Bee year: Basic physiological strategies to cope with seasonality

• Published in: Comparative biochemistry and physiology. Part A, Molecular & integrative physiology Vol. 264; p. 111115
• Main Authors: Kodrík, Dalibor, Krištůfek, Václav, Svobodová, Zdeňka
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01.02.2022
• Subjects: Adipokinetic hormone; Animals; autumn; bee venoms; Bee Venoms - metabolism; Bees - physiology; Biomarkers - metabolism; carbohydrates; central nervous system; Central Nervous System - metabolism; Digestive System - enzymology; energy metabolism; hemolymph; Hemolymph - metabolism; honey; Insect Hormones - metabolism; lipids; Melitten - metabolism; melittin; Metabolism; midgut; Oligopeptides - metabolism; Pyrrolidonecarboxylic Acid - analogs & derivatives; Pyrrolidonecarboxylic Acid - metabolism; Seasonal fluctuations; Seasons; Venom; Vitellogenin; Vitellogenins - metabolism; winter; adipokinetic hormones; Venom; Adipokinetic hormone; Metabolism; Seasonal fluctuations; Vitellogenin; central nervous system
• ISSN: 1095-6433; 1531-4332; 1531-4332
• DOI: 10.1016/j.cbpa.2021.111115

Worker honey bees are subject to biochemical and physiological changes throughout the year. This study aimed to provide the reasons behind these fluctuations. The markers analysed included lipid, carbohydrate, and protein levels in the haemolymph; the activity of digestive enzymes in the midgut; the levels of adipokinetic hormone (AKH) in the bee central nervous system; the levels of vitellogenins in the bee venom and haemolymph; and the levels of melittin in the venom. The levels of all the main nutrients in the haemolymph peaked mostly within the period of maximal bee activity, whereas the activity of digestive enzymes mostly showed a two-peak course. Furthermore, the levels of AKHs fluctuated throughout the year, with modest but significant variations. These data suggest that the role of AKHs in bee energy metabolism is somewhat limited, and that bees rely more on available food and less on body deposits. Interestingly, the non-metabolic characteristics also fluctuated over the year. The vitellogenin peak reached its maximum in the haemolymph in winter, which is probably associated with the immunoprotection of long-lived winter bees. The analysis of bee venom showed the maximal levels of vitellogenin in autumn; however, it is not entirely clear why this is the case. Finally, melittin levels showed strong fluctuations, suggesting that seasonal control was unlikely. [Display omitted] •Bee workers prefer carbohydrate metabolism.•Two-peak activity of digestive enzymes reflects food availability.•AKH role in bee energy metabolism is somewhat limited.•Vitellogenins in haemolymph and in venom play different roles.•Fluctuation of melittin in venom does not seem to be controlled by seasonality.