My design for a bait hive
I have been using two of the commercially available flower-pot shaped swarm traps for years. Each year I hang them up at the recommended height (8-12 feet) and facing the recommended direction (south or southeast). Each year I purchase fresh pheromone lures (the three-component USDA-endorsed type) and each year I check the traps every day during swarm season. At the end of the year I take them down and store them. Storage is the worst part because they are huge and oddly shaped.
Of course, I have never caught a swarm in one and probably never will. I persist in hanging them up every year because I paid for them—or, more to the point, I paid for the oversize postage. So I will most likely continue this ridiculous pastime until they disintegrate, or until I do, whichever comes first.
But last year after a swarm settled into my empty top-bar hive, I became absolutely enthralled with the idea of building a bait hive from old bee boxes and frames. If I can catch anything it will probably be my own swarms, but that is fine. I’d rather catch my own then have them go off into the woods or nest in my neighbor’s barn. In fact, my bees seem healthy and I’d rather not introduce bees with an unknown provenance into my apiary.
According to Thomas Seeley in Honeybee Democracy, bees on the run prefer a nesting cavity that is approximately 40 liters. This morning I measured the inside dimensions of a deep brood box and it came to 14.75” x 18.38” x 9.63” or 2610.74 cubic inches (they really add up.) I ran this through Convert and came up with 42.78 liters. So, one deep brood box should do it.
Seeley also says that bees prefer an entrance that is 15 cm2. Again using Convert this comes to 2.33 square inches. (Sorry, but as a denizen of Fahrenheitland, I think in inches.) The square root of 2.33 is 1.53. So I can use a square hole of 1.5 inches on a side or a circular hole with a diameter of 1.72 inches (2.33=3.14r2).
I measured the larger opening on my entrance reducers and it is 5.2” x 0.38” or 1.95 square inches. So the question is this: should I enlarge the rectangular opening, or should I make a circular or square opening? Seeley says bees don’t have a preference for entrance shape, but all his nest box photos show square holes.
Just for fun I calculated the area of the entrance in the top-bar hive that the swarm moved into last year. It consists of three one-inch diameter holes. When I calculate the total area, it comes to 2.36 square inches (A = 3.14 x 0.52 x 3). Amazing! Just 0.03 square inches different from Seeley’s ideal size! Seeley never mentions whether the entrance area can be piecemeal, but it is an interesting question.
To make this easy, I think I will mount the brood box on a regular bottom board and block off part of the standard entrance. The entrance is 0.75” high, so I will allow a little over 3 inches of it to remain open (2.33/0.75 = 3.11). Okay, that’s two questions answered.
Height of the bait hive is the third issue. According to Seeley, bees prefer to nest high in the trees. (The wild hives he found averaged 21 feet off the ground.) But in his experiments, most of his bait hives were low to the ground. My top-bar hive is only about two feet off the ground. So I think I won’t bother trying to suspend this thing from a tree because, for me, it is just too heavy and impractical. I will just put it on one of my regular hive stands, face it south, and call it good.
From my reading in the past few months, I’ve learned that drawn comb that previously contained brood is one of the biggest attractants for a swarm, so I will definitely use old comb. Slumgum has also been mentioned as a swarm attractant, so I will smear some of that near the entrance. I will dispense with the regular lemongrass attractant because I have used that in my swarm traps for years to no avail.
So there you have it: my plans for a bait hive. About the only things I have to do are find some used brood comb, cut an entrance reducer, render some wax so I can collect slumgum, and then smear the stuff around. Mud pies for adults. I will let you know what happens.