Queen Bee Chemistry

It is so easy to jump to conclusions when observing and studying honeybees. To the uninitiated, the female workers seem to be the key to the hive. After all, they do so much. They start off early in their lives cleaning the nest. A few days later they are feeding larvae, then secreting wax to build the honeycomb. At about the age of 20 days, they act as guards to the entrance of the nest, and when their glands degenerate, they’re off collecting pollen and nectar for the rest of their lives. After a successful trip, they perform elaborate symbolic dances, revealing both the angular and scalar components of their displacement from flowers to hive. In contrast, the males and the queen bee don’t do any of the above.

But the female workers, as industrious as they may be, do not reproduce and do not exert the strongest influence in the hive. The failure of a single and other type of individual is consistently listed as a cause of honeybee colony mortality.  That individual is the queen bee. She is born in a cell built larger than the others to accommodate her bigger size. But what makes her develop into a queen? After observing that the queen bee larva and adult queen is only fed a so-called royal jelly, a white mixture of protein and sugar secreted from the heads of worker bees, it was long assumed that the mixture held the secret. But a few years ago it was revealed that the key was not necessarily contained in the royal jelly but in what the queen bee was not fed: pollen and nectar. The latter food- source for other larvae contains flavonoids, some of which include inhibitors. Investigators reared larvae in the lab on a royal jelly diet adulterated with para coumaric acid, and by the time they developed into adults, ovary development had been stunted.

queencourt

A queen bee courted by other females. Notice her  larger size and the yellow marker added by a biologist. http://articles.extension.org/pages/73133/honey-bee-queens:-evaluating-the-most-important-colony-member

When not exposed to such gene-silencers, a queen bee will normally emerge from her larval stage five days sooner than other bees. After killing competing virgin queens, she diversifies genetic input by mating with 7 to 17 drones, who die soon afterwards. With the ability to store about seven million sperm, the queen will then be fed and groomed by workers while she lays eggs for the rest of her life. In what surely is a matriarch’s fantasy, the older a queen bee gets, the more prolific she becomes in laying eggs, becoming even more attractive to her servants. But how does this happen?

JBFree_source-Pheromones

The various effects on bee behavior controlled by a complex of a chemical signals from the queen bee. Source: JB Free

It has been known for decades that a pheromone (chemical messenger) is released from the queen bee’s mandibular gland in her lower mouth.  In subsequent experiments, however, the compound that had been identified as E-9-oxodec-2-enoic acid, could not on its own exert any retinue behaviour on worker bees. Retinue behaviour is what’s used to described the way workers groom and feed the queen. It’s only part of the influence that the queen bee’s chemical messengers can have on bee behaviour, as revealed in the adjacent illustration. There are a series of effects with immediate impacts (releaser) and those with long term consequences(primer) on the endocrine and reproductive systems of workers.

beehormones

Three of at least 9 compounds released to make sure the queen bee gets groomed and fed by other females.

Eventually, in the late 1980s Canadian researchers from Simon Fraser University revealed that the original compound was really a mixture of two mirror-image molecules known as enantiomers. They also identified three other compounds from the mandibular gland. When a tube containing the 5-compound mixture was placed in a beehive, the workers left the cells that they were building for new queens and started to press their antennae against the glass while licking the synthetic queen. But the mystery wasn’t entirely solved. As the authors of the same study stated in a review paper 16 years later, the 5-compound mixture is ineffective in some strains of honeybees. The response is influenced by variable genetic factors and by at least 4 other compounds, specifically coniferyl alcohol, another alcohol, methyl oleate and linolenic acid. As the queen ages she releases higher concentrations of the compounds to ensure a positive correlation between the attention she receives and the amount of eggs she lays.

When looking beyond the queen and to the general health of bees, including solitary ones, it was assumed that the concentration of pesticides found in bees was too low to harm them. If inspected individually, each pesticide’s level is indeed below the bee’s threshold. But collectively, along with bee diseases and diminishing flower diversity, pesticides have a detrimental impact on a highly beneficial insect. Whether or not bees produce honey and wax for us, they are the sole and essential pollinators of plants such as squash, zucchini, pumpkins, kiwi, watermelon, cantaloupes and Brazil and macadamian nuts. Besides, their mysteries have justifiably inspired more research than any other insect.

Sources:

  • Honey Bee Queens: Evaluating the Most Important Colony Member
    Bee Health October 07, 2015  Philip A. Moore, Michael E. Wilson, John A. Skinner
    Department of Entomology and Plant Pathology, The University of Tennessee, Knoxville
  •  A dietary phytochemical alters caste-associated gene expression in honey bees. Wenfu Mao, Mary A. Schuler, and May R. Berenbaum. 2015. Science Advances 1(7).

  • Pheromone Communication in the Honeybee (Apis mellifera L.) KEITH N. SLESSOR,1 MARK L. WINSTON,2 and YVES LE CONTE3 Journal of Chemical Ecology, Vol. 31, No. 11, November 2005 (#2005) DOI: 10.1007/s10886-005-7623-9
  • New components of the honey bee (Apis mellifera L.)
    queen retinue pheromone. Christopher I. Keeling*†, Keith N. Slessor*, Heather A. Higo‡, and Mark L. Winston‡ Proc Natl Acad Sci U S A. 2003 Apr 15;100(8):4486-91. Epub 2003 Apr 3.
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When Math-Shortcuts Involved Little or No Technology

There are some great tools available to anyone who wants to do math, regardless of the level involved. And whether it’s a calculator, spreadsheet or software package, they don’t just cater to time-savers. Many are programmable and therefore thought-provoking. But in the old days of hand-calculations, people did not necessarily surrender to tedium. They often came up with shortcuts, some of which were excellent approximations, while others gave an exact result. Let’s look at an example of each variety.

Whether you’re on a plane, hill or mountain, if you know your altitude, what is the easiest way of calculating the distance to the horizon?

SANYO DIGITAL CAMERA

How far is the horizon from the top of the 390 foot (119 m) peninsula(Cape St Mary’s)? About 24.2 miles (almost 39 km), but in this old picture my daughter was looking for birds and was not concerned with distances.

It turns out you don’t have to resort to the tangent to a circle and the Pythagorean theorem. The shortcut consists of multiplying the altitude in feet by 1.5 (its units not shown) and to square root the product. The answer is a close approximation of the distance in miles!

To understand why the shortcut works we need to look at the longer and more accurate way of solving the problem. The distance, d, from an altitude, h, is simply the leg of a right-angled triangle. One angle is 90 degrees because the line of sight is tangent to the radius (R) of the earth, an approximate circle. Finally the hypotenuse is the sum of R and h.

circleSince d² + R² = (h+R)², after expanding and eliminating the common R² term, we obtain:

d² = h² + 2hR

The radius of the earth is about 3959 miles and there are 5280 feet in a mile, so plugging in R and solving for d we obtain

d = √( h² +  41 807 040 h ) in feet.

But the trick claims that d =√(1.5h) in miles. Converting to  feet ,

d =5280√(1.5h).

Equating the two expressions for d:

√( h² +  41 807 040 h) = 5280√(1.5h).

Squaring both sides:

h² +  41 807 040 h = 5280²(1.5)h.

Dividing through by h and simplifying the right hand side:

h +  41 807 040  = 41 817 600.

For any h value between 1 and 40 000 feet, the left hand sum will differ from the right hand side by a maximum of 0.07%. And so the trick works well. But how was it devised?

My guess is that if someone plotted various values of height in feet versus the distance in miles using the Pythagorean expression, she would have noticed a square root function going through the origin of the form y = a√h, where a is constant. To verify it, she likely calculated successive changes in distance per changes in the square roots of height. I’ve tried that and I obtained values in the neighborhood of 1.224 and 1.225. Then all she had to do was recognize that those values are pretty close to the square root of 1.5.

The second shortcut is a simple algorithm for computing averages mentally.  I came up with it independently when I was a high school student, and needless to say this trick has also occurred to many other people!

Instead of adding up values x1, x2, x3 …. xn and dividing by the number of values, n,  if you have no calculator, we begin with a convenient estimate. Then add up the differences from the estimate, divide the sum by n and add the result to the estimated value. For example, for the average of 78, 82, 97, 60 and 77, we could use an estimate of 80. The differences from the values are -2, +2, +17, -20 and -3. Mentally the numbers are smaller so it’s easy to come up with the sum of -6. Finally the average is -6/5 + 80 = -1.2 + 80 = 78.8, also a very feasible mental calculation.

Here’s why it works. Let E = estimate for the average(Xavg) of an n number of values: x1, x2, x3…xn

The first step involves adding up the differences (call the sum Sd) from E:

x1 – E  + x2 – E + x3 – E… + xn – E = Sd =  x1 + x2 + x3 … + xnnE

The we divide through by the sum by n:

Sd/n = (x1 + x2 + x3 … + xn nE)/n = (x1 + x2 + x3 … + xn)/nnE /n.

But on the right hand side , the first term is the definition of average, so:

Sd/n = Xavg – E

Or  Xavg =  Sd/n + E

And how did I and others devise such a trick? Intuitively, at least that’s how I came up with it, from what I recall. That’s is even more fun than trying to figure out how someone else stumbled upon it.