Drone Pheromones in Apis mellifera
Honey bees communicate extensively through pheromones, with most research focused on the queen and workers. Drones (male bees) also produce pheromones, although far less is
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known about them. Recent studies have begun to illuminate the chemical signals male honey bees produce, when they produce them, and how these cues function in mating and colony dynamics (Gryboś et al., 2025).
Pheromone Sources and Chemical Nature in Drones
Male honey bee pheromones derive
primarily from the drones’ mandibular glands. Chemical analyses show that drone
mandibular gland secretions are dominated by fatty acids (both saturated and
unsaturated, some with methyl branching) ranging roughly from 9 to 22 carbons
in length (Villar et al., 2018). Notably, two major components identified are
hexadecanoic acid (palmitic acid) and (Z)-9-octadecenoic acid (oleic acid)
(Lensky et al., 1985). These compounds and a few others make up the bulk of the
drone’s pheromonal blend. In contrast to queens – whose mandibular glands
produce potent mixtures like 9-ODA and other specialized acids – the drones’
blend consists mostly of relatively simple fatty acids. Drones also lack
certain pheromone glands present in workers; for example, males have no sting
(hence no alarm pheromone) and do not use Nasonov orientation pheromone,
reflecting their limited roles in colony labor. While small tarsal (foot)
glands exist in males, their secretions appear minimal and are not known to
play a significant communicative role in the colony. In short, the drone’s
known pheromones are few, with the mandibular gland being the key source
identified so far.
Onset of Pheromone Production and Maturation
Drone honey bees do not produce
effective pheromones immediately upon emergence. Pheromone production ramps up
as the drone matures sexually. Drones typically reach sexual maturity about 1–2
weeks after emergence (around 9–12 days old) (Bastin et al., 2017).
Correspondingly, studies show that only sexually mature drones produce the
pheromonal cues that attract others. In laboratory experiments, young drones
(2–3 or 7–8 days old) showed no attraction to the odor of their peers, whereas
sexually mature drones (12–15 days old) were strongly attracted to the scent of
other mature males (Bastin et al., 2017). This indicates that pheromone
production (or release) begins in earnest as drones become capable of mating.
Histological observations confirm that the drone’s mandibular glands develop
and fill with secretions in the first week or so of adult life, then begin to
degenerate around the onset of sexual maturity (Lensky et al., 1985).
Functions in Mating and Drone Congregation Behavior
Unlike worker or queen pheromones
which regulate complex social tasks in the hive, drone pheromones serve a more
singular purpose: reproduction. The primary function of drone pheromones is to
mediate interactions during mating. In the afternoons of the mating season,
mature drones leave their hives and gather in the air at specific locations
known as drone congregation areas (DCAs) – sometimes thousands of males from
many colonies converge in one spot (Bastin et al., 2017). How do all these
males find the same location? A combination of environmental cues and
pheromones is at work. Landmark cues (such as treelines or topography) help
orient drones to the general area, but in the final localization,
drone-produced pheromones draw males together into the tight congregation
(Wanner & Nishida, 2017).
Decades ago, researchers hypothesized
that an aggregation pheromone emitted by drones facilitates DCA formation
(Lensky et al., 1985). This was first supported when extracts of drone
mandibular glands were found to attract flying drones in field tests (Lensky et
al., 1985). More recently, controlled lab studies confirmed that drones are
indeed attracted to the odor of other drones, validating the existence of a
drone aggregation signal (Wanner & Nishida, 2017). Importantly, this
pheromonal attraction is specific to drones – a synthetic blend of the six main
mandibular fatty acids or the natural gland extract will lure other drones, but
will not attract worker bees inside or outside the hive (Villar et al., 2018).
In other words, the drone pheromone is a releaser signal aimed at fellow males
(and perhaps queens), not a colony-wide messenger.
The ultimate purpose of drone
congregation is to mate with virgin queens. Here, drone pheromones intersect
with queen pheromones. Virgin queen honey bees generally arrive at DCAs after
the drones have already assembled (Bastin et al., 2017). Drones detect and
chase the queen largely by sensing the queen’s own sex pheromone – the queen
mandibular pheromone (QMP), especially its key component 9-oxo-2-decenoic acid
(9-ODA) (Gryboś et al., 2025). In fact, drones have highly tuned antennae and
brain olfactory centers (macroglomeruli) specifically devoted to detecting
9-ODA, which triggers their frenzied pursuit of a queen in flight (Brockmann et
al., 2006). However, queens may also use drone pheromones to their advantage:
lab experiments have demonstrated that virgin queens are attracted to the odor
bouquet of a group of drones (Wanner & Nishida, 2017). A sexually receptive
queen oriented toward an array of drone scent in a wind chamber, whereas she
ignored worker bee odors. This suggests that a drone-produced odor cue helps
queens locate congregation sites in the final stage of their nuptial flight.
Notably, drone pheromones seem to have
little or no direct role in daily colony social dynamics beyond mating. Worker
bees do not exhibit obvious behavioral or physiological responses to the
presence of drone pheromone inside the hive (Villar et al., 2018). Drones are
typically tolerated in the hive during the breeding season due to hormonal and
resource cues rather than any known drone-emitted primer pheromone. In lean
times, workers evict drones in autumn, again seemingly without a specific drone
chemical signal driving the process. Thus, the drone’s chemical communication
is narrowly focused on its reproductive mission, unlike the queen’s pheromones
which influence everything from worker task allocation to suppression of new
queens, or the workers’ pheromones that coordinate foraging, alarm, and brood
care.
Evolutionary and Ecological Context
The specialized nature of drone
pheromones reflects the drone’s singular role in the honey bee superorganism.
Drones exist only to spread the colony’s genes via mating, and accordingly
their pheromones have evolved for mate location and competition. In many
insects, either the female produces a sex attractant or the males produce
aggregation signals – honey bees have elements of both strategies. The queen’s
powerful sex pheromone (9-ODA in QMP) has an immediate effect of arousing
copulatory behavior in drones and drawing them in toward her (Brockmann et al.,
2006). Drones, on the other hand, appear to cooperate (unwittingly) by emitting
an odor that helps form large congregations, which in turn increases each
male’s chance to encounter a queen (Wanner & Nishida, 2017).
From an evolutionary perspective, a
drone aggregation pheromone likely benefits all participating males by creating
a predictable “mating marketplace” that virgin queens can find. Drones from
many hives mix at DCAs, promoting outbreeding and genetic diversity in the
species. The consistency of DCA locations year after year – some spots have
been used by drones for decades – implies that aggregation cues are robust and
long-standing in honey bee reproductive ecology. Environmental factors (like
terrain landmarks and even geomagnetic anomalies) help drones roughly orient to
a site, but the final assembly into a dense drone cloud likely requires the
pheromone signal as a short-range cue to cluster within a defined space.
Compared to the multi-functional
pheromones of queens and workers, drone pheromones are limited but crucial.
They do not regulate colony labor or development, yet they are indispensable
for successful mating. The existence of a male-produced pheromone in Apis
mellifera also invites comparisons to other bees: for instance, males of
some bumblebee species produce pheromonal scents to mark perch sites and
attract queens, and males of solitary bees often emit pheromones during mating
swarms. Honey bee drones fit into this broader context of male chemical
signaling, but their pheromones had remained elusive until recently. Now, with
advanced analytical chemistry and creative bioassays (like drone walking
simulators), scientists have confirmed that drones indeed contribute their own
chemical voice to the honey bee communication repertoire.
References
Bastin, F., Savarit, F., Lafon, G.,
& Sandoz, J.-C. (2017). Age-specific olfactory attraction between Western
honey bee drones (Apis mellifera) and its chemical basis. PLOS ONE,
12(10), e0185949. https://doi.org/10.1371/journal.pone.0185949
Brockmann, A., Dietz, D., Spaethe, J.,
& Tautz, J. (2006). Beyond 9-ODA: Sex pheromone communication in the honey
bee. Apidologie, 37(2), 138–154. https://doi.org/10.1051/apido:2005076
Gryboś, A., Staniszewska, P., Bryś, M.
S., & Strachecka, A. (2025). The pheromone landscape of Apis mellifera:
Caste-determined chemical signals and their influence on social dynamics. Molecules,
30(11), 2369. https://doi.org/10.3390/molecules30112369
Lensky, Y., Cassier, P., Notkin, M.,
Delorme-Joulie, C., & Levinsohn, M. (1985). Pheromonal activity and fine
structure of the mandibular glands of honeybee drones (Apis mellifera
L.). Journal of Insect Physiology, 31(4), 265–276.
https://doi.org/10.1016/0022-1910(85)90031-3
Villar, G., Wolfson, M. D., Hefetz,
A., & Grozinger, C. M. (2018). Evaluating the role of drone-produced
chemical signals in mediating social interactions in honey bees (Apis
mellifera). Journal of Chemical Ecology, 44(1), 1–8.
https://doi.org/10.1007/s10886-017-0910-2
Wanner, K. W., & Nishida, R.
(2017). Virgin queen attraction toward males in honey bees. Scientific
Reports, 7, 40697. https://doi.org/10.1038/s41598-017-06241-9
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