Nutritional and Temporal Effects on Hypopharyngeal Glands of Africanized Honeybees (Hymenoptera – Apidae)

Abstract

The hypopharyngeal gland (HG), along with the mandibular gland from Apis mellifera workers plays a fundamental role on the development of the hive. The protein based substances produced by the hypopharyngeal and mandibular glands are two important component of the royal jelly, which is responsible for caste differentiation and used to feed larvae, drones and the queen. Several factors may alter the physiology of glandular structures in honeybees and consequently their role within the beehive, and one of the most important factors is their nutritional status. However, few studies have evaluated the development of HG against different diets on Africanized honeybees. Our experiment was composed of four diets (treatments) offered to different groups of workers: (T1) honey, (T2) honey + soybean extract, (T3) honey + pollen and (T4) sucrose solution. The development of the glands was evaluated in two periods: 7 and 10 days of exposure to the diet types. According to the results, an interference of the diet on the acini area of the HG was observed. Bees that were fed with the sucrose solution or soybean extract presented the smallest acini areas as compared to the other treatments. The time of exposure to the different types of diets also had an effect on acini areas. Worker bees fed with honey and soybean extract for 10 days presented smaller acini areas when compared to bees dissected at the 7th day of exposure to those same diet types. Nevertheless, we also observed that factors other than just nutrition are important to the full development of the HG, such as the stimulus promoted by the young breeds.