POLLINATORS POLLINATION AND FOOD PRODUCTION

THE ASSESSMENT REPORT ON POLLINATORS, POLLINATION AND FOOD PRODUCTION
to exit were shown to collect 31% to 97% of their pollen
from outside the greenhouses (Murray et al., 2013). This
presents a risk to native bumble bees in the regions to
which they are introduced, so that the prevalence of bumble
bee pathogens shows considerable variation among sites
(Gillespie, 2010) and among species (Koch et al., 2012).
Available data show that commercially produced bumble
bee colonies can pose a significant risk to native pollinators
(e.g. Szabo et al., 2012), not only due to introduction of
parasites in populations that may have a low prevalence of
pathogens, but also because the movement of commercial
colonies may disrupt spatial patterns in local adaptation
between hosts and parasites (Meeus et al., 2011). This
risk could even be higher when bumble bees are used for
open field pollination; this is a noted limitation in all of the
mentioned studies that used greenhouses as a focal point
for the spillover hypothesis. Another factor that increases
the risk is that commercial bumble bees have been noted to
have a higher prevalence of several diseases than their wild
counterparts.
Movement of managed bumble bees may also pose risks
to other bee species, because diseases are spread by
transfer of pathogens between bumble bees and other
bees through shared flowers. Following importation,
commercially produced bumble bees interact with native
bumble bees and other pollinators during shared flower
use (Whittington and Winston, 2004), creating a risk for the
community of pollinators as a whole (Durrer and Schmid-
Hempel, 1994).
TABLE 2.4.2
Bumble bee management and its effects on crop and wild plant pollination and other native wild pollinators. For a list of crops
pollinated, see Klein et al. (2007).
Species (managed first, year, when known)
Bombus terrestris dalmatinus
(Europe 1997, Asia 1992, South America 1998)
B. t. audax (Introduced from UK to New
Zealand in approx. 1900)
Negative effects on wild pollinators
Displacement of native bumblebee due to a potential combination of competition for
resources and pathogen spillover (Morales et al. 2013, Schmid-Hempel et al. 2014, Arbetman
et al. 2013).
STRONG EVIDENCE
Genetic pollution of local population by managed individuals of distant populations or
subspecies
(Kraus et al. 2010)
MEDIUM EVIDENCE
Hybridization of native and non-native bumblebees (Tsuchida et al. 2010)
MEDIUM EVIDENCE
Introduction of non-native species causing disturbance in native bee diversity and competing
with native species (Inoue et al. 2007)
MEDIUM EVIDENCE
May compete with native species for nectar and pollen from a range of plant species
(Howlett & Donovan 2010)
WEAK EVIDENCE
B. impatiens (North America 1990) Greenhouse escapees infect local populations with parasites/pathogens, raising the natural
local level of pathogens (Colla & Packer 2008)
STRONG EVIDENCE
B. ignitus (Japan 1999, China 2000) This will result in introduction of exotic pathogens/parasites (Goka et al. 2006)
STRONG EVIDENCE
B. t. terrestris (Norway)
B. t. canariensis (Canary Islands 1994)
B. t. saccaricus (Sardinia)
B. occidentalis (North Amerca 1990)
No studies
Finally, other significant risks are the possibility of
hybridization of native and non-native bumble bees, which
thus far has been shown to occur only at the intraspecific
level, or the risk of reproductive failure consecutive to
interspecific mating. In Poland, (Kraus et al., 2010) have
demonstrated 33% to 47% introgression of the commercial
subspecies B. terrestris dalmatinus and B. t. sassaricus to
the local B. terrestris, indicating a potential risk of loss of
genetic diversity, even when moving colonies of the same
species. This suggests that for commercial species, the
colonies should be moved only to areas where local bees
are genetically close.
2.4.2.3 Stingless bee management
Stingless bees (Meliponini) are a traditional honey, propolis
and wax source in South and Central America (Cortopassi-
Laurino et al., 2006, Nates-Para, 2001; 2004), Australia
(Heard and Dollin, 2000), Africa (Kwapong et al., 2010),
and Asia (Cortopassi-Laurino et al., 2006), but recently
their role as possible managed pollinators of agricultural
crops is also raising interest (Slaa et al., 2006, Giannini et
al., 2014). Stingless bees are an important asset to fulfill
the growing agricultural demand for pollination, because
they could compensate for the local declines in honey bee
populations (Brown and Paxton, 2009, Jaffé et al., 2010,
van Engelsdorp and Meixner, 2010) by assuring enough
pollinators (Aizen and Harder, 2009) and by pollinating
crops more effectively (Garibaldi et al., 2013). Across
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2. DRIVERS OF CHANGE OF POLLINATORS,
POLLINATION NETWORKS AND POLLINATION