davis, UC Santa Barbara, UC Berkeley, Stanford and seven other academic institutions in the United States, the United Kingdom, and Greece.See more information on the UC Davis Entomology Web site.