Epsilon Archive for Student Projects

Abstract

The European honeybee, Apis mellifera, is essential for global agriculture, significantly contributing to the pollination of 35% of agricultural land and supporting the production of 87 leading food crops. However, the species is under threat from the ectoparasitic mite Varroa destructor, which originally parasitized the Asian honeybee, Apis cerana, before making a host switch approximately 65-105 years ago. This switch has led to the rapid and widespread infestation of A. mellifera populations, causing severe colony losses worldwide, with USA losses reported at 40.5% in 2015-2016, rising to 45.5% by 2020-2021.
Varroa impacts its host by feeding on haemolymph and body fat, reducing bee weight and lifespan, and by transmitting viruses such as Deformed Wing Virus (DWV), which causes high brood mortality and deformities. Two different host switches have resulted in two primary haplotypes: the less virulent Japanese and the more destructive Korean, with the latter spreading throughout Europe, Asia, and the Americas.
Given the limited natural defences of A. mellifera against Varroa, current control methods involve the use of various acaricides. However, these methods face challenges such as resistance development and potential contamination of honey and other bee products. This report aims to synthesize existing knowledge on naturally resistant A. mellifera populations and their traits, providing an overview of these traits and the status of feral colonies that survive without treatment. By examining these resistant populations and their adaptive behaviours, this report seeks to inform and enhance sustainable management strategies against Varroa in global apiculture.