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In recent decades, pyrethroid pesticides have been deemed a safer
alternative to previously used pesticides. While some evidence supports
this assumption in mammals and birds, exposure to certain pyrethroids can
affect concentrations of hormones vital to reproduction in fish. Thus, we
hypothesized that pyrethroid exposure impacts fish reproductive behavior
and the expression of genes associated with reproduction. We tested our
hypothesis by examining effects of the widely used pyrethroid pesticide,
bifenthrin, on the reproductive behaviors of the broadly distributed
livebearing western mosquitofish, Gambusia affinis. We exposed sexually
mature female fish to one of five environmentally relevant concentrations
of bifenthrin and conducted behavioral assays to assess reproductive,
social, and space use behaviors before and after exposure. We did not
detect changes in behaviors measured in response to bifenthrin. However,
exposure was associated with increased expression of an estrogen receptor
gene (ER-α) and glucocorticoid receptor (GR) in brain tissue at bifenthrin
concentrations at concentrations of 5.90 and 24.82 ng/L, and 5.90 and
12.21 ng/L, respectively. Our study supports the perspective that the use
of multiple endpoints through integrative approaches is essential for
understanding the cumulative impact of pollutants. Integrating
physiological, morphological, and behavioral investigations of nonlethal
concentrations of pollutants like bifenthrin may heighten our potential to
predict their impact on individuals, populations, and communities.
238 views reported since publication in 2019.