Influence of Hyperthermia Treatment on Varroa Infestation, Viral Infections, and Honey Bee Health in Beehives.

Abstract

The mite Varroa destructor is widely acknowledged as the most destructive threat to honey bee (Apis mellifera) colonies on a global scale. Varroa mite infestations in bee colonies are intricately linked with viral infections, collaboratively leading to diminished bee populations and accelerated colony losses. Extensive research has firmly established the correlation between varroa mites and viruses, underscoring the mite's efficiency in spreading viruses among bees and colonies. The effective control of varroa mites is expected to result in a decrease in viral infections within bee colonies. Research suggests that thermal treatments (hyperthermia) present a viable approach to combat varroa mites, with studies demonstrating the role of heat stress in reducing viral infections in affected bees. This article examines the extant literature surrounding the utilization of hyperthermia as a potential method to ameliorate the adverse impacts of varroa mites and their associated viral infections on honey bee colonies. It also outlines the thermal characteristics of these stressors. Diverse devices can be used for subjecting colonies to hyperthermia treatment, targeting mites both within and outside of brood cells. The application of thermal treatments, typically ranging between 40 and 42 °C for 1.5-3 h, as a method to reduce varroa mites and viral infections, has shown promise. Notably, the precise effectiveness of hyperthermia treatment in comparison with alternative varroa mite control measures remains uncertain within the available literature. The potential deleterious repercussions of this control mechanism on immature and mature honey bees are evaluated. Concurrently, the detrimental implications of prolonged treatment durations on colonies are discussed. Regarding viral infections, hyperthermia treatment can impact them negatively by either reducing varroa mite infestations or by inducing the production of heat shock proteins that possess potential antiviral properties. Various factors are identified as influential on hyperthermia treatment efficacy within bee colonies, including the device type and treatment duration, necessitating further empirical investigations. Additionally, this article highlights the existing gaps in the knowledge and provides insights into the prospective directions of research concerning this control method.