BIP National Loss Survey Comparison with NASS Results

Bee Informed Partnership   By Ariela Haber    August 22, 2017

The National Agricultural Statistical Service (NASS) recently reported the results of its second honey bee colony loss survey. The Bee Informed Partnership (BIP) also recently published preliminary loss results covering the same period. Despite the differences in methodology and sample sizes, these two surveys yielded comparable results. Specifically, we estimate 33.23% losses based on the BIP survey, and we estimate 35.39% losses when we use BIP methods to calculate losses from the NASS survey (Table 1). This is reassuring as it suggests past BIP surveys are representative of national losses despite the non-random nature of the BIP respondent pool.

Both of these surveys were created to track honey bee colony losses in the US, but they differ in survey design (participants’ recruitment and questions asked), delivery, data presentation, and the methodology by which loss rates are calculated. This blog aims to help compare the results of these two surveys while taking into account the limitations of these comparisons.

An explanation of our methodology can be found in previous peer reviewed reports.

To compare NASS and BIP estimates, we combined the quarterly numbers published by NASS to correspond to BIP’s division of the year into “summer” and “winter” (see Table 1). The reasoning for these recalculations is provided in last year’s blog and details of calculations are presented below (Tables 2-5). It is important to note that this comparison was done by BIP personnel using publically available NASS data. 

 NASS does not include in its loss estimates the splits (“added”) made during the respective quarter. In our opinion, when pooling 2 quarters together, the splits made during the first quarter need to be added to the pool of starting colonies, as their loss (if any) would be counted in the second quarter. We therefore include them in the divisor of our recalculations of seasonal loss estimates. For annual estimates, the additions from the first 3 quarters are added to the starting colonies. In each case, as per NASS standards, splits made during the most recent quarter (most recent splits) are not considered in the pool of colonies at risk. We welcome recommendations on an alternative method to pool quarterly results into seasonal (summer/winter) estimates. 

To imitate the BIP methodology of indirectly calculating the number of colonies lost over a season, we used the published numbers of colonies at the start of the season and colonies added. We estimated the number of colonies at the end of the season using the number of colonies at the start of the following season.  

This is an adaptation of an original work by NASS. Views and opinions expressed in the adaptation are the sole responsibility of the author of the adaptation and are not endorsed by NASS.

Nation's Beekeepers Lost 33 Percent of Bees in 2016-17

May 26, 2017

Nation's Beekeepers Lost
33 Percent of Bees in 2016-17

Annual losses improved over last year;
winter losses lowest in survey history

Beekeepers across the United States lost 33 percent of their honey bee colonies during the year spanning April 2016 to April 2017, according to the latest preliminary results of an annual nationwide survey. Rates of both winter loss and summer loss--and consequently, total annual losses--improved compared with last year.

Total annual losses were the lowest since 2011-12, when the survey recorded less than 29 percent of colonies lost throughout the year. Winter losses were the lowest recorded since the survey began in 2006-07.

The survey, which asks both commercial and small-scale beekeepers to track the survival rates of their honey bee colonies, is conducted each year by the nonprofit Bee Informed Partnership in collaboration with the Apiary Inspectors of America. Survey results for this year and all previous years are publicly available on the Bee Informed website.

"While it is encouraging that losses are lower than in the past, I would stop short of calling this 'good' news," said Dennis vanEngelsdorp, an assistant professor of entomology at the University of Maryland and project director for the Bee Informed Partnership. "Colony loss of more than 30 percent over the entire year is high. It's hard to imagine any other agricultural sector being able to stay in business with such consistently high losses."

Beekeepers who responded to the survey lost a total of 33.2 percent of their colonies over the course of the year. This marks a decrease of 7.3 percentage points over the previous study year (2015-16), when loss rates were found to be 40.5 percent. Winter loss rates decreased from 26.9 percent in the previous winter to 21.1 percent this past winter, while summer loss rates decreased from 23.6 percent to 18.1 percent.

The researchers noted that many factors are contributing to colony losses, with parasites and diseases at the top of the list. Poor nutrition and pesticide exposure are also taking a toll, especially among commercial beekeepers. These stressors are likely to synergize with each other to compound the problem, the researchers said.

"This is a complex problem," said Kelly Kulhanek, a graduate student in the UMD Department of Entomology who helped with the survey. "Lower losses are a great start, but it's important to remember that 33 percent is still much higher than beekeepers deem acceptable. There is still much work to do."

The number one culprit remains the varroa mite, a lethal parasite that can easily spread between colonies. Mite levels in colonies are of particular concern in late summer, when bees are rearing longer-lived winter bees.

In the fall months of 2016, mite levels across the country were noticeably lower in most beekeeping operations compared with past years, according to the researchers. This is likely due to increased vigilance on the part of beekeepers, a greater availability of mite control products and environmental conditions that favored the use of timely and effective mite control measures. For example, some mite control products contain essential oils that break down at high temperatures, but many parts of the country experienced relatively mild temperatures in the spring and early summer of 2016.

This is the 11th year of the winter loss survey, and the seventh year to include summer and annual losses. More than 4,900 beekeepers from all 50 states and the District of Columbia responded to this year's survey. All told, these beekeepers manage about 13 percent of the nation's estimated 2.78 million honey bee colonies.

The survey is part of a larger research effort to understand why honey bee colonies are in such poor health, and what can be done to manage the situation. Some crops, such as almonds, depend entirely on honey bees for pollination. Honey bees pollinate an estimated $15 billion worth of crops in the U.S. annually.

"Bees are good indicators of the health of the landscape as a whole," said Nathalie Steinhauer, a graduate student in the UMD Department of Entomology who leads the data collection efforts for the annual survey. "Honey bees are strongly affected by the quality of their environment, including flower diversity, contaminants and pests. To keep healthy bees, you need a good environment and you need your neighbors to keep healthy bees. Honey bee health is a community matter."

This summary chart shows the results of an 11-year annual survey that tracks honey bee
colony losses in the United States, spanning 2006-2017. Credit: University of Maryland/BeeInformed Partnership

Preliminary: 2016-2017 State Total and Average Losses

Bee Informed Partnership   Published May 26, 2017

The Bee Informed Partnership has released preliminary state losses for 2016-2017. If there are fewer than 5 respondents in a state, we will not release those numbers to preserve confidentiality. These tables represent Annual loss, Winter Loss and Summer Loss. We also report Total Loss and Average Loss.

For further details regarding the difference between Total and Average loss, please read on. The Bee Informed Partnership traditionally reports total loss, or a weighted loss rate. Total loss treats each colony the same or more simply stated, “One colony one vote.” This means that the total loss rate is more representative of commercial beekeeper loss as they manage a large majority of the colonies in the survey. The average loss rate, which we no longer report in our preliminary summary, is an unweighted rate where we calculate the loss rate for each responding beekeeper and average these rates. So average loss, more simply stated is, “One beekeeper, one vote.” As there are many more backyard beekeepers than commercial beekeepers, average loss rates are more influenced by these smaller beekeepers.

The Figure provide a heat map of Annual Total losses by state and in the tables below, N represents the number of beekeepers from that state answering those survey questions.

2016-2017 Total Annual Loss by State

2016-2017 Annual Loss by State or Territory:

To Save Honey Bees, Human Behavior Must Change

Science Daily    Source: Entomological Society of America    April 6, 2017

Poor management practices have enabled spread of bee pathogens, bee researcher argues

In the search for answers to the complex health problems and colony losses experienced by honey bees in recent years, it may be time for professionals and hobbyists in the beekeeping industry to look in the mirror.

In a research essay to be published this week in the Entomological Society of America's Journal of Economic Entomology, Robert Owen argues that human activity is a key driver in the spread of pathogens afflicting the European honey bee (Apis mellifera) -- the species primarily responsible for pollination and honey production around the world -- and recommends a series of collective actions necessary to stem their spread. While some research seeks a "magic bullet" solution to honeybee maladies such as Colony Collapse Disorder, "many of the problems are caused by human action and can only be mitigated by changes in human behavior," Owen says.

Owen is author of The Australian Beekeeping Handbook, owner of a beekeeping supply company, and a Ph.D. candidate at the Centre of Excellence for Biosecurity Risk Analysis (CEBRA) at the University of Melbourne. In his essay in the Journal of Economic Entomology, he outlines an array of human-driven factors that have enabled the spread of honey bee pathogens:

  • Regular, large-scale, and loosely regulated movement of bee colonies for commercial pollination. (For instance, in February 2016 alone, of the 2.66 million managed bee colonies in the United States, 1.8 million were transported to California for almond crop pollination.).
  • Carelessness in the application of integrated pest management principles leading to overuse of pesticides and antibiotics, resulting in increased resistance to them among honey bee parasites and pathogens such as the Varroa destructor mite and the American Foul Brood bacterium (Paenibacillus larvae),
  • The international trade in honey bees and honey bee products that has enabled the global spread of pathogens such as varroa destructor, tracheal mite (Acarapis woodi), Nosema cerana, Small Hive Beetle (Aethina tumida ), and the fungal disease chalkbrood (Ascosphaera apis).
  • Lack of skill or dedication among hobbyist beekeepers to adequately inspect and manage colonies for disease.

Owen offers several suggestions for changes in human behavior to improve honey bee health, including:

  • Stronger regulation both of global transport of honey bees and bee products and of migratory beekeeping practices within countries for commercial pollination.
  • Greater adherence to integrated pest management practices among both commercial and hobbyist beekeepers.
  • Increased education of beekeepers on pathogen management (perhaps requiring such education for registration as a beekeeper).
  • Deeper support networks for hobby beekeepers, aided by scientists, beekeeping associations, and government.

"The problems facing honeybees today are complex and will not be easy to mitigate," says Owen. "The role of inappropriate human action in the spread of pathogens and the resulting high numbers of colony losses needs to be brought into the fore of management and policy decisions if we are to reduce colony losses to acceptable levels."

Story Source: Materials provided by Entomological Society of America.

Journal Reference: Robert Owen. Role of Human Action in the Spread of Honey Bee (Hymenoptera: Apidae) Pathogens. Journal of Economic Entomology, 2017; DOI: 10.1093/jee/tox075

2014-2015 Bee Informed Partnership (BIP) National Management Survey

The results for the 2014 – 2015 Bee Informed Partnership (BIP) National Management Survey are posted on the BIP website.  This survey was done in conjunction with the National Colony Loss Survey and represents the management practices of over 6,000 Beekeepers from across the country.  Together, the beekeepers who took part in the survey collectively managed nearly 400,000 colonies representing about 14.5% of the 2.74 million colonies in the United States.  We would like to give a big thanks to all of the beekeepers who participated in the survey – your participation is highly valued by the Bee Informed Partnership and other beekeepers that are able to review which management strategies work and those that do not.  As part of our analysis for the National Management Survey, we compared the losses of beekeepers that employed specific management practices against other practices that are available for beekeepers.  By conducting this analysis, we are able to obtain the proportion of colonies lost relative to other practices, highlighting which practices are most effective.

Please note, in explaining the results we always caveat it with the caution that “Correlation does not equal causation.”  What this means is that just because one management practice is resulting (correlating) in lower colony losses does not mean that using this management practice is the cause for lower losses.  One of the great examples of this idea would be the statement that “As ice cream consumption increases, shark attacks also increase.”  In this example, the explanation seems obvious.  Ice cream consumption does not cause shark attacks, it just happens that both of these statistics peak during summer months.  There are various confounding variables that are effecting changes in ice cream consumption and shark attacks.  As the weather gets warmer ice cream becomes more appealing and more people are likely to go swimming in the ocean.  Ice cream consumption is not causing shark attacks and vice versa.  When reading through the results for the National Management Survey it is important to keep in mind that there are many correlative relationships but not all are causative; however, in viewing the results, it allows us to make more data and hypothesis driven research.

To read through the results for the National Management Survey, please follow the link below to view the different beekeeping management practices and the colony losses associated with those practices.

2014 – 2015 National Management Survey Results