POLLINATORS POLLINATION AND FOOD PRODUCTION

THE ASSESSMENT REPORT ON POLLINATORS, POLLINATION AND FOOD PRODUCTION
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2. DRIVERS OF CHANGE OF POLLINATORS,
POLLINATION NETWORKS AND POLLINATION
Fusarium, Mucor or even Saccharomyces species; however,
the role of most of these species is uncertain (Inglis, 1993).
2.4.1.4.5 Pests of solitary bees
Solitary bees also host a large variety of parasites, starting
from numerous phoretic mites and ending on parasitic
wasps feeding on bee larvae. Due to their economic
importance mostly parasites of the intensively managed
species are described in literature together with possible
methods of protection against them. Most of these
parasites are not strictly species specific, and are found
in various solitary bee species (Krunić et al., 2005).
The most widespread are various chalcid wasps, like
Monodontomerus and Melittobia sp., beetles (Trichodes
sp.), flies (Cacoxenus indagator, Anthrax anthrax), mites
(Chaetodactylus sp.), etc. (Bosch and Kemp, 2001; Krunić
et al., 2005). Chalcid wasps are widespread parasitizing
Megachile (Eves et al., 1980) and Osmia (Bosch and Kemp,
2001; Krunić et al., 2005). Using artificial nesting material or
insecticide strips (Hill et al., 1984) the level of these parasitic
wasps was found to be controllable (Krunić et al., 2005).
Melittobia sp. wasps have high reproductive potential, short
life cycle, and are often found in managed bee nests (Bosch
and Kemp, 2001; Krunić et al., 2005) causing significant
losses in O. coerulescens populations (Purves et al., 1998).
Other species like Sapyga pumila or S. quinquepunctata
also attack the nests of solitary bees, however in their
case some effective control methods are already available
(Torchio, 1979). Cleptoparasitic Chaetodactylus mites
were also found to cause losses in managed Osmia sp.
populations (Bosch, 1992; Bosch and Kemp 2002; Yamada
1990) and thermal shock treatment is used to control these
pests (Yamada, 1990). The checkered beetle (Trichodes
apiarius) is commonly found in Europe and North Africa
parasitizing both Megachile and Osmia species (Krunić et
al., 2005), while T. ornatus is common in North America
(Fairey et al., 1984; Bosch and Kemp, 2001). According to
Eves at al. (1980) this beetle can cause losses up to 89%,
but on average around 30% in managed colonies. Methods
of control are usually mechanical, like sorting the cocoons
(Fairey et al., 1984) or eliminating the beetles using aromatic
attractant bait traps (Wu and Smart, 2014). Anthrax flies and
most probably also other flies are of less concern due to low
infestation rates (3% of Anthrax sp. in Washington, USA in
alfalfa leafcutter bee colony) (Eves et al., 1980).
2.4.2 Pollinator management
2.4.2.1 Honey bee management
The management of honey bees has facilitated the
movement of different bee species to areas of the world
where they are not native. This movement, while beneficial
in some cases for honey production and pollination,
has also had negative impacts through disease spread
and replacement of local pollinators (Goulson, 2003).
However, when using native bees, beekeeping can be
viewed as a conservation tool and enhance local fauna
and food production (Jaffé et al., 2010). The number of
colonies managed in any given area can be linked to
supply and demand for pollination and or the price of
honey (vanEngelsdorp and Meixner, 2010). Thus, the
actual number of colonies managed and the need for
those colonies are driven by external factors beyond the
control of the beekeeper (Morse and Calderone, 2000; van
Engelsdorp and Meixner, 2010). Lastly, the demand for
pollination is growing faster than the supply of managed
pollinators in developing areas of the world (Aizen and
Harder, 2009).
The name honey bee refers to all bees in the genus Apis
with two major species managed around the world; the
western honey bee Apis mellifera and the eastern honey
bees Apis cerana and Apis indica. Both cavity-nesting bees
can be managed in human-made containers and moved to
follow honey flows or for pollination (Crane, 1983). Modern
beekeeping started with the invention of the movable frame
hive in 1853 (Langstroth, 1853), allowing beekeepers to
harvest honey without destructively cutting out combs,
inspect for disease, and to remove frames to start new
colonies (see Chapters 1, 3 and 5 for more on historical
bee management). One example of disease spread and
reduction in pollination availability comes from the use of
non-movable comb hives in South Korea where a viral
disease, Thai sacbrood, wiped out 90% of A. cerana hives
resulting in the need for hand pollination of pears and other
fruit trees (Yoo et al., 2012).
Growing demands for pollination and searching for better
honey production areas have driven beekeepers to become
migratory in many areas of the world. This migratory
trend has increased recently but bees have been moved
since humans began to manage them (e.g., on the Nile in
ancient Egypt, Crane, 1983). Because honey production
depends on the availability of flowers in the immediate
area, beekeepers quickly learned that by moving hives
to areas of better forage (nectar flows as they are called)
they could produce more honey. The need to move hives
for honey production, and more recently pollination, has
made migratory beekeeping standard practice in many
parts of the world (Pettis et al., 2014). Bee colonies are
most often moved at night over short distances but if
longer distances are required then bees may be closed with
screens or nets and placed on large trucks for transport.
During a move some bees are lost or left behind, and this
can spread diseases and pests to new areas. The most
extreme migratory beekeeping for pollination occurs in
the U.S. each year, when 1.5 million or more colonies are
moved from across the U.S. to California to pollinate almond