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LDDigip Bee Science Sympos
ium
"Current Developments in Bee Research"
ABSTRACTED PROCEEDINGS
Mar
ch 12, 1993
Cornwallis Room, Agricultural Centre, Kentville, Nova Scotia,Canada
Sponsored by the Nova Scotia Beekeeper
s' Association and the
Nova Scotia Department of Agriculture and Marketing
with assistance from the Human Resource Deve
lopment component of
the Canada/Nova Scotia Agri-Food Development Agreement
FORWARD
On Ma
rch 12, 1993 a unique symposium on current scientific research
related to honeyb
ees and their diseases and pests was held in the
Cornwallis Room at the AgriculturalCentre, Kentville, N.S. The
speakers at thi
s symposium are recognized worldauthorities from
the U.K., U.S., Alberta, Ontario and Nova Scotia. The topics
coveredgenetic en
gineering, selective breeding, viral diseases an
d
their transmission,honeybees as vectors of biological control
agents, and pest
s of bumblebees.The following are abstracts of t
he
presentations except in one case a summarytranscript is included.
C O N T E N T S
1. Dr. Brenda V. Ball, Honey Be
e Virus Infections Associated
with Varroa jacobsoni Infestation.
2. Don Stoltz, Virologist, Development of Diagostic Tools f
or
Virus Infection in the Honeybee.
3. John Phillips, Engineering a Gene for Insecticide Resistance
in the Honeyb
ee.
4.
Thomas E. Rinderer, Breeding of Resistance to Varroa
jacobsoni.
5. Dr. Don Nelson, Tracheal Mites Detection and Control
Meth
ods.
6. John C. Sutton, Use of Bees to Deliver Biocontrol Agents for
Controlling F
lower-Infecting Pathogens.
7. Richard
M. Fisher, Bumble Bees: Parasites, Predators,
Disease.
8. Summary List of Speakers, Addresses and Fax Numbers.ڝ$
1. Honey Bee Virus Infections Associated with Varroa jacobsoni
InfestationBrend
a V. Ball, AFRC Institute of Arable Cr
ops Research,
Rothamsted ExperimentalStation, Harpenden, Herts. AL5 2JQ Fax:
0582 760981.
ABSTRACT
The parasitic mite Varroa jacobsoni causes little apparent damage
in colonies of
itsnatural host Apis cerana, the e
astern hive bee.
The transfer of the mite to theEuropean honey bee, Apis mellif
era
and its spread to every continent except Aus
tralasiahas been
accompanied by reports of devastating colony losses, although t
he
effects ofinfestation seem variable and are s
till poorly
understood. Differences in thereproductive potential of mites on
di
fferent species and races of bees and hostbehavi
oral responses
may account for some of this variability. However, recentresearc
h
has shown that the mite affects the type and p
revalence of honey
bee virusinfections causing mortality. This talk will consid
er the
role of V. jacobsoni as anactivator and v
ector of honey bee viruses
and examine some of the factors affectingdisease outb
reaks in
infested colonies.ڵ
2. Development of Diagostic Tools for Virus Infection in the
HoneybeeDon Stolt
z, Department of Microbiology & Immunology,
Dalh
ousie University, Halifax,Nova scotia B3H 4H7 Fax:
902-494-5125.
ABSTRACT
My laborator
y has been developing approaches to diagnostics which
we think will proveuseful
in the not-too-distant future. For
example, in
preliminary studies we havefound that virus infection
in a single bee pupa can b
e readily detected by Westernblotting.
Our prim
ary focus thus far, however, has been directed towards an
assessmentof polymeras
e chain reaction (PCR)-based technology for
the
detection of black queencell and Kashmir bee viruses. Use of
PCR primers specif
ic for conserved humanenterovirus sequences gave
rise to several products; one of these, a 450 base pairamplicon
from KBV has no
w been cloned and sequenced. Computer analysis
indicate thatthis sequence comes from the viral RNA polymerase gene
and shares s
ignificant homologywith the same gene found in a
variety of known picornaviruses - including humanhepatitis A - and
with many pl
ant virus genomes as well. Future work will be
directedtowards the development of both universal picornavirus
primers and prime
rs specificfor individual bee viruses.ڦ
3. Engineering a Gene for Insecticide Resistance in the
HoneybeeJoh
n Phillips, University of Guelph, Department of
Molecular Biology and Genetics,Guelph, Ontario, Canada Fax:
519-837-2075.
ABSTRACT
We are
applying current techniques of insect molecular biology to
the design andintrod
uction of useful genes in beneficial insects.
S
uch genes would include thoseencoding resistance to conventional
insecticides.
A potentially useful insecticideresistance gene,
the
`opd' gene, has been identified and cloned from bacteria. Thisgene
specifi
es a unique phosphotriesterase which efficiently
cleaves and
detoxifiesa broad spectrum of organophosphorus insecticides. We
ha
ve redesigned this gene tofunction in insects an
d have
transferred it into the genome of the model insect,Drosophila
melanogaste
r, where it functions to confer significant resi
stance
toorganophosphate toxicity. This demonstrates the feasibility of
conferr
ing usefultraits on strains of insects through t
he design
and introduction of carefully designedgenes. We are now refining
the
structure of the gene to target expression in sp
ecifictissues
and developmental stages in order to enhance the efficacy of
insec
ticideresistance. In addition, we have begun to
develop
techniques for transferring thisand/or other useful genes into the
hone
ybee genome to confer useful and novel traitson
the beneficial
insect species.
4. Breeding for Resistance
to Varroa jacobsoniThomas E. Rinderer,
United St
ates Department of Agriculture, Agricultural
ResearchServices, Honey-Bee Breedin
g Genetics & Physiology
research, Baton Rouge, L
ouisiana Fax: 504-389-0383.
ABSTRACT
A stock of honey bees was bred in Yugoslavia for resistance to the
parasitic
mite,Varroa jacobsoni. This stock was imported by the
USDA to the US and extens
ively testedin field trials in Florida.
These t
ests showed that the stock has some degree ofresistance to
Varroa jacobsoni, a s
trong resistance to a second parasitic
mite,Acar
apis woodi, which is also a relatively new and
economically troubling pest of ho
neybees in the US, and excellent
general beekeep
ing characteristics. Based on theseresults, the
Yugoslavian honey bee stock is
scheduled to be released to industry
nextspring.
This release will be the first honey bee stock
released from the USDA toindust
ry in decades. The general
potential for develo
ping honey bee stocks resistantto parasitic
mites will be examined.
Editor's Note:An excellent article by Rinderer, et al, in t
he
March '93 issue of American BeeJournal, covers this subject in
detail.
h
5. Tracheal Mites Detection and
Control MethodsDr. Don Nelson,
Agriculture Canada, Research Station, Beaverlodg
e, Alberta Fax:
403-354-8171
ABSTRACT
Tracheal mites are becoming a common pest of honey bee colonies in
most of Canad
a. Therefore, it i
s important to know when colonies
are infested and at what levels. Atthe same t
ime it is important
to know at what levels trach
eal mites are detrimentalto colonies,
and how to control their buildup.The only
method of detection at
present is the dissection
(and microscopic examination)of the
thorax of individual bees. This method is
time consuming and
costly. TheBeaverlodge Rese
arch Station has developed a
monoclonal antibody specific to thetracheal mite an
d is currently
using and evaluating an ELISA (En
zyme-LinkedImmunosorbent Assay)
method for detection of tracheal mites in bulk b
ee samples.
Withfurther evaluation this method
may become a preferred
alternative to individual beeanalysis.Several approaches
to
reducing or minimizing the effect of tracheal
mites are
beingstudied; a) chemical control, b) management practices and c)
sel
ecting stock forresistance. The emphasis in the
short term has
certainly been to have one or moreregistered chemical controls
a
vailable. Chemicals currently approved for use
in Canadafor the
control of tracheal mites are menthol and formic acid (by sprin
g
of 1993). For the short and mid-term, several
management practices
along with chemical controlsseem promising and for the long
term
selecting bees more resistant to the trach
eal miteholds great
promise. Ultimately, all three methods will be used in
vari
ouscombinations to provide the best results.
6. Use of Bees to Deliver Biocontrol Agents for Controlling
F
lower-Infecting PathogensJohn C. Sutton, Departm
ent of
Environmental Biology, University of Guelph, Guelph,Ontario, Canada
N1G
2W1 Fax: 519-837-0442
Honey bees (Apis melli
fera) were found in recent studies to
efficiently vector inoculumof microbial bi
ocontrol agents to
flowers of strawberry (Peng e
t al. 1992), raspberry(J.C. Sutton
1991, unpublished observations), apple and pe
ar (Thompson et al.
1992). These observations we
re made a century after Waite (1891)
reported for the first timethat honey bees
vectored a pathogen,
Erwinia amylovora, to flowe
rs of pear trees. Foreffective
biocontrol of flower-infecting pathogens, it is
likely that
intensivevectoring of biocontrol age
nts is required. To achieve
adequate vectoring of agentsto flowers of crop plan
ts, inoculum of
the organisms must be suitably f
ormulated toallow effective
acquisition, transport, and deposition by bees.Bees
successfully
vectored spores of various biocontr
ol agents (eg. Gliocladium
roseum,Epicoccum purpurascens, and Alternaria alterna
ta) when
formulated as powders with talc,pulveri
zed corn meal, wheat flour,
soya flour or corn starch (Peng et al. 1992, Israela
nd Boland
1992). The bacterial antagonists Pseu
domonas fluorescens and
Erwiniaherbicola were vectored to apple and pear flowers
when
absorbed to pollen of apple orcattail (Tho
mson et al. 1992). The
bees were contaminated with the formulations inspecial i
noculum
dispensers or pollen inserts inside hive
s. Bees acquired
inoculumon their legs and bodies and especially on the setae.I
n a
biocontrol study of fruit rot of strawberry
caused by Botrytis
cinerea, bees eachacquired 88,000 - 1,800,000 (mean 570,000)
cfu
G. roseum in a talc formulation (5 x108 cfu/
g) and maintained an
inoculum density of 1,600 - 27,000 cfu of the antagoniston
each
flower (Peng et al. 1992). By comparison i
noculum density in plots
sprayedweekly with spore suspensions (107 conidia/mL) o
f G. roseum
ranged from 300 to 15,000cfu/flower.
Propagule density was more
stable and often higher on flowers of the bee-vecto
red treatment
than in spray-treated flowers, but
the treatments were about
equallyeffective in suppressing incidence of the path
ogen on
stamens and petals, and incontrolling fr
uit rot.Efficiency of
inoculum deposition on flowers by bees probably depends on
subtletiesin physical contact between the bee a
nd the flower as
well as the load and distributionof inoculum on the bee. Size
and
morphology of the flowers and of the bees, a
nd theactivity and
posturing of bees while on the flowers undoubtedly affect the
amount ofinoculum deposited and where it is dep
osited on the
flower. In studies at theUniversity of Guelph, bees delivered
abo
ut 10 to 18 times more conidia of G. roseumper f
lower to
strawberry than to raspberry. The formulation and concentration
ofinoc
ulum used was the same in all studies. While st
rawberry
flowers are much largerthan raspberry flowers, and foraging
frequencies
by bees on the two types of lower mayhave diffe
red, the
bees also behaved differently on strawberry than on raspberry
(J.C.Sutt
on, unpublished observations). In strawberry, b
ees tended
to move actively overthe face of the flower, often in a rotational
pa
ttern, and their legs and bodiesfrequently conta
cted the stamensh)and other flower parts. In raspberry howe
ver, thebees moved only
slightly and tended to c
ling to the elongate stamens by means of
distalportions of their legs, and achie
ved only minor body contact
with the flower. Wh
iledensity of vectored inoculum on raspberry
was low, the antagonist nonetheless
effectively suppressed Botrytis
fruit rot.Many v
ariables influence the frequency of visits by bees
to flowers and may thusinflue
nce vectoring of biocontrol agents and
the effec
tiveness of biocontrol. Cooltemperature, wind and rain
generally discourage for
aging by bees (Free 1968 a,b),however in
our stu
dies in strawberry, bees vectored high densities of G.
roseum to theflowers unde
r a wide range of weather conditions (Peng
et al
. 1992). Foraging in testplots or in commercial crops can be
affected by the p
roximity and attractiveness tobees of other kinds
of flowers in the area that compete as sources of nectar and
pollen(Levin 1978)
. For example, biocontrol of B. cinerea in
stra
wberry by means of bee-vectored G. roseum soon became
ineffective when the bees
preferentially visited freshlyblooming
rapeseed
in nearby field plots (Peng et al. 1992). Chemical
attractants canbe used in so
me instances to maintain foraging in
the target
crop.The mobility and foraging patterns of bees present
special problems in fiel
d studies. Screens generally are needed to
separ
ate treatments with bees from those without bees,but may
modify microclimate and
exclude important pollinators. Bees
confined i
n screencages may forage and vector differently from
freely-ranging bees. Scree
ning of alltreatments equalizes
microclimatic mo
dification but is impractical when plots or
hostplants are large, and can be cos
tly. Vectoring of biocontrol
agents will requir
especial studies in commercial crops to determine
the numbers, size and distribu
tionof bee colonies needed for
effective vectori
ng of microbial antagonists and forbiocontrol.
In bee-vectoring studies in Utah
, the antagonist Pseudomonas
fluorescenswas dete
cted on only 556% of apple flowers at 61 m from
a hive, and on only 72% of pearf
lowers at 7 m from a hive, with an
average popul
ation of 102 cfu per flower (Thomsonet al. 1992) - A
stain of E. herbicola was d
etected on 92 - 96% of apple flowers ina
2.6 ha
orchard (10-5700 cfu per flower). To encourage bees to
establish foragingpatter
ns in a crop as opposed to other plants in
the a
rea, it is important to introducebee colonies shortly after
the crop begins to f
lower.Various bees potentially could be used
to
vector microbial antagonists to many kindsof plant for
biocontrol of various flo
wer-infecting pathogens. Several kinds
ofdomest
icated bees, including bumble bees (Bombus spp.) and leaf
cutting bees (Megachil
espp., Osmia spp.) as well as honey bees, may
ha
ve potential as vectors. Wild speciesof halictid bees and
andrenid bees also po
ssibly could be used, and contaminated
withbioco
ntrol agents at bait stations. Various berry crops,
orchard fruits, crucifercro
ps, beans, clovers, and cucurbits
possibly could
be protected by bee-vectoredantagonists.
Imaginative research could lead to ef
fective, efficient,
andenvironmentally safe bioc
ontrol of many crop diseases by means
of bee-vectoredantagonists.
Literature cited
FREE, J.B., 1968. The pollination of strawb
erries by honey bees. h)J. Hortic. Sci. 43:107-111.
FREE, J.B., 1968. The foraging behaviour of honey bees
(Apis
mellifera) and bumblebees(Bombus spp.) on blackcurrant (Rubus
nigrum), ra
spberry (Rubus idaeus) and strawberry(Fragaria x
ananassa) flowers. J. Appl. Ecol. 5: 157-168.
ISRAEL, M., & BOLAND, G.J., 1992. Influence of formulation on
efficacy of hone
y beesto transmit biological control for management
of Sclerotinia sclerotiorum.
Can. J.Plant Pathol. (Abstr.) (In
press).
LEV
IN, D.A., 1978. Pollination behaviour and the breeding
structure of plantpopula
tions. Pages 133 - 150 in A.J. Richards,
ed., T
he pollination of Flowers byInsects. Academic Press, London.
213 pp.
PENG. G., SUTTON, J.C. & KEVAN, P.G., 1992. Effectivene
ss of honey
bees for applyingthe biocontrol agent Gliocladium roseum to
strawber
ry flowers to suppress Botrytiscinerea. Can. J.
Plant
Pathol. 14: 117-129.
THOMSON, S.V., hansen, D.R., FLINT, K.M. & VANDENBERG, J.D., 1992.
The dissemin
ationof bacteria an
tagonistic to Erwinia amylovora by
honey bees. Plant Dis. 76: 1052-1056.
WAITE, M.B., 1891. Results from recent investigation
s in pear
blight. Am. Assoc. Adv.Sci. Proc. 40:315.
7.
Bumble Bees: Parasites, Predators, DiseaseRichard
M. Fisher,
Department of Biology, Acadia University, Wolfville, Nova
Scotia,Can
ada Fax: 902-542-3466
ABSTRACT
During the 1980
's, advances in bumble bee domestication technology
permitted the cost-effective
use of these bees for greenhouse
tomato pollina
tion. At present, threespecies are used for this
purpose (Europe and New Zealan
d: B. terrestris; eastern
NorthAmerica: B. impat
iens (Cr.); western North America; B.
occidentalls (Grne). Threeprimary concern
s have been associated
with the intensive labora
tory culture of thesespecies: 1)
depopulation of bees in areas where queens are
captured; 2) the
impactof species introductions
into new area; 3) the possible
spread of disease,either amongBombus populations
, or
interspecifically between bumblebees and ot
her bees, notablyApis
mellifera. Data are presented which demonstrate the genus
specificity of a numberof bumble bee pests and
pathogens, including
mites, the microsporidian Nosema bombi,and a number of soci
al
parasites. The possible propagation of disea
ses among
culturedBombus species can be eliminated (or at least minimized)
throu
gh proper managementpractices.ڦ
8. SPEAKERS
Brenda V. BallAFRC Institue of Arable Crops ResearchRothamsted
Experimental Stat
ionHarpenden, Herts AL5 2JQF
ax: 0582 760981
Don StoltzDepartment of Microbiology & ImmunologyDalhousie
UniversityHalifax, No
va ScotiaB3H 4H7Fax: (902) 494-
5125
John PhillipsUniversity of GuelphDepartment of Molecular Biology
& GeneticsGuelp
h, OntarioN1G 2W1Fax: (519) 837-2075
Thom
as E. RindererUnited States Department of
AgricultureAgricultural Research Servi
ces, Mid South AreaHoney-Bee
Breeding, Genetics
& Physiology Research1157 Ben Hur RoadBaton
Rouge, Louisiana 70820Fax: (504)
389-0383
Don NelsonAgriculture CanadaResearch S
tationBeaverlodge, AlbertaT0H
0C0Fax: (403) 354-8171
John C. SuttonDepartment of Environmental BiologyUniversity of
GuelphGuel
ph, OntarioN1G 2W1Fax: (519) 837-0442
Richard M. FisherDepartment of BiologyAcadia UniversityWolfville,
Nova scotiaB0P
1X0Fax:
(902) 542-3466
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