Fluctuating asymmetry in Bobwhite quail chicks (Colinus virginianus) does not follow a predictable dose-response relationship following maternal exposure to four different herbicides

Most biomonitoring studies that have investigated the relationship between fluctuating asymmetry (FA) and anthropogenic stressors have measured organisms from polluted ecosystems and compared them to organisms at reference sites. What has received little attention is whether FA follows a dose-response relationship with stress, a key criterion of a useful biomarker. Using chicks from currently mandated avian reproductive tests we tested whether a composite index of FA (FAC), was related to the dose or duration of exposure of their parents to one of four different herbicides, and if FAC was indeed a more sensitive marker of stress than standard reproductive endpoints measured from this test. We found no consistent relationship between FAC and dose or duration of herbicide exposure in any of the four studies. Exposure to one of the four pesticides did result in significant reproductive toxicity but this was not accompanied or foreshadowed by higher levels of FAC. Our results do not support the hypothesis that FA is a reliable general biomarker of pesticide exposure.