Abstract:
Secretions from tergal glands are part of a queen’s
pheromonal control of worker reproduction in honey bees.
However, in queenless honey bee colonies, workers compete
to gain pheromonal, and hence reproductive dominance, over
nestmates with ontogenetic changes in their glandular secretions
that affect the behavioral or physiological responses of
other individuals. Using gas chromatography/mass spectrometry,
we investigated for the first time the age-dependent changes
in tergal gland secretions of queenless workers of the clonal
lineage of Apis mellifera capensis and workers of A. m.
scutellata. The reproductive status of honey bee workers was
determined by recording the presence of spermathecae and the
level of ovarian activation. The tergal gland chemicals identified
in both A. m. scutellata workers and A. m. capensis clone
workers were oleic acid, n-tricosene, n-pentacosene, and
n-heptacosene, with three additional compounds, palmitic acid,
n-heneicosene, and n-nonacosene, in A. m. capensis clones.We
report ethyl esters as new compounds from honey bee worker
tergal gland profiles; these compounds increased in amount
with age. All A. m. capensis clone workers dissected had
spermathecae and showed ovarian activation from day 4, while
ovarian activation only started on day 7 for A. m. scutellata
workers that had no spermathecae. Tergal gland secretions were
present in higher quantities in bees with activated, rather than inactive ovaries. This suggests that tergal gland secretions from
reproductive workers could act as releaser and primer pheromones
in synergy with other glandular compounds to achieve
pheromonal and reproductive dominance.
