School of Biological Sciences, Monash University, Victoria, Australia.
School of Biological Sciences, Monash University, Victoria, Australia.
Environ Pollut. 2018 Jul;238:238-247. doi: 10.1016/j.envpol.2018.03.006. Epub 2018 Mar 20.
Contamination of aquatic habitats with pharmaceuticals is a major environmental concern. Recent studies have detected pharmaceutical pollutants in a wide array of ecosystems and organisms, with many of these contaminants being highly resistant to biodegradation and capable of eliciting sub-lethal effects in non-target species. One such pollutant is fluoxetine, a widely prescribed antidepressant, which is frequently detected in surface waters globally and can alter physiology and behaviour in aquatic organisms. Despite this, relatively little is known about the potential for fluoxetine to disrupt mechanisms of sexual selection. Here, we investigate the impacts of 30-day exposure to two environmentally realistic levels of fluoxetine (low and high) on mechanisms of pre- and post-copulatory sexual selection in the eastern mosquitofish (Gambusia holbrooki). We tested 1) male mating behaviour in the absence or presence of a competitor male, and 2) sperm quality and quantity. We found that high-fluoxetine exposure increased male copulatory behaviour in the absence of a competitor, while no effect was detected under male-male competition. Further, fluoxetine exposure at both concentrations increased total sperm count relative to males from the control group, while no significant change in sperm quality was observed. Lastly, low-fluoxetine males showed a significant reduction in condition index (mass relative to length). Our study is the first to show altered mechanisms of both pre- and post-copulatory sexual selection in an aquatic species resulting from environmentally realistic fluoxetine exposure, highlighting the capacity of pharmaceutical pollution to interfere with sensitive reproductive processes in wildlife.
水生栖息地受到药物污染是一个主要的环境问题。最近的研究在广泛的生态系统和生物中检测到药物污染物，其中许多污染物具有很强的抗生物降解性，并能对非目标物种产生亚致死效应。其中一种污染物是氟西汀，一种广泛使用的抗抑郁药，它在全球范围内的地表水经常被检测到，并且可以改变水生生物的生理和行为。尽管如此，对于氟西汀是否有可能破坏性选择机制，人们知之甚少。在这里，我们研究了 30 天暴露于两种环境现实水平的氟西汀（低和高）对东部食蚊鱼（Gambusia holbrooki）的预交配和交配后性选择机制的影响。我们测试了 1）在没有或存在竞争雄性的情况下雄性的交配行为，以及 2）精子质量和数量。我们发现，高氟西汀暴露增加了雄性在没有竞争雄性的情况下的交配行为，而在雄性竞争的情况下则没有检测到这种影响。此外，两种浓度的氟西汀暴露都增加了总精子数，与对照组的雄性相比，而精子质量没有明显变化。最后，低氟西汀雄性的条件指数（相对于长度的质量）显著降低。我们的研究首次表明，由于环境现实的氟西汀暴露，水生物种的交配前和交配后性选择机制发生了改变，这突出了药物污染干扰野生动物敏感繁殖过程的能力。
