Biology of Thai honey bees: natural history and threats

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In: Bees: Biology, Threats and Colonies ISBN # 978-1-61324-825-6
Editor: Richard M. Florio, pp. 1-98 © 2011 Nova Science Publishers, Inc.






Chapter 1



BIOLOGY OF THAI HONEYBEES: NATURAL HISTORY
AND THREATS


Guntima Suwannapong1 Mark Eric Benbow2 and James C. Nieh3
1 Department of Biology, Faculty of Science
Burapha University Chon Buri 20131
Thailand
2 Department of Biology, University of Dayton
College Park, OH 45469-2320
USA
3Section of Ecology, Behavior and Evolution
Division of Biological Sciences
University of California
San Diego 92093
USA


Abstract

Honeybees play an important ecological role as pollinators of many plant species,
and their products are the basis for a multi-million dollar commercial industry in the US
and more than a thousand million Bath in Thailand. This chapter provides a summary of
the natural history of Thai honeybees. We focus on the role of Thai honeybees in
pollination ecology, potential threats to honeybees, and commercial applications of
products derived from honeybees. This chapter covers how honeybees reproduce,
variation in caste development among Thai species, and how sex determines the division
of labor in these populations. The discovery of the oldest bee species and the evolution of
honeybees also will be discussed. In addition to behavior related to nesting and colony
defense. We will also examine honeybee pheromones: how honeybees produce
pheromones, how they detect pheromones and other odorants, and how they respond after
exposure to pheromones. Finally, we will focus on the role of parasites (i.e., wax moth,
mites), predators and pathogens on the ecology of Thai honeybees, and explore the
consequences for honeybee commercial product and pollination.

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There are seven sections in this chapter on Thai honeybees, 1) natural history,
evolution and taxonomy; 2) castes, development, and age polyethism; 3) anatomy,
including the structure of the pheromone glands and exocrine glands; 4) olfaction, odor
production, odor perception and pheromones, 5) pollination, 6) beekeeping, and 7)
honeybee pathogens, parasites and predators. Our goal is not to exhaustively discuss each
topic, but provide relevant information about native species of Thai honeybees in
regional context. Much more information is known about the European honeybee (Apis
mellifera) than other species of Apis. In some of these sections, we will therefore be
necessarily brief.


1. NATURAL HISTORY, EVOLUTION, & TAXONOMY

Life history of Thai honeybees
In recent years, interest in tropical bees has increased. This is appropriate because
honeybees like originated in Tropical Africa and spread from South Africa to Northern
Europe and East into India and China (Otis, 1990). The first bees appear in the fossil record in
deposits dating about 40 million years ago in the Eocene. The oldest bee fossil is preserved in
a piece of amber found from a mine in northern Burma. It is believed to date back as far as
100 million years to the time when bees and wasps split into two different lineages. The
fossilized insect appears to share features both common to the bee and wasp, but is more
similar to bees than wasps (Danforth et al., 2006). The earliest known honeybee fossil (genus
Apis) was found in Europe dating back 35 million years. About 30 million years ago,
honeybees appear morphologically very similar to modern honeybees (Koning, 1994). The
genus Apis is evidently tropical in origin. It is native to Asia, Africa and Europe including
such continental islands as Japan, Taiwan and the Philippines (Seeley, 1985). Honeybees did
not appear in the Americas, Australia or New Zealand until European settlers introduced them
in the 17th century (Zander and Weiss, 1964). Thailand is a tropical country that has a wide
variety of flowering plants and animals. Perhaps due to high temperature, the native tropical
bees generally build their nest as a single air open nest and rely upon aggressive behavior to
defend these exposed nests (Collins and Kubasek, 1982).
Honeybees of the genus Apis are the most studied because of their fascinating and
complex lifestyle, communication systems (Nieh, 1998; Nieh and Roubik, 1995), role as
keystone pollinators of native plants, pollination of agricultural crops, and the valuable hive
products that they produce, such as honey, royal jelly, bee wax, bee pollen, propolis and even
bee venom. Honeybees belong to the order Hymenoptera, superorder Apocrita, infraorder
Acuelata, superfamily Apoidea, family Apidae, subfamily Apinae, tribe Apini. There are
more than 11 extant species of Apis worldwide (Michener, 2000). Four species are native to
Thailand: Apis andreniformis, A. cerana, A. dorsata and A. florea (Oldroyd and Wongsiri,
2006). A. mellifera was introduced for beekeeping. Honeybees of Thailand are classified as
follows:
Kingdom Animalia
Phylum Arthropoda
Class Insecta
Order Hymenoptera

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Family Apidae
Genus Apis
Species A. andreniformis
A. cerana
A. dorsata
A. florea
A. mellifera (Ruttner, 1988)
Honeybees are hymenopterans, a group that generally feed on pollen and nectar and
constitute about 20,000 species throughout the world, known taxonomically as the
superfamily Apoidea (Michener, 2000). Although the question of how many honeybee
species exist is still debated among taxonomists, at least four species are commonly
recognized: the dwarf or midget bee (A. florea), the giant or rock bee (A. dorsata), the Asian
bee (A. cerana), and the common European honeybee (A. mellifera). The existence of another
giant bee (A. laboriosa), was recently confirmed in Nepal, but little is known about its
biology (Seeley, 1985; Otis, 1990). Apis species are classified into two groups, based upon
nesting. The first group builds single comb, open-air nests: A. andreniformis, A. florea, A.
dorsata, A. breviligula, A. binghami and A. laboriosa. These bees are restricted to the Asian
tropics and subtropics. The second group consists of species that nest inside cavities where
they build multiple combs: A. cerana, A. koschevnikovi, A. nigrocincta, A. nuluensis, and A.
mellifera (Hepburn and Radloff, 2011; Michener, 2000).

Honeybees that build single-comb, open-air nests
The architectural design of the comb of all honeybee species is essentially similar. It
consists of adjoining hexagonal cells made of wax secreted by the workers' wax glands. The
bees use these cells to rear their brood and to store their food. The general utilization of comb
space is also similar among the species. Honey is stored in the upper part of the comb.
Beneath the honey storage area, there are commonly rows of pollen-storage cells, worker-
brood cells, and drone-brood cells, respectively. The larger queen cells are normally built at
the lower edge of the comb (Seeley, 1985; Wongsiri et al., 1991; Otis, 1990).

The black dwarf honeybee, Apis andreniformis Smith, 1858
Apis andreniformis was reported in Thailand by Wongsiri et al. in 1990 from the coastal
flats and near the foothill areas (1-100 meter above sea level) of Chantaburi province,
Thailand to high mountainous and forest areas (approximately 1600 m altitude) in the
northern parts of Thailand (Wongsiri et al., 1996a). This species was rediscovered in South
China in the same habitat as a. It was the fifth honeybee species to be described of the eleven
known Apis species, and its biology and geographic distribution remain relatively poorly
understood (Maa, 1953; Tirgari, 1971; Wongsiri et al., 1996a; Wu and Kuang, 1987). Only
recently, this species has been diagnostically separated from the closely related A. florea
because there are sites where both species live conspecifically. Both species are distributed
throughout tropical and subtropical Asia, including Southeast China, India, Burma, Laos,
Vietnam, Malaysia, Indonesia (Java and Borneo), and the Philippines (Palawan)
(Akratanakul, 1976; Maa, 1953; Otis, 1990; Tirgari, 1971; Wongsiri et al., 1996; Wu and
Kuang, 1987). In body size, A. andreniformis is smaller than A. florea.

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Morphologically, A. andreniformis has stripes of black hairs on the metathoracic tibia and
on the dorsolateral (back and side) surface of the metathoracic basitarsus (Wongsiri et al.,
1996a). Additionally, the pigmentation of A. andreniformis is blackish, while that of A. florea
is yellowish. Other distinguishing characteristics include a difference in cubital indexes,
which is the ratio of two of the wing vein segments of honeybees. The pattern of the veins of
the fore wings is specific for each breed of bees. The cubital index is consistent for a given
race of bee. It can be used to distinguish between similar populations of honeybees and to
determine degrees of hybridization: A. andreniformis has an index of 6.37, and that of A.
florea is 2.86. The proboscis of A. andreniformis has a length of 2.80 mm, while that of A.
florea is 3.27 mm. This physical difference may contribute to differences in the types of
flowers visited by different species. Finally, there are differences in the barbs of the stinger,
and in the basitarsus of the drones (Rinderer et al., 1995; Wongsiri et al., 1996a). Apis
andreniformis nests in quiet forests, generally in darker areas where there is 25 to 30% of
ambient sunlight. The hive is built in the branches of trees or shrubs usually 1-15 m above
ground, although the average height is 2.5 m. The nest typically ranges from 70-90 mm in
size (Wongsiri et al., 1996a).

Figure 1. The single open nesting of Apis andreniformis.
Almost nothing is known about the recruitment communication behavior of A.
andreniformis. However, all studied Apis species can waggle dance to communicate food
location (Nieh et al., 2003), and thus it is highly likely that A. andreniformis also uses this
behavior (Dyer and Seeley, 1991; Dyer, 2000; 2002). Given, its similarity with A. florea, and
the fact that it also builds single-comb, open nests it is reasonable to expect that A.
andreniformis also waggle dances on exposed comb. Drone “dances” have been observed on
the open comb surface of A. andreniformis nests (Wongsiri et al., 1996a), although the

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significance of this behavior is unclear. Further studies of this species’ communication
abilities are needed.

The red dwarf honeybee, Apis florea Fabricius, 1787
As its name implies, the dwarf honeybee is small in body size. This species does well in
very hot, arid climates. A nest of A. florea consists of a single comb, typically built in small
trees. Apis florea nests in the open, but nests are camouflaged. Most nests are hung from
slender branches of trees or shrubs covered with relatively dense foliage, from 0.3 to 8 m
above the ground (Hepburn, and Radloff, 2011; Wongsiri et al., 1996a). In Oman, where A.
florea nests are frequently found in caves, such combs lack the crest that is the honey storage
area and that surrounds the branch on which the comb is suspended (Akratanakul, 1976). Apis
florea is generally distributed throughout Thailand and it is an economically important
species as well as important to crop and wild plant pollination. The single comb nest contains
cells of four sizes. The large storage cells for the honey are very deep and constructed in such
a manner that the comb bulges out on either side and at the top. The small worker cells (2.7-
3.1 mm) are located below the honey storage cells. The considerably larger drone cells (4.2-
4.8 mm) are mostly found in the lower part of the comb. The pear shape queen cells, which
are the largest of the cells, are located near the bottom. These can be observed when a colony
loses its queen, and are emergency queen-cells (Ruttner, 1988).

Figure 2. The single open nesting of Apis florea showing ant barriers made of resin (propolis) at the
edges of a branch.

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This species applies a sticky resin (propolis) like substance to branches to support its
comb and prevent ants and other insects from invading the nest (Akratanakul, 1976; Wongsiri
et al., 1996a). The communication dance by scouts, announcing the discovery of a food
source, also takes place on the platform of honey storage area and is a classic “figure eight”
waggle dance However, unlike the cavity-nest species, A. florea foragers dance upon the
relatively flat upper comb area above the branch supporting the nest. Because they dance
upon this horizontal surface, foragers orient towards celestial cues rather than to gravity or
towards landmarks if the celestial cues are unavailable (Dyer, 2002). As a result, these
foragers dance with the waggle phase pointing directly at the indicated resource, with visual
cues (celestial or landmark) used to correctly orient the waggle phase (Lindauer, 1956; 1961).


The giant honeybee, Apis dorsata Fabricius, 1793
This species has the largest individual body size of all honeybees (Michener, 2000).
Interestingly, queen, workers, and drones of this species are all produced in cells similar in
size and shape (Richards, 1953). The average cell diameter ranges between 5.42-6.35 mm
(Dietz, 1992; Graham, 1992). The nest is made as a single comb about 1-2 meters long,
approximately 0.5 m high on thick branches (20-40 cm diameter to support comb weight) on
the upper parts of large trees that are 30-60 meters high. Other preferred nesting sites include
overhanging rocks, cliffs, or cavities of large buildings (Lindauer, 1961). In general, A.
dorsata may occur singly or several nests are formed aggregately, usually 20-50 nests in a
single tree in the forests of Thailand.
Some populations of this species are very aggressive (Wongsiri et al., 1990; 1996b).
About three-quarters of the worker population of a colony of giant honeybees is engaged in
colony defense, forming a protective curtain that is three to four bees thick, similar to A.
florea. While birds are common predators of A. dorsata, they are evidently well protected
against ant invasion. Thus, the sticky bands of propolis around the nests of the dwarf
honeybee are not found surrounding the nests of A. dorsata, nor are the nests hidden by dense
foliage (Akaratanakul, 1976).
In Thailand, A. dorsata has relatively high levels of genetic diversity. There is a lack of
genetic population differentiation between A. dorsata originating from geographically
different regions when using microsatellite polymorphisms (Insuan et al., 2007). However,
there are significant genetic differences between bees from the north-to-central region (north,
northeast, and central regions), peninsular Thailand, and Samui Island (Insuan et al., 2007).
The range of the giant honeybee is similar to that of the dwarf honeybee. It occurs from
Pakistan (and, perhaps, parts of southern Afghanistan) in the west, through the Indian
subcontinent and Sri Lanka to Indonesia and parts of the Philippines in the east. Its north-
south distribution spans southern China to Indonesia; it is not found in New Guinea or
Australia. In Thailand this species is particularly found in forested areas with a large variety
of wild plant species. The organization of the comb is similar to that in the other honeybee
species: honey storage at the top, followed by pollen storage, worker brood and drone brood
(Hepburn, and Radloff, 2011; Otis, 1990; Wongsiri et al., 1996b).
At the lower part of the nest is the colony’s active area, known as the mouth, where
workers take off and land and where communication dances by scouts announcing the
discovery of food sources take place (Akaratanakul, 1976). This dance takes place on the

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vertical surface of the comb, and during its progress, the bees must have a clear view of the
sky to observe the exact location of the sun. Unlike other species of honeybees, A. dorsata
has the unusual habit of continuing foraging after sunset on bright moonlit nights (Wongsiri
et al., 1991), a nocturnal ability that is not reported in other honeybee species (Suwannapong
and Wongsiri, 1999, Suwannapong et al., 2010a). Apis dorsata foragers can fly at night in
part because of large concentrations of visual pigment in the retinular cells of their ommatidia
(Suwannapong and Wongsiri, 1999).

Figure 3. The aggregated single open nesting of Apis dorsata.


Honeybees that Build Multi-Comb Nests in Enclosed Cavities

The Asiatic hive honeybee, Apis cerana Fabricius, 1793
The Asiatic hive honeybee, A. cerana is widespread in temperate and tropical Asia
(Smith et al., 2000). The range for this species is greater than that of A. florea and A. dorsata.
It is found throughout Thailand. There are two subspecies of A. cerana in Thailand: A. cerana
cerana and A. cerana indica. Apis cerana populations have high genetic diversity in the
mainland (north, central, northeast and peninsular Thailand), but limited diversity in the
Samui population, implying that genetic drift or founder effects may have occurred in this
population (Hepburn et al., 2001; Hepburn, and Radloff, 2011; Otis, 1990; Wongsiri et al.,
1996). There are five conspecific populations of A. cerana in Thailand. These are assigned to

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four different genetic groups: north and central region, peninsular Thailand, Samui island and
northeast (Sittipraneed et al., 2001).
Apis cerana provides honey, beeswax, and the invaluable service of crop pollination.
They tend to swarm, abscond and migrate quite frequently (Akratanakul, 1976; Maa, 1953;
Morse and Moch, 1971; Otis, 1990; Richards, 2001; Smith et al., 2000; Wongsiri et al., 1996;
Wu and Kuang, 1987). Among the native bees of Asia, A. cerana will likely become an
increasingly important beekeeping resource. Its nest structure is similar to that of A. mellifera
because it builds multiple combs inside a nest cavity (Figure 4). It also performs waggle
dances inside the nest, usually in the dark, like A. mellifera (Lindauer 1956). Because A.
cerana has not been domesticated to the same extent as A. mellifera, it poses some problems
for apiculture such as high swarming and absconding rates, a different set of parasites, and
more limited honey storage capabilities. However, they are strongly resistant to Varroa
jacobsoni and predatory wasps (Kerr et al., 1974, Ruttner, 1988; Wongsiri et al., 1996a).

Figure 4. The cavity hive of Apis cerana in a clay jar.
In the wild, these bees construct their nests in dark enclosures such as caves, rock cavities
and hollow tree trunks. The normal nesting site is usually close to the ground, not more than
4-5 meters high. The bees' habit of nesting in the dark enables one to keep them in specially
constructed vessels. For thousands of years A. cerana has been kept in various kinds of hives
(clay pots, logs, boxes, wall openings, etc). Despite the relatively recent introduction of
Langstroth-frame hives, colonies of A. cerana kept in traditional hives are still common in the
villages of most Asian countries (Akratanakul, 1976; Hepburn, and Radloff, 2011). As a
result, feral nests of A. cerana are less hunted by man than nests of dwarf and giant

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honeybees (Akratanakul, 1976; Maa, 1953; Otis, 1990; Tirgari, 1971; Wongsiri et al., 1996b;
Wu and Kuang, 1987). The several combs in an A. cerana colony are built parallel to each
other, and have a uniform distance known as the "bee space" between them. The body size of
A. cerana workers is relatively small and there are two sizes of brood comb cells: smaller for
worker and larger for drone brood. Queen cells are built on the lower edge of the comb. As in
the other Apis species, honey is stored in the upper part of the combs, but also found in the
outer combs, adjacent to the hive walls (Akratanakul, 1976; Maa, 1953; Otis, 1990; Wongsiri
et al., 1996b).

Figure 5. The cavity hive of Apis cerana in the hole of a coconut tree trunk.

The European honeybee, Apis mellifera Linnaeus, 1758
Apis mellifera was brought to Thailand for beekeeping about 60 years ago (Suppasat et
al., 2007). Three common and five rare composite haplotypes exist among colonies in North,
Central, Northeast and South Thailand. This species builds multiple-comb nests in dark
cavities (like A. cerana), has an intermediate individual body size, and shares a similar social
organization and division of labor with other honeybee species (Akratanakul, 1976; Maa,
1953; Otis, 1990; Tirgari, 1971). Beekeeping with A. mellifera in Thailand is quite successful.
This species is used for honey production and is an integral part of Thai agriculture. It is used
for pollination of longan, litchi, durian, rambutan and other crops. Although this species is
one of the most studied, efforts over the past few decades to introduce A. mellifera into Asia
have encountered a number of problems, such as the inter-species transmission of bee pests
and diseases (Crane, 1990; Seeley, 1985). In addition, this species needs much more sugar

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feeding during dearth periods and is highly susceptible cold temperatures (Partap and Verma,
1994; 1998).
This species builds their multiple combs nest in the cavity of the hole that provides
protection of the colony against predators, and from climatic changing including rain
(Schmidt and Hurley, 1995). However, this species displays the ancestral characteristics of
open nesting behavior since they can also nest in the open (Butler, 1975; Butler et al., 1970).
This open nesting behavior could indicate a swarming nest that honeybees choose for a
temporary place before determining the final cavity nest site (Raffiudin, 2002; Raffiudin and
Crozier, 2007).
With respect to communication, A. mellifera is the best studied of all species of
honeybees. All species of honeybees share the ability to “dance,” performing repetitive
cycling behaviors on the surface of the comb that indicate the presence of a resource outside
the nest and, in the case of the waggle dance, the resource location (von Frisch 1967).
Resources communicated include pollen, nectar, water, resin (propolis), and nest sites (Dyer
2002). Near the nest (the exact cutoff distance varies with the species and the bee but is
generally less than 50 m for A. mellifera), bees perform a round dance which consists of the
dancer moving in a circle and then periodically making a sharp turn to double back. Far away
from the nest, bees perform a repeating waggle dance that consists of a figure-eight pattern in
which bees waggle during the center portion. Generally, this occurs for resources greater than
100 m away from the nest (in A. mellifera, von Frisch 1967). The waggle portion
communicates the distance to the resource and its direction.
There are differences in the coding of distance in different species of honeybees
(Lindauer, 1956; Punchihewa et al., 1985) that are thought to be tuned to the foraging range
of the species. Thus, species with different foraging ranges should have a different distance
codings. Dyer and Seeley (1991) found no significant differences between the distance coding
“dialects” of the different Asian species of honeybees, A. florea, A. cerana, and A. dorsata
although, based upon reading dances for natural food sources, there were significant
differences in the flight range. The much larger-bodied species, A. dorsata, had
approximately twice the foraging range (95% of dances were for distances estimated to be
less than 3.8 km) of A. florea (1.3 km for 95% point) or A. cerana (0.9 km for 95% point).
The authors point out that observations over a variety of seasons is required for a more robust
test of the dance dialect tuning hypothesis (Beekman et al., 2008; Dyer and Seeley, 1991;
Lindauer, 1956; Otis, 1991; Punchihewa et al., 1985; Raffiudin and Crozier, 2007; Wongsiri
et al., 1996b).
In general, much remains to be learned about the communication of Asian honeybees.
For example, drone dances are reported in the dwarf honeybees (A. andreniformis and A.
florea). Drones of A. andreniformis are reported to engage in runs on the surface of the
colony’s protective curtain, running in circular loops (similar to the round dance) with their
wings somewhat spread out. A dancing drone can attract another drone to follow its dance
and result in both drone followers and the drone flying off together. Drones of A. florea are
not reported to dance (Rinderer et al., 1995; Wongsiri et al., 1996a). Unfortunately, there have
been no subsequent studies of this interesting phenomenon.

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Figure 6. The multiple comb nest of Apis mellifera.


2. HONEYBEE DEVELOPMENT, CASTES, AND AGE POLYTHEISM

Honeybee caste and development
There are three main forms or “castes” of honeybee in every honeybee colony: a single
queen, a few hundred drones and several thousand workers (all female). The queen is a fertile,
functional female that can produce males and females, the worker is an unfertilized female
capable of only producing males (due to the haplodiploid sex determination system found in
honeybees) and the drone is male (Tribe and Fletcher, 1977; Winston, 1979). Honeybees
undergo complete metamorphosis, and all of the honeybee castes (worker, queen, and drone)
pass through the same four stages during their development: egg, larva, pupa and adult. All
three castes spend three days for their egg stages (Winston, 1979; 1987; 1992). The larval
stages last for different amounts of time, depending caste, genetics, and the environment. The
mean duration of the uncapped larval period is about 4.5 days for queen, 5.5 days for workers
and 6.5 days for drones. The total developmental times average 16, 21 and 24 days for queen,
workers and drones, respectively (Tribe and Fletcher, 1977; Winston, 1979; 1987; 1992).
The Queen: There is generally one queen in honeybee colony. The queen honeybee is
effectively the “mother” of the colony. Her main role is to lay eggs. Through the production
of queen pheromone, she influences the physiology and behaviour of the workers. Under
normal circumstances, the queen is the only egg-laying bee in the colony. If there are enough
cells available she will lay up to 2,500 a day (Winston, 1992). A queen starts out as a simple

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fertilized egg that can be laid in a queen cell (for most species, a larger cell specially built for
queen-rearing) or laid in a worker cell that is subsequently transformed (by the workers) into
a queen cell. To create a queen cell, workers extend one or more existing worker cells in the
honeycomb to form “queen cups”. These will usually be towards the bottom or edge of the
main brood area of the comb. The queen lays an egg in these queen cups and once hatched (3
-3½ days after being laid) the new larva is fed a rich diet of “royal jelly” by the “nurse” bees.
Immediately after being laid, there is no difference between an egg that will become a queen
or a worker. Whether or not an egg becomes a queen is largely due to worker actions. If the
colony is ready to swarm, detects that it has a failing queen, or lost its queen, “house” worker
bees will alter how they feed one or more larvae that hatch out. This rich food allows the
larvae to grow larger and more quickly than a normal worker (Allen, 1955; Winston, 1979;
1992).
The new queen (known as the “virgin queen”) emerges 16 days after the egg was laid.
This compares to 21 days for a worker bee or 24 by the drone. If a queen is lost for whatever
reason (e.g. is killed accidentally by predators), the colony will resort to making emergency
queen cells (Seeley, 1985; Winston, 1987; 1992). Providing there are eggs or very young
larvae (up to 3 days old) present, the colony will use these young eggs to raise several new
queens. They will build out existing cells and start feeding what would have been ordinary
worker larvae with royal jelly. The rich diet fed to the developing queen larva alters the
anatomy of the larva (from that of the worker). The abdomen becomes notably longer than
that of her sister workers. The larger abdomen accommodates the enlarged reproductive
organs, namely the ovaries and spermatheca (Anderson, 1963; Mackensen, 1943; Winston,
1992). When the virgin queen is ready to emerge, one of four fates await her; 1) She will be
attacked and possibly killed by another queen that emerged ahead of her, 2) She will seek out
and find other emerging queens and kill them (sometimes by stinging through the cell before
the victim has emerged), 3) She will be ushered out of the colony by workers to fly off with a
number of other bees from the colony (a swarm), or 4) She will be accepted by the colony, the
workers of which will immediately start to care for her(Anderson, 1963; Mackensen, 1943;
Winston, 1992).
The virgin queen will typically stay in the colony for a few days in order to feed and gain
strength and allow her reproductive organs to mature a little further (Mackensen, 1943;
Winston, 1992; Woyke, 1963; 1969, 1973). Following this initial “rest period,” the virgin
queen emerges from the colony and makes a several reconnaissance flights. She may do this
to ensure she knows where the hive is and also to find where drones congregate (Anderson,
1963; Mackensen, 1943; Winston, 1987; Woyke, 1969). Due to her large size, the queen is
particularly vulnerable to being captured by predator like birds, and therefore avoids long
flights (Anderson, 1963; Mackensen, 1943; Winston, 1992; Woyke, 1969, 1973).
When ready, usually any time up to around 21 days from emerging from her cell, the
queen will make a “mating flight”. She will head straight for the drone congregation site
usually in the vicinity of the queen’s colony and up to 30 metres from the ground. The queen
flies up to the drones and mates repeatedly with several of them. Once her spermatheca is full,
she heads back to the colony. She relies on the attendant workers for her every need. They
feed her, groom her, and remove her wastes (Mackensen, 1943; Winston, 1987; 1992;
Woyke, 1963; 1969). The queen will spend the remainder of her life laying eggs. The number
she lays will largely depend on the activities of the colony. Workers control how many cells
remain vacant for egg laying (increasing and decreasing the amount of stores of pollen and

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honey according to seasonal variations) and will control her egg production by varying the
amount of food she is fed (Anderson, 1963; Brouwers, 1982; 1983; Mackensen, 1943;
Winston, 1992; Woyke, 1973).
The queen produces a pheromone called queen mandibular gland pheromone. As the
workers clean her, they distribute queen substance around the colony. This serves to maintain
the colony in a “normal” state. However, as the queen gets older, typically coinciding with a
steady reduction in the number of eggs laid, she produces less queen substance (Winston,
1992; Woyke, 1969; 1973). The colony senses this and begins preparation for her ultimate
removal. This occurs by a process of supercedure where a new queen is raised and the old one
is killed off either by the workers or the new queen. Supercedure is a natural process that will
face nearly every queen. Supercedure may occur within the colony or once a colony has
swarmed. A prime swarm (the first to leave a colony) will have the incumbent queen. Once
the swarm establishes its new home, a new queen is raised and the old queen is killed. Queens
occasionally lay fertilized eggs in worker cells, which develop into males called diploid
drones (Mackenson, 1943). Male diploid drones are quickly eaten by workers (Woyke, 1963;
1969, 1973).


Figure 7. The emergency queen cell of A. andreniformis and A. florea surrounded by drone cells.

Workers: The worker bees, as the name implies, do almost all colony tasks. Workers are
all sterile females. They carry out almost all the duties that go into building and maintaining a
colony such as brood rearing, comb building, house cleansing, foraging, and colony defence
(Winstons, 1992; Wongsiri et al., 1996a; 1996b). Workers generally have a smaller body size
than either drones or the queen. There are about 8,000-25,000 workers in A. andreniformis
and A. florea colonies, 40,000-50,000 workers in A. mellifera colony, 20,000-40.000 workers
for A. cerana and, 50,000-80,000 for A. dorsata (Otis, 1990; Winston, 1992; Wongsiri et al.,
1991, 1996). Worker bees, like the queen, possess a sting that is a modified ovipositor or egg

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Guntima Suwannapong Mark Eric Benbow and James C. Nieh
14
laying tube. Despite the presence of reproductive organs, the workers are infertile and lack the
reproductive capacity of the queen.
The worker bee starts out as a normal egg laid by the queen. The larva is fed “brood
food” which is largely a combination of nectar, pollen and enzymes from the saliva of the
“nurse” bees (Anderson, 1963; Mackenson, 1943; Winston, 1992). The pollen provides the
necessary protein required for rapid growth. Sugar is the energy source. A worker larva is fed
approximately half the quantity of brood food fed to a queen larva. However, there is little
difference in the ingredients of the food that is fed to each. Instead, the difference is related to
the relative proportions of those ingredients. Research suggests that the queen larva is fed a
significantly higher proportion of sugar in its food (royal jelly) and that this extra energy
boost given to a larva within its first 3 days promotes an increase in certain growth hormones
that cause what would otherwise become a worker to become a queen. Recently, Kamakura
(2011) made a major breakthrough and discovered a 57 kDa protein, royalactin, that induces
honey bee larvae to become queens. Workers may lay eggs, under certain conditions, which
develop into drones since workers never mate and they have no sperm to fertilize their eggs
(Anderson, 1963; Mackenson, 1943). However, in a normal queenright colony, worker
policing occurs and workers consume eggs produced by other workers (Ratnieks, 1993). In A.
cerana, unlike A. mellifera, there can be a relatively large number of laying workers in a
queenright colony (Partarp and Verma, 1998).
Drones: Drone bees are males. They do not work in the nest, and die after workers stop
feeding them and then drive them from the nest. They seemingly have little or no purpose
within the colony. However, drones perform one vital role. Their primary purpose is to mate
with virgin queens, contributing their genes to different colonies. The body sizes of drones are
larger than workers, but normally smaller than the queen. They are characterised by their
large compound eyes, which appear to come together at the top, and rounded stocky bodies.
They arise from unfertilised eggs laid by a queen or worker. Drones are “haploid”, they only
posses one half of the pairs of genes found in the “diploid” workers and queen (Anderson,
1963; Mackenson, 1943; Winston, 1992).
Usually, drone eggs are laid only by the queen as unfertilized eggs. The queen holds the
eggs and sperm separately and has the choice as to whether or not an egg is fertilized as it is
laid. When the queen lay an egg, she determines whether that egg is being laid in a worker or
in a drone cell, likely by inspection of the cell within her forelegs prior to egg laying or by the
angle of her abdomen during oviposition (Koeniger, 1979, 1983). The queen will lay drone
eggs in drone cells that are larger in diameter in order to accommodate the larger body size of
the drone. The queen can detect the difference in cell type and lays worker or drone eggs
accordingly. If the egg is going into the drone cell, the queen does not release any sperm: the
unfertilized egg is haploid (Winston, 1992). The drone larva is progressively fed by workers
until it spins a cocoon within the cell and undergoes metamorphosis, turning into a pupa. The
drone emerges as a young adult on day 24. The young drone, being unable to gather food for
itself, is fed by the workers (Koeniger, 1969, 1970; Winston, 1992).
After a few days, the drone will begin to carry out reconnaissance flights. Their ability to
navigate is probably the best of all three castes because they typically have around 75-80%
more facets in their compound eyes than the workers or queen (Gary, 1963; Koeniger, 1969,
1970; Ruttner, 1966; Winston, 1992). This should give them better vision. Around 2 weeks
after the drone emerges from the cell, it will be mature enough to mate. Drones typically

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Biology of Thai Honeybees: Natural History and Threats
15
come together in areas known as “drone congregation areas” or “mating yards”. These areas
are often several metres from the ground (up to 30 m) and will typically be in the vicinity of
the apiary or cluster of natural colonies. However, drones can fly several miles to find other
established congregation areas (Gary, 1963; Koeniger, 1969, 1970; Ruttner, 1966; Winston,
1992).
How drones find these congregation areas, particularly from kilometers away, remains a
major mystery. They may be able to sense the odours of other drones over some distance
using their enlarged and highly sensitive antennae. However, this may not account for their
long-distance orientation to drone congregation sites. It is possible that all drones possess
similar innate preferences for congregation sites that lead to choose a few locations. Once
they are close enough to a favored site, the odor of other drones may then enhance their
orientation. However, this explanation is speculative and requires experimental verification.
A congregation area may have several hundred to several thousand drones (Gary, 1963;
Koeniger, 1969, 1970; Ruttner, 1966). A virgin queen will have already found such a
congregation area from early reconnaissance flights. On her mating flight the queen will head
straight for the congregation area (Gary, 1963; Koeniger, 1969, 1970). The drones will sense
her arrival (their notably large antennae have 10 times more sensory receptors than those of
workers or queens) and will immediately pursue her. Several drones will mate with the queen.
Each drone mounts the queen in turn and inserts his endophallus into the queen. The drone’s
sex organs inflate (almost explosively) within the queen, pumping sperm into her. This rapid
inflation and expulsion of sperm causes him to spring backwards and fall away from the
queen. The endophallus is gripped by the opening of the queen’s oviduct and results in the
drone’s endophallus and part of the drone’s gut contents being ripped out of his abdomen.
Each additional drone will remove from the queen the endophallus of his predecessor before
undergoing the same fate. After mating, the drone will often fall to the ground where he will
die (Gary, 1963; Koeniger, 1969, 1970; Ruttner, 1966; Winston, 1992).

Figure 8. The different developmental stages of A. florea workers.