Effects of field-relevant concentrations of clothianidin on larval development of the butterfly Polyommatus icarus (Lepidoptera, Lycaenidae)

Basley, Kate and Goulson, Dave (2018) Effects of field-relevant concentrations of clothianidin on larval development of the butterfly Polyommatus icarus (Lepidoptera, Lycaenidae). Environmental Science and Technology, 52 (7). pp. 3990-3996. ISSN 0013-936X

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Abstract

Arable field margins are often sown with wild flowers to encourage pollinators and other beneficial or desirable insects such as bees and butterflies. Concern has been raised that these margins may be contaminated with systemic pesticides such as neonicotinoids used on the adjacent crop, and that this may negatively impact on beneficial insects. The use of neonicotinoids has been linked to butterfly declines, and species such as the common blue butterfly (Polyommatus icarus) that feed upon legumes commonly sown in arable field margins, may be exposed to such toxins. Here, we demonstrate that the larval foodplants of P. icarus growing in an arable field margin adjacent to a wheat crop treated with the neonicotinoid clothianidin, not only contain the pesticide at concentrations comparable to and sometimes higher than those found in foliage of treated crops (range 0.2 to 48 ppb), but remain detectable at these levels for up to 21 months after sowing the crop. Overall, our study demonstrates that non-target herbivorous organisms in arable field margins are likely to be chronically exposed to neonicotinoids. Under laboratory conditions, exposure to clothianidin at 15ppb (a field-realistic dose) or above reduced larval growth for the first 9 days of the experiment. Although there was evidence of clothianidin inducing mortality in larvae, with highest survival in control groups, the dose-response relationship was unclear. Our study suggests that larvae of this butterfly exhibit some deleterious sublethal and sometimes lethal impacts of exposure to clothianidin, but many larvae survive to adulthood even when exposed to high doses.

Item Type: Article
Schools and Departments: School of Life Sciences > Evolution, Behaviour and Environment
Depositing User: David Goulson
Date Deposited: 20 Apr 2018 15:39
Last Modified: 01 Jul 2019 18:16
URI: http://sro.sussex.ac.uk/id/eprint/75296

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