Effects of agricultural spraying of methyl parathion on cholinesterase activity and reproductive success in wild starlings (Sturnus vulgaris)
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In June 1984, methyl parathion (phosphorothioic acid, O, O‐dimethyl O‐[4‐nitrophenyl] ester) was applied at 1.4 kg a.i./ha to a cultivated field in Skagit Valley, Washington. Brain cholinesterase (ChE) activity was determined in adult and nestling starlings (Sturnus vulgaris) in artificial nesting boxes on the peripheries of a treated and a control field for up to 1 week following application of the pesticide. Brain ChE activities in nestling starlings from the control field increased linearly from age 6 to 19 d. Brain ChE levels in chicks taken from the treated fields were more variable. From the treatment field, 92% of adults collected up to 7 d posttreatment exhibited marked depressions of brain ChE, while during the same period, 29% of the nestlings showed similar responses. A significant correlation was demonstrated between the levels of brain ChE depression in adult and in the nestling starlings collected from the same nests. Measures of reproductive success (i.e., hatching of eggs and fledging of young) were also determined in a portion of the nestboxes to assess any potential adverse effects. The spraying of methyl parathion did not significantly reduce hatchability of the starling eggs. The mean (±SE) number of young fledged per nest on the sprayed field, 2.22 ± 0.29, was not significantly different from that on the control site, 3.33 ± 0.17. However, collectively, the number of nestlings fledging from the treatment field postspray was significantly lower than from the control field. Copyright © 1988 SETAC
author list (cited authors)
Robinson, S. C., Kendall, R. J., Robinson, R., Driver, C. J., & Lacher, T. E.