Juvenile hormone functions as a metabolic rate accelerator in bumble bees (Bombus terrestris)

• Published in: Hormones and behavior 2021-11, Vol.136, p.105073-105073, Article 105073
• Main Authors: Shpigler, Hagai Y., Magory Cohen, Tali, Ben-Shimol, Einat, Ben-Betzalel, Roi, Levin, Eran
• Format: Article
• Language: English
• Subjects: Animals; Bees; Bumble bee; Diapause; Insecta; Juvenile hormone; Juvenile Hormones - metabolism; Metabolic rate; Metamorphosis, Biological; Reproduction - physiology; Stable isotopes; δ13C
• ISSN: 0018-506X; 1095-6867
• DOI: 10.1016/j.yhbeh.2021.105073

Juvenile hormone (JH) is a modulator of many physiological transitions in insects, including molting, metamorphosis, diapause, and reproduction. These processes often include metabolic changes. Here we show that JH accelerates metabolic rate in bumble bees (Bombus terrestris). We reduced JH levels in worker bumble bees by removing their corpora allata (allatectomy) and elevated JH levels in queens through a topical application of JH-III. Natural and high JH levels increased the metabolic rate in both workers and queens and triggered an increased protein turnover rate. Following the treatments, JH also caused an increase in food consumption and a reduction in lipid levels and flight muscle mass of queens, and a reduction in lipids levels in workers. Furthermore, the topical application of a JH analog to queens prior to their diapause caused a decline in their survival of diapause. These findings support the hypothesis that JH acts as a metabolic rate accelerator, initiating a resource shift in bumble bees, and thereby reducing diapause survival in queens. Based on previous studies on JH we suggest that, additional to its behavioral or physiological effects, JH's function as an accelerator of metabolic processes is conserved across different life stages and insect species. •Juvenile hormone (JH) is a modulator of many physiological transitions in insects.•JH increase food consumption and reduced fat amounts in worker and queen bumble bees.•JH increased metabolic rate and protein turnover in bumble bees.•JH reduced diapause survival of queen bumble bees.•JH suggests functioning as an accelerator of metabolic and anabolic process in insects.