What’s really behind bee declines? It’s rarely one cause

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Bee decline has long been blamed on one villain — pesticides — but this research shows there are multiple causes at play. “All researchers basically agree now that different things are going on with pollinator decline,” said lead researcher Maryann Frazier. Those include things ranging from loss of habitat/flowers to pesticide exposure, as well as parasites and pathogens.

A major 2014 review paper in the Proceedings of the Royal Society written by 10 scientists identified additional culprits such as invasive species, changes in weather patterns, and increased agricultural intensification. Most notably, they pointed out that pollinator numbers have been decreasing prior to the introduction of neonicotinoids in the 1990s. As such, banning neonicotinoids would probably not result in an immediate return of the bees, they conclude.

One factor considered extremely damaging is the Varroa mite, which can make beehives vulnerable to other pathogens.

Factors can work together too. For example, a 2016 review (Sanchez-Bayo et al) found that “neonicotinoids and some fungicides contribute to the spread and abundance of honey bee pathogens and parasites”. Nutritionaly weak bees are more susceptible to both disease and pesticides – so flowers really do count here.

*Most of this is from honey bee research though, what’s happening with wild bees isn’t as well known…

In short – we need to focus on habitat, reducing pesticide exposures and controlling parasites.

Pollinators are essential to our ecosystem! What can we do as individuals (on our farms) for them?