Insect body defence reactions against bee venom: do adipokinetic hormones play a role?
We have found that bee venom has significant effects on the physiological processes in the body of Periplaneta americana cockroaches; however, the main novelty of this study was that some effects are modulated by cockroach adipokinetic hormone (referred to as Peram-CAH-II).
Figure description: Left panel: General activity of the bee venom in P. americana adult body
Right panel: Transmission electron microscopy photos of the thoracic muscles from P. americana adults 24 h after treatment with (A) Ringer saline (control), (B) 40 pmol Peram-CAH-II, (C) 0.5 μl bee venom (see myofibrils destruction), and (D) 0.5 μ bee venom +40 pmol Peram-CAH-II together. Scale bars in the Figs = 2 μm.
The honey bee stinging apparatus is a sophisticated organ that serves primarily as a defensive or offensive weapon in worker bees. The bee stinger is connected to the venom gland, combines the advantages of a mechanical weapon with those of a chemical one. Bees originally developed their stinging apparatus and venom against members of their own species from other hives or against predatory insects. Nevertheless, the biological and biochemical response of arthropods to bee venom is not well studied. Thus, in this study, the physiological responses of a model insect species (American cockroach, Periplaneta americana) to honeybee venom were investigated. Bee venom toxins elicited severe stress (LD50 = 1.063 μl venom) resulting in a significant increase in adipokinetic hormones (AKHs) in the cockroach central nervous system and haemolymph. Venom treatment induced a large destruction of muscle cell ultrastructure, especially myofibrils and sarcomeres. Interestingly, co-application of venom with cockroach adipokinetic hormone (Peram-CAH-II) eliminated this effect. Thus, AKH can be considered as an inhibiting factor of myonecrosis, which may have interesting theoretical and practical applications in the future. Envenomation modulated the levels of carbohydrates, lipids, and proteins in the haemolymph and the activity of digestive amylases, lipases, and proteases in the midgut. Bee venom significantly reduced vitellogenin levels in females: vitellogenins are mostly known as yolk precursors involved in reproduction, but they also play important roles in protection against oxidative stress, wound healing, and insect immunity, with strong activity against various pathogens. Dopamine and glutathione (GSH and GSSG) insignificantly increased after venom treatment. However, dopamine levels significantly increased after AKH application and after co-application with bee venom, while GSH and GSSG levels immediately increased after co-application. The results suggest a general reaction of the cockroach body to bee venom and at least a partial involvement of AKHs.
Bodláková K., Černý J., Štěrbová H., Guráň R., Zítka O. and Kodrík D. (2022) Insect body defence reactions against bee venom: do adipokinetic hormones play a role? Toxins 14: 11 DOI: 10.3390/toxins14010011
