Subject: _Apis_ 4/96

From: [email-masked] (Adam Finkelstein)
Date: 1 May 1996 11:14:20 GMT

Florida Extension Beekeeping Newsletter
    Apis--Apicultural Information and Issues (ISSN 0889-3764)
                 Volume 14, Number 4, April 1996

      Copyright (c) 1996 M.T. Sanford "All Rights Reserved"

      TOWARD HONEY BEE DOMESTICATION--THE VARROA CONNECTION

     1987 was a pivotal year in U.S. beekeeping.  Introduction of
the Varroa mite in October sent a shock wave through the
beekeeping community that reverberates to this day (see October
1987 APIS).  It has meant changes in management practices,
increases in operating expenses and losses of many honey bee
colonies.  Paradoxically, it has also ushered in renewed
opportunities for beekeepers in the pollination area, as growers
and others noticed reduced numbers of honey bee pollinators in
the environment (see July 1995 APIS).  So far, only anecdotal
information and "guesstimates" have been made about the full
impact of Varroa on unmanaged honey bee populations.  Given the
dynamics of the situation, we probably will never know the full
story.

     It is clear that a new kind of honey bee management is
emerging from the parasitizing effects of the Varroa bee mite.
Two kinds of beekeepers can now be identified; those with
experience "before Varroa," and those who began apiculture "after
Varroa."   Persons in the latter category cannot appreciate the
relative laissez-faire beekeeping possible in the past.  This
state of affairs is also being reflected in the bees themselves.
No longer able to exist in large numbers in the wild, these
insects are being pushed toward a greater reliance on humans that
can only be called "domestication."

     According to Dr. D.F. Morey, "Some time in the past 12,000
or so years, most of humankind began to experience a profound
shift in life style.  Stone Age hunters and gatherers of wild
foodstuffs started to cultivate plants and raise animals for
their own use."  (The Early Evolution of the Domestic Dog,
American Scientist:82, Jul-Aug, 1994, pp. 336-347).  Given the
role of animal and plant domestication in human welfare, Dr.
Morey says, there is no surprise to find argument about what it
really is, how it originated and why.  There are two theories on
the subject:  1) domestication was a rational decision by people
to raise, cultivate and manipulate organisms, or 2) domestication
was the consequence of evolutionary chang in physiology
(processes) and morphology (structure) by organisms in response
to a new ecological niche--association with humans.

     Dr. Morey concludes that the former of the above questions
is flawed because it focuses on the human role in the process.
An evolutionary model, he says, is more scientific and would
include not only morphological, but behavioral changes not
necessarily the result of human action.  The major problem, Dr.
Morey concludes, is that we cannot get into an early human's
brain to figure out what was being thought at the time.

     The dog is likely the first domestic animal Dr. Morey says
and provides some insight into how it indeed has changed to adapt
to living with humans.  A range of other animals along with their
time of domestication is published in a chart accompanying Dr.
Morey's article.  Significantly, no insect appears.  Two possible
candidates would be the silk worm and honey bee.  Most beekeepers
know the history of the latter, a creature that historically
resisted domestication at every turn and to which humans had to
adapt.  As far as we know, few changes occurred in either honey
bee structure or behavior to accommodate to humans similar to
those in the domestic dog.  This is in spite of the fact that
both organisms have been associated with humans for almost as
long.

     The coming of Varroa, however, may signal an end to this
historic independence of honey bees from humans.  Wild colonies
are declining and managed ones need beekeepers far more than ever
before to survive the devastating effects of the mite.  And
unlike with early humans domesticating the dog, we can determine
intent.  Beekeepers could simply let all colonies infested with
Varroa go without treatment.  It would take a great many years,
but in the end a mite-resistant or -tolerant bee would emerge.
Instead, humans keep honey bee colonies alive by chemical
intervention because they are valuable to us for a number of
reasons, a clear case of willful domestication.

       THE AFRICANIZED HONEY BEE--A RISK TO HUMAN HEALTH?

     The coming of the Africanized honey bee has prompted a
review of the possible human health risks posed by this insect.
Dr. M.J. Schumacher and
N.B. Egen, Department of Pediatrics, University of Arizona
College of Medicine, Tucson, AZ, published their findings on this
important topic (ARCH INTERN MED: Vol. 155, pp. 2038-2043) in
October 1995.  The paper describes the effects of the venom,
evaluation and treatment of multiple bee stings (toxic
envenomation) and the recognition, management and prevention of
allergic reactions to Africanized bee stings.

     The last topic above also includes European honey bees, for
the authors conclude there is little difference between the
venoms of the races.  Both have almost equal amounts of similar
major components:  melittin, phospholipase A2 (PLA2),
hyaluronidase, apamin, histamine and mast cell degranulating
peptide.  This means that there is little difference between risk
to humans posed by the venom of either Africanized or European
bees.

     The major difference between the two bee types, according to
the authors, is the possibility of mass attack, shown to be more
prevalent in Africanized honey bees.  Many individual stings can
result in poisonous (toxic) reactions to the venom that are not
related to allergy.  And such reactions (toxic envenomation) can
occur from as few as 50 stings.  Studies of specific incidents
show that the dose of venom per body weight is extremely
important in determining subsequent effects.  Specific symptoms
and treatment for toxic envenomation are described by the
authors.  Things can also get more complicated when both
envenomation and allergic reactions occur together, according to
the authors.  It may not be easy to determine which is in fact
occurring, and they recommend treating for both conditions if in
doubt.

     The article gives advice on prevention of both envenomation
and anaphylaxis (allergic reaction).  In particular the authors
recommend education programs to alert the public about what to do
in case of attack: outrun the bees and cover the mouth and nose
prevent airway stings.  They say only trained personnel should
attempt to remove established bee nests in areas of Africanized
bees, and people enjoying outdoor recreation should  always be on
the alert.  Most at risk are workers who clear vegetation or cut
tall weeds and grass with machinery.

     Athough massive stinging attacks by Africanized honey bees
are now rare, this bee may spread to warmer areas, the authors
concede.  Treatment of severe toxic reactions to multiple stings
should include management of shock and possible organ damage.
And patients with trivial allergy could be more at risk from
anaphylaxis because of multiple stings.  Any physician treating
bee stings could do well to have this article on hand for its
relevant, complete and up-to-date information.  I will send a
copy to anyone upon request.

                SEX DETERMINATION--WHITHER THE Y?

     The genetics of honey bees is complex and confusing.  The
queen honey bee, a single individual, is the source of all the
eggs in a colony, half the genetic material of any individual
worker bee and the full amount provided to every drone.  In the
worker's case, the other half of their genetic material is
donated by the drone in the form of sperm; the queen mates with
several drones (see following article).  She stores their sperm
in her body until it is needed.  This system results in a colony
of several related subfamilies with the same queen mother, but
different fathers.  Each subfamily may also have a different
penchant for certain work in a colony.  For example, there may be
nectar foraging, pollen foraging and undertaking specialties in
these groups, reminiscent of guilds or professions in human
society.

     The queen honey bee has the ability to choose whether or not
to fertilize each egg she produces.  All fertilized eggs become
females in a colony; they are characterized by 16 pairs of
chromosomes (32 total).  This organization composed of chromosome
pairs is called diploid.  Drones are produced only from
unfertilized eggs, a process called parthenogenesis.  They are
haploid, having only one-half the number of chromosomes (16
total) that have no complementary pairs.  This honey bee genetic
system, therefore is named as a combination of both conditions,
haplodiploid .  It results in interesting things such as half
sisters, super sisters and on rare occasions, diploid drones.
For social insects, haplodiploidy allows individuals to give up
their lives through "altruistic" behavior with a minimum loss of
their own genetic contribution.  It also results in a supremely
female society, a matriarchy of the first order where males a
relegated to a relatively minor role.  They not only become
expendable during the mating act, but are the first members of
the colony to be eliminated in the face of stressful
environmental conditions.

     The genetic system in humans is quite different.  All eggs
are fertilized, so all individuals are diploid.  Sex
determination is the result of combinations of two sex
chromosomes, the X and Y.  If an X and Y come together, a male
results; two X's become a female.  Pretty simple.  And, as
Kenneth Miller suggests in "Whither the Y" (Discover, February
1995, pp. 36-41), his Y chromosome has dominance in all cases,
whether it be use of the male pronoun when gender is unknown or
immediate access to jobs, promotions and raises in what some call
"good-old-boy circles."  In addition, the male surname is also
the default bestowed on any female becoming married in most
western human societies.

     Male gender was a defining force in school, Mr. Miller says,
where he learned that boys did indeed have something that girls
lack, even in their genes.  If a Y chromosome exists, for
example, no matter how many X's there might be in humans, the
male sex prevails, Mr. Miller says, ensuring human male
supremacy.  Here is his vision of fertilization:  "I imagined the
poor little passive X chromosome just waiting to see whether the
lucky sperm...carried an X or a Y.  In either case, the X had to
wait for the male to show up and make the decision.  The Y really
is the boss."

     Although perhaps dominant, however, unlike a single X
chromosome, the Y cannot go it alone.  It requires an X for
development to continue, Mr. Miller says, his ego somewhat
deflated.  That's because the X carries many genes required for
muscle development, blood clotting and color vision.
Unfortunately, Mr. Miller is forced to conclude, the human Y
chromosome turns out to be a genetic wimp, carrying only 15 genes
to the 1,500 to 5,000 found on the X.

     The puny Y is a result of a Faustian bargain Mr. Miller
says, quoting Dr. William Rice, University of California, Santa
Cruz.  Not only do the X and Y chromosomes become different over
time (the Y loses genes as it becomes more "self-centered"), but
the Y also loses its genetic repair mechanism in the bargain.
Presence of the small Y limits protection from defective genes
that may be found on the X, the reason color blindness,
hemophilia, Duchennes muscular dystrophy and many other
conditions occur mainly in men.  The two more robust X
chromosomes in females can often recombine with each other to fix
errors that might occur due to mutations or other factors.  The
Y, however, has very few genes to compensate for (complement)
mutations on the X and this all-important recombining ability is
compromised.  Thus, Mr. Miller says, "...the Y accumulates one
mistake after another as it is passed from father to
son...shrinking in function, until nearly all but the sex-
determining gene has been discarded."

     Mr. Miller concludes that this process could elminate the Y
chromsome altogether.  The defining genetic feature of human
maleness, therefore, might not be the presence of something, but
lack of it--a chromsome.  The result: a species where females are
XX and males are XO.  This has already happened in some fruit
flies and fish.  Mr. Miller mourns what he sees as the eventual
loss of the Y chromosome and suggests that the male pronoun rule
and other privileges are nothing more than logical compensation
for the genetic weakenesses endured by men.

     Taken to the extreme, could male humans end up like male
fruit flies, as Mr. Miller fears?  Or even worse, like honey bee
drones?  My sources say it's not likely.  Although XO's are
males, so are XY's, the normal situation in some fruit fly
species.  More significantly, only the sex chromosomes are
involved, the rest of those in the body do not have the same
dynamics.  Drone honey bees are a different kettle of fish.  They
are effectively XO in the strictist sense for all genes.  With
only a single set of chromosomes, none have a complement, leaving
all of them unprotected against deleterious genetic change on the
X chromosome.

                        HOW MANY DRONES?

     How do we know what we know?  This question can plague the
educator  who is supposed to be on top of things.  It stops us
cold at times.  We have said it for so long, it seems like second
nature.  Yet, often we don't really know its source.  Take the
following question, for example.  How many drones mate with a
queen during the brief time when she is receptive?  I usually say
10 to 15, perhaps 17 when I'm expansive. Thanks to Steve Taber,
retired from the U.S. Department of Agriculture for many years,
but who continues to write in American Bee Journal, I now know
where this information comes from.

     In his recent article (April 1966, pp 261-2), Mr. Taber
gives us the scoop, not in spades, but in marbles.  For after all
is said and done it becomes a statistical question.  Mr. Taber
put it this way to a statistician:  "Given:  a large container
with black and white marbles, (the marbles represent marked and
unmarked drones), which are well shaken up, you reach in with a
scoop and withdraw some and record whether the marbles are either
all black, all white or of both colors.  At the end of several
hundred of these samples the question is asked, 'What is the
average number of marbles in each scoop sample?'  Of course the
'scoop' represents the queen on a mating flight."

     The results from Mr. Taber's data and investigations into
the matter agree with those of some other studies.  The
conclusion is a happy one.  It vindicates what we educators
"knew" all along.  Queens mate with about 10 drones on the
average during their mating period.

Sincerely,

Malcolm T. Sanford
Bldg 970, Box 110620
University of Florida
Gainesville, FL 32611-0620
Phone (904) 392-1801, Ext. 143
FAX: 904-392-0190
BITNET Address: MTS@IFASGNV; INTERNET Address:
[email-masked]
APIS on the World Wide Web--
http://gnv.ifas.ufl.edu/~entweb/apis/apis.htm
Copyright (c) M.T. Sanford 1995  "All Rights Reserved"

-- 
_________________
Adam Finkelstein                    
[email-masked]