Large-scale monitoring of effects of clothianidin-dressed oilseed rape seeds on pollinating insects in northern Germany: residues of clothianidin in pollen, nectar and honey

Abstract

This study was part of a large-scale monitoring project to assess the possible effects of Elado® (10 g clothianidin & 2 g β-cyfluthrin/kg seed)-dressed oilseed rape seeds on different pollinators in Northern Germany. Firstly, residues of clothianidin and its active metabolites thiazolylnitroguanidine and thiazolylmethylurea were measured in nectar and pollen from Elado®-dressed (test site, T) and undressed (reference site, R) oilseed rape collected by honey bees confined within tunnel tents. Clothianidin and its metabolites could not be detected or quantified in samples from R fields. Clothianidin concentrations in samples from T fields were 1.3 ± 0.9 μg/kg and 1.7 ± 0.9 μg/kg in nectar and pollen, respectively. Secondly, pollen and nectar for residue analyses were sampled from free flying honey bees, bumble bees and mason bees, placed at six study locations each in the R and T sites at the start of oilseed rape flowering. Honey samples were analysed from all honey bee colonies at the end of oilseed rape flowering. Neither clothianidin nor its metabolites were detectable or quantifiable in R site samples. Clothianidin concentrations in samples from the T site were below the limit of quantification (LOQ, 1.0 µg/kg) in most pollen and nectar samples collected by bees and 1.4 ± 0.5 µg/kg in honey taken from honey bee colonies. In summary, the study provides reliable semi-field and field data of clothianidin residues in nectar and pollen collected by different bee species in oilseed rape fields under common agricultural conditions.

The Environmental Risks of neonicotinoid pesticides: a review of the evidence post-2013

“…Bumblebees collected an average of 68.1% wildflower pollen and 31.9% oilseed rape pollen. Rolke et al (2016) Thiamethoxam was found in this pollen at an average concentration of 18 ng/g and thiacloprid at an average concentration of 2.9 ng/g. These levels are much higher than the levels found in honeybee collected pollen from the same study area in the same year of 3.09 ng/g total neonicotinoids, though a much higher proportion (91.9%) of pollen was collected from wildflowers .…”

“…Similar trends are found in the nectar results, though fewer studies are available. Rolke et al (2016) found neonicotinoid concentrations of 0.68-0.77 ng/ml in honeybee collected nectar samples from apiaries adjacent to neonicotinoid-treated oilseed rape, compared to <0.3 ng/ml from apiaries adjacent to untreated oilseed rape. However, Rundlöf et al (2015) found concentrations of 5.4 ng/ml in bumblebee collected nectar and 10.3 ng/ml in honeybee collected nectar taken from bees originating from nests placed adjacent to treated oilseed rape compared to 0-0.1 ng/ml from bees from nests adjacent to untreated oilseed rape.…”

“…Most of these studies used honeybees, placing apiaries out next to neonicotinoid-treated and untreated crops. As summarised in Section 2.1.1, bees placed near to treated crops collected pollen with higher concentrations of neonicotinoids Rundlöf et al 2015;Long and Krupke 2016;Rolke et al 2016). The highest levels of acute contamination are found when a large proportion of crop pollen is collected.…”

An update of the Worldwide Integrated Assessment (WIA) on systemic insecticides. Part 2: impacts on organisms and ecosystems

“…It should also be noted that all treatments including controls also received fungicide treatments and that different fungicides were used in the three different countries. Rolke et al (2016) carried out a large field study of the effects of clothianidin-dressed oilseed rape on honey bees, finding no adverse effect of treatment on numbers of adult bees or brood, although the study had no replication (only one treated and one control site) and therefore these results should be accorded little weight. Wegener et al (2016) have measured 28 biochemical, biometrical, and behavioral aspects of honeybees (A. mellifera) to investigate the effect of imidacloprid and fenoxycarb on colony productivity and survival.…”

Pesticide exposure affects flight dynamics and reduces flight endurance in bumblebees

“…However, neonicotinoids have been implicated as a threat to eusocial bees (Gill et al, 2012;Goulson, 2013;Lundin, Rundlöf, Smith, Fries, & Bommarco, 2015;Tsvetkov et al, 2017;Whitehorn, O'Connor, Wackers, & Goulson, 2012;Woodcock et al, 2017). Foraging eusocial bees are frequently exposed to neonicotinoids in treated landscapes (Botías, David, Hill, & Goulson, 2017;Botías et al, 2015;David et al, 2016;Mitchell et al, 2017;Rolke, Persigehl, Peters, Sterk, & Blenau, 2016), and controlled exposure experiments have demonstrated impaired homing ability (Fischer et al, 2014) and foraging efficiency of workers, including longer foraging trips and reduced rate of pollen collection (Feltham, Park, & Goulson, 2014;Gill & Raine, 2014;Stanley & Raine, 2016). A possible explanation for these reported impairments is that certain aspects of foraging flight dynamics, such as endurance and speed, are affected by neonicotinoid exposure.…”