Neonicotinoid pesticides are a type of neuro-active insecticides, equivalent in chemical structure to nicotine. The pesticides are used by farmers, in some parts of the world, to kill aphids. This is on the basis that aphids destroy valuable crops. Examples include imidacloprid, thiamethoxam and clothianidin.
In parts of Europe and Canada, restrictions have been placed on the use of neonics. In some parts of the world, including areas of the U.K., the pesticides are used. The reason for the restrictions and controversy around the chemicals is the effect they seem to exert on bee populations. This is to the extent that the pesticides could be contributing to the rapid decline in bee populations around the world (there are other reasons for the decline in bees, such as mite infestations which trigger colony collapse disorder, and climate changes.)
In addition to bees, a new study from Stirling and Sussex universities indicates that the insecticide could also kill butterflies. This is because residues of neonicotinoids can remain in the environment, absorbed by wildflowers growing at the edge of fields. These flowers provide a source of nectar for butterflies and leaves are eaten by caterpillars.
In the study, 15 out of 17 species of butterfly were seen to have declined in areas in the U.K. where the use of the pesticides are permitted. One of the lead researchers, Dr Andre Gilburn, told The Independent newspaper: “Our study not only identifies a worrying link between the use of neonicotinoids and declines in butterflies but also suggests the strength of their impact on many species could be huge.”
The results are published in the journal Peerj, in a paper titled “Are neonicotinoid insecticides driving declines of widespread butterflies?”
Meanwhile, the U.K. parliament is set to debate the issue of neonicotinoids on December 7. This follows a public campaign and a petition that attracted almost 100,000 signatures.
