During Spring pollination, a colony of 8-frame (of bees) strength can send out 7 to 10 times as many workers as a 4-frame colony
For most crop pollination, the range of prices for bee rentals – 0 to $60 or more – is large enough to make a seasoned economist throw up his hands in despair. Colonies placed for no charge (“freebees”) are placed solely for the location (usually a truckload at one site) while colonies at the high end of the price scale usually reflect the strength of the colony and the time and effort a beekeeper has put into the colonies (such colonies are usually scattered in groups of 12 or more).
To get paid at the high end of the scale, the beekeeper must convince a grower that his (the grower’s) money is being spent wisely. When a grower spends $100 per acre for bees he wants to make sure the bees (now his workers) are putting in a good day’s work. The grower will observe the colonies (usually from a vehicle) and if he sees enough colonies over the years he will eventually find one or two that have less activity than the others – this is his first clue that not all bee colonies are equal.
A more indelible impression occurs when the grower finds one or two colonies that are working far better than the others, a situation often followed by a call to the beekeeper asking why all the colonies aren’t as active “as that one there.” Occasionally “that one there” is a colony that is being robbed out by other colonies but more often, differences in bee activity among colonies represent differences in colony strength.
The savvy grower (and most growers are savvy or they don’t remain in business) soon realizes that he’d be better off paying twice as much to rent colonies that do 2 to 3 times the work. Beekeepers can hasten this learning curve on the part of a grower by opening a few colonies for a grower to let the grower see what he’s paying for (perhaps taking along a dead-out for comparison).
For cool weather (e.g., Spring) pollination, the economic advantage of strong colonies becomes even greater because during cool weather, proportionally more bees must remain home to keep the brood nest at the desired 95ºF. During spring pollination, a colony of 8-frame (of bees) strength can send out 7 to 10 times as many workers as a 4-frame colony. In this situation, a grower that pays twice as much for the 8-frame colony gets a bargain since one-seventh the number of colonies can be rented.
The vastly superior pollinating effectiveness of strong colonies was neatly demonstrated by John Edson in a 1976 experiment (published in the Feb. 1977 American Bee Journal, pp. 78, 79, 92). During almond bloom (late Feb., temperatures in the low sixties) Edson compared the amount of pollen collected by 4 colonies of 4-frame strength and found that the 8-frame colonies collected 7 times more pollen (than the 4-frame colonies). Edson maintained the same colonies through prune bloom (late March, temperatures in the low seventies, at which time the “strong” and “weak” colonies were 10 and 5 frames of bees respectively) and found that the strong colonies collected “only” 3 times as much pollen. Edson’s study is summarized in Table 1.
|Table 1 – John Edson study, 1976
GRAMS OF POLLEN COLLECTED DAILY (per colony)
|@61.5ºF (late Feb.)*
8 frame bees 12.8 g
4 frame bees 1.8 g
10 frame bees 30.2 g
5 frame bees 11.1 g
|*4 day period, almond bloom
**4 day period, prune bloom
About the same time that Edson’s study came out I had a personal experience that confirmed much of his work. At the time I owned several hundred bee colonies and had about 100 of them on melon pollination (mid-May when temperatures are in the 80’s). My bees had just come out of oranges (as most melon bees do) and were 2 boxes, full of bees. About a week after the bees were placed on the melons, a severe pesticide kill occurred (from Orthene on nearby cotton). Both the melon grower and the cotton grower were surprised when I complained because a beekeeper on a neighboring melon field (closer to the sprayed cotton) had assessed his bees and concluded that there was “no problem”. Indeed, there were no more than the normal amount of dead bees in front of the neighbor’s hives while the ground in front of my hives was black with dead bees. The “mystery” was solved when the county bee inspector came out to check on the kill – it turned out the neighboring colonies had only a few frames of bees in them while mine still looked good in spite of the kill. (It is possible that my bees were foraging earlier in the morning when the cotton was sprayed.)
Thus, although not recommended, a pesticide application can reveal colony strength. After a bee poisoning incident, the dead bees in front of a hive represent mainly foraging bees and account for only part of a bee kill (some poisoned foragers don’t make it back to the hive and some are carried away by “housekeeper” bees). In this case, the melon grower took note, and didn’t complain about our high prices again.
An inadvertent pesticide application during the 1999 almond pollination season provided a further opportunity to evaluate colonies of varying strength. A grower on which we placed 12-frame strength colonies rented cheaper bees from another beekeeper. Although I didn’t look at the other bees, the grower and beekeeper assessed them at a “weak 8-frames” (the grower had contracted for 8-frame colonies from both of us). Both ours and the other colonies were placed in the same bee drive, with sets only a few trees apart. On February 15th a pesticide application took place and above average numbers of dead bees could be seen in front of both ours and the other beekeeper’s hives; the bees continued to die the following day (high temperatures were 56º and 61ºF for the 2 day period). Because there appeared to be far more dead bees in front of our hives, it was decided to count the number of dead bees; the data are shown in Table 2.
|Table 2 – PESTICIDE KILL DURING 1999 ALMOND POLLINATION|
|Dead bees per colony*
|*Six 12-frame colonies and eight 7-frame colonies were used to get the per-colony average.
**evaluated as a “weak 8”
The 7 to 1 dead bee ratio shown in Table 2 conforms neatly to the 7:1 ratio found by Edson. (Temperatures during the 1999 “test” were slightly cooler than during Edson’s test; had they been warmer, the ratio might have been less than 7:1).
Providing only strong colonies for a pollination project is costiy for a beekeeper. It requires culling out sub-standard colonies and, for early spring pollination, it usually requires feeding of both sugar – syrup and pollen (or pollen substitute) in order to build colony populations to 8 or more frames of bees. This extra work can easily cost $10 or more per colony.
There is ample evidence that high rental fees for strong bee colonies are a bargain based on their superior foraging activity. Growers that have made first-hand observations (counting in-out bee flight) have confirmed this, but don’t count on such growers to give you a price increase unless you ask for one.
To recoup the expense of providing strong colonies, the beekeeper must convince the grower that the extra money is a sound investment. For almond pollination we have done this by offering a sliding price scale for colonies of varying strength – 2, 4, 6 and 8 frames of bees – and providing information (such as Edson’s data) that the 8-frame’ colonies are the best buy. In 25 years of business we have had only one grower that wanted bees of less than 8-frame colonies (and several paid even more for 10-frame colonies).
Putting pollen traps on selected colonies (as Edson did) represents another way to convince growers to pay more for pollination. Year to year variables (mainly weather) make it difficult to come up with “pollen collected” standards but pollen traps (perhaps serviced by the grower) at least demonstrate that the bees are putting in a good days work.
For most pollination jobs, the target crop is over-stocked with bees (to make sure pollination is adequate) and as a result, colonies lose weight – a 20 to 30 pound loss per colony is normal for many pollination jobs. Setting up scale colonies at the pollination site can show the grower the honey (money) you are losing. Weighing truckloads before and after a pollination job (in-out weights) will more accurately demonstrate the honey lost. (Make sure surround crops aren’t significant honey producers before going too far with weight-loss demonstrations.)
I have found that the best way to convince growers that it’s worth paying more for strong colonies is to open our hives for them – let them see for themselves. Then remind them that an 8-frame colony can do up to 10 times the work of a 4-frame colony and their per-acre pollination costs can be reduced by cutting down on the total number of colonies used rather than cutting back on the rental price per colony.
Joe Traynor is a pollination broker in Bakersfield, CA.
The author is indebted to beekeeper Anne Woodard for gathering and putting together the information on the 1999 almond test.