Physiological and Immunological Status of Adult Honeybees (Apis mellifera) Fed Sugar Syrup Supplemented with Pentadecapeptide BPC 157

Various factors contribute to a decline in diversity and number of bees. Here, an integrated approach in experimental BPC 157 therapy was implemented, combining laboratory-controlled and field study results. The aim of a study was to assess the effects of BPC 157 additional feeding of newly emerged worker honeybees on few biochemical and immunological parameters in hemolymph (glucose, trehalose, lipids, proteins, vitellogenin, glucose-oxidase (GOX)), and hypopharyngeal gland (HPG), in laboratory-controlled conditions. Additionally, to examine the physiological status of protein digestion, the enzymatic activity of leucine aminopeptidase (LAP) in the mid-guts of worker honeybees was analyzed. It was found that individual honeybees, in hoarding cages, following BPC 157 administration through carbohydrate food, showed positive physiological changes when compared to the control groups. Those results were complemented by strong and visible LAP activity, particularly noticeable in the apical parts of the epithelial cells in the mid-guts of young worker honeybees originated from treated hives, suggesting a link between alternative oral therapy with BPC 157 and honeybees’ immunity.

The Importance of Time and Place: Nutrient Composition and Utilization of Seasonal Pollens by European Honey Bees (Apis mellifera L.)

Honey bee colonies have a yearly cycle that is supported nutritionally by the seasonal progression of flowering plants. In the spring, colonies grow by rearing brood, but in the fall, brood rearing declines in preparation for overwintering. Depending on where colonies are located, the yearly cycle can differ especially in overwintering activities. In temperate climates of Europe and North America, colonies reduce or end brood rearing in the fall while in warmer climates bees can rear brood and forage throughout the year. To test the hypothesis that nutrients available in seasonal pollens and honey bee responses to them can differ we analyzed pollen in the spring and fall collected by colonies in environments where brood rearing either stops in the fall (Iowa) or continues through the winter (Arizona). We fed both types of pollen to worker offspring of queens that emerged and open mated in each type of environment. We measured physiological responses to test if they differed depending on the location and season when the pollen was collected and the queen line of the workers that consumed it. Specifically, we measured pollen and protein consumption, gene expression levels (hex 70, hex 110, and vg) and hypopharyngeal gland (HPG) development. We found differences in macronutrient content and amino and fatty acids between spring and fall pollens from the same location and differences in nutrient content between locations during the same season. We also detected queen type and seasonal effects in HPG size and differences in gene expression between bees consuming spring vs. fall pollen with larger HPG and higher gene expression levels in those consuming spring pollen. The effects might have emerged from the seasonal differences in nutritional content of the pollens and genetic factors associated with the queen lines we used.

Prisoners receive food fit for a queen: honeybees feed small hive beetles protein-rich glandular secretions through trophallaxis

The honeybee nest parasite Aethina tumida (small hive beetle), uses behavioural mimicry to induce trophallactic feeding from its honeybee hosts. Small hive beetles are able to induce honeybee workers to share the carbohydrate–rich contents of their crops, but it is not clear whether the beetles are able to induce to workers to feed them the protein-rich hypopharyngeal glandular secretions fed to the queen, larvae and other nest mates. Protein is a limiting macronutrient in an insect's diet, essential for survival, growth and fecundity. Honeybees obtain protein from pollen, which is consumed and digested by nurse bees. They then distribute the protein to the rest of the colony in the form of hypopharyngeal gland secretions. Using 14C-phenylalanine as a qualitative marker for protein transfer, we show that small hive beetles successfully induce worker bees to feed them the protein-rich secretions of their hypopharyngeal glands during trophallaxis, and that females are more successful than males in inducing the transfer of these protein-rich secretions. Furthermore, behavioural observations demonstrated that female beetles do not preferentially interact with a specific age cohort of bees when soliciting food, but males tend to be more discriminate and avoids the more aggressive and active older bees.

The effects of different levels of protein and silymarin on the population growth and hypopharyngeal gland surface of honey bee workers (Apis mellifera meda)

A pollen substitute is a valuable resource to maintain bee colonies strong and healthy, in the absence of pollen in sufficient quantities in nature. Hence, the current study was performed to investigate the effects of different levels of dietary proteins and silymarin (SM) as a natural antioxidant, on honey bee worker colonies. The study was carried out as a completely randomized design in an experiment conducted using 36 honey bee colonies in a completely randomized design with nine experimental treatments (four levels of crude protein 0, 20, 30 and 40%, two levels of silymarin 0 and 0.2 mM and pure pollen (control)), and four replications at Agricultural Sciences and Natural Resources University of Khuzestan in autumn 2015. In current study parameters such as workers in sealed broods, newborn workers bee weight, body protein and, the amount of development of Hypopharyngeal gland surface were studied. Soybean meal, maize and wheat gluten were included as pollen substitutes. Based on the results of the pre-experiment, SM supplement at a dose of two-tenths mM improved the survival of bees. Capped broods number using the divided box into squares with 2 ? 2 cm, newborn workers bee weight using the balance, body protein based on the percentage of body weight and development of the Hypopharyngeal gland surface using microscopes and micrometers were measured. The results showed that there was a significant difference between treatments in terms of laying eggs (P <0.05). The highest and lowest rate of workers in sealed broods were related to treatment containing 30% protein and SM (12467 cells) and sucrose treatment (2042 cells), respectively. Also, the highest and lowest newborn workers bee weight were related to pollen treatment and the sucrose treatment, respectively (P <0.05). Body protein of worker bees in studied treatments had significant differences (P <0.05), so that the widest and narrowest percent body protein were observed in a diet containing 30% protein and SM and sucrose treatment, respectively. The Hypopharyngeal gland surface in the colonies fed with different diets was significantly different (P<0.05) and the widest and narrowest of its surface were observed in the diet containing 30% protein and SM and sucrose treatment, respectively. According to the current results, to maximize the reproduction of bees, a diet containing 30% crude protein is proposed.

Acetylcholine and Its Receptors in Honeybees: Involvement in Development and Impairments by Neonicotinoids

Acetylcholine (ACh) is the major excitatory neurotransmitter in the insect central nervous system (CNS). However, besides the neuronal expression of ACh receptors (AChR), the existence of non-neuronal AChR in honeybees is plausible. The cholinergic system is a popular target of insecticides because the pharmacology of insect nicotinic acetylcholine receptors (nAChRs) differs substantially from their vertebrate counterparts. Neonicotinoids are agonists of the nAChR and are largely used in crop protection. In contrast to their relatively high safety for humans and livestock, neonicotinoids pose a threat to pollinating insects such as bees. In addition to its effects on behavior, it becomes increasingly evident that neonicotinoids affect developmental processes in bees that appear to be independent of neuronal AChRs. Brood food (royal jelly, worker jelly, or drone jelly) produced in the hypopharyngeal glands of nurse bees contains millimolar concentrations of ACh, which is required for proper larval development. Neonicotinoids reduce the secreted ACh-content in brood food, reduce hypopharyngeal gland size, and lead to developmental impairments within the colony. We assume that potential hazards of neonicotinoids on pollinating bees occur neuronally causing behavioral impairments on adult individuals, and non-neuronally causing developmental disturbances as well as destroying gland functioning.

Sodium Selenium Enhances the Antioxidative Activities and Immune Functions of Apis mellifera (Hymenoptera: Apidae) and Increases the Selenium Content in Royal Jelly

Selenium (Se), as an essential micronutrient, has been demonstrated to play an important role in life activities. In this study, we studied the effects of sucrose solutions containing sodium selenite on Apis mellifera (L.). We obtained the appropriate level of sodium selenite for A. mellifera by determining the life span by lab rearing, and then, we studied the effects of sodium selenite on antioxidant activity, phenol oxidase activity, development of the hypopharyngeal gland, Se content of body tissues and royal jelly (RJ), and related gene transcription levels for a bee colony. The results of lab rearing showed that a concentration of 0.57 mg/liter sodium selenium could extend life. After feeding the colony sodium selenium at concentrations of 0.3 mg/liter and 0.6 mg/liter, the results showed that 0.6 mg/liter sodium selenite could enhance the antioxidant and immune activity of 6-d-old larvae and 1-d-old and 9-d-old worker bees (P &lt; 0.05), increase the Se content of body tissues (P &lt; 0.05) and RJ (P &lt; 0.05), and improve the expression of related genes (P &lt; 0.05).