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Can #micropollutants like human and veterinary drugs affect wildlife behaviour? What are the implications for exposed populations? For my #AnimBehav2021 thread, I’ll be sharing new work uncovering impacts of a potent steroid pollutant on reproductive behaviour in fish 
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Pharmaceuticals have become widespread in ecosystems and organisms around the globe. In fact, more than 600 different drugs have now been detected in the environment, spanning 71 countries and covering all continents ( http://tinyurl.com/yx9y5gt8 ) [2/7] #AnimBehav2021
![Pharmaceuticals have become widespread in ecosystems and organisms around the globe. In fact, more than 600 different drugs have now been detected in the environment, spanning 71 countries and covering all continents ( http://tinyurl.com/yx9y5gt8 ) [2/7] #AnimBehav2021](https://pbs.twimg.com/media/Esp365bXMAAY3U1.jpg "Pharmaceuticals have become widespread in ecosystems and organisms around the globe. In fact, more than 600 different drugs have now been detected in the environment, spanning 71 countries and covering all continents ( http://tinyurl.com/yx9y5gt8 ) [2/7] #AnimBehav2021")
This includes growth-promoting hormones used in agriculture, like trenbolone ( http://tinyurl.com/y4nga4bw ). After implantation, cattle excrete trenbolone metabolites, including 17β-trenbolone (17β-TB), a powerful androgen repeatedly found in freshwater habitats [3/7] #AnimBehav2021
![This includes growth-promoting hormones used in agriculture, like trenbolone ( http://tinyurl.com/y4nga4bw ). After implantation, cattle excrete trenbolone metabolites, including 17β-trenbolone (17β-TB), a powerful androgen repeatedly found in freshwater habitats [3/7] #AnimBehav2021](https://pbs.twimg.com/media/Esp4C1gW4AAEjk0.jpg "This includes growth-promoting hormones used in agriculture, like trenbolone ( http://tinyurl.com/y4nga4bw ). After implantation, cattle excrete trenbolone metabolites, including 17β-trenbolone (17β-TB), a powerful androgen repeatedly found in freshwater habitats [3/7] #AnimBehav2021")
![This includes growth-promoting hormones used in agriculture, like trenbolone ( http://tinyurl.com/y4nga4bw ). After implantation, cattle excrete trenbolone metabolites, including 17β-trenbolone (17β-TB), a powerful androgen repeatedly found in freshwater habitats [3/7] #AnimBehav2021](https://pbs.twimg.com/media/Esp4C15XAAEicMh.jpg "This includes growth-promoting hormones used in agriculture, like trenbolone ( http://tinyurl.com/y4nga4bw ). After implantation, cattle excrete trenbolone metabolites, including 17β-trenbolone (17β-TB), a powerful androgen repeatedly found in freshwater habitats [3/7] #AnimBehav2021")
To test for effects on complex behaviours in wildlife, we exposed male guppies to either an environmental level of 17β-TB or fresh water for 21 days, before testing male mating behaviour towards two sequentially presented large or small unexposed females. [4/7] #AnimBehav2021
![To test for effects on complex behaviours in wildlife, we exposed male guppies to either an environmental level of 17β-TB or fresh water for 21 days, before testing male mating behaviour towards two sequentially presented large or small unexposed females. [4/7] #AnimBehav2021](https://pbs.twimg.com/media/Esp4KrPXMAAiPrz.jpg "To test for effects on complex behaviours in wildlife, we exposed male guppies to either an environmental level of 17β-TB or fresh water for 21 days, before testing male mating behaviour towards two sequentially presented large or small unexposed females. [4/7] #AnimBehav2021")
What did we find? Both 17β-TB and unexposed males conducted more courtship behaviour towards larger females during both female presentations, as expected given the positive association between size and fecundity in guppy females ( http://tinyurl.com/y6x2ey67 ). [5/7] #AnimBehav2021
![What did we find? Both 17β-TB and unexposed males conducted more courtship behaviour towards larger females during both female presentations, as expected given the positive association between size and fecundity in guppy females ( http://tinyurl.com/y6x2ey67 ). [5/7] #AnimBehav2021](https://pbs.twimg.com/media/Esp4R96XEAEZeqK.jpg "What did we find? Both 17β-TB and unexposed males conducted more courtship behaviour towards larger females during both female presentations, as expected given the positive association between size and fecundity in guppy females ( http://tinyurl.com/y6x2ey67 ). [5/7] #AnimBehav2021")
However, we also saw increased ‘sneak’ mating behaviour in 17β-TB males across both female presentations—the first time a pharmaceutical has been shown to alter male reproductive behaviour when encountering females sequentially ( http://tinyurl.com/y689lehp ). [6/7] #AnimBehav2021
![However, we also saw increased ‘sneak’ mating behaviour in 17β-TB males across both female presentations—the first time a pharmaceutical has been shown to alter male reproductive behaviour when encountering females sequentially ( http://tinyurl.com/y689lehp ). [6/7] #AnimBehav2021](https://pbs.twimg.com/media/Esp4Y7XWMAAoBvM.jpg "However, we also saw increased ‘sneak’ mating behaviour in 17β-TB males across both female presentations—the first time a pharmaceutical has been shown to alter male reproductive behaviour when encountering females sequentially ( http://tinyurl.com/y689lehp ). [6/7] #AnimBehav2021")
![However, we also saw increased ‘sneak’ mating behaviour in 17β-TB males across both female presentations—the first time a pharmaceutical has been shown to alter male reproductive behaviour when encountering females sequentially ( http://tinyurl.com/y689lehp ). [6/7] #AnimBehav2021](https://pbs.twimg.com/media/Esp4Y7rXcAMpV0c.jpg "However, we also saw increased ‘sneak’ mating behaviour in 17β-TB males across both female presentations—the first time a pharmaceutical has been shown to alter male reproductive behaviour when encountering females sequentially ( http://tinyurl.com/y689lehp ). [6/7] #AnimBehav2021")
We have shown this effect at a range of 17β-TB levels, when the male and female are exposed, and under male-male competition—likely increasing female harassment and hindering female choice in the wild. More here 
http://michaelbertram.com [7/7] #AnimBehav2021 (Video: @marktbowler)
http://michaelbertram.com [7/7] #AnimBehav2021 (Video: @marktbowler)
