Sex in troubled waters: Widespread agricultural contaminant disrupts reproductive behaviour in fish Michael G. Bertram a, ⁎, Minna Saaristo a,b , John B. Baumgartner c , Christopher P. Johnstone a , Mayumi Allinson d , Graeme Allinson d,e , Bob B.M. Wong a a School of Biological Sciences, Monash University, Victoria, Australia b Department of Biosciences, Åbo Akademi University, Turku, Finland c ARC Centre of Excellence for Environmental Decisions, School of Botany, The University of Melbourne, Victoria, Australia d Centre for Aquatic Pollution Identification and Management (CAPIM), The University of Melbourne, Bio21 Institute, Victoria, Australia e Department of Environment and Primary Industries (DEPI), Victoria, Australia abstract article info Article history: Received 4 October 2014 Revised 11 March 2015 Accepted 13 March 2015 Available online 19 March 2015 Keywords: Endocrine disrupting chemical EDC Hormonal growth promotant 17β-Trenbolone Trenbolone acetate Guppy Poecilia reticulata Behavioural ecotoxicology Sexual selection Reproductive behaviour Chemical pollution is a pervasive and insidious agent of environmental change. One class of chemical pollutant threatening ecosystems globally is the endocrine disrupting chemicals (EDCs). The capacity of EDCs to disrupt de- velopment and reproduction is well established, but their effects on behaviour have received far less attention. Here, we investigate the impact of a widespread androgenic EDC on reproductive behaviour in the guppy, Poecilia reticulata. We found that short-term exposure of male guppies to an environmentally relevant concentration of 17β-trenbolone—a common environmental pollutant associated with livestock production—influenced the amount of male courtship and forced copulatory behaviour (sneaking) performed toward females, as well as the receptivity of females toward exposed males. Exposure to 17β-trenbolone was also associated with greater male mass. However, no effect of female exposure to 17β-trenbolone was detected on female reproductive behaviour, indicating sex-specific vulnerability at this dosage. Our study is the first to show altered male repro- ductive behaviour following exposure to an environmentally realistic concentration of 17β-trenbolone, demon- strating the possibility of widespread disruption of mating systems of aquatic organisms by common agricultural contaminants. © 2015 Elsevier Inc. All rights reserved. Introduction Chemical pollutants have accumulated in ecosystems globally, endan- gering wildlife, ecosystem function and human health (Schwarzenbach et al., 2006). One class of chemical pollutant, known as endocrine disrupting chemicals (EDCs), comprises environmental contaminants with the capacity to disrupt the natural hormonal functioning of organisms (Colborn et al., 1993). Endocrine disruptors are of particular concern given their extreme potency, with exposure to concentrations as low as nanograms per litre having deleterious effects, as well as the propensity of some EDCs to bioaccumulate, persist temporally and act transgenerationally (Diamanti-Kandarakis et al., 2009). Conventionally, studies in ecotoxicology have focussed on direct mortality and chronic sub-lethal effects of EDCs on development and reproduction (Melvin and Wilson, 2013). However, EDCs can also induce alarming changes in behaviour. Indeed, the particular sensitivity of behaviour to EDCs has driven recent interest in behavioural ecotoxicology as a tool for investi- gating endocrine disruption at environmentally relevant pollutant con- centrations (reviewed in Melvin and Wilson, 2013). Existing studies in behavioural ecotoxicology typically focus on EDCs that disrupt gonadal steroid signalling by interacting with vertebrate estrogen or androgen re- ceptors, as chemical interference with this pathway has the potential to disrupt sexual selection (e.g., Saaristo et al., 2009). However, the vast ma- jority of these efforts have concentrated on EDCs with estrogenic activity. This is surprising because the handful of studies that have considered an- drogenic EDCs suggest that they are also capable of markedly altering an- imal behaviour (e.g., Hoffmann and Kloas, 2012). An androgenic EDC of particular concern is 17β-trenbolone, the most bioactive metabolite of trenbolone acetate, a hormonal growth promotant used extensively in livestock production around the world (Kolodziej et al., 2013). Trenbolone acetate is a powerful steroid, with androgenic and anabolic potency 15–50 times greater than testosterone (Kolodziej et al., 2013; Neumann, 1976). Its metabolite 17β-trenbolone acts as a powerful androgen receptor agonist in the environment, is high- ly temporally persistent (with a half-life of approximately 260 days; Hormones and Behavior 70 (2015) 85–91 ⁎ Corresponding author at: School of Biological Sciences, Monash University, Senior Zoology Bldg. 18, Wellington Road, Clayton Campus, Victoria 3800, Australia. E-mail address: michael.g.bertram@monash.edu (M.G. Bertram). http://dx.doi.org/10.1016/j.yhbeh.2015.03.002 0018-506X/© 2015 Elsevier Inc. All rights reserved. Contents lists available at ScienceDirect Hormones and Behavior journal homepage: www.elsevier.com/locate/yhbeh