Metal pollutants have additive negative effects on honey bee cognition

Environmental pollutants can exert sublethal deleterious effects on
animals. These include disruption of cognitive functions underlying
crucial behaviours. While agrochemicals have been identified as a major
threat to pollinators, metal pollutants, which are often found in complex
mixtures, have so far been overlooked. Here we assessed the impact of
acute exposure to field-realistic concentrations of three common metal
pollutants, lead, copper, arsenic, and their combinations, on honey bee
appetitive learning and memory. All treatments involving single metals
slowed down learning and disrupted memory retrieval at 24 h. Combinations
of these metals had additive negative effects on both processes,
suggesting common pathways of toxicity. Our results highlight the need to
further assess the risks of metal pollution on invertebrates.