Further confirmation has emerged of the danger that pesticides pose to bees and to biodiversity in general. While awaiting fresh assessments from the European Food Safety Authority, which is expected to rule on the main insecticides currently in use within the first months of 2017, a study published in Scientific Reports today confirms: neonicotinoids, and Imidacloprid in particular, are harmful to the health of bees. Even at very low doses.

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The study, conducted by the Neurophysics Laboratory at the University of Trento, investigates the neurological effects that the world's most widely used pesticide may have on pollinating insects.

Killer pesticides

It has long been known that pesticides have harmful effects on the health of bees. But now, thanks in part to studies carried out by CIMeC and the Department of Physics in Trento, it has been possible to establish how these substances interact with the insects' nervous system, affecting memory and orientation and, for the first time, causing loss of the sense of smell.

"The active ingredients in this type of pesticide are highly neurotoxic: they bind to nicotine receptors at synapses and block the transmission of information at brain level," said Albrecht Haase of CIMeC in a press release. "Our study shows that the damage is found not only in the more advanced, sophisticated functions of the bee brain, but also in the basic, fundamental ones, such as the sense of smell."

Neonicotinoids responsible for loss of the sense of smell

What has been observed over the years is that, despite the use of these pesticides being banned during certain periods of the year, their effects continue to be felt on forager bee populations. This means that the substance remains in the environment even many months later and goes on to impede communication between insects.

"An important communication channel between bees operates chemically, through pheromones," the researcher continues. "Even very small changes linked to a reduction in the sense of smell can seriously compromise the life of a hive, because they affect its social organisation and the colony's reproductive capacity. For example, if information about the queen bee's illness does not reach the colony correctly, the bees will not trigger the mechanisms underlying the production of new queens, and the hive will be destined to collapse."