Bee Culture, April 2009
by Walt Wright
Reviewing my list of possible article subjects, there are two items that could be integrated into one submittal. “Why use patties?” and a “description of the brood nest dome” are interrelated and can be treated as a unit. This discussion will treat them in reverse order.
A discussion of the shape of the top of the colony brood nest may seem like a nothing subject. The literature would support that impression. You won’t find much on it there, but its important to the bees. I remember writing somewhere that honey bees majored in physics and minored in mathematics. That tongue-in-cheek statement would be revised today to include a second minor in chemistry. Not relevant.
Here we want to explore the colony’s application of the physics of heat rise. Try to visualize the rounded top of the cluster as a blunt spear to penetrate upward in periods of brood nest expansion. Too far out for you? Sorry. We’ll go on without you.
Through the winter and into the buildup excess bees congregate at the top of the cluster. The insulating band around the cluster is thickest at the top. Dr. Farrar’s sketches of cluster cross sections in Wisconsin winters snow nearly twice the thickness of the insulating band at the top. This has several benefits in conserving their heat generated in the cluster interior. The extra thickness of concentrated bees at the top tends to block or cap the brood nest heat rise – a definite honey conservation measure.
Let’s spend a few seconds on heat rise. Heat generated at the outside tends to fold inward to concentrate in the center of the source. Sticks on the outside of your campfire go out – the heat to support combustion is directed inward. The heat rise of the campfire is centered. This is no less true for the lower heat levels of the brood nest. You can often see a column of bees active above the center of the brood nest at very cold temperatures. Are you beginning to see “spear” effect on colony growth?
As the population grows in the early buildup, more bees accumulate at the top. The increase in concentrated bees at the top serves at least two major purposes. First, they have to condition the overhead honey for expansion that they intend to grow into. Their overall survival format allows for contingencies. If the honey immediately overhead has granulated, it will expedite expansion to liquefy it. Although honey is reported to liquefy at brood nest temps, it’s a slow process. At least, I didn’t have the patience to confirm that it might be true. It even takes several hours to liquefy my honey at 130 degrees.
Later in the buildup the established colony must develop wax making capability. During the frosty morning period of swarm preps, into late winter, they must build a large corps of wax makers. Establishment of the swarm in a new location goes nowhere without comb for stores and brood. It is reported in some obscure literature that wax makers need at least 100° to generate wax with their wax glands. That’s well above reported brood nest temperatures.
One could conclude that the concentrated bees above the brood nest actually increase the temperature there. It might be the metabolic heat of each bee in proximity or perhaps the increase is deliberate by some action. Not that it matters, but accumulated body heat can be significant. Over the years, I have lost two colonies in transport with a screened top and entry. The bees, wanting out, built a barrier to air flow. They didn’t suffocate, but melted down in their own body heat. Just didn’t realize the populations of the hives. Marginally relevant.
Both the liquefying of honey overhead and the generation of wax makers would be supported by accumulation of bees above the brood. Note that the accumulation is also dome shaped. If you look at the incremental brood nest expansion – it comes in steps. The colony consumes the liquid feed overhead, prepares those cells for brood, and populates those cells with eggs as a batch. The band of cells for that increment of brood nest expansion is normally the widest at the top and the width trails off away from center. That maintains the brood dome shape through each step in expansion.
The intent of the forgoing was to describe how the shape of the brood dome contributes to the centralization of the heat rise. You know about the shape of the dome – you see it essentially all year, every year. You also see the effects of the colony preference for working in the heat rise from the brood nest. Even in the main flow, outside frames of honey supers are the last to be filled. However, working in the brood nest heat rise is more significant in the early, cool weather period of buildup. Obstructing the heat rise slows colony growth. Slowing colony growth is not in your best interest. Stronger colonies make more surplus.
Patties, pads, or pillows have been used for a long time to feed or treat colonies for pests. Recommendations for use usually direct you place the item directly over, and close to, the top of the broodnest. What happens? Brood nest heat is deflected by the obstruction to the outside fringes before it can turn upward. Not only is the heat rise weakened by dispersal, but it disrupts the colony instincts for building up and out from the center. As long as the obstruction stays in place colony growth is impaired. Regardless of how well-intentioned the obstruction was, you have “shot yourself in the foot” from a honey production standpoint. The Mite Away II® pad, for example, is recommended to stay in place for 2 to 3 weeks. Seeing the effects on colonies, made me want to remove it in the minimum time of two weeks. No overhead growth for two weeks is a significant impact in my area with a short build up time in the “explosion” period of growth.
The “experts” continue to overlook this feature of colony development, and that is reason enough for you to “think outside the box”, it is not mandatory for you to follow the one with the bell on – like goats. It is permissible for you to think about the effects of what you do. There are many ways to treat or feed your bees without shutting down colony growth. I’ll offer a couple that I have tried with success. If you have the capacity to think, you’ll come up with others.
The T mite penetrated my area in my second year of beekeeping – lost 8 of 10. Menthol crystals were being touted at the time as the best treatment. When I called the supply house to inquire how the packets were used, the order-taker at Kelly said she didn’t know, and didn’t refer me to anyone else. She mentioned that a beekeeper in Texas was having success with grease patties. Okay, I know how to do grease patties – I’ll try that first. The first season, standard patties were used, sandwiched between sheets of waxed paper per instructions. After that first season when it appeared to help, the application was streamlined to trim unnecessary time. The bucket of grease mix was taken to the bee yard and a couple of scoops scattered on the top of the brood nest, top bars. Some falls through to the bottom board. It’s much better than patty application for many reasons. Better distribution of the grease film that kills mites (both kinds). It’s cheap and quick. Food grade ingredients can be applied at anytime you have colony access. Does not seem to affect colony operations. And relevant to this submittal, it does not interfere with brood nest heat rise. It’s still my primary line of defense against mites.
An aside: I find it difficult to believe beekeepers are still using menthol packets. Do they not see the affects? When I tried them half the brood area shut down. The only brood was in the other end of the brood chamber. The bees can’t stand the overpowering smell. Fall, when the colony needs to rear young bees for wintering, is not the time to limit brood rearing. Couldn’t get those menthol packets out of the hive as fast as I would have liked, but they wintered ok. But bees are quite resilient to abuse. The packets, when removed, were coated with propolis in an effort to contain the overpowering stench. I wonder what would have happened if the packets had stayed in until the pellets completely vaporized. I wonder, but I really don’t want to know. End of aside.
Back to the subject: In the ’07 season where a late freeze stopped field pollen for three months, wanted to see if the colonies would take some commercial protein supplement – ordered just in case. The sticky mess (overshot the doughy consistency with too much sugar water) was placed on three inch strips of wax paper and placed on both ends of the brood chamber. The “main flow” was already in progress and the foragers were bringing nectar.
Dare I digress again so soon? The foragers prefer to travel through the brood nest. They could easily circumvent brood nest congestion by traveling up/down on the inside walls of the hive, but they don’t. Instead, they will cue up above and below the brood nest waiting their turn to get through. My guess is that passing though the brood nest improves communication between the decision makers of the brood nest and status of field conditions as seen by foragers.
The narrow strips, fore and aft, permitted the colonies to do it their way. The foragers could travel through the brood nest and work in the overhead heat rise from the brood nest. Incidentally, they devoured the protein supplement. They were desperate. A week later, the only evidence of having had it at all were a few shreds of wax paper out front. A second dose at that time, provided the same results. However, later in the season when field pollen was available, they took little interest in an identical offering.
To close, let me start you thinking about alternative ways to avoid blocking the heat rise from the brood nest. Although the Tennessee Crackpot has not tried them, a couple ways come to mind. Cutting the patty into strips or pie slices might be effective. With open spaces between the strips or slices, warmer air would not be diverted to the outside.