Global honeybee health decline factors and potential conservation techniques

Pesticide exposure, heavy metal pollution, and biological stressors drive a worldwide, ongoing, and rapid population decline of the crucial pollinator honeybee. Drastic colony loss of honeybees may well precipitate a food security crisis. Here a systematic review was conducted, examining reports on a global scale to propose a bench line for common pesticides and potentially toxic element (PTE) residue levels in plant rewards and honeybees and to assess the health risk of chemical residues via oral exposure to honeybees. Relevant articles were retrieved from Scopus, PubMed, ISI Web of Science, and Embase. Recent findings on how chemical and biological stressors cripple honeybee health, and conservation techniques were also summarized. We identified a number of chemical residues at lethal or sublethal risk to honeybees based on their average concentrations, as well as primary evidence pertaining to the bio-accumulative propensity of certain substances. Moreover, combinations of pesticide stressors (“pesticide cocktails”), which are frequently encountered in agricultural landscapes, often interact synergistically with honeybee health via detoxification suppression. Finally, we discuss and describe the relevance of novel, biotechnology-based, approaches to counteract agrochemical and PTE poisoning.