Tuesday, March 26, 2013

Harsh March

A Minnesota beekeeper checks his hive and finds plenty of bees and ample stored honey. Shortly afterward, cold weather set in for several days. Two weeks later, he finds the bees in the hive are dead even though the hive still holds plenty of honey. March is often the harshest month for honey bees. Bee populations are growing; the increasing population of bees requires a lot of food; the hive's food stores are rapidly diminishing; and there are not many flowers blooming for bees to forage. On warm days, worker bees may expend more energy searching for food than they would consume if they remained in the hive. Also, when there is brood in the hive, the bees must warm the brood nest to 95 degrees Fahrenheit, requiring the consumption of honey to generate heat. The most likely cause of the death of the Minnesota bees is starvation. Starvation is easy to identify; the beekeeper finds the dead bees clustered with dead bees head-first inside empty cells as in today’s photo. Often, ample stores of honey surround the dead, starved bees.

In starvation, here's what typically happens: The bees expand their winter cluster on warm days and contract the cluster on cold nights. On warm days the bees eat the stored honey surrounding the cluster. Then, when outside temperatures fall, the cluster contracts leaving a ring of emptied cells surrounding the bees. If the winter colony has no brood, the cluster may move about the hive. However, if there is brood present, the clustered bees will not move away from the brood. During a prolonged period of cold weather the bees remain tightly clustered, and they can't move the few inches to the stored honey. Because the colony shares food, all of the bees die when the colony runs out of food that they can access. If beekeepers detect a hive is short of food stores in late winter, they can provide emergency feeding of dry sugar or fondant candy.

Friday, March 8, 2013

Managing Top Bar Hives

Fall and spring hive management in top bar hives is similar to that of Langstroth hives. Bees tend to build their brood nest in a top bar hive near the hive entrance and expand horizontally with new combs. Two combs holding honey and pollen near the hive entrance provide food for the brood. Hive manipulations can be visualized as if a Langstroth hive is lying on its side. Just as the beekeeper moves the winter cluster downward in the fall in a Langstroth hive, he or she moves the cluster forward toward the top bar hive entrance. Over winter, the bees move horizontally away from the entrance into the honey storage combs. In the spring, empty combs near the entrance should be moved to the rear, and the brood nest pushed toward the entrance.

 All bee hive manipulations of modern hives can be accomplished with top bar hives if the bees build straight combs centered on the top bars. Carefully built top bars of 32 millimeter width are necessary for comb management. If the bees build combs connecting the top bars, the hive can’t be easily manipulated. Bees tend to curve their combs toward the hive entrance. Cutting away curved portions of combs encourages the bees to build straight combs centered on the hive's top bars. Ethiopian beekeeper Teshome recognizes that by building top bar hives of standardized dimensions he can move combs between hives. This allows him to de-queen poorly performing colonies or those with defensive behavior and bring in combs of eggs and larvae from his best colonies to control and improve bee genetics. He can also rear new queens and make colony divisions in his top bar hives. Today’s photo: a mud and dung coated Tanzanian top bar hive in use in Ethiopia. The Tanzanian hive design employs vertical box walls. This rear view shows one empty frame behind top bars. Under a thatched roof, the hive stand’s plastic sheeting and oiled posts protect hives from ants.

Thursday, March 7, 2013

Top Bar Hives

Beekeepers are making preparations for adding new colonies in the spring. While most will house their bees in modern bee hives, some will chose hives of other designs. The Kenyan top bar hive is the choice of a number of hobbyists who want to keep a few bee hives at their home. This removable comb hive is simply a box with sticks, called top bars, to hold combs. A benefit of top bar hives is that they can be constructed at low cost from locally available materials using ordinary hand tools and simple building skills.

Larry Tomkins, a knowledgeable beekeeper from Northeast Arkansas, shared his top bar beekeeping experience with the Arkansas Beekeepers Association. Tomkins, who began beekeeping with Langstroth hives, explained how he enjoys building top bar hives that he constructs from scrap lumber. Tompkins uses the hive design developed by the Peace Corps, http://www.tc.umn.edu/~reute001/Plan%20files/pTop%20bar%20Kenya.pdf. Tompkins built the top bar hive that he brought to the ABA Spring Conference for 79 cents, the cost of screws. There are no standardized top bar hive plans; there is only one critical measurement: Top bars must be 32 millimeters in width. A beer bottle cap makes a handy measuring device for constructing top bars. Building top bars of the proper width is important for maintaining bee space. Bees build cross combs on improperly designed top bars. Top bar hives are attractive to some beekeepers because, unlike modern bee hives, there are no heavy boxes to lift. All hive work is accomplished at a comfortable waist-level height by removing one comb at a time from the hive. Since harvesting of honey from top bar hives involves destroying the honeycomb, old beeswax is continuously replaced in the hive. Comb replacement is good for colony health; environmental chemicals and bee disease spores are removed from the hive. Today’s photo is a Kenyan top bar hive in use in Ethiopia.