I have written a
great deal about the importance of new findings about bees for the 21st century,
particularly PHEROMONES. However, and perhaps even more important to the beekeeper,
who has been beleaguered
with mites and now resistant American Foul Brood, is the "hygienic behavior"
of his selected race or stock of bees. You know people who are always neat, tidy,
and clean, and you really don't expect them to be "sickly", because they obviously
use a lot of soap and water and keep away from garbage, refuse, and other
sites that breed germs and disease. Conversely, there are those people that don't
even bother to wash their hands after using the rest room, or don't protect a
cut on their finger with an antiseptic and band aid.
There are very few
things that we ALL agree on, but curtailing the use of chemicals to treat against
tracheal and/or Varroa mites surely is one thing all of us would like. Based on
the work of numerous bee scientists and researchers going back over 40 years,
but gaining strong support during the past 5-6 years, I strongly believe that
the use of hygienic
bees will greatly diminish the need of any chemicals. You certainly are going
to ask "Where do we get hygienic bees?" Right now, there are only two breeders
who are advertising hygienically bred bees or queens: Heitkam's New World Carniolan
field bred queens in the $10-$12 price range, and Glenn Apiaries Artificially
inseminated Italian queens for $40. There has to be a major push or demand put
upon the queen breeders of the country to modify their breeding procedures to
select only those bees demonstrating "hygienic behavior" for them to use as larval
sources for queen production. Your personal letters, a "drive" by American Beekeeper's
Federation, as well as a "drive" by Eastern Apicultural Society, hopefully will
get the reticent queen breeders "off their butt" and into the 21 st century way
of doing things. Of course, you know that all will hear from "Old George". The
American Public would like more U.S. honey, the vegetable and fruit growers need
more pollination of their crops, beeKEEPERS need bees that are not sickly, beeHAVERS
need bees that don't have to be treated, and our bee breeders need the mental
uplift that they would get from HEALTHY bees that don't need any chemical treatment
that stresses the bee.
If you (and I hope
you do) read Bee Culture, American Bee Journal, Speedy Bee, some states WEB sites,
and George's PINK PAGES, you are going to see more and more articles about HYGIENIC
BEES. This is your time to get on the "first floor" about the importance of hygienic
behavior and its value to the bee itself, and the relieving of you "doctoring"
your bees. BE INFORMED, BE A "KEEPER" RATHER THAN A "HAVER" of apis
famous scientists "toyed" with the term 'hygienic behavior, perhaps the principal
exponents of "hygienic behavior" over 40 years ago were W. C. Rothenbuhler, S.
Taber, and M. Gilliam. Although working independently of each other, their work
was all pointed in the same direction, i.e., that certain stocks of bees who demonstrated
quick and constant removal from the hive of "unclean" things like dead brood,
dead bees, wax cappings
and all those things that might have pathogens, tended to be more resistant to
disease than the stocks of bees who were not tidy or clean. Their work was aimed
at the abatement of American Foul Brood and Chalk Brood. Many other researchers
worked on this same
assumption, but I don't want to name names in fear of slighting someone.
However, due to the lack of research funds, and indeed, the lack of interest of
most benefactors, this work was "put on the back burner", until the "devilish"
mites arrived just 15 years ago. Struggling to find bees resistant to mites
as well as resistant to chemicals used in treatment for mites, initiated research
again on "hygienic behavior".
How do bees demonstrate
"hygienic behavior", or WHAT CHARACTERISTICS should be looked for? Sammataro and
Avitabile write in their BEEKEEPER'S HANDBOOK the following: Nest cleaning activities
include cleaning cells in preparation for egg deposition and keeping the nest
free from debris and disease, as well as removing dead brood and even HEALTHY
brood when there is a dearth of nectar or when the colony can no longer take care
of the brood. Another nest-cleaning activity is
coating the interior hive parts and the entrance with propolis.
before anything (eggs, nectar, pollen, or honey) are put in them. Cell preparation
is accomplished by very young workers, only a few hours old. These young bees
remove cocoon remains arid larval feces from brood cells. The cleaned cells are
then acceptable by the queen, who will lay eggs in them. Honey, nectar, and pollen
will also be placed in these cleaned cells. Any remaining or uncleanable surface
is covered by fresh wax or propolis.
Cleaning, or hygienic,
behavior is a genetic
trait, one that is desirable for beekeepers to perpetuate. For example, the
continual quick removal of dead brood from the cells or the bottom board is considered
hygienic behavior. Colonies whose workers demonstrate good hygiene are more likely
to be free from some diseases, and such behavior may also help reduce mite
Older workers take
on the tasks of keeping the rest of the hive clean. Some examples are:
Removing dead or dying
brood and adult bees from the hive. Some bee colonies recognize varroa-killed
brood and remove it.
debris such as pieces of grass of leaves as well as old comb and cappings.
honey or dry sugar and moldy pollen.
Coating the inside
of the hive and wax cells with propolis.
and movable hive parts, including bottom board and inner cover.
or drone adults when the colony is starving.
Laidlaw and Page
in their 1997 book, Queen Rearing and Bee Breeding, have a good bit to say regarding
Hygienic Behavior in Chapter IX, The Genetic Basis of Disease Resistance. Beekeeping
problems resulting from diseases and parasites are continually becoming more
abundant, costly, and difficult to control. Typically, the solutions have been
chemical applications to hives with the inherent risks of contaminating wax
resistance in the target organism. The use of chemical remedies is also
becoming less acceptable to the public, leading to increasingly more restrictions
in their use, particularly around food products like honey. Therefore,
in the future, breeding resistant stocks of honey bees will become increasingly
important for maintaining a viable beekeeping industry.
The basis of all
resistance to diseases and parasites is some mechanism whereby the host, the
honey bee, defeats the disease agent. In order to select for resistance, there
must be genetic variability for a mechanism. Genetic variability has been demonstrated
for three general classes of disease resistance in honey bees:
physiological, behavioral, and anatomical.
The best known
example of disease resistance in honey bees is the, hygienic behavior first
described by O.W. Park in -1937. Apparently, there are two independent behavioral
activities: uncapping cells and removing diseased larvae from uncapped cells.
These two activities were shown by Rothenbuhler in 1964 to be under the control
of two independent genetic mechanisms. Hygienic behavior has also been shown
to be an effective behavioral mechanism against chalkbrood disease and
infestations of varroa.
There are remarkably
few documented examples of
controlled breeding for resistance to honey bee diseases and parasites.
This is unexpected when considering the economic importance of honey bees, and
the dramatic results obtained in those few cases where selective breeding was
practiced. The first successful breeding program for resistance to AFB was implemented
in 1934 by O.W. Park et al. Over the next 15 years, they successfully selected
a resistant stock. The percentage of AFB innoculated colonies that became diseased
dropped from 70% to 10% at the end of 5 years and to 0% t the end of 15 years!
Park demonstrated that one mechanism of resistance was behavioral. He found
some colonies quickly tore down and removed comb inserts containing scales
of AFB that had been purposely paced there. Those hives that removed the
diseased combs had a lower incidence of AFB disease. Park also demonstrated
that the bees were responding to the presence of the disease, not just the foreign
reviewing the work of Park, also believed that hygienic behavior alone was not
sufficient to explain all resistance to AFB. As a consequence, he started a
breeding program in 1954 specifically to study the potential genetic mechanisms
of resistance. Using resistant and susceptible strains, Rothenbuhler demonstrated
one behavioral, three physiological, and one anatomical mechanism. The results
of studies of AFB resistance demonstrate the diversity of resistance mechanisms
that can simultaneously occur when colony selection is used. Colony selection
focuses on the occurrence of the disease, not the specific mechanisms responsible
for resistance. Single factor resistance may occur if only a single mechanism
is selected, e.g., hygienic behavior. However, multifactor resistance is probably
with Varroa mites is the most serious problem for beekeeping,worldwide.
As a consequence, it is remarkable that there are no examples of successful
artificial selection for resistance. However, much is known about the biology
of varroa. This understanding of biology suggests potential mechanisms of resistance,
some of which have demonstrated to vary genetically. An Example of Hygienic
are able to detect capped brood cells that are infested with mites. They
open the cells, remove, and kill the mites. apis
workers apparently can also detect and remove varroa mites from infested
brood cells in a way similar to
If an infested cell is uncapped, the immature mites die, and the adult female
mites must search for another larval cell, or are killed by the bees. This should
slow the population growth of varroa mites in the colony.
The worldwide eradication
of any honey bee disease is unrealistic. Therefore, in order to reduce economic
damage, the beekeeping industry must depend on methods that maintain pathogens
and parasites at reduced levels, now thoughtof as IPM, integrated pest management.
The widespread use of chemical treatments has serious potential costs and risks
resulting from the evolution of chemically resistant strains of disease agents,
and the chemical contamination of hive products. Thus, the development of control
methods that do not depend on chemicals should receive more attention. The evidence
presented suggests that there is sufficient variability for resistance to diseases
to make selective breeding a viable component of commercial honey bee management.
The work of Dr.
Marla Spivak, Professor and Extension Specialist at the University of Minnesota
is noteworthy. She has bred selected stocks of bees that can produce queens
whose progeny exhibit habits of "hygienic behavior"; and these
artificially inseminated Italian queens were made available through Glenn
Apiaries in California this year, 2000. At this time, I do not know of any naturally
mated queens for sale. Further, one queen breeder and package producer, Heitkam's
Honey Bees, also in California, has been espousing and advertising "We are selecting
for hygienic behavior".
Dr. Marla Spivak
has given me permission to pint out for you PINK PAGE readers a few paragraphs
from her recent paper, The Hygiene Queen. Gary Reuter is a Research Technician
who works with Marla.
THE HYGIENE QUEEN
by Marla Spivak & Gary Reuter
of honey bees is the primary natural defense against American foulbrood (Park
et al., 1937; Woodrow and Holst, 1942; Rothenbuhler, 1964) and chalkbrood (Gilliam
et al., 1983). Hygienic bees detect, uncap, and remove diseased brood from the
combs before the disease becomes infectious. Hygienic behavior also is one defense
against Varroa mites (Peng et al., 1987), and although it is not the main mechanism
of resistance to the mites (Harbo and Hoopingarner, 1997), it appears to limit
their reproduction and population growth to some degree. Our studies have shown
that it is possible to select for hygienic behavior without compromising honey
production or gentleness
(Spivak, 1996; Spivak and Reuter, in press). The trait can be found in approximately
10 percent of the
managed colonies found in the United States, in any race or stock of
bees. We feel it would benefit the beekeeping industry to have hygienic lines
of bees commercially available.
In this article,
we present a simple way of screening colonies for hygienic behavior. We also
discuss some frequently asked questions about the behavior, and how to breed
For years, we screened
colonies for hygienic behavior by cutting out a section of comb (2 x 2.5 inches)
containing sealed brood, freezing it for 24 hours, then
placing the frozen comb section in the colony to be tested. If the test
colony was hygienic, the bees would uncap and remove the freeze-killed brood
within 48 hours when tested repeatedly (Taber, 1982; Spivak and , Downey, 1998).
Cutting comb sections out of frames is relatively messy and damages the
combs, so we sought a better way of killing brood without having to handle the
Dr. Jerry Bromenshank
at the Oniversity of Montana was the first to suggest using liquid nitrogen
(N2) to freeze a section of sealed brood within the frame. He found that freezing
the brood this way was more efficient than -cutting, freezing, and replacing
comb inserts. Based on his suggestions, we conducted several tests to determine
how much liquid N2 was necessary to completely kill the brood, and whether the
test yielded the same results as cutting and freezing comb sections. We are
now convinced that freezing brood with liquid N2 is the best screening procedure
found to date for assaying hygienic behavior.
Often we are asked if hygienic
colonies tend to have clean bottomboards, or if they tend to remove debris (such
as wax paper, newspaper or cardboard) from the colony more quickly than other
colonies. Mayer (1996) suggested that if colonies eat grease patties quickly,
they might be hygienic. Removing debris from the hive is a form of cleanliness,
but it is not necessarily a sign that the bees carry the hygienic trait.
Although the common
usage of the word hygienic denotes cleanliness, hygienic behavior is a specific
response by the bees to diseased and parasitized brood. A colony that keeps
its hive clean does not imply that it will be resistant to diseases. Colonies
must be screened for hygienic behavior using an assay such as the one described
above. If a colony removes all of the freeze-killed brood within 48 hours, the
colony will probably be resistant to diseases and will tend to remove mite-infested
pupae. To determine whether they can actually resist the diseases or mites,
the colony would have to be challenged with American foulbrood, chalkbrood or
we encounter concerns the difference between hygienic and grooming behaviors.
Grooming behavior involves an interaction between adult bees; one bee removes
mites or debris from the body of another bee. Alternatively, a bee may groom
herself. Grooming and hygienic behaviors are different traits, and selecting
for one does,not
imply selection for the other.
It is assumed by
some beekeepers that hygienic behavior is associated with a high degree of defensive
(stinging) behavior. This
assumption stems from the reputation of the Brown line of hygienic bees studied
by Rothenbuhler. Rothenbuhler (1964) showed that stinging behavior and
hygienic behavior are inherited separately. Our experience has shown that hygienic
colonies are as gentle as the stock from which they were bred.
Any race or line
of bees can be bred for hygienic behavior. We recommend that bee breeders select
for hygienic behavior from among their best breeder colonies; i.e., from those
that have proven to be productive, gentle, and that display' all the characteristics
desired by the breeder. A breeder can get a head start on selecting for hygienic
behavior simply by rearing queens from colonies that do not have chalkbrood.
rear queens from unrelated hygienic colonies each year to avoid the negative
effects of inbreeding. In time, if many bee breeders select for hygienic behavior,
the frequency of the trait should increase in' the general population of bees,
which will increase the chances that any queen will encounter drones that carry
The effects of
American foulbrood, chalkbrood and Varroa mites can be alleviated if queen producers
select for hygienic behavior from their own lines of bees. Because a small percentage
of the managed colonies today express hygienic behavior, it is important for
many bee breeders to select for the behavior to maintain genetic variability
within and among bee lines. Our experience has shown there are no apparent negative
characteristics that accompany the trait. Years of research experience have
shown it would greatly benefit the beekeeping industry if productive, hygienic
lines were available commercially.
Maria is the Secretary
of the American Association of Professional Apiculturists, of
which I am a member; and both Gary and I are on the RESEARCH committee
of the American Beekeepers Federation (and you should be a member of ABF, too).
Beekeeping needs lots of research and research costs lots of money. YOU, beeHAVERS
and beeKEEPERS need the ABF, and ABF needs your $25 for membership. Just ask
ME, and I will send you the membership forms and my personal thanks!
I will end this
now, hoping that you understand why I feel so strongly that honey bee stock
that is selected because of its HYGIENIC BEHAVIOR might well be the solution
to our present disease and pest problems and "freeing" the bees from the use
of those NASTY chemicals. Unfortunately, my age coupled with the strokes I have
already suffered probably will prevent my witnessing this great accomplishment,
but at least I know right now that some scientists are actively including "hygienic
behavior" as a highly desirable criteria for selection of
breeder queens for queen breeders.