Effect of season on the development of hypopharyngeal glands and its morphological characteristics under brood rearing conditions in honey bee colonies (Apis mellifera)

Abstract

Introduction: The hypopharyngeal glands (HPGs) are a major member of protein synthesis
in worker bees, which is involved in larval growth. In this experiment, the effect of season
(summer, winter and spring) on the development of HPGs and its morphological
characteristics under brood rearing conditions in honey bee colonies (Apis mellifera) was
investigated.
Materials & Methods: To carry out this experiment, 10 honey bee colonies with the same
conditions in all seasons were used.
Results: The results showed that there was a significant difference between the different
seasons in the acini area of the HPGs of worker bees (at the ages of 3, 6, 9 and 15 days). The
highest acini area in winter, summer and spring was 0.130, 0.189 and 0.079 mm2,
respectively. During the winter, spring and summer, the HPGs fully developed under brood
conditions but had morphological differences. Also, the highest level of unsealed/uncapped
brood rearing was related to spring (2300 cm2).
Conclusion: According to the results obtained from the development of HPGs in summer
and winter, an upward and downward trend in glands growth was observed, which is known,
but in the spring we saw a steady trend in the growth of glands, which could be a new theory
of the development of HPGs in the spring according to the level of brood rearing.