Final Report for FS13-265
Project Information
Modern beekeeping involves many variables. Most of these, the beekeeper has limited control over, such as mite pressure, viruses, diseases, forage and weather. Here, the beekeeper's best defense is often to maintain strong, healthy colonies. To this end, one of the beekeeper's most valuable tools is the ability to supplement nutrition. This idea was popularized in Doug Somerville's publication "Fat Bees Skinny Bees" (Canberra, 2005). Here, the author describes the benefits of providing supplemental nutrition in terms of colony health and consequently as an effective means of decreasing colony mortalities. Implicit in his research is a simple principle acknowledging that well-nourished colonies can "out-grow" many of their maladies. Supplementing nutrition stimulates growth, which enables the colony to replace bees that may be turning-over at an accelerated rate due to disease, virus, and/or mite pressure. The principle is analogous to a bathtub that can lose water without completely draining provided that the facet is adding water at a proportional rate. In this same way, a colony can sustain considerable pressure as long as bees are being replenished faster than they are being lost.
Introduction
In "Fat Bees Skinny Bees" the author convincingly demonstrates the benefits of supplementing honeybee nutrition through the use of sucrose/high fructose corn syrup (hfcs) and pollen supplements which have been greatly improved in recent years. While providing supplemental nutrition through these vehicles has become standard industry practice, there are alternatives. Many operators relocate hives as forage availability shifts geographically as opposed to managing a "fixed" operation. This can include moving bees in terms of latitude, elevation or to take advantage of specific commodities such as canola or cotton. The purpose of this project was to consider another alternative, namely to establish a forage plot as a means to supplement nutrition. More specifically, the project compared traditional supplemental feeding methods in the pre-spring nectar flow time frame with access to six acres of rapeseed. During this portion of the season there is a gap in nectar sources between the substantial red maple bloom and the primary spring flow (blackberries, holly, tulip poplar). This same "gap" is the best time to mate queens, resulting in heavier stocking rates in mating yards where resources often are not adequate to support the colonies necessary to achieve sufficient drone saturation.
The objective of the project was to evaluate the potential for planting rapeseed as an alternative to providing nutrition via conventional feeding methods that rely on sucrose/hfcs and formulated pollen supplements. Rapeseed ('dwarf essex') was specifically chosen for three reasons. The first was alluded to above in the sense that as a flower source, rapeseed bridges a gap between significant nectar/pollen sources, which also corresponds with an increased demand for resources necessary for honeybee breeding programs. Second, canola, an improved strain of rapeseed, is becoming a popular alternative to winter wheat in crop rotations across the South. Many beekeepers have taken advantage of this trend by locating colonies near large plantings during the flowering period as a means of building colonies. Canola/rapeseed is particularly valuable for growing colonies given its high protein pollen. However, canola has its downside for beekeepers which is the third reason why rapeseed was chosen for this project. Nearly all canola seed is treated with pesticides that are possibly expressed in the pollen, which is in-turn fed to brood. The sub-lethal effects of this infinitesimal exposure to developing bees (as well as adult bees) is a subject of much controversy between beekeepers, researchers, and the manufactures of these specific pesticides. Regardless of the effects, locating honeybees on canola adds a variable that can complicate managing colonies that already face a number of other challenging variables. Alternatively, rapeseed, being less desirable as an oil crop due to its high eruric acid content, is rarely treated.
Cooperators
Research
The project was laid out as a two year study so as not to introduce a variable into the project by using two different sites simultaneously that would inevitably differ in available forage. Consequently, the variability of weather between the two seasons was a factor that has to be considered in drawing conclusions from the project.
Season one involved tracking 40 production colonies that were fed 1 gallon of sucrose mixed 1:1 with water and one pound of a commercially available pollen supplement once a week between 3/4 and 4/15. Colonies were evaluated weekly in terms of size (brood frames) and consumption of both carbohydrates (sucrose) and protein (pollen supplement).
Season two tracked the same 40 production colonies at the same site, six acres of which had been planted to rapeseed the preceding fall. Colonies again were evaluated weekly on the same basis so as to compare colonies' build-up on rapeseed versus the conventional feeding regiment of season one.
As a means of eliminating the variable of weather alluded to above, and specifically the variation related to the over-wintering of colonies from year to year, a side experiment was conducted. Here, 50 three-frame nucleus colonies (nucs) were made up the first week of April and daughter queens introduced. Half of the colonies were placed at the rapeseed planting and the other half at a yard 4 miles away. These colonies were evaluated weekly in terms of brood frames and drawn comb (nucs were given foundation) in an effort to determine the benefit of access to rapeseed. Later, these same colonies were tracked through the summer in terms of honey production in an effort to quantify any effect that rapeseed may have had on the colonies' pre-flow build-up.
The portion of the project involving over-wintered colonies was significantly affected by the accumulation of growing degree days in the second season which resulted in a shorter span between early forages and the primary flow. Also at play was likely the severe winter die-back caused by the polar-vortex event described in the annual reports. Rapeseed typically flowers for six weeks and is most useful in years when it flowers early. In 2015, a cool March delayed flowering two to three weeks, causing the bloom period to overlap prominently with the primary nectar flow when forage is so abundant that there is no need for supplemental nutrition.
This same phenomenon may explain the results of the nuc trials conducted in the second season. The 25 nucs stocked at the rapeseed site showed no measurable difference from the 25 nucs stocked four miles away on available forage. Even further, the later group actually went on to produce 9% more honey collectively than the former group after the colonies were relocated to summer production yards.
Educational & Outreach Activities
Participation Summary:
Outreach will be offered through the Extension network with an emphasis on identifying farmers with an interest in growing pollinator-friendly cover crops and the possibility of forming partnerships with beekeepers in need of large tracks of forage.
Project Outcomes
At $387/acre to establish, the rapeseed plot did not seem to bring a meaningful return on the investment. Moreover, the labor portion of this figure is probably significantly under-valued given that the time required to prepare and plant the site was competing with limited labor resources required to adequately prepare colonies for winter. While this project did not find any significant advantages to having rapeseed available in 2014, the question is whether 2014 was an anomaly or the norm?
There is a reason why beekeepers have established mutually beneficial relationships with canola growers and go to the trouble of hauling colonies sometimes hundreds of miles to canola production areas. Moreover, we have grown rapeseed for several years on a smaller scale with positive results. Based on my experiences, rapeseed holds it's greatest value to beekeepers in years when spring comes early and growing degree days accumulate evenly. Given the weather-related dieback issues, slow spring, and then quick accumulation of growing degree days of 2014, it is easy to see how different weather conditions may have yielded different results.
Potential Contributions
This project resulted in two interesting findings that were not necessarily related to the stated objective of the project. First, as related in the 2013 annual report, not all honeybee stocks use supplemental feed the same. This observation followed from an earlier project (FS10-244) that examined different stocks and their adaptability to Western North Carolina. This project acknowledged that different stocks build quite differently during the spring in response to available resources. Understanding this relationship between a given stock and its potential reaction to supplemental nutrition is paramount for the beekeeper wishing to get the most bang for the buck when it comes to feed.
Second, the value of "doing nothing" with land may result in the best nutrition over-all for honeybees. The majority of agricultural land in our area is devoted to cattle production in that it is either grazed or mowed for hay. Either way, this land offers very little for the honeybee population. Our project removed six acres of fescue from hay production, replacing it with rapeseed after which the land was "let go" (following an unsuccessful buckwheat planting described in 2014 annual report). The resulting floral diversity was remarkable even after just one season. The flora that replaced the fescue was not only beneficial to pollinators, but also was adaptable, not requiring amendments and management like rapeseed.
Future Recommendations
The reduction in available bee forage is perhaps the greatest obstacle for beekeepers trying to maintain strong, healthy colonies. High grain prices and the availability of short-season corn and soybean varieties have converted a large percentage of the Upper Midwest from bee-friendly forage to monocultures of crops useless to pollinators. In response, the USDA has initiated programs aimed at reversing this phenomenon in the interest of creating improved pollinator habitat by paying farmers to plant honeybee-friendly forages.
Southern beekeepers face similar circumstances. High cattle prices have resulted in less agricultural land that is not mowed or grazed. At high elevation sites that we rely on for summer forage, we compete with real estate development for access to dwindling sites conducive to stocking bees. In the South, the cause is different and the scale is smaller, but the problem is the same: a reduction in forage that is adversely affecting our honeybee population.
An antidote that expresses this phenomenon occurred to me recently when I visited my wife's family farm where they have grown row crops for generations. During the 1980's, when grain prices were low, the "corners" of the fields were rounded, where a continuos tractor pass was made with an implement in tow. It was not worth the time and effort to stop, back up, and plant the "corners". Now, every corner is a right angle.
There is a price to pay for intensive agriculture that under-values diversity--we may be experiencing it in terms of a reduction in pollinator-friendly habitat and the consequences it is having on our honeybee population.
