Cover Story

July 2014

A Comparative Test of the Pollen Subs

Part 1 - Experimental Design and Execution


The growth and health of honey bee colonies is primarily dependent upon the availability of high-quality pollen. Pollen and its fermented form, beebread, is the colony’s primary source of protein, lipids, vitamins, minerals, and sterols.[1]
When there is a dearth of quality pollen, colonies suffer.[2] Broodrearing comes to a halt and the nurses may cannibalize eggs and larvae. Colonies stop growing or go downhill. Protein-starved colonies are unable to hold their own against parasites and pathogens; diseases set in. Inadequate protein nutrition in late summer and fall leads to poor wintering and colonies unable to make grade for almonds.

To mitigate the above problems during times of pollen dearth, beekeepers have long fed protein supplements (commonly called “pollen subs,” although none to date are truly complete substitutes for quality natural pollen). In recent years, successful beekeepers are spending more on pollen subs than ever before (I could not run a successful operation in my area without them). Due to this demand, a number of (ostensibly) improved pollen supplement formulas have recently come onto the market, but the formal testing of such[3] has been limited (and often involved those with a proprietary interest). So I decided to perform a Consumer Reports® type of test to find out how the various products compare.
It occurs to me that the reader may be interested in the sorts of actual details and problems encountered in the design and execution of field trials. So instead of presenting this as a typical dry scientific paper, I’m writing this article as an expanded version of my log book in order to show what sort of thought processes go into a trial, how things often don’t go as planned, how exciting seeing positive results can be, and the decisions that the researcher must make in presenting and interpreting the data. I’m then going to follow this article with additional recent studies that I’ve done related to bee nutrition (as I write this, I’ve already begun a follow up trial).

2013/14 Pollen Supplement Trial
Principal Investigator:
Randy Oliver, assisted by Eric and Ian Oliver

Funding sources: Independently funded by beekeeper donations to Special thanks to almond pollinators contracting with Joe Traynor of Scientific Ag Company, and beekeepers Jeff Becker and Ray Olivarez, Jr.
Experimental Objectives:

  1. To determine whether colonies can be built up for almonds in late summer and over the California winter on artificial diet (sugar and pollen sub) without substantial natural forage available; that is, can today’s formulations substitute for natural pollen?
  2. To rank the commercially-available pollen supplements by their ability to promote colony growth.
  3. To determine the overall cost of building 5-frame nucs on foundation to almond pollination strength.
  4. To compare the attractiveness and consumption rates of the various pollen supplement formulas.
  5. To determine the cost effectiveness of the various subs at growing colony populations.

Experimental Design and Considerations:

I designed this experiment as an “acid test” of pollen subs by forcing colonies to build up their populations during a time when natural sources of pollen are inadequate. Based upon my 35 years’ experience in the Sierra Foothills, that condition typically occurs from mid August through December, during which time colonies not given protein supplement go decidedly downhill.

Then I had to consider which size and strength of colonies to use for the trial. Full-size doubles, having already reached maximum strength, would be poor indicators of the nutritional utility of the pollen subs for “growing bees.” In addition, large hives might contain reserves of beebread that could add a variable, they are difficult to accurately grade for strength, and must be disturbed to put the patties in contact with the broodnest.[4] The Coloss BeeBook[5] suggests starting with colonies on the order of 5-frame nucs to allow for a robust comparison of the effects of the treatments on growth rates. This sounded good to me, and I thought that I’d add new combs of foundation in order to minimize the variables inherent in drawn combs, such as pesticide residues, pathogens, or existing beebread.
I’d start with well-established nucs headed by recently-mated queens (mated in the same nuc). I’d feed the colonies with pollen sub patties and sugar syrup[6] to encourage them to draw out and occupy the frames of foundation, aiming to grow them into double deep hives (the use of foundation would allow room for the storage of the necessary stimulative syrup over a long period of time).

I’d grade the colonies for strength (using standard “almond grading” of cluster size) at various time points to quantify colony strength, with the final grading at almond bloom in February.

In order to minimize variables, I’d feed all the pollen subs as 1-lb standard patties in waxed paper. Syrup would be fed via inverted half-gallon feeder jars.

I wanted to test a variety of pollen subs from various manufacturers and a wide range of formulations, and came up with the following list (in alphabetical order, with their abbreviated names; formulations in Appendix):

  1. BeePro: from Mann Lake, as an example of a typical soy/yeast formulation long used by beekeepers.[7]
  2. Experimental yeast (Yeast): Suggested by Mann Lake to test a yeast-based formulation recommended by beekeepers in the Midwest.
  3. FeedBee: A Canadian formulation sold in the U.S. and worldwide.
  4. “Homebrew” formula: my “everything but the kitchen sink” formula which included ingredients not found in the others, such as dried egg yolk, plant phytochemical extracts, Latshaw vitamin/mineral formulation, and corn/canola and coconut oils.
  5. Mann Lake experimental bulk (Bulk): developed as a cost-effective bulk sub to be chopped into chunks in the field.
  6. MegaBee (Mega): developed by Dr. Gordon Wardell, and carried by Dadant.
  7. UltraBee (Ultra): Mann Lake’s flagship product.
  8. Positive control of natural Calif foothill bee-collected pollen (Natural): mixed trapped foothill pollen from California beekeeper Jeff Becker, blended with sucrose and HFCS, and made into patty form (compliments of Mann Lake Ltd.).
  9. Negative control without protein supplementation (Negative): no patty given, but the same amount of sugar syrup as given the other groups.

Experimental considerations: There were other formulations that I considered testing, but most were similar to ones above. An exception was the patty produced by California beekeeper (and good friend) Keith Jarrett; after deliberation, he opted to pass on this particular trial. In hindsight, I wish that I had included it. I also contacted the developers of each product, and asked them for comments on feeding their products for optimum effect, since some had been unhappy with the design of other published trials.

A trial of this sort should include both positive and negative control groups, i.e., one receiving a treatment that you already know will give a measurable effect (natural pollen), as well as a negative control that receives no treatment. Technically, the Negative Control group should be fed a sham patty of moistened sugar alone to account for the effect of the sugar (roughly 50%) in the protein patties. On the other hand, the treatment of feeding protein patties adds a hive disturbance and potential bee-crushing variable that an unsupplemented hive would not normally receive. In the case of this trial, since I would be feeding sugar in the syrup (at least 3.25 lbs fed per each patty fed) far in excess of that in the patties (about 0.5 lbs per patty), I felt that a compensatory sugar feeding was unnecessary for the Negative Controls (in all hives, sugar was fed in excess of nutritional requirements, as indicated by the weight gains (not shown) of the colonies).

I wanted enough colonies in each group to be able to detect statistical differences due to treatment (type of pollen sub), so set up 18 hives for each treatment (162 hives total). As a general rule, due to the natural variability of colonies, a minimum of 12 hives should be in each treatment group in order to detect statistically significant differences.

Description of the (First) Experimental Apiary Location
This yard was located in a grassy clearing in an oak/pine habitat at a ranch at 2700-ft elevation in the Sierra foothills. The yard was chosen mainly due to its easy access for the multiple required feedings and for its uniform flat terrain. Its drawback was that it is on the outskirts of town, so there was some opportunity for the bees to forage on natural pollen. This drawback was partially offset by competition between the large number of managed colonies in this and two nearby apiaries of my own.

Abbreviated Experimental Log
Advance preparation: Mann Lake Ltd. prepared their own formulations, and generously volunteered to mix and prepare the Homebrew and Natural patties to my specifications[8], using ingredients that I shipped to them. I purchased MegaBee patties directly from Dadant. FeedBee patties were custom prepared to the manufacturer’s specifications by Global Patty.[9] A minimum of 360 lbs of patties (20 lbs per hive) was obtained for each group, and stored in a cool room (Fig. 1).

July 23-31, 2013 Set up 9 groups of 18 colonies in the test yard. Started with 5-frame nucs with new queens that had been laying for 2-5 weeks; nucs from various queen mothers distributed equally into all test groups. Laid out the 9 groups w/ all hives facing the same direction, each group separated by built landmarks (drums, cinder blocks, and pallets) (Fig. 2).

We checked all colonies for health and queenrightness, replacing any questionable ones. We worked all the nucs into singles containing only 5 frames, so as to be able to easily see the size of the starting cluster; we equalized all until the two visible sides of the outside frames were covered with a single layer of bees (Fig. 3). There was a light nectar flow on, and colonies started building small amounts of comb from the lids, so after equalization we added a frame of foundation to either side.

August 8--Time Point 0: Natural pollen flow nearly over, colonies slowing down broodrearing. No noticeable change in strengths. Assigned treatment groups by random number generator, and filled the boxes to 10 frames with additional foundation (Fig. 3b). Feeding #1: fed each colony 1 patty plus ½ gal syrup (9:1 Pro-Sweet:water[10]).

Experimental considerations: Treatment groups should always be either randomly (not arbitrarily or haphazardly) or systematically assigned to avoid any inadvertent investigator effect.
I needed to control varroa infestation as a variable, but didn’t want to stress the nucs with my usual formic acid or thymol treatments. So I used (for my first time) 1 Apivar® amitraz strip hung in the center of each nuc, hoping to obtain a near complete mite kill by using this extended-release synthetic miticide. Since we’d also seen some EFB in the operation this spring, I also treated each colony with 1 Tbl Terra Pro® OTC antibiotic (we observed no EFB during the course of the trial).

August 12-18: Four more feedings of ½ gal Pro-Sweet syrup diluted to 60% sugar. Queens laying well due to syrup stimulation, but little young brood. Still ...