Beekeepers around the world have been reporting the ongoing weakening of honeybee health and subsequently the increasing colony losses since 1990. However, it was not until the abrupt emergence of colony collapse disorder (CCD) in the 2000s that has raised the concern of losing this important perennial pollinator. In this report, we provide a summary of the sub-lethal effects of pesticides, in particular of neonicotinoids, on pollinators’ health from papers published in peer-review journals.
Solitary bees are frequently exposed to pesticides, which are considered as one of the main stress factors that may lead to population declines. A strong immune defence is vital for the fitness of bees. However, the immune system can be weakened by environmental factors that may render bees more vulnerable to parasites and pathogens.
Leonard et al. (1) presented an interesting approach to limit the impact of pathogens on honeybees by stimulating immunity via engineered symbionts. The urgency to safeguard pollinator services is undoubted. Massive declines in bees, insects in general, pose major concerns for ecosystem stability and food production. However, we see potential pitfalls in such technology driven approaches. Leonard et al. attribute high honeybee colony mortality to the parasitic mite Varroa destructor via synergistic interactions with RNA viruses. However, Varroa is only a significant concern for honeybees.
Bayer verkoopt al zo'n drie decennia zogenaamde neonicotinoïden, een groep insecticiden die het bedrijf ooit heeft uitgevonden. Ze worden ervan verdacht een roemloze rol te spelen in het wereldwijde verlies van bijen en insecten. De EU heeft nu drie van de vijf goedgekeurde neonicotinoïden in Europa verboden en wetenschappers over de hele wereld waarschuwen voor een "ecologisch armageddon". In het coververhaal van tijdschrift NATUR 3/20 ("Toxic Seed") wordt de chemische reus van verschillende kanten beschuldigd kritische wetenschappers en imkers te hebben geïntimideerd.
Our mechanistic understanding of the toxicity of chemicals that target biochemical and/or physiological pathways, such as pesticides and medical drugs is that they do so by binding to specific molecules. The nature of the latter molecules (e.g., enzymes, receptors, DNA, proteins, etc.) and the strength of the binding to such chemicals elicit a toxic effect in organisms, which magnitude depends on the doses exposed in a given timeframe.
Since 2013, a European Union (EU) moratorium has restricted the application of three neonicotinoids to crops that attract bees because of the harmful effects they are deemed to have on these insects. Yet researchers from the CNRS, INRA, and the Institut de l'Abeille (ITSAP) have just demonstrated that residues of these insecticides -- and especially of imidacloprid -- can still be detected in rape nectar from 48% of the plots of studied fields, their concentrations varying greatly over the years.
Neonicotinoid insecticides, also known as neonics, are doing more than killing bees and other insects in record numbers, according to a report issued last month by the Natural Resources Defense Council, an international environmental advocacy group. Neonics, the council says, are contaminating New York State’s soil and water and “hollowing out ecosystems from the bottom up.”
Until the beginning of the 20th century, the British Isles were home to the European Dark Honeybee, which we now usually call the Black Bee. Its Latin name is Apis mellifera mellifera, and it was the dominant honeybee here since the last Ice Age, adapting to our changeable and unpredictable climate and thriving in all kinds of weather alongside our native bumblebees and solitary bees.