Commonly used insecticides have been found on wild flowers as well as on crops.

Neonicotinoid pesticides applied to the seeds of some crops end up in the nectar and pollen of adult plants, so the chemicals are a suspected cause of the global decline in bee populations. Because most crops flower only briefly, it was unclear how bees could be exposed to enough pesticide to feel toxic effects. Now Cristina Botías and her colleagues at the University of Sussex in Brighton, UK, show that these chemicals are present in the pollen of wild flowers growing near fields where neonicotinoids were used.

The team measured neonicotinoid levels in pollen sampled from fields of oilseed rape (Brassica napus), nearby wild flowers and local beehives, and estimated that 97% of these compounds that were brought back to beehives originate from wild flowers.

The wild flowers had higher levels of insecticide in their pollen than crop plants did, and they bloom for much longer.

Environ. Sci. Technol. http://doi.org/8bk (2015)