Honey bee colony losses
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Neumann, Peter and Carreck, Norman L (2010) Honey bee colony losses. Journal of Apicultural
Research, 49 (1). pp. 1-6. ISSN 2078-6913
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GUEST EDITORIAL
Honey bee colony losses
Peter Neumann
1,2,*
and Norman L Carreck
3,4
1
Swiss Bee Research Centre, Agroscope Liebefeld-Posieux Research Station ALP, CH-3033 Bern, Switzerland.
2
Department of Zoology and Entomology, Rhodes University, Grahamstown 6140, South Africa.
3
International Bee Research Association, 16, North Road, Cardiff, CF10 3DY, UK.
4
Department of Biological and Environmental Science, University of Sussex, Falmer, Brighton, East Sussex, BN1 9QG, UK.
Received 13 December 2009, accepted subject to revision 15 December 2009, accepted for publication 16 December 2009.
*Corresponding author: Email: peter.neumann@alp.admin.ch
Keywords:
Apis mellifera,
colony losses. honey bee,
Varroa destructor
Journal of Apicultural Research
49(1): 1-6 (2010) © IBRA 2010
DOI 10.3896/IBRA.1.49.1.01
Apiculture has been in decline in both Europe and the USA over recent
decades, as is shown by the decreasing numbers of managed honey
bee (
Apis mellifera
L.) colonies (Ellis
et al
., 2010; Potts
et al
., 2010).
It therefore is crucial to make beekeeping a more attractive hobby
and a less laborious profession, in order to encourage local apiculture
and pollination. Apart from socio-economic factors, which can only be
addressed by politicians, sudden losses of honey bee colonies have
occurred, and have received considerable public attention. Indeed, in
the last few years, the world’s press has been full of eye catching but
often uninformative headlines proclaiming the dramatic demise of the
honey bee, a world pollinator crisis and the spectre of mass human
starvation. “Colony Collapse Disorder” (CCD) in the USA has attracted
great attention, and scientists there and in Europe are working hard
to provide explanations for these extensive colony losses. Colony
losses have also occurred elsewhere (Figs 1 and 2), but examination
of the historical record shows that such extensive losses are not
unusual (vanEngelsdorp and Meixner, 2009).
Almost exactly a century ago, in 1906, beekeepers on the Isle of
Wight, a small island off the south coast of England, noticed that
many of their honey bee colonies were dying, with numerous bees
crawling from the hive, unable to fly. Despite some sceptical
beekeepers suggesting that this was “paralysis”, a condition which
had long been known, the colony losses were widely reported in the
media, and beekeepers became convinced that the cause was a novel
USA:
~30% losses
Europe:
1.8%-53%
Middle East:
10-85%
Japan:
25% beekeepers
sudden losses
South America:
no reports
of high losses
Africa:
no reports
of high losses
Australia:
no reports
of high losses
USA:
~30% losses
Europe:
1.8%-53%
Middle East:
10-85%
Japan:
25% beekeepers
sudden losses
South America:
no reports
of high losses
Africa:
no reports
of high losses
Australia:
no reports
of high losses
Fig. 1.
The
Varroa destructor
equator of global colony losses. So far, elevated colony losses have recently been reported from Europe
(Crailsheim
et al
., 2009), the USA (vanEngelsdorp
et al
., 2009; 2010), the Middle East (Haddad
et al
., 2009; Soroker
et al
., 2009), and Japan
(Guttierrez, 2009), but not from South America, Africa and Australia. Colonies of African honey bees and Africanized honey bees in South
America survive without
V. destructor
treatment, whilst the mite has not yet been introduced into Australia. This global picture indicates a
central role of this particular ectoparasitic mite for colony losses.
and highly infectious disease, and the condition was soon reported
from all parts of Britain. Within a few years, all losses of bees in Britain,
from whatever cause, were ascribed to “Isle of Wight Disease” (Bailey
and Ball, 1991; Bailey, 2002).
The response of the scientific community was instructive. Initially,
the UK Government sent the eminent entomologist A D Imms to the
Isle of Wight, but being unfamiliar with bees, he was unable to throw
much light on the problem (Bailey and Ball, 1991). Other
scientists soon made suggestions. By 1912, Fantham and Porter became
convinced that the cause was the microsporidium
Nosema apis
, but
this view was overshadowed by the discovery in 1919 of the
tracheal mite
Acarapis woodi
(Rennie
et al
., 1921). Conventional
wisdom and beekeeping text books soon accepted that this impressive
mite was the cause of the “Isle of Wight Disease”, yet close
examination of the original paper shows that this could not be so.
Rennie
et al
.’s experimental results clearly demonstrated that some
bees heavily infested with the mite were able to fly normally, yet
other crawling bees, exhibiting the symptoms of the disease, contained
no mites. One can only conclude that carried away by the excitement
of their new discovery, they had failed to test Koch’s Postulates, and
had jumped to conclusions.
Sober reassessment of the “Isle of Wight Disease” many years
later (Bailey and Ball, 1991; Bailey, 2002) led to the conclusion that
the disease had been due to a combination of factors, in particular,
infection by chronic bee paralysis virus (completely unknown at the
time), together with poor weather which inhibited foraging, and an
excess of bee colonies being kept for the amount of forage available.
The recent concern over CCD has much in common with the his-
torical “Isle of Wight Disease” episode, and many lessons can be
learned. Initial concern about colony losses in one particular area, the
USA, has led to global media attention. Moreover, colony losses
throughout the world are being ascribed to CCD, yet that term was
2 Neumann, Carreck
Fig. 2.
Overview of recent colony losses in Europe. For details on individual countries please refer to papers in this Special Issue:
Austria (Brodschneider
et al
., 2010); Bulgaria (Ivanova and Petrov, 2010); Croatia (Gajger
et al
., 2010); Denmark (Vejsnæs and Kryger,
2010); England (Aston, 2010); Greece (Hatjina
et al.
, 2010); Italy (Mutinelli
et al
., 2010); Norway (Dahle, 2010); Scotland (Gray
et al.
,
2010); Switzerland (Charrière and Neumann, 2010).
= 20% colony losses
specifically coined to describe a precisely defined set of symptoms
(vanEngelsdorp
et al
., 2009) and not colony losses
per se
. Indeed,
honey bee colonies can die in many ways, and CCD is just one of
them (vanEngelsdorp
et al
., 2010). Finally, since both honey bee host
and pathogens are genetically diverse, the symptoms and causes of
colony losses may well be different in different regions.
Many well intentioned suggestions as to the possible causes of
colony losses, including such improbable ideas as mobile telephones,
genetically modified crops and nanotechnology, have perhaps over-
shadowed much more likely explanations such as pests and diseases,
pesticides, loss of forage and beekeeping practices. For example, the
long known major pest of
A. mellifera
apiculture, the ectoparasitic
mite
Varroa destructor
has recently received comparatively little
attention, but is certainly involved. Indeed, the broad patterns of CCD
coincide with continents with different pressures from
V. destructor
(Fig. 1). Since African and Africanized honey bees survive without
treatment for
V. destructor
(Martin and Medina, 2004), and the mite
has not yet been discovered in Australia, this supports a central role
of
V. destructor
for the current colony losses. In fact, data by Dahle
(2010) strongly support this view, showing that regions with
established mite populations had consistently higher losses than those
without. After the development and dissemination of adequate mite
control methods, however, losses due to
V. destructor
remained at
tolerable limits until recently, suggesting that the mite alone cannot
explain all of the recent losses.
Despite comprehensive recent research efforts on these colony
losses, no single driver has yet emerged as the definitive cause of the
phenomenon. Instead, interactions between multiple drivers are the
most probable explanation for elevated over-wintering mortality,
similar to the conclusions for the Isle of Wight disease (Bailey, 2002).
At a global scale, most managed
A. mellifera
colonies are infested by
V. destructor
, facilitating the potential interaction between this factor
and multiple other potential drivers almost anywhere in the world.
Moreover, many other prominent honey bee pathogens are now also
almost globally distributed, for example
Nosema
spp. and several
viruses (Allen and Ball, 1996; Ellis and Munn, 2005; Maori
et al
.,
2007; Fries, 2009). Multiple infections with pathogens and also inter-
actions between pathogens and other suspected drivers of honey bee
loss are therefore almost inevitable, at least in areas with established
mite populations. Whilst the list of these other potential drivers is not
novel, the evidence of such interactive effects, although limited, is
important and growing. These interactions are particularly worrying,
as sub-lethal effects of one driver could make another one more
lethal; for example a combination of pesticides and pathogens.
Ascribing a definitive cause to losses has also been made much
more difficult because of differing pathogen virulence and
different host susceptibility in different regions, and different methods
used by scientists in previous surveys and experiments. In order to
eliminate this latter variability, an international standardisation of
methods is urgently required (Nguyen
et al
., 2010). Moreover, the
complex interactions between individual drivers of colony mortality
and the high number of interacting factors easily exceed the research
facilities of individual bee laboratories or even entire countries. Thus,
efforts by individual countries to reveal the drivers of colony losses
are probably doomed. The international COLOSS network (Prevention
of honey bee COlony LOSSes) has therefore been created to coordinate
efforts to explain and prevent large scale losses of honey bee colonies
at a global scale (Figs 3 and 4). For that purpose, international
standards will be developed for monitoring and research in the form
of an online BEE BOOK, analogous to the RED BOOK of the
Drosophila
community (Lindsley and Zimm, 1992). Only this will enable
collaborative large scale international research efforts to identify the
Colony losses 3
Fig. 3.
The global COLOSS network (“Prevention of honey bee COLony LOSSes”, consisting of 161 individual members from 40 countries
(= grey areas).
underlying factors and mechanisms, such as global ring tests conducted
to ensure common practices across diagnostic laboratories. These
efforts appear critical for the development of adequate emergency
measures and sustainable management strategies.
The COLOSS network does not directly fund research, but aims to
coordinate national research activities across Europe and worldwide
(Fig. 4). COLOSS comprises all three groups of stakeholders; scientists,
beekeepers and industry with the aim of complementing rather than
duplicating research approaches, and to create transnational synergies.
Initiatives to obtain sustainable support for the network are in prepa-
ration. Networking is facilitated through conferences and scientific
exchange programmes, but more importantly also through a large
series of workshops for extension specialists and apiculturists. Only if
we succeed in bridging the gap between bee science and apiculture
will we achieve sustainable progress in the prevention of colony losses
at a global scale.
For these reasons, this Special Issue of the
Journal of Apicultural
Research
addresses the subject of colony losses. A mixture of Original
Research Articles, Review Articles and Notes and Comments address
the possible causes of honey bee colony losses: viruses (Berthoud
et
al
., 2010; Carreck
et al
., 2010a,b; Martin
et al
., 2010);
Nosema
ceranae
(Paxton, 2010; Santrac
et al
., 2010);
Varroa destructor
(Carreck
et al
., 2010b; Dahle, 2010; Martin
et al
., 2010); pesticides
(Chauzat
et al
., 2010b; Medrzycki
et al
., 2010); the effects of
acaricides (Harz
et al
., 2010); the loss of genetic diversity (Meixner
et
al
., 2010; and loss of habitats (Potts
et al
., 2010). In addition, gathered
together for the first time in one place, a group of papers report on
colony losses and possible causes in sixteen individual countries:
Austria (Brodschneider and Crailsheim, 2010; Brodschneider
et al
.,
2010); Bosnia and Herzegovia (Santrac
et al
., 2010); Bulgaria
(Ivanova and Petrov, 2010); Canada (Currie
et al
., 2010); Croatia
(Gajger
et al
., 2010); Denmark (Vejsnæs and Kryger, 2010); England
(Aston, 2010); France (Chauzat
et al
., 2010a,c); Greece (Hatjina
et
al
., 2010); Italy (Mutinelli
et al
., 2010); the Netherlands (Van der Zee,
2010); Norway (Dahle, 2010); Poland (Topolska
et al
., 2010);
Scotland (Gray
et al
., 2010); Switzerland (Charrière and Neumann,
2010); and the USA (Ellis
et al
., 2010; vanEnglesdorp
et al
., 2010).
Finally, two further papers consider the general status of both
managed honey bees (Potts
et al
., 2010) and non-
Apis
bees (Roberts
and Potts, 2010) in Europe.
Acknowledgements
COLOSS is funded by EU COST Action FA0803. We are grateful to
Dr Judy Chen and Dr Jay Evans for their valuable comments on this
paper. We would also like to express our gratitude to all the authors
and referees for their contributions to this important Special Issue and
to Sarah Jones and Tony Gruba for editing and production.
4 Neumann, Carreck
Executive committee: T Blacquière (Netherlands), K Crailsheim (Austria),
JD Ellis (USA), F Hatjina (Greece), A Özkirim (Turkey)
1. Monitoring
& Diagnosis
Romée
van der Zee
(Netherlands)
Yves Le Conte
(France)
2. Pests &
Pathogens
Elke Genersch
(Germany)
Annette Bruun
Jensen
(Denmark)
3. Environment
& Beekeeping
Karl
Crailsheim
(Austria)
Aleš Gregorc
(Slovenia)
4. Diversity
& Vitality
Marina
Meixner
(Germany)
Cecilia Costa
(Italy)
Action Chair: P Neumann (Switzerland)
Executive committee: T Blacquière (Netherlands), K Crailsheim (Austria),
JD Ellis (USA), F Hatjina (Greece), A Özkirim (Turkey)
1. Monitoring
& Diagnosis
Romée
van der Zee
(Netherlands)
Yves Le Conte
(France)
2. Pests &
Pathogens
Elke Genersch
(Germany)
Annette Bruun
Jensen
(Denmark)
3. Environment
& Beekeeping
Karl
Crailsheim
(Austria)
Aleš Gregorc
(Slovenia)
4. Diversity
& Vitality
Marina
Meixner
(Germany)
Cecilia Costa
(Italy)
Action Chair: P Neumann (Switzerland)
Fig. 4.
Structure of the COLOSS network. Organizational matters are addressed by an executive core group. The four working groups
(WG) concentrate on different aspects relevant for honey bee colony losses. WG 1 focuses on monitoring and diagnosis which are crucial to
obtain reliable field data on losses, comparable between countries and years (Nguyen
et al
., 2010). WGs 2-4 address in detail factors
governing honey bee health at both individual and colony level (see Meixner
et al
., 2010 for WG4). Co-operation across working groups is
fundamental to address the interactions between factors driving mortality (e.g. between pathogens and pesticides for WGs 2 and 3).
