Burrowing in the Freshwater MusselElliptio complanatais Sexually Dimorphic and Feminized by Low Levels of Atrazine

Abstract

The widely used herbicide atrazine (ATR) may have endocrine-associated adverse effects, including on behavior. In this study, 120 adult freshwater mussels, Elliptio complanata, were exposed to ATR at the environmentally-relevant concentrations of 1.5, 15, or 150 μg/L. Burrowing depth was evaluated hourly for 6 hr and at sacrifice animals were sexed by gonad smear. Female controls burrowed overall approximately 30% less than males, the first report of sexual dimorphism in this behavior. Atrazine at 15 μg/L feminized burrowing in both sexes in that exposed animals burrowed 20% less than their same sex controls. Males treated with 1.5 μg /L ATR displayed approximately 20-fold higher vitellogenin (VTG) levels than same sex controls. Higher concentrations of ATR were not associated with increasing effects. A scatterplot showed a weak binomial curve associating low burrowing with high VTG levels. Taken together, these data suggest a non-linear dose-response in behavioral and physiological feminization produced by ATR and support the need to reconsider the widespread use of this compound.

Use of a suite of biomarkers to assess the effects of carbamazepine, bisphenol A, atrazine, and their mixtures on green mussels, Perna viridis

“…Our findings are similar to those of Quinn et al [41], who reported vitellogenin induction in both sexes of freshwater mussels (Dreissena polymorpha) after exposure to municipal effluents containing a mixture of endocrine-disrupting chemicals including BPA. Vitellin-like proteins' induction was also observed in both sexes of organisms exposed to ATZ at concentrations 10-fold higher than environmental levels, confirming the observations of Flynn et al [42] with the freshwater mussel, Elliptio complanata, exposed to ATZ at 1.5 mg/L. The mechanisms by which BPA disturbs invertebrate reproductive and endocrine systems remain unknown [43], but the poor ability of male mussels to clear vitellin-like protein could lead to an accumulation to concentrations that have adverse health effects and may ultimately compromise their reproduction or lead to a higher incidence of hermaphroditism in exposed populations.…”

Deciphering the Link between Doubly Uniparental Inheritance of mtDNA and Sex Determination in Bivalves: Clues from Comparative Transcriptomics

“…2008 ; Zieritz and Aldridge 2011 ; Haag 2012 ). Interestingly, sexual dimorphism in burrowing behavior has also been reported in the freshwater mussel DUI species Elliptio complanata ( Flynn et al. 2013 ).…”

Is altered behavior linked to cellular energy regulation in a freshwater mussel (Elliptio complanata) exposed to triclosan?

“…In our case, we used this modeling approach to describe intensity of burrowing and movement following TCS exposure. This approach to analyzing mussel behavioral data is appropriate because some individuals did not conduct behaviors during the study duration and therefore the data are considered right-censored, which the proportional hazard model accommodates (see Waller et al, 1999;Hazelton et al, 2014); the alternative approach is to remove non-responding individuals from the dataset and use a group means statistical test (e.g., Flynn et al, 2013). The parameter estimates are generated as a proportional likelihood of an event occurring relative to the control group.…”