The Remarkable Honey Bee - May 2013

Propolis

by Larry Connor

(excerpt)

Propolis is a plant product collected by bees from plants within their normal foraging territory. The substance, understood to be largely unaltered by the bees, is comprised of resin from various species of plants, the exact sources of which are difficult to determine due to logistical reasons. However many of the North American propolis samples are collected from the tree genus Populus, commonly known as poplars. Propolis sources from other parts of the world appear to possess properties directly related to the available plant forage visited to obtain the material. Not all plant resins are identical.

Plant bud resins and their functions
Plant resins are believed to protect a plant’s buds and leaves from water loss and have a component of insect repellency. The resins are found in trees like the poplars and cottonwoods, trees that form new buds in the summer and early fall. The primordial tissue inside the bud does not produce propolis, but the stipules that form the bud scales secrete a resin that fills the bud. As the leaves grow and unroll in the spring, they produce glands that secrete resin. There may be extra floral nectaries located near the resin glands that are responsible for the guttation of sap (seen as drops of water at leaf edges, often exuded when there is high soil moisture) and nectar secretion1.
Humans use poplar buds for medicine, and continue to make poplar bud oil from cottonwood poplar buds, especially from Populus trichocarpa. They collect winter buds, macerate them and cover them with water and oil. This may be heated at a low level for several days and then stored for a month or more. Then the oil is carefully removed from the mixture and bottled. Any medicinal properties are attributed to the plant bud resins and salicylates in the bud tissue. Some people are allergic to this solution and may develop anaphylaxis2.
As a group, plant resins are known to be powerful chemicals. They are the source of the greasy build-up that forms when burning buds of cannabis, or while smoking leaf tobacco. As insect repellents, plant buds must contain powerful molecules to successfully minimize leaf feeders, either by a repellency (by an odor or tactile reaction) or toxic effects when ingested.

How do bees collect and use propolis?
Bees collect propolis in the same manner as pollen, packing it into their corbicula (pollen basket) and flying back to the hive. Upon arrival, the forager bee is assisted in the removal of the sticky substance that is then applied to the sides of the nest chamber, on the top of the wax brood comb (apparently to strengthen the hexagon-shaped wax to withstand bee foot traffic) and wherever a hole or crack needs to be filled. Beekeepers are all too familiar with propolis, especially when the bees have fastened combs together with the material (to keep them from moving in the wind?), securing the nest. Bees of certain races use large amounts propolis to reduce the size of the entrance of the hive, blocking potential intruders and cold winds. Hive invaders that die within the hive, and are too large for the bees to remove, are encased in propolis to arrest their decay and prevent the byproducts of decomposition from affecting the population of the hive. Beekeepers have found mice and large insects preserved, mummified in effect, in propolis.

Distribution, where and possible functions
The most apparent use of propolis is the patching of small holes, cracks and spaces less than 3/8 inch in the hive. Bees tend to use beeswax to fill spaces larger than 3/8 inch. While reducing the hive entrance is somewhat useful in deterring pests and predators, hives require ventilation to thrive, which brings our focus to another consideration: propolis and colony health. Propolis serves as an anti-fungal and anti-microbial agent, effectively working as a prophylactic tool used against a number of non-specialized threats to the bees’ health.
In feral bee colonies, in tree cavities or rock outcroppings, bees coat the top and sides of the structure with a thin layer of propolis. In addition to the anti-microbial action of the resin, the layer serves as a water and vapor barrier. This ensures that the dankness of a rotting tree or a rock cavity does not promote unhealthy conditions in the colony. The resins thwart the growth of fungi, bacteria and viruses. The propolis is like an envelope or biological shield that provides colonies with a more stable environment in which to grow.
Bees also scrape the entrance of the nest to remove loose bark or dirt and coat the hive entrance with propolis. This may provide the bees with a smoother surface for takeoff and landing activities as they forage.
Propolis is used in the comb area of the hive, as evidenced by thin layers of resin on the brood comb and between comb and their attachment to the tree or rock homesite. In managed bee colonies, the bees’ use of propolis is considered an essential part of colony health. Within the first season of use with new combs, most colonies add abundant propolis along the frame ends, where the wood parts of the frame contact the frame rest. With additional beekeeper manipulations, there will be additional layers of propolis added to the initial layers, used to re-secure the frames.

 

The Remarkable Honey Bee - April 2013

The Queen's Life

by Larry Connor

In what season does a queen start her life?
We might assume that the majority of queens are reared during swarming. This is a major colony event during of the spring buildup period of the season. Swarms may first appear in February in Florida, Georgia and south Texas, but not until May or later in the northern reaches of the North American continent. Each area has a peak swarming period of about six weeks, and this peak swarming season moves north as the calendar progresses, influenced by cold fronts, heat waves, drought conditions, and floral abundance. If bees are unable to forage, the swarm season is delayed and its intensity may be diminished. If there is abundant food, good foraging conditions, then the season arrives early, there may be many swarms, even from each colony. The first swarm is called the prime swarm, and is usually the largest, and often carries with it the old queen. The parent hive that issues the prime swarm will have queen cells in production when this occurs, in fact, this swarming business happens quickly, and the swarm cells may not yet be sealed. Many beekeepers miss the signs of swarming, and the beekeepers never know their colony has swarmed.
Incoming resource abundance is clearly a major key to determining the time of the production of natural queen cells by colonies outside a beekeeper’s manipulations of feeding and colony division. Nectar and pollen abundance determines the speed of colony development, for both plant and colony development rates are directly influenced by increased spring warming. Colonies on a spring nectar flow are stimulated to expand the brood nest, while incoming pollen stimulates brood production with the engorgement of the hypopharyngeal, or brood food, gland of young worker bees. Because royal jelly cannot be stockpiled like honey or pollen, it must be fed to developing larvae, as there are no cells filled with surplus royal jelly. It takes food abundance to produce abundant bees, and these numerous bees are necessary for production of queen cells during the swarming season. The queen receives this food during her entire larval life; ordinarily she is unable to consume it as fast as the nurse bees provide it, so there is unconsumed royal jelly inside the cell of each developing queen cell.

What triggers queen cell production?
During buildup, healthy queens oviposit 1,200 to 1,500 eggs per day to build a colony’s bee population to a robust level. With a vigorous queen most of the cells in the colony are filled with developing bees, the brood, or with pollen and honey. Her chemical messengers that control the colony are reduced by a combination of dilution and crowding. Triggered by self-monitoring feed-back mechanism that informs her that her pheromones are diluted, the old queen places eggs into queen cups built by her workers, initiating the production of the daughter queen cells that will ultimately provide her replacement. For an older but vigorous queen at swarming season, the relationship is like this:

Pollen and nectar in abundance - Stimulation of brood production - Dilution of queen pheromone - Queen puts eggs into cups

 

Compare this to a colony with an old queen, one that is two or three years old, her egg-laying is reduced, with the nectar flows filling the emerging cells in the brood combs. They are not involved in the swarming process, but supersedure, queen replacement. This drop in brood production is associated with a similar decline in the queen’s production of queen substance or pheromone.
The supersedure queen replacement process looks like this:

Reduction of egg laying and reduced stimulation of brood pheromones - Dilution of queen pheromone - Queen puts eggs into cups

The process is basically the same, as the outcome is the production of queen cells. The queen lays the eggs placed into these cells. The difference is in the different stimuli: abundance of food and brood in swarming and the decline of egg-laying and brood pheromone in supersedure. Queen cups are available throughout the year for use for queen cell production, but swarm cells are often at the bottom of the comb, or frame. When the brood area is reduced, due to egg-laying reduction, the cells are often on the face of the comb.
With a change of colony fortune, a swarm cell may be used for supersedure without swarming. Less often a supersedure cell may be used to provide a queen for a small swarm.
Royal jelly is not fed throughout the life of larval worker and drone bees. There may be a small surplus of royal jelly at the bottom of their cells, but only for the first two days or so. Then the nurse bees switch the larvae to a diet of honey and pollen, a gruel for the masses, while the queen larvae continues her special diet until the cell is sealed by other worker bees. When small, larvae require fewer visits for feeding, but as they grow in size, very rapidly in about five days, the number of feeding visits increases dramatically because the larva is larger and consumes more food.

Theories of abundance
Bee colonies in nature are often sparsely spaced, and the evolution of the mating behavior of bees using drone congregation areas appears to be Nature’s way to ensure that queens and drones from different colonies are able to find each other in a otherwise rarefied environment. Increased abundance of food (or water in the desert) may result in more bee colonies in one area, and while this may seem to be counterproductive by increasing competition for finite food reserves, areas with larger colony numbers tend to have healthier colonies. This same result has been shown with goldfish and butterflies, that an increase in mating opportunities produces a healthier population. We do not think of a young, unmated queen as a lone predator, searching great distances for a mate. Instead, drone congregation areas provide abundant mating partners, enough of them to satisfy a queen’s need for 20, 40 or 60 sexual partners, as recent studies have shown.
The need for abundant, sexually mature male bees, the drones, at the time the queen leaves for her nuptial flights is met by increased drone production during the spring increase, and many beekeepers use the appearance of the first sealed drone brood as one method of predicting when their colonies are likely to reach their peak swarming.
If a group of colonies are left to themselves, the healthy overwintered colonies will reach a swarming peak in May where I live in Southwestern Michigan. Some will be reported in April and there will be more swarms throughout June and July, but the largest numbers will issue in May on beautiful spring mornings after a few days of showery confinement.
There are two kinds of queens in swarms. The first often carries with it the old queen, the one that helped build the colony, and survived a winter or two with her colony. She may have been a new queen the previous season or longer than that. My experience suggests that three-year old queens are possible, but infrequent. Dr. Joe Latshaw, who produces breeder queens for the beekeeping industry, calls three-year old queens Grand Old Ladies. I agree that selection for queen longevity is an excellent goal. We need to understand how some queens live longer than others.
When the old queen travels with the swarm to a new nest, she is responsible for the colony’s rapid growth during the first months of the colony’s occupation of its new home. It is usually unlikely that a new swarm will generate another swarm during the same season it swarmed, but will be stimulated to produce a large nest of new honey comb and store resources adequate for winter survival. Nearly all the brood comb the colony will ever build will be constructed during the spring and early summer as the nectar flow provides the raw ingredients for this task. The older queen will have time to serve her colony, but eventually her pheromone level will begin to fall. As as the supersedure process begins, she will keep the colony going during the nectar flow as her daughter completes metamorphic development, emerges, matures, mates and starts to lay eggs in the comb. As the old queen fails, her life is over, and worker bees working the role of undertaker bees will remove her body from the hive.
The second swarm queen type is characterized by swarms containing a number of virgin queens that travel with the mass of bees and enter the new nest. As the colony settles in, the virgins fight each other, leaving just one young queen to leave the hive and mate with drones within the surrounding region, in a distance or radius of two or three miles.  She too seeks to find and mate with 20, 40 or 60 drones; they are very likely in abundance at this time of the swarming season. When she returns, successful from her last mating, the last drone’s endophallus will still be in her median oviduct, and is called the mating sign. She will rest for a few days as hormones stimulate her ovaries to swell and produce ova in 350-400 ovarioles in her abdomen. The new swarm queen is likely to remain in the new location for at least a year, and perhaps two, before the nest becomes so crowded that the colony swarms much like the parent hive. This constant swarming continues the species.
Should a queen fail to mate due to weather confinement, she may become a drone-laying queen. If a dragonfly or kingbird eats her during her mating flight, her death will lead to the ultimate death of the colony. In a broodless condition, the workers are liberated of the queen pheromone that suppresses the development of their ovaries, and, because they cannot mate, will produce unfertilized eggs that will produce only haploid individuals, all drones.
The chart provided summarizes the difference between the two queen types found in swarms.
Perhaps most queens are produced during the swarming period of the spring season, whenever that is where you keep bees. But other queens are produced later in the season, probably during the nectar flow while there are still drones available for mating. This difference in the time of mating is asynchronous, indicating a lack of concurrence of timing of the mating event. Having different times of queen mating reflects the honey bee species’ flexibility in adjusting to differing food supplies and the abundance of male bees. Most beekeepers don’t spend much time thinking about this, as we think the bees are excellent in deciding when to produce queens and produce a new swarm or replace an old queen. We should be careful to think that this asynchronous mating behavior always works for queen production, and reflect on this when we find a nucleus or colony that has failed to replace its queen, with or without swarming.
Look for the new revised edition of  Dewey Caron and Lawrence Connor’s Honey Bee Biology and Beekeeping, due out later this season. Check www.wicwas.com for availability and ordering information.
Interested in a queen rearing course? Dr. Connor will offer one if there are enough beekeepers interested on May 31, June 1 & 2, in Galesburg, Michigan. Email LJConnor@aol.com should you be motivated. More advanced breeding methods will be discussed than in prior courses.