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  • Exposure to a widespread non-pathogenic bacterium magnifies sublethal pesticide effects in the damselfly Enallagma cyathigerum: from the suborganismal level to fitness-related traits.

Exposure to a widespread non-pathogenic bacterium magnifies sublethal pesticide effects in the damselfly Enallagma cyathigerum: from the suborganismal level to fitness-related traits.

Environmental pollution (Barking, Essex : 1987) (2013-03-19)
Lizanne Janssens, Robby Stoks
ABSTRACT

While there is increasing concern that pesticide stress can interact with stress imposed by antagonistic species including pathogens, it is unknown whether this also holds for non-pathogenic bacteria. We exposed Enallagma cyathigerum damselfly larvae to the pesticide chlorpyrifos and a non-pathogenic Escherichia coli strain. Both exposure to chlorpyrifos and E. coli reduced growth rate and fat storage, probably due to the observed energetically costly increases in physiological defence (glutathione-S-transferase and Hsp70) and, for E. coli, immune defence (phenoloxidase). Moreover, these stressors interacted for both fitness-related traits. Most importantly, another fitness-related trait, bacterial load, increased drastically with chlorpyrifos concentration. A possible explanation is that the upregulation of phenoloxidase in the presence of E. coli changed into a downregulation when combined with chlorpyrifos. We argue that the observed interactive, partly synergistic effects between pesticides and widespread non-pathogenic bacteria may be common and deserves further attention to improve ecological risk assessment of pesticides.

MATERIALS
Product Number
Brand
Product Description

Supelco
Chlorpyrifos, certified reference material, TraceCERT®
Supelco
Chlorpyrifos, PESTANAL®, analytical standard