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Abstract

Hormonal growth promoters (HGPs), widely used in beef cattle production globally, make their way into the environment as agricultural effluent—with potential impacts on aquatic ecosystems. One HPG of particular concern is 17β-trenbolone, which is persistent in freshwater habitats and can affect the development, morphology and reproductive behaviors of aquatic organisms. Despite this, few studies have investigated impacts of 17β-trenbolone on non-reproductive behaviors linked to growth and survival, like boldness and predator avoidance. None consider the interaction between 17β-trenbolone and other environmental stressors, such as temperature, although environmental challenges confronting animals in the wild seldom, if ever, occur in isolation. Accordingly, this study aimed to test the interactive effects of trenbolone and temperature on organismal behavior. To do this, eastern mosquitofish (Gambusia holbrooki) were subjected to an environmentally-relevant concentration of 17β-trenbolone (≤5.1 ± 0.5 ng/L) or freshwater (i.e. control) for 21 days under one of two temperatures (20 and 30 °C), after which the predator escape, boldness and exploration behavior of fish were tested. Predator escape behavior was assayed by subjecting fish to a simulated predator strike, while boldness and exploration were assessed in a separate maze experiment. We found that trenbolone exposure increased boldness behavior. Interestingly, some behavioral effects of trenbolone depended on temperature, sex, or both. Specifically, significant effects of trenbolone on male predator escape behavior were only noted at 30 °C, with males becoming less reactive to the simulated threat. Further, in the maze experiment, trenbolone-exposed fish explored the maze faster than control fish, but only at 20 °C. We conclude that field detected concentrations of 17β-trenbolone can impact ecologically important behaviors of fish, and such effects can be temperature dependent. Such findings underscore the importance of considering the potentially interactive effects of other environmental stressors when investigating behavioral effects of environmental contaminants.

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... Several characteristics of 17β-TB make its presence in the environment particularly concerning. This includes that 17β-TB is highly temporally persistent (half-life in effluent:~260 days; Schiffer et al., 2001), is rapidly taken up by, and can be bioconcentrated in, various fish species (Ankley et al., 2003;Schultz et al., 2013;Lagesson et al., 2019), and affects androgen receptor signalling pathways that are evolutionarily conserved across diverse taxa (McGinnis et al., 2002). A large body of evidence now exists suggesting that field-realistic levels of 17β-TB are sufficient to cause adverse biological effects in a wide variety of aquatic species (e.g. ...
... Larsen and Baatrup, 2010). Furthermore, relatively recent research has uncovered that exposure to 17β-TB at environmentally realistic levels can alter a range of key fitness-related behaviours in aquatic species, including activity and exploration (Bertram et al., 2018a;Lagesson et al., 2019), feeding and foraging (Bertram et al., 2018a), sociability (Bertram et al., 2018a), risktaking behaviour (Heintz et al., 2015;Lagesson et al., 2019), and reproductive behaviour (Saaristo et al., 2013;Bertram et al., 2015;Tomkins et al., 2016Tomkins et al., , 2017Bertram et al., 2018b;Tomkins et al., 2018). ...
... Larsen and Baatrup, 2010). Furthermore, relatively recent research has uncovered that exposure to 17β-TB at environmentally realistic levels can alter a range of key fitness-related behaviours in aquatic species, including activity and exploration (Bertram et al., 2018a;Lagesson et al., 2019), feeding and foraging (Bertram et al., 2018a), sociability (Bertram et al., 2018a), risktaking behaviour (Heintz et al., 2015;Lagesson et al., 2019), and reproductive behaviour (Saaristo et al., 2013;Bertram et al., 2015;Tomkins et al., 2016Tomkins et al., , 2017Bertram et al., 2018b;Tomkins et al., 2018). ...
Article
Pharmaceutical contaminants are being detected with increased frequency in organisms and ecosystems worldwide. This represents a major environmental concern given that various pharmaceuticals act on drug targets that are evolutionarily conserved across diverse taxa, are often persistent in the environment, and can bioconcentrate in organisms and bioaccumulate in food chains. Despite this, relatively little is known about the potential for pharmaceutical contaminants to affect animal behaviour, especially across multiple fitness-related contexts. Here, we investigated impacts of 21-day exposure of wild-caught male eastern mosquitofish (Gambusia holbrooki) to a field-realistic level of the veterinary pharmaceutical 17β-trenbolone—a growth-promoting steroid used extensively in beef production worldwide and a potent androgenic endocrine disruptor repeatedly detected in surface waters affected by livestock effluent run-off. First, we examined male boldness, activity, and exploratory behaviour in a novel environment (maze arena) and found no significant effect of 17β-trenbolone exposure. Second, the same males were tested in a reproductive assay for their tendency to associate with a stimulus (unexposed) female behind a partition. Exposed males exhibited reduced association behaviour, taking longer to first associate with, and spending less time within close proximity to, a female. Third, all males were assayed for sperm function (computer-assisted sperm analysis, sperm viability) or quantity (total sperm count) and, although no significant main effects of 17β-trenbolone were seen on sperm traits, exposure altered the relationship between male morphology and sperm function. Lastly, morphological traits were assessed and exposed males were found to have, on average, increased mass relative to length. In combination, these results demonstrate that exposure to a field-realistic level of 17β-trenbolone can produce subtle but important trait alterations in male fish—including context-specific behavioural changes, disruption of key sperm function trade-offs, and altered morphology—with potential impacts on exposed wildlife.
... Given the widespread use of TBA, 17β-TB has repeatedly been detected in environments impacted by livestock operations (reviewed in Ankley et al., 2018), including in manure (0.5-4.3 μg/kg; Schiffer et al., 2001), soil (0.5-6.1 μg/kg; Schiffer et al., 2001;Webster et al., 2012), feedlot run-off and lagoon water (0.0015-270 ng/L; Schiffer et al., 2001;Soto et al., 2004;Durhan et al., 2006;Bartelt-Hunt et al., 2012;Khan and Lee, 2012;Parker et al., 2012;Webster et al., 2012), and dilute river water (0.0013-20 ng/L; Soto 2004; Durhan et al., 2006). This is worrying given that 17β-TB is temporally persistent (half-life:~260 days in effluent; Schiffer et al., 2001), can bioconcentrate and bioaccumulate in aquatic species (Ankley et al., 2003;Lagesson et al., 2019), and is known to affect androgen receptor signalling pathways at low environmentally realistic exposure concentrations. A large body of research has demonstrated that 17β-TB exposure causes changes in endocrine function (e.g. ...
... skewed sex ratios, impacts on fertility and fecundity) (reviewed in Ankley et al., 2018). Furthermore, over the last five years, it has been revealed that exposure to 17β-TB can disrupt a range of key behaviours in non-target species, including activity and exploratory behaviour (Bertram et al., 2018a;Lagesson et al., 2019), foraging (Bertram et al., 2018a), shoaling (Bertram et al., 2018a), boldness (Lagesson et al., 2019), risk-taking (Heintz et al., 2015), and mating behaviour (Saaristo et al., 2013;Bertram et al., 2015Bertram et al., , 2018bBertram et al., , 2019Tomkins et al., 2016Tomkins et al., , 2017. Such disturbances can drastically alter fitness (reviewed in Saaristo et al., 2018), particularly when reproductive behaviours are affected (reviewed in Candolin and Wong, 2019). ...
... skewed sex ratios, impacts on fertility and fecundity) (reviewed in Ankley et al., 2018). Furthermore, over the last five years, it has been revealed that exposure to 17β-TB can disrupt a range of key behaviours in non-target species, including activity and exploratory behaviour (Bertram et al., 2018a;Lagesson et al., 2019), foraging (Bertram et al., 2018a), shoaling (Bertram et al., 2018a), boldness (Lagesson et al., 2019), risk-taking (Heintz et al., 2015), and mating behaviour (Saaristo et al., 2013;Bertram et al., 2015Bertram et al., , 2018bBertram et al., , 2019Tomkins et al., 2016Tomkins et al., , 2017. Such disturbances can drastically alter fitness (reviewed in Saaristo et al., 2018), particularly when reproductive behaviours are affected (reviewed in Candolin and Wong, 2019). ...
... Ankley et al., 2003;Baumann et al., 2014;Bertram et al., 2019;Ye et al., 2014), as well as changes in anxiety-related behaviours seen in fish species (e.g. Heintz et al., 2015;Lagesson et al., 2018). ...
... 5.1.5; open source physics, USA), adapted from previously established protocols (Lagesson et al., 2018;Martin et al., 2017). Tadpoles were tracked at 1 fps and, from this, the total distance each tadpole moved was calculated, using 1 cm gridlines marked on the inside of the respirometry tank as a distance calibration. ...
... In the present study, we did not detect a significant effect of 17βtrenbolone on the anxiety-related behaviour of tadpoles. This contrasts with past studies that have uncovered effects of 17β-trenbolone exposure on the behaviour of non-target species, with the majority of this research focusing on reproductive behaviours of fish (Bertram et al., 2015;Bertram et al., 2019;Bertram et al., 2020;Heintz et al., 2015;Lagesson et al., 2018;Tan et al., 2021;Tomkins et al., 2017;Tomkins et al., 2018). Indeed, as far as we are aware, only four studies have investigated the impacts of 17β-trenbolone pollution on anxiety-related endpoints of non-target species, all of which have been in fish (Bertram et al., , 2019Heintz et al., 2015;Lagesson et al., 2018). ...
Article
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Globally, amphibian species are experiencing dramatic population declines, and many face the risk of imminent extinction. Endocrine-disrupting chemicals (EDCs) have been recognised as an underappreciated factor contributing to global amphibian declines. In this regard, the use of hormonal growth promotants in the livestock industry provides a direct pathway for EDCs to enter the environment—including the potent anabolic steroid 17β-trenbolone. Emerging evidence suggest that 17β-trenbolone can impact traits related to metabolism, somatic growth, and behaviour in non-target species. However, far less is known about possible effects of 17β-trenbolone on anuran species, particularly during early life stages. Accordingly, in the present study we investigated the effects of 28-day exposure to 17β-trenbolone (mean measured concentrations: 10 and 66 ng/L) on body size, body condition, metabolic rate, and anxiety-related behaviour of tadpoles (Limnodynastes tasmaniensis). Specifically, we measured rates of O2 consumption of individual tadpoles as a proxy for metabolic rate and quantified their swimming activity and their time spent in the upper half of the water column as indicators of anxiety-related behaviour. Counter to our predictions based on effects observed in other taxa, we detected no effect of 17β-trenbolone on body size, metabolic rate, or behaviour of tadpoles; although, we did detect a subtle, but statistically significant decrease in body condition at the highest 17β-trenbolone concentration. We hypothesize that 17β-trenbolone may induce taxa-specific effects on metabolic function, growth, and anxiety-related behaviour, with anurans being less sensitive to disruption than fish, and encourage further cross-taxa investigation to test this hypothesis.
... Environmental concentrations of 17β-TB typically range from 0.0015 to 270 ng/L in feedlot run-off and lagoon water (Bartelt-Hunt et al., 2012;Challis et al., 2021;Durhan et al., 2006;Khan and Lee, 2012;Parker et al., 2012;Schiffer et al., 2001;Soto et al., 2004;Webster et al., 2012), and 0.0013 to 20 ng/L in lake and river water (Durhan et al., 2006;Soto et al., 2004;Zhou et al., 2016). Upon exposure, 17β-TB has been shown to rapidly bioaccumulate in fish (Ankley et al., 2003;Lagesson et al., 2019;Schultz et al., 2013). Notable effects of 17β-TB exposure on animals observed in past studies include alteration of sex ratios towards a greater proportion of males, increases in growth, impacts on fertility and fecundity, and changes in gonadal histopathology (reviewed in Ankley et al., 2018). ...
... Notable effects of 17β-TB exposure on animals observed in past studies include alteration of sex ratios towards a greater proportion of males, increases in growth, impacts on fertility and fecundity, and changes in gonadal histopathology (reviewed in Ankley et al., 2018). Moreover, recent studies have demonstrated that 17β-TB can also disrupt key behaviours such as activity and exploration (Bertram et al., 2018c;Lagesson et al., 2019), foraging (Bertram et al., 2018c), sociality (Bertram et al., 2018c), boldness (Heintz et al., 2015;Lagesson et al., 2019), risk-taking (Heintz et al., 2015;Lagesson et al., 2019), and sexual behaviours (Bertram et al., 2019;Bertram et al., 2015;Bertram et al., 2018b;Bertram et al., 2020;Saaristo et al., 2013;Tomkins et al., 2016;Tomkins et al., 2018;Tomkins et al., 2017). Because 17β-TB is expected to induce effects primarily by activating the androgen receptor (Ankley et al., 2018), it is likely that reproductive traits are one of the most sensitive biological endpoints affected by exposure. ...
... Notable effects of 17β-TB exposure on animals observed in past studies include alteration of sex ratios towards a greater proportion of males, increases in growth, impacts on fertility and fecundity, and changes in gonadal histopathology (reviewed in Ankley et al., 2018). Moreover, recent studies have demonstrated that 17β-TB can also disrupt key behaviours such as activity and exploration (Bertram et al., 2018c;Lagesson et al., 2019), foraging (Bertram et al., 2018c), sociality (Bertram et al., 2018c), boldness (Heintz et al., 2015;Lagesson et al., 2019), risk-taking (Heintz et al., 2015;Lagesson et al., 2019), and sexual behaviours (Bertram et al., 2019;Bertram et al., 2015;Bertram et al., 2018b;Bertram et al., 2020;Saaristo et al., 2013;Tomkins et al., 2016;Tomkins et al., 2018;Tomkins et al., 2017). Because 17β-TB is expected to induce effects primarily by activating the androgen receptor (Ankley et al., 2018), it is likely that reproductive traits are one of the most sensitive biological endpoints affected by exposure. ...
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It is now well-established that reproduction in wildlife can be disrupted by anthropogenic environmental changes, such as chemical pollution. However, very little is known about how these pollutants might affect the interplay between pre- and post-copulatory mechanisms of sexual selection. Here, we investigated the impacts of 21-day exposure of male eastern mosquitofish (Gambusia holbrooki) to a field-realistic level (average measured concentration: 11 ng/L) of the endocrine-disrupting chemical 17β-trenbolone (17β-TB) on pre- and post-copulatory reproductive traits. We examined male reproductive behaviour by testing the time spent near a female behind a partition, as well as the number of copulation attempts made, and the time spent chasing a female in a free-swimming context. Sperm traits were also assayed for all males. We found that exposure of male fish to 17β-TB altered the relationship between key pre- and post-copulatory reproductive traits. Furthermore, 17β-TB-exposed males had, on average, a higher percentage of motile sperm, and performed fewer copulation attempts than unexposed males. However, there was no overall effect of 17β-TB exposure on either the time males spent associating with or chasing females. Taken together, our findings demonstrate the potential for chemical pollutants to affect both pre- and post-copulatory sexual traits, and the interplay between these mechanisms of sexual selection in contaminated wildlife.
... Still, alteration of fish behavior due to contaminant exposure has been identified as a potential driver of ecosystem change . Fish behaviors are not only changing in response to traditional metal pollutants but also in response to a variety of anthropogenic stressors such as microplastics (McCormick et al., 2020), other emerging contaminants Dzieweczynski et al., 2016;Lagesson, Saaristo, et al., 2018;Vignet et al., 2015), elevated temperature (Biro et al., 2010;Briffa et al., 2013;Závorka et al., 2020), acidification (Nilsson et al., 2012), acoustic emissions (McCormick et al., 2018;Mills et al., 2020;Nedelec et al., 2017;Sabet et al., 2015), release of hatchery reared individuals (Roberts et al., 2011) and selective harvesting of bold and more exploratory individuals (Biro & Post, 2008). While various forms of fish and behavioral trials have been used in these studies, they all have in common that they show that anthropogenic stressors can affect fish's boldness (Figure 1), a personality trait that affects predation risk and therefore fitness (Lind & Cresswell, 2005;Smith & Blumstein, 2008). ...
... Here, the fish can become either bolder (and exploratory) or shyer (less willing to take risks) depending on stressors. While pharmaceutical contaminants (anxiolytics, antidepressants and hormones) generally are believed to act via their therapeutic mode of action Dzieweczynski et al., 2016;Lagesson, Saaristo, et al., 2018), increased boldness in response to reduced pH is both caused by reduced ability to recognize predators cues at low pH values (Brown et al., 2012) and direct pH impacts on the GABAa receptor in the nervous system (Nilsson et al., 2012). Note that the importance of pH-driven behavior changes has recently been questioned (Clark et al., 2020). ...
Article
Modified fish behaviors in response to anthropogenic stressors, such as chemicals, microplastics, acoustic emissions and fisheries, are a debated driver of change in freshwater ecosystems and oceans. Our ability to judge the severity of observed behavioral responses is hampered by limited knowledge regarding how subtle behavior modifications in prey fish affect ecosystems. Here we show that anthropogenic stressors affecting fish boldness, are not expected to cause population collapse, but rather elusive effects on fish length, population biomass, reproduction and ecosystem state shifts. We use a physiologically structured population model (three trophic levels), well fed with empirical data, to simulate how previously suggested alterations of fish boldness traits due to anthropogenic stressors affect ecosystem structure. Our results suggest that these stressors may cause ecosystem structure effects, such as skewed size distributions, reduced fish biomass and reduced reproduction success, by altering the foraging behavior of fish. However, the specific structure effects depend on where the boldness‐shyness continuum change occurs and on the species‐specific life‐stages. The model also highlights somewhat counterintuitive effects leading to possible extinction of predators when the foraging behavior of the prey is hampered. We conclude that anthropogenic forcing of fish behavior may be a hidden mechanism behind ecosystem structure changes in both freshwater and marine ecosystems.
... These useful compounds yet harmful can be toxic to the environment especially when found in concentrations that have the potential to target and adversely affect humans and animals. Pharmaceuticals are complex molecules with different physiochemical and biological properties, which makes them ideal to be used for the specific activity they perform in the body (Jelic et al., 2011;Lagesson et al., 2019;Pereira et al., 2015). There have been over 3,000 various active pharmaceutical substances with more than 200 compounds already identified as contaminants (Deblonde et al., 2011;Mackulak et al., 2019). ...
... There have been over 3,000 various active pharmaceutical substances with more than 200 compounds already identified as contaminants (Deblonde et al., 2011;Mackulak et al., 2019). These substances identified include antibiotics, anti-inflammatory, anti-epileptics, anti-diabetics, antihistamines, cardiovascular drugs, hormones and nonsteroidal substances (Binh et al., 2018;Fekadu et al., 2019;Lagesson et al., 2019;Mackulak et al., 2017;Terechovs et al., 2019). These substances when in contact with other chemical substances in the environment have the potential to cause synergistic acute and chronic toxic effects (Cui et al., 2019;Frédéric and Yves, 2014;Kümmerer et al., 2019). ...
Article
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Pharmaceuticals and personal care products are now known as microcontaminants due to their effects on bacterial resistance and effect on non-targeted organisms. Most recently, these substances have been found in surface water, sewage, hospital and care home wastewaters and landfill. Pharmaceuticals have been known to pose acute and chronic effects especially when exposed at higher concentrations and for longer durations. This study adopted the spectrophotometric method to assess the acute and chronic effects of seven pharmaceuticals on Bacillus subtilis bacteria. The effects were observed in terms of the conversion of 3-(4.5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)- 2-(4-sulfophenyl)-2H-tetrazolium, inner salt; (MTS) to a colored formazan product. The effect of pharmaceuticals was measured as a reduction of tetrazolium solution and expressed as percentage. The results indicate that both acute and chronic effects exist with Bezafibrate, Diclofenac, Diatrizoate, Ibuprofen and Atenolol inhibiting bacterial growth at 50 μg/ml. Consequently, at 500 μg/ml, all the pharmaceuticals inhibited growth thereby posing acute effects. In addition, all the eight pharmaceutical substances tested inhibited bacterial growth at 50 μg/ml and 500 μg/ml when exposed to pharmaceuticals for more than 24 h. The implication is that wastewater from hospitals can likely inhibit biological process of breaking waste in the wastewater treatment plants.
... Many studies have reported a decrease in sex hormone synthesis and/or plasma steroid concentrations in fish of both sexes exposed to 17b-TBOH (Ankley et al., 2003;Zhang et al., 2008;Garcia-Reyero et al., 2009;Ekman et al., 2011;Schultz et al., 2013;Massart et al., 2015). In addition, 17b-TBOH changes the sexually dimorphic behaviours of fish (Tomkins et al., 2017;Lagesson et al., 2019). However, little is known about the biological effects of 17b-TBOH on mammals. ...
Article
17β-Trenbolone (17β-TBOH) is an endocrine disruptor that has been widely reported in aquatic organisms. However, little is known about the effect of 17β-TBOH on mammals, particularly on the development of adolescents. Through a series of behavioural experiments, exposure to at 80 μg kg -1 d -1 and 800 μg kg -1 d -1 17β-TBOH during puberty (from PND 28 to 56, male mice) increased anxiety-like behaviours. Exposure to the low dose of 80 μg kg -1 d -1 resulted in a clear social avoidance behaviour in mice. The two doses affected testicular development and endogenous androgen synthesis in male mice. In addition, 17β-TBOH exposure altered the differentiation of oligodendrocytes and the formation of the myelin sheath in the medial prefrontal cortex (mPFC). These results reveal the effects of 17β-TBOH on the behaviours, gonadal and neurodevelopment of adolescent mammals. In addition, the inhibition of the secretion of endogenous hormones and decrease in the formation of the myelin sheath in mPFC may be associated with the 17β-TBOH-induced behavioural changes in mice.
... These factors have drastically altered not only the natural habitats of many native species, but also their behaviour responses, development and reproduction. For example, 17b-trenbolone, a highly potent endocrine disruptor with androgen-mimicking activity, is commonly used as a hormonal growth promoter in the beef industry (Lagesson et al. 2019). This chemical enters aquatic ecosystems via livestock effluent run-off and alters the course of reproduction and sexual selection in freshwater fish. ...
Article
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The 2019 meeting of the Society for Reproductive Biology (SRB) provided a platform for the dissemination of new knowledge and innovations to improve reproductive health in humans, enhance animal breeding efficiency and understand the effect of the environment on reproductive processes. The effects of environment and lifestyle on fertility and animal behaviour are emerging as the most important modern issues facing reproductive health. Here, we summarise key highlights from recent work on endocrine-disrupting chemicals and diet- and lifestyle-induced metabolic changes and how these factors affect reproduction. This is particularly important to discuss in the context of potential effects on the reproductive potential that may be imparted to future generations of humans and animals. In addition to key summaries of new work in the male and female reproductive tract and on the health of the placenta, for the first time the SRB meeting included a workshop on endometriosis. This was an important opportunity for researchers, healthcare professionals and patient advocates to unite and provide critical updates on efforts to reduce the effect of this chronic disease and to improve the welfare of the women it affects. These new findings and directions are captured in this review.
... Therefore, as with previously published ecotoxicological studies (e.g. Bertram et al., 2018a;Bertram et al., 2018b;Lagesson et al., 2019;Martin et al., 2017;Saaristo et al., 2019;Sundin et al., 2019), fish were not exposed to fluoxetine during experimental trials. The respirometry chambers had three holes in the lid to accommodate inflow and outflow tubing (3 mm diameter) and an oxygen probe (Oxygen Dipping Probe DP-PSt7; PreSens Precision Sensing GmbH). ...
... 17b-trenbolone exposed influenced courtship behavior (Bertram et al., 2015;Tomkins et al., 2017) and mating behavior (Bertram et al., 2015(Bertram et al., , 2018aTomkins et al., 2018). Besides, 17b-trenbolone disturbed activity and exploration of a novel environment (Bertram et al., 2018b;Lagesson et al., 2019), feeding and foraging behaviors (Bertram et al., 2018b), sociability (Bertram et al., 2018b), boldness and risk-taking (Heintz et al., 2015). However, what might be the consequences of 17btrenbolone on the development and behavior of zebrafish embryos and larvae are seldom studied. ...
Article
17β-trenbolone (17β-TBOH) is one of the dominant metabolites of trenbolone acetate, which is widely applied in beef cattle operations around the globe. The effects of environmental concentrations of 17β-trenbolone on the early development of zebrafish embryos have received very little attention. Melatonin could regulate sleep-wake cycle and plays a protective role in various adverse conditions. Here, environmentally realistic concentrations of 17β-trenbolone (1 ng/L, 10 ng/L, 50 ng/L) has been exposure to zebrafish embryos at 2 h postfertilization (hpf). The results showed that 10 ng/L and 50 ng/L 17β-trenbolone disturbed the distribution of caudal primary motoneurons and downregulated expression of motoneuron development related genes along with locomotion decreasing. While melatonin could recover the detrimental effects caused by 17β-trenbolone. Interestingly, 17β-trenbolone exposure increased waking activity and decreased rest even in a low dose (1 ng/L). Moreover, it upregulated hypocretin/orexin (Hcrt) signaling which promotes wakefulness. Melatonin restored the insomnia-like alternation induced by 17β-trenbolone exposure. Collectively, we conclude that 17β-trenbolone disturbed motoneuron development and altered sleep/wake behavior, while melatonin could alleviate the deleterious influence on motoneuron development and recover the circadian rhythm.
... 30,46,47 We predicted, instead, that activity increases with temperature. 48 ■ MATERIALS AND METHODS Study Species. The guppy is a small poeciliid fish native to freshwaters of northern South America. ...
... From an ecotoxicological perspective, steroids are strongly associated with endocrine disrupting effects. As such many steroids have shown to interact with the endocrine system of fish at very low concentrations (often below 1 ng L -1 ) and cause deleterious effects on fish populations [118,125,126]. In a risk-based prioritization of pharmaceuticals for the aquatic environment, E2 and diclofenac were scored with a risk > 1 and > 10, respectively for chronic risks in the aquatic environment [127]. ...
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Along with a worldwide growth of the human population, the aquatic environment on our planet is facing an ever increasing chemical input. With the aim of regulating chemical use and protecting both humans and the environment a number of regulatory frameworks for chemicals have been introduced in the European Union (EU). Yet, these regulations mainly focus on a limited list of priority pollutants that represent only a minor fraction of potentially water-emitted chemicals. In addition, even though there exist regulatory frameworks for the marine environment, risk assessment for the latter does not require ecotoxicity data for marine species. To partly address the herewith associated ecotoxicity data gap for marine species, in the present work, marine ecotoxicity data was generated for a total of 23 chemicals of emerging concern (CECs) with two species representing algae and crustacean (Chapter 4). While algae did show low sensitivity to all tested substances, relatively low effect concentrations on crustacean were found for 4 neonicotinoid insecticides. Acute and sub-chronic ecotoxicity data for crustacean was subsequently used together with existing literature data to derive Environmental Quality Standards (EQS) for the marine environment. Inclusion of the marine copepod data from this study led to a refinement of the EQS for clothianidin and thiamethoxam. An in-depth risk assessment for the Belgian part of the North Sea (BPNS) based on the derived EQS for the 4 neonicotinoid insecticides and their mixture (Chapter 4) resulted in an exceedance of predicted no-effect concentrations (PNECs) in the harbors of Ostend and Zeebrugge and a low margin of safety (MoS) for one coastal locations in front of each of these harbors. Such derivation of EQS and risk assessments are time-intensive processes that require in-depth ecotoxicological and regulatory knowledge. Considering the huge amount of chemicals present in the marine environment, from a regulatory perspective, there are only two promising approaches to handle this complex task: i) automation of EQS/PNEC derivation and associated risk assessment on a substance-by-substance level or ii) moving from a single substance-based to a mixture-based risk assessment. Therefore, in Chapter 5 an automated calculation algorithm was developed and applied in a screening-level risk assessment for the BPNS. This screening-level marine risk assessment suggests to prioritize in future work Bisphenol A, certain herbicides, neonicotinoid insecticides and steroids for further ecotoxicological testing and/or refined PNEC calculation. Additionally, a comparison of grab sample and passive sampler-based risk assessment revealed no obvious differences between the two sampling methods. Although providing a useful tool for prioritization within the prevailing regulatory frameworks, a single-substance-based risk assessment bears the risk of neglecting interactive effects of chemicals. Yet, environmental risk assessment is meant to assess the real impact on ecosystems or species that are exposed to chemicals and for most of our waters this means simultaneous exposure to various chemicals. This indicates that there is a need for mixture-based risk assessment methods. To answer this need, we developed a novel method for passive sampler-based ecotoxicity testing of environmentally realistic chemical mixtures (ERCMs) in Chapter 6. This passive sampler-based method combines environmental sampling and ecotoxicity testing of chemical mixtures. During method development insights into the preservation of complex mixture samples were gained and the importance of a reduction of passive sampler extract handling and storage time were highlighted. With a relatively low sample enrichment of < 2 the developed method had one major drawback. This drawback was tackled in Chapter 7 where the previously developed method was modified to allow sample enrichment up to a relative enrichment factor (REF) of 44 as compared to environmentally realistic concentration levels. Further, the method was extended with a MoS assessment serving as indicator for potential risks in the BPNS. Here, margins of safety were found to be < 10 for 5 out of 8 samples from different sampling campaigns (SCs) and locations. According to current risk assessment procedures this suggests ecological risks for these locations since the lowest assessment factor (AF) in use is 10. This effect-based method addresses the lack of current environmental regulations that do not provide guidance on how to deal with mixtures of chemicals although simultaneous exposure to multiple chemicals is the prevailing scenario for aquatic organisms. Yet, a change in environmental regulation from single substance to mixture-based risk assessment is not to be expected in the near future since many of the current EU frameworks have only recently entered into force. Thus, to align our effect-based monitoring method with current risk assessment procedures, we recommend to extend the biotest battery with at least one crustacean and one fish biotest to comply with regulatory requirements. In a first attempt to identify mixture toxicity driving chemicals, we applied multivariate statistics to find chemical concentration patterns in different speedisk extracts that might be associated with the toxicity observations (Chapter 7). Unfortunately, no clear patterns distinguishing between toxic and non-toxic samples could be identified based on 89 target personal care products (PCPs), pesticides and pharmaceuticals. Nevertheless, some chemicals like sodium diclofenac or naproxen, that had also been identified in the screening-level risk assessment to be potentially problematic substances, were found to be correlated with the first two principal components (PCs) that explained 55 % of the data inherent variability. Yet, in order to gain better insights into the effect-driving chemicals in a mixture including non-target chemical data is highly recommended. This would be another step forward from a single substance-based and priority pollutant-focused to an unbiased mixture-based risk assessment.
... Others have documented other non-reproductive behavioral effects of estrogens and androgens in fish. Lagesson et al. (2019) exposed eastern mosquitofish (Gambusia holbrooki) to environmentally relevant levels (3 ng/L) of trenbolone at one of two temperature regimes for 21 days and found that trenbolone increased fish boldness behavior and altered predator escape behavior (but only at the higher temperature). Three-spined sticklebacks (Gasterosteus aculeatus) exposed to EE2 during early development and assayed for behavioral endpoints 8 months after exposures showed a reduction in anxiety behavior related to scototaxis (light/dark preference) (Porseryd et al., 2019). ...
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The inland silverside, Menidia beryllina, is a euryhaline fish and a model organism in ecotoxicology. We previously showed that exposure to picomolar (ng/L) levels of endocrine disrupting chemicals (EDCs) can cause a variety of effects in M. beryllina, from changes in gene expression to phenotypic alterations. Here we explore the potential for early life exposure to EDCs to modify the epigenome in silversides, with a focus on multi- and transgenerational effects. EDCs included contaminants of emerging concern (the pyrethroid insecticide bifenthrin and the synthetic progestin levonorgestrel), as well as a commonly detected synthetic estrogen (ethinylestradiol), and a synthetic androgen (trenbolone) at exposure levels ranging from 3 to 10 ng/L. In a multigenerational experiment, we exposed parental silversides to EDCs from fertilization until 21 days post hatch (dph). Then we assessed DNA methylation patterns for three generations (F0, F1, and F2) in whole body larval fish using reduced representation bisulfite sequencing (RRBS). We found significant (α = 0.05) differences in promoter and/or gene body methylation in treatment fish relative to controls for all EDCs and all generations indicating that both multigenerational (F1) and transgenerational (F2) effects that were caused by strict inheritance of DNA methylation alterations and the dysregulation of epigenetic control mechanisms. Using gene ontology and pathway analyses, we found enrichment in biological processes and pathways representative of growth and development, immune function, reproduction, pigmentation, epigenetic regulation, stress response and repair (including pathways important in carcinogenesis). Further, we found that a subset of potentially EDC responsive genes (EDCRGs) were differentially methylated across all treatments and generations and included hormone receptors, genes involved in steroidogenesis, prostaglandin synthesis, sexual development, DNA methylation, protein metabolism and synthesis, cell signaling, and neurodevelopment. The analysis of EDCRGs provided additional evidence that differential methylation is inherited by the offspring of EDC-treated animals, sometimes in the F2 generation that was never exposed. These findings show that low, environmentally relevant levels of EDCs can cause altered methylation in genes that are functionally relevant to impaired phenotypes documented in EDC-exposed animals and that EDC exposure has the potential to affect epigenetic regulation in future generations of fish that have never been exposed.
... However, few reports have addressed this issue. Animals make adjustments to various behaviors to adapt to the environment; these behaviors include those pertaining to exploration, avoidance, sociability, aggressiveness, mating, feeding, and cognitive performance (Meijide et al., 2018;Lagesson et al., 2019). In particular, impaired exploration tendencies can affect the ability of fish to access habitats of sufficient quality (Reader, 2015). ...
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Silver and silver nanoparticles are used in several consumer products, particularly sterilizing agents. Ag+ released from the particles causes physiological damages of aquatic organisms. However, the effects of silver on neural and behavioral functions of fish remain unclear. Here, we used zebrafish as a model to investigate the impacts of silver on learning and memory behaviors in teleost. Adult zebrafish showed mortality rates of 12.875% and 100% on 72-h exposure to 30 and ≥50 ppb of silver nitrate, respectively. Silver accumulation in the brain increased on exposure to 10 and 30 ppb of AgNO3. The physical fitness of the zebrafish, measured by novel tank diving test and swimming performance, decreased after 72-h incubation in 30 ppb of AgNO3. Exposure to 10 ppb of AgNO3 impaired social preference, social recognition, learning, and memory, but did not affect anxiety level, aggressiveness, and shoaling behavior. In situ hybridization of c-fos mRNA showed that AgNO3 treatment decreased neural activity in the brain areas crucial for learning, memory, and social behaviors, including the medial and dorsal zones of the dorsal telencephalic area. In conclusion, 72-h exposure to AgNO3 in a sublethal level impaired learning and social behaviors, indicating neurotoxicity in adult zebrafish.
... For example, environmental factors such as temperature may alter the effects of toxicants on behavior. Jacquin et al. [36] found that high temperatures aggravated the effects of pesticides in goldfish, and Lagesson et al. [37] found that exposure to a hormonal growth promoter increased boldness behavior in mosquitofish, but that this increase depended on temperature. Araujo et al. [38] observed that shrimps balanced exposure to contaminants with a sheltering behavior that protects individuals from predators; when confronted with a choice between a cleaner habitat with no shelter and a contaminated habitat with shelter, shrimps preferred the cleanest area, but when the uncontaminated area contained a predator signal, shrimps balanced the risk of predation and exposure to contamination by selecting a moderately contaminated area further away from predator signals, thereby increasing their exposure to the contaminant. ...
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Indirect effects in ecotoxicology are defined as chemical- or pollutant-induced alterations in the density or behavior of sensitive species that have cascading effects on tolerant species in natural systems. As a result, species interaction networks (e.g., interactions associated with predation or competition) may be altered in such a way as to bring about large changes in populations and/or communities that may further cascade to disrupt ecosystem function and services. Field studies and experimental outcomes as well as models indicate that indirect effects are most likely to occur in communities in which the strength of interactions and the sensitivity to contaminants differ markedly among species, and that indirect effects will vary over space and time as species composition, trophic structure, and environmental factors vary. However, knowledge of indirect effects is essential to improve understanding of the potential for chemical harm in natural systems. For example, indirect effects may confound laboratory-based ecological risk assessment by enhancing, masking, or spuriously indicating the direct effect of chemical contaminants. Progress to better anticipate and interpret the significance of indirect effects will be made as monitoring programs and long-term ecological research are conducted that facilitate critical experimental field and mesocosm investigations, and as chemical transport and fate models, individual-based direct effects models, and ecosystem/food web models continue to be improved and become better integrated.
... [88][89][90] Experimental studies have also shown that global warming could be particularly harmful to pollutantexposed wildlife. 91,92 The complex interactions between climate change and environmental contaminants may be especially challenging for species living at the border of their physiological tolerance limit where acclimation capacity is low. 82 Responding to the global environmental change ...
... This means that hormonal residues can be found in animal excreta, which can directly pollute the soil and indirectly affects water quality through leaching [16]. In the environment, these substances are persistent [17]. More concerning is their endocrine-disrupting properties, even at extremely low concentrations [18]. ...
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The presence of endocrine disruptors in surface waters can have negative implications on wildlife and humans both directly and indirectly. A molecularly imprinted polymer (MIP) was explored for its potential to enhance the UV-Vis determination of trenbolone in water using solid-phase extraction (SPE). The synthesized MIP was studied using Fourier transform infrared spectra (FTIR) and scanning electron microscopy (SEM). Using the MIP resulted in a preconcentration and enrichment factor of 14 and 8, respectively. Trenbolone binding on the MIP was shown to follow a Langmuir adsorption and had a maximum adsorption capacity of 27.5 mg g−1. Interference studies showed that the MIP selectivity was not compromised by interferences in the sample. The MIP could be recycled three times before significant loss in analyte recovery.
... Micropollutants, such as pharmaceutically active compounds (PhACs), illicit drugs, and their metabolites enter the aquatic environment from various sources with the discharge of sewage effluent, agricultural run-off, with the recycled municipal wastewater from parks and gardens being a prime source of contamination [1,2]. Concentrations of PhACs in the sewage system are affected by the offerings of the pharmaceutical industry, the specific water consumption per capita, the specific consumption of individual PhACs, the seasonal changes, weather, and the type of sewage system involved [3,4]. ...
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Wastewaters are considered a remarkable source of micropollutants capable of influencing the environment both directly and indirectly. Here we tested porous ecological carbon (Biochar), an effective sorbent material for removing pharmaceuticals, drugs, and their metabolites found in wastewaters. The tested Biochar type was first characterised and used for adsorption experiments of selected micropollutants from a municipal WWTP (wastewater treatment plant) effluent sample. The sorption efficiency was studied on selected pharmaceuticals due to their common presence in aquatic ecosystems. The results show that the studied Biochar type removed the pharmaceuticals with high efficiency (above 90%), so this material can potentially be applied in wastewater treatment. We achieved greater than 99% efficiency in total RNA removal from wastewater. Wastewater might contain infectious RNA fragments of the SARS-CoV-2 virus. However, Biochar can be used as a sorbent in wastewater treatment to remove antibiotic resistance genes. We have also observed a total DNA removal ability of Biochar. On the other hand, the total number and antibiotic-resistant coliform bacteria and enterococci were not changed after Biochar wastewater treatment.
... An illustrative example is a temperature-dependent response to the synthetic hormonal growth promoter 17β-trenbolone in eastern mosquitofish (Gambusia holbrooki). A behavioral test revealed that higher temperatures (30 vs 20°C) enhanced the proactivity of males, measured by exploratory activity, but slowed down the response in the test of predatorescape compared to females [257]. Here, the sex-biased behavioral results were influenced not only by the neurobiological reactivity and by a sensibility of the HPG axis to feedback regulation by xenoestrogens, but also by the individual behavioral differences and the poikilothermy hardwired in fish lineages that influences and limits the repertoire of physiological outcomes. ...
Chapter
The increasing knowledge and awareness concerning the presence of pharmaceutical residues and their negative impact on the marine environment create a need to develop new tools to investigate and monitor their pathways. Multiresidue methods allow the determination of a vast number of target compounds from different classes of pharmaceuticals in a single analysis. The application of these methods to seawater samples is more complicated compared with freshwater analysis due to matrix impact and dilution of the target compounds. This chapter presents a review of the published research papers from the last decade and discusses the analytical methodologies presented there. Based on the current knowledge, authors also try to predict and point out the future trends and challenges in multiresidue analysis methodology.
... An illustrative example is a temperature-dependent response to the synthetic hormonal growth promoter 17β-trenbolone in eastern mosquitofish (Gambusia holbrooki). A behavioral test revealed that higher temperatures (30 vs 20°C) enhanced the proactivity of males, measured by exploratory activity, but slowed down the response in the test of predatorescape compared to females [257]. Here, the sex-biased behavioral results were influenced not only by the neurobiological reactivity and by a sensibility of the HPG axis to feedback regulation by xenoestrogens, but also by the individual behavioral differences and the poikilothermy hardwired in fish lineages that influences and limits the repertoire of physiological outcomes. ...
Chapter
The effects of pharmaceutical-related endocrine disruptors (phEDCs) in marine habitats encompass toxic effects, metabolic disturbances, and growth impairments, mainly in freshwater environments and in a few key model species. phEDCs include a set of components (non-steroidal anti-inflammatory drugs, antibiotics, cytostatic drugs, anti-epileptics, antidepressants, anti-neoplasics, β-blockers, blood lipid-lowering agents, and steroidal hormones, among others) designed to target specific signaling pathways. In doing so, phEDCs are able to damage hierarchical cascades of mutual influencing endocrine circuitry in vertebrates, namely, the gonadal, thyroid, and stress-related axis, which, in turn, affect immune and behavioral responses to endocrine breakdown. In marine invertebrates, several orthologues of vertebrate endocrine mediators remain evolutionary conserved, but the adaptive mechanisms of cross-talk between high-order physiological regulatory systems have been extensively analyzed in fish and specifically in teleosts. In this chapter, we review the effects of phEDCs in marine organisms, with a focus on fish, based on thyroidal, gonadal, and behavioral aspects.
... It was seen that endocrine disruptors interfere with the molecular mechanisms that support behavior, such as gene expression, hormone levels and neurotransmitter levels [29,88]. The eff ects of exposures to these compounds are predominantly implicated in the interruption of typical reproductive behaviors, such as cohort and parental sexual behavior [89], but also with non-reproductive behaviors, such as anxiety, aggression, and risk behavior [90,91]. Some studies focusing on the deleterious eff ects on the behavior of rodents due to exposure to atrazine are briefl y described in table 5 and detailed below. ...
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Herbicides represent the largest portion of pesticides used both worldwide and in Brazil. Many of these compounds are applied on a large scale in native forests and in urban and industrial water environments, including atrazine. Due to its low cost, ability to remain active in the soil for long periods and potential effect on weed removal, atrazine ranks 5th in the ranking of most used pesticide in Brazil. Although the use of pesticides increases agricultural production, their intensive use can often cause negative effects on fauna and flora. Studies have shown that exposure to atrazine can cause various harmful effects in mammals, of both sexes, such as structural, neuroendocrine and/or behavioral changes. Considering the seriousness of the situation and the possible toxicological and pathological implications that atrazine can generate in the animal organism, the objective of this work was to carry out an integrative literature review in order to verify the scientific panorama on issues related to atrazine exposure and its impacts, mainly with regard to its toxicity on the central nervous system. To carry out this article, a bibliographic survey of scientific material obtained in the following databases was carried out: US National Library of Medicine - National Institutes of Health (PubMed), Virtual Health Library (Latin American and Caribbean Literature in Health Sciences - LILACS), Science Direct and Google® Academic, in the last 25 years. The MeSH Terms used in the search were: “Parkinson's disease”, “atrazine”, “herbicide” and “endocrine disruptor”. The following were found in the Science Direct indexers: 115 records, PubMed 52 records, in LILACS no articles were found, and 1330 records were found in Google® Academic.
... In Uganda, appreciable antibiotic resistance was primarily found for inexpensive antibiotics that were readily available over the counter without a prescription (Goldberg et al., 2007). However, while such single species case studies are available and many studies have highlighted the impacts of pharmaceuticals on aquatic organisms, especially fish (Lagesson et al., 2019), the general effects of pharmaceuticals on terrestrial mammals, especially in the tropics, have received almost no attention. ...
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Sixty years ago, Rachel Carson published her book Silent Spring, which focused the world's attention on the dangers of pesticides. Since that time human impacts on the environment have accelerated and this has included reshaping the chemical landscape. Here we evaluate the severity of exposure of tropical terrestrial mammals to pesticides, pharmaceuticals, plastics, particulate matter associated with forest fires, and nanoparticles. We consider how these environmental contaminants interact with one another, with the endocrine and microbiome systems of mammals, and with other environmental changes to produce a larger negative impact than might initially be expected. Using this background and building on past conservation success, such as mending the ozone layer and decreasing acid rain, we tackle the difficult issue of how to construct meaningful policies and conservation plans that include a consideration of the chemical landscape. We document that policy solutions to improving the chemical landscape are already known and the path of how to construct a healthier planet is discernible.
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Among the various pollutants, pharmaceutical and personal care products (PPCPs) have emerged as a great threat to human and aquatic life due to their unique tendency to cause physiological effects in humans at low concentrations. Although PPCPs and their metabolites have modest concentrations in the environment, their toxicity and risk to humans and animals is relatively substantial. The environmental risk imposed by PPCPs is observed in light of persistence, bioaccumulation, and toxicity levels. The inefficiency of the traditional water treatment procedures in removing PPCPs from wastewater has caused widespread concern. Traditional methods for such remediation such as ion exchange, membrane filtration, etc. are either becoming insufficient or getting more expensive to meet the current strict regulatory effluent limits. As a result, the demand for alternative, cost-effective solutions is significant. Thus, depending upon the type of contaminants, including PPCPs, specific biochars can be used for their removal from wastewater. This approach of using different biochars will definitely reduce the exposure and associated risks of PPCP residues to the environment and humans. This chapter presents the usage of biochar in wastewater treatment for the remediation of PPCPs.
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Although many pharmaceutical compounds (and their metabolites) can induce harmful impacts at the molecular, physiological and behavioural levels, their underlying mechanistic associations have remained largely unexplored. Here, we utilized RNA-Seq to build a whole brain transcriptome profile to examine the impact of a common endocrine disrupting pharmaceutical (17α-ethinyl estradiol, EE2) on reproductive behaviour in wild guppies (Poecilia reticulata). Specifically, we annotated 16,791 coding transcripts in whole brain tissue in relation to the courtship behaviour (i.e. sigmoid display) of EE2 exposed (at environmentally relevant concentration of 8 ng/L for 28-days) and unexposed guppies. Further, we obtained 10,960 assembled transcripts matching in the non-coding orthologous genomes. Behavioural responses were assessed using a standard mate choice experiment, which allowed us to disentangle chemical cues from visual cues. We found that a high proportion of the RNAseq reads aligned back to our de novo assembled transcriptome with 80.59% mapping rate. Behavioural experiments showed that when males were presented only with female visual cues, there was a significant interaction between male treatment and female treatment in the time spent in the preference zone. This is one of the first studies to show that transcriptome-wide changes are associated with the reproductive behaviour of fish: EE2 exposed male guppies that performed high levels of courtship had a gene profile that deviated the most from the other treatment groups, while both non-courting EE2 and control males had similar gene signatures. Using Gene Ontology pathway analysis, our study shows that EE2-exposed males had gene transcripts enriched for pathways associated with altered immunity, starvation, altered metabolism and spermatogenesis. Our study demonstrates that multiple gene networks orchestrate courting behaviour, emphasizing the importance of investigating impacts of pharmaceuticals on gene networks instead of single genes.
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Worldwide, biologically active pharmaceuticals, such as psychoactive drugs, are routinely detected in aquatic ecosystems. In this regard, selective serotonin reuptake inhibitors (SSRIs), a class of antidepressant, are of major environmental concern. Through targeted action on evolutionarily conserved physiological pathways, SSRIs could alter ecologically important behaviours in exposed organisms. Here, using two field-realistic dosages (measured concentrations: 18 and 215 ng/L) of the SSRI fluoxetine (Prozac), we examined the effects of exposure on anxiety-related behaviours in wild-caught female mosquitofish, Gambusia holbrooki. Anxiety-related behaviour was assessed using a light/dark transition test, with the swimming activity of fish recorded under two alternating light conditions, complete darkness and bright light, with the shift in light condition used to induce an anxiety-like response. Fluoxetine exposure resulted in a nonmonotonic decrease in anxiety-related behaviour (i.e. nonlinear with dose), with fish in the low-fluoxetine treatment being less responsive to shifts in light condition compared to unexposed fish. There was no such difference between unexposed and high-exposed fish. Further, we detected a significant interaction between exposure treatment and fish weight on general swimming activity, suggesting the presence of a mass-specific effect of fluoxetine. More broadly, contaminant-induced disruption of animal behaviour—as documented here—could have wide-reaching effects on population-level fitness.
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A method for sensitive analysis of 19 anabolic steroids (AS) in animal oil using enhanced matrix removal lipid (EMR-Lipid) cleanup and ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed. Oil samples were extracted with 20 mL of acetonitrile aqueous solution and purified using EMR-Lipid cartridges. The eluent was evaporated to dryness under nitrogen and analyzed by UHPLC-MS/MS using 0.1% formic acid-acetonitrile and 0.1% formic acid-water solutions as the mobile phase via gradient elution. The method effectively removed unwanted matrix co-extractives better than other extraction cleanup techniques while still delivering acceptable recovery results for most of the AS. The established quantification method showed AS recovery in the range of 72.9-110.7% with good precision (relative standard deviation < 15%).
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Increasingly, studies are revealing that endocrine disrupting chemicals (EDCs) can alter animal behavior. Early life exposure to EDCs may permanently alter phenotypes through to adulthood. In addition, the effects of EDCs may not be isolated to a single generation - offspring may indirectly be impacted, via non-genetic processes. Here, we analyzed the effects of paternal atrazine exposure on behavioral traits (distance moved, exploration, bottom-dwelling time, latency to enter the top zone, and interaction with a mirror) and whole-brain mRNA of genes involved in the serotonergic system regulation (slc6a4a, slc6a4b, htr1Aa, htr1B, htr2B) of zebrafish (Danio rerio). F0 male zebraFIsh were exposed to atrazine at 0.3, 3 or 30 part per billion (ppb) during early juvenile development, the behavior of F1 progeny was tested at adulthood, and the effect of 0.3 ppb atrazine treatment on mRNA transcription was quantified. Paternal exposure to atrazine significantly reduced interactions with a mirror (a proxy for aggression) and altered the latency to enter the top zone of a tank in unexposed F1 offspring. Bottom-dwelling time (a proxy for anxiety) also appeared to be somewhat affected, and activity (distance moved) was reduced in the context of aggression. slc6a4a and htr1Aa mRNA transcript levels were found to correlate positively with anxiety levels in controls, but we found that this relationship was disrupted in the 0.3 ppb atrazine treatment group. Overall, paternal atrazine exposure resulted in alterations across a variety of behavioral traits and showed signs of serotonergic system dysregulation, demonstrating intergenerational effects. Further research is needed to explore transgenerational effects on behavior and possible mechanisms underpinning behavioral effects.
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Animal behaviour is remarkably sensitive to disruption by chemical pollution, with widespread implications for ecological and evolutionary processes in contaminated wildlife populations. However, conventional approaches applied to study the impacts of chemical pollutants on wildlife behaviour seldom address the complexity of natural environments in which contamination occurs. The aim of this review is to guide the rapidly developing field of behavioural ecotoxicology towards increased environmental realism, ecological complexity, and mechanistic understanding. We identify research areas in ecology that to date have been largely overlooked within behavioural ecotoxicology but which promise to yield valuable insights, including within-and among-individual variation, social networks and collective behaviour, and multi-stressor interactions. Further, we feature methodological and technological innovations that enable the collection of data on pollutant-induced behavioural changes at an unprecedented resolution and scale in the laboratory and the field. In an era of rapid environmental change, there is an urgent need to advance our understanding of the real-world impacts of chemical pollution on wildlife behaviour. This review therefore provides a roadmap of the major outstanding questions in behavioural ecotoxicology and highlights the need for increased cross-talk with other disciplines in order to find the answers.
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Pollutants, such as endocrine disrupting chemicals (EDCs), are increasingly being detected in organisms and ecosystems globally. Agricultural activities, including the use of hormonal growth promotants (HGPs), are a major source of EDC contamination. One potent EDC that enters into the environment through the use of HGPs is 17β-trenbolone. Despite EDCs being repeatedly shown to affect reproduction and development, comparatively little is known regarding their effects on behaviour. Amphibians, one of the most imperilled vertebrate taxa globally, are at particular risk of exposure to such pollutants as they often live and breed near agricultural operations. Yet, no previous research on amphibians has explored the effects of 17β-trenbolone exposure on foraging or antipredator behaviour, both of which are key fitness-related behavioural traits. Accordingly, we investigated the impacts of 28-day exposure to two environmentally realistic concentrations of 17β-trenbolone (average measured concentrations: 10 and 66 ng/L) on the behaviour and growth of spotted marsh frog tadpoles (Limnodynastes tasmaniensis). Contrary to our predictions, there was no significant effect of 17β-trenbolone exposure on tadpole growth, antipredator response, anxiety-like behaviour, or foraging. We hypothesise that the differences in effects found between this study and those conducted on fish may be due to taxonomic differences and/or the life stage of the animals used, and suggest further research is needed to investigate the potential for delayed manifestation of the effects of 17β-trenbolone exposure.
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Chemical contaminants (e.g. metals, pesticides, pharmaceuticals) are changing ecosystems via effects on wildlife. Indeed, recent work explicitly performed under environmentally realistic conditions reveals that chemical contaminants can have both direct and indirect effects at multiple levels of organization by influencing animal behaviour. Altered behaviour reflects multiple physiological changes and links individual-to population-level processes, thereby representing a sensitive tool for holistically assessing impacts of environmentally relevant contaminant concentrations. Here, we show that even if direct effects of contaminants on behavioural responses are reasonably well documented, there are significant knowledge gaps in understanding both the plasticity (i.e. individual variation) and evolution of contaminant-induced behavioural changes. We explore implications of multi-level processes by developing a conceptual framework that integrates direct and indirect effects on behaviour under environmentally realistic contexts. Our framework illustrates how sublethal behavioural effects of contaminants can be both negative and positive, varying dynamically within the same individuals and populations. This is because linkages within communities will act indirectly to alter and even magnify contaminant-induced effects. Given the increasing pressure on wildlife and ecosystems from chemical pollution, we argue there is a need to incorporate existing knowledge in ecology and evolution to improve ecological hazard and risk assessments.
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Mortality through predation is often selective, particularly at life-history bottlenecks. While many studies have looked at the importance for survival of specific prey characteristics in isolation, few have looked at a broad array of attributes and how they relate to survival in a realistic context. 2.Our study measures 18 morphological, performance and behavioural traits of a juvenile damselfish that have been hypothesized as important for prey survival, and examines how they relate to survival in the field immediately after settlement. These attributes included size, relative false eye-spot size, fast-start escape response kinematics, thigmotaxis, laterality, and space use and activity in the field. 3.Using conditional inference trees we identify the most important drivers out of a reduced suite of 13 characters. Fast-start response latency, boldness, feeding rates and two measures of activity were found to significantly contribute to survival. Morphological variables and most laboratory measures of performance appeared to contribute little to survival. 4.Results suggest selection works on a suite of characters associated with boldness. Bold and active fish are those that will be best able to learn using public information, but because of the relatively naïveté of newly metamorphosed fishes, speed to react to a strike from an unknown predator is of critical importance. 5.Findings substantiate the ecomorphological paradigm by suggesting that selection on behaviour modifies the correlations of morphological and performance variables with survival probabilities, since behaviour modifies performance capabilities by making them specific to context. This article is protected by copyright. All rights reserved.
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As a consequence of anthropogenic environmental change, the world is facing a possible sixth mass extinction event. The severity of this biodiversity crisis is exemplified by the rapid collapse of hundreds of amphibian populations around the world. Amphibian declines are associated with a range of factors including habitat loss/modification, human utilisation, exotic/invasive species, environmental acidification and contamination, infectious disease, climate change, and increased ultraviolet-B radiation (UVBR) due to stratospheric ozone depletion. However, it is recognised that these factors rarely act in isolation and that amphibian declines are likely to be the result of complex interactions between multiple anthropogenic and natural factors. Here we present a synthesis of the effects of ultraviolet radiation (UVR) in isolation and in combination with a range of naturally occurring abiotic (temperature, aquatic pH, and aquatic hypoxia) and biotic (infectious disease, conspecific density, and predation) factors on amphibians. We highlight that examining the effects of UVR in the absence of other ecologically relevant environmental factors can greatly oversimplify and underestimate the effects of UVR on amphibians. We propose that the pathways that give rise to interactive effects between multiple environmental factors are likely to be mediated by the behavioural and physiological responses of amphibians to each of the factors in isolation. A sound understanding of these pathways can therefore be gained from the continued use of multi-factorial experimental studies in both the laboratory and the field. Such an understanding will provide the foundation for a strong theoretical framework that will allow researchers to predict the combinations of abiotic and biotic conditions that are likely to influence the persistence of amphibian populations under future environmental change.
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Understanding the combined effects of anthropogenic impacts such as climate change and pollution on aquatic ecosystems is critical. However, little is known about how predicted temperature increases may affect the activity of endocrine disrupting compounds (EDCs), particularly in species with plasticity in sex determination. We investigated the effects of a concomitant increase in temperature and exposure to estrogenic EDCs on reproduction and development in an estuarine model organism (Menidia beryllina) across multiple generations. Parents (P) were exposed to environmental levels of the estrogenic insecticide bifenthrin or ethinylestradiol (EE2) at 22 °C and 28 °C for 14 days prior to the initiation of spawning trials. Embryos in the F1 generation were exposed to EDCs until 21 days post hatch (dph), reared to adulthood in clean water at elevated temperatures, and spawned. F1 sex ratios were significantly influenced by elevated temperature and EDCs, potentially altering adaptive development. We also observed fewer viable offspring and increased developmental deformities in the F1 and F2 generations, with a greater impact on F2 juveniles. These findings enhance our understanding of responses to EDCs in the context of climate change and may demonstrate heritable effects. Our study represents the first multigenerational assessment of elevated temperatures in combination with environmentally relevant concentrations of commonly detected endocrine disruptors in a model vertebrate species.
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Behavioral assays constitute important research tools when assessing how fish respond to environmental change. However, it is unclear how behavioral modifications recorded in laboratory assays are expressed in natural ecosystems, a limitation that makes it difficult to evaluate the predictive power of laboratory-based measurements. In this study, we hypothesized that exposure to a benzodiazepine (i.e., oxazepam) increases boldness and activity in laboratory assays as well as in field assays – that is, laboratory results can be used to predict field results. Moreover, we expected the modified behavior to affect other important ecological measures such as habitat selection and home range. To test our hypothesis, we exposed European perch (Perca fluviatilis) to oxazepam and measured subsequent changes in behavioral trials both in laboratory assays and in a lake ecosystem populated with a predatory fish species, pike (Esox lucius). In the lake, the positions of both perch and pike were tracked every three minutes for a month using acoustic telemetry. In the laboratory assay, the oxazepam-exposed perch were bolder and more active than the non-exposed perch. In the lake assay, the oxazepam-exposed perch were also more bold and active, had a larger home range, and used pelagic habitats more than the non-exposed perch. We conclude that ecotoxicological behavioral assays are useful for predicting the effects of exposure in natural systems. However, although individual responses to exposure were similar in both the laboratory and field trials, effects were more obvious in the field study, mainly due to reduced variability in the behavior measures from the lake. Hence, short-term behavioral assays may fail to detect all the effects expressed in natural environments. Nevertheless, our study clearly demonstrates that behavior modifications observed in laboratory settings can be used to predict how fish perform in aquatic ecosystems.
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The effect of semi-synthetic steroid trenbolone acetate (TBA) on the ornamental fish Poecilia reticulata (guppy) was studied. The steroid at a dose of 300 mg/kg feed was administered to 30 days old juvenile specimens during 60 days. Forty days after treatment was ended, an evaluation aimed to determine the steroid residual effect was undertaken. Survival, masculinization ratio and the drug anabolic effect were analyzed. Results showed TBA to be effective to induce masculinization, differing (P < 0.001) with the control group, which registered 32% males and 68% females. TBA turned out to be an excellent anabolic as well, since treated fish showed weight increase, a larger body and an increased size of caudal fin. The steroid did not cause any damage on the treated population. The survival factor was 93.3% for the treated fish as compared to 83% for the control group.
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Transgenerational effects of environmental toxins require either a chromosomal or epigenetic alteration in the germ line. Transient exposure of a gestating female rat during the period of gonadal sex determination to the endocrine disruptors vinclozolin (an antiandrogenic compound) or methoxychlor (an estrogenic compound) induced an adult phenotype in the F1 generation of decreased spermatogenic capacity (cell number and viability) and increased incidence of male infertility. These effects were transferred through the male germ line to nearly all males of all subsequent generations examined (that is, F1 to F4). The effects on reproduction correlate with altered DNA methylation patterns in the germ line. The ability of an environmental factor (for example, endocrine disruptor) to reprogram the germ line and to promote a transgenerational disease state has significant implications for evolutionary biology and disease etiology.
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Global climate change is impacting organisms, biological communities and ecosystems around the world. While most research has focused on characterizing how the climate is changing, including modeling future climatic conditions and predicting the impacts of these conditions on biodiversity, it is also the case that climate change is altering the environmental impacts of chemical pollution. Future climate conditions are expected to influence both the worldwide distribution of chemicals and the toxicological consequences of chemical exposures to organisms. Many of the environmental changes associated with a warming global climate (e.g., increased average – and possibly extreme – temperatures; intense periods of drier and wetter conditions; reduced ocean pH; altered salinity dynamics in estuaries) have the potential to enhance organism susceptibility to chemical toxicity. Additionally, chemical exposures themselves may impair the ability of organisms to cope with the changing environmental conditions of the shifting climate. Such reciprocity in the interactions between climate change and chemicals illustrates the complexity inherent in predicting the toxicological consequences of chemical exposures under future climate scenarios. Here, we summarize what is currently known about the potential reciprocal effects of climate change and chemical toxicity on wildlife, and depict current approaches and ongoing challenges for incorporating climate effects into chemical testing and assessment. Given the rapid pace of new man-made chemistries, the development of accurate and rapid methods to evaluate multiple chemical and non-chemical stressors in an ecologically relevant context will be critical to understanding toxic and endocrine-disrupting effects of chemical pollutants under future climate scenarios.
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Humans have brought about unprecedented changes to environments worldwide. For many species, behavioral adjustments represent the first response to altered conditions. In this review, we consider the pivotal role that behavior plays in determining the fate of species under human-induced environmental change and highlight key research priorities. In particular, we discuss the importance of behavioral plasticity and whether adaptive plastic responses are sufficient in keeping pace with changing conditions. We then examine the interplay between individual behavioral responses and population processes and consider the many ways in which changes in behavior can affect ecosystem function and stability. Lastly, we turn to the evolutionary consequences of anthropogenic change and consider the impact of altered behaviors on the evolutionary process and whether behavior can facilitate or hinder adaptation to environmental change.
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Anthropogenic sensory pollution is affecting ecosystems worldwide. Human actions generate acoustic noise, emanate artificial light and emit chemical substances. All of these pollutants are known to affect animals. Most studies on anthropogenic pollution address the impact of pollutants in unimodal sensory domains. High levels of anthropogenic noise, for example, have been shown to interfere with acoustic signals and cues. However, animals rely on multiple senses, and pollutants often co-occur. Thus, a full ecological assessment of the impact of anthropogenic activities requires a multimodal approach. We describe how sensory pollutants can co-occur and how covariance among pollutants may differ from natural situations. We review how animals combine information that arrives at their sensory systems through different modalities and outline how sensory conditions can interfere with multimodal perception. Finally, we describe how sensory pollutants can affect the perception, behaviour and endocrinology of animals within and across sensory modalities. We conclude that sensory pollution can affect animals in complex ways due to interactions among sensory stimuli, neural processing and behavioural and endocrinal feedback. We call for more empirical data on covariance among sensory conditions, for instance, data on correlated levels in noise and light pollution. Furthermore, we encourage researchers to test animal responses to a full-factorial set of sensory pollutants in the presence or the absence of ecologically important signals and cues. We realize that such approach is often time and energy consuming, but we think this is the only way to fully understand the multimodal impact of sensory pollution on animal performance and perception. © 2015 The Author(s) Published by the Royal Society. All rights reserved.
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Endocrine disrupting compounds (EDCs) enter aquatic habitats from a variety of anthropogenic sources and can mimic, block, or modulate the synthesis of natural hormones. EDCs affect both reproductive and non-reproductive behaviors because hormones mediate responses associated with aggression and fear. We examined the effects of two EDCs on risk-taking behaviors in guppies (Poecilia reticulata). We quantified risk-taking in terms of propensity to forage in a risky location and tendency to join groups in the presence of a predator. We found that male and female guppies responded oppositely to environmentally relevant concentrations of an estrogenic EDC, 17α-ethinylestradiol (EE2), or an androgenic EDC, 17β-trenbolone (TB). Males decreased risk-taking with increasing EE2 concentration (as predicted), but females increased risk-taking (contrary to prediction). In contrast, females increased risk-taking with increasing TB concentrations (as predicted), but males decreased risk-taking (contrary to prediction). These results did not match our expectation that EE2 would reduce risk-taking and TB would increase risk-taking in both sexes. We suspect EE2 and TB produced these counterintuitive effects by downregulating their corresponding hormone receptors and thus reducing levels of circulating endogenous hormones in females and males, respectively. These results show that EDCs can alter fish behavior and potentially reduce fitness in unexpected ways.
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Endocrine-disrupting chemicals (EDCs) in municipal effluents directly affect the sexual development and reproductive success of fishes, but indirect effects on invertebrate prey or fish predators through reduced predation or prey availability, respectively, are unknown. At the Experimental Lakes Area in northwestern Ontario, Canada, a long-term, whole-lake experiment was conducted using a before-after-control-impact design to determine both direct and indirect effects of the synthetic oestrogen used in the birth control pill, 17 alpha-ethynyloestradiol (EE2). Algal, microbial, zooplankton and benthic invertebrate communities showed no declines in abundance during three summers of EE2 additions (5-6 ng l(-1)), indicating no direct toxic effects. Recruitment of fathead minnow (Pimephales promelas) failed, leading to a near-extirpation of this species both 2 years during (young-of-year, YOY) and 2 years following (adults and YOY) EE2 additions. Body condition of male lake trout (Salvelinus namaycush) and male and female white sucker (Catostomus commersonii) declined before changes in prey abundance, suggesting direct effects of EE2 on this endpoint. Evidence of indirect effects of EE2 was also observed. Increases in zooplankton, Chaoborus, and emerging insects were observed after 2 or 3 years of EE2 additions, strongly suggesting indirect effects mediated through the reduced abundance of several small-bodied fishes. Biomass of top predator lake trout declined by 23-42% during and after EE2 additions, most probably an indirect effect from the loss of its prey species, the fathead minnow and slimy sculpin (Cottus cognatus). Our results demonstrate that small-scale studies focusing solely on direct effects are likely to underestimate the true environmental impacts of oestrogens in municipal wastewaters and provide further evidence of the value of whole-ecosystem experiments for understanding indirect effects of EDCs and other aquatic stressors.
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Pharmaceuticals are highly bioactive compounds now known to be widespread environmental contaminants. However, research regarding exposure and possible effects in non-target higher vertebrate wildlife remains scarce. The fate and behaviour of most pharmaceuticals entering our environment via numerous pathways remain poorly characterized, and hence our conception and understanding of the risks posed to wild animals is equally constrained. The recent decimation of Asian vulture populations owing to a pharmaceutical (diclofenac) offers a notable example, because the exposure route (livestock carcasses) and the acute toxicity observed were completely unexpected. This case not only highlights the need for further research, but also the wider requirement for more considered and comprehensive ‘ecopharmacovigilance’. We discuss known and potential high risk sources and pathways in terrestrial and freshwater ecosystems where pharmaceutical exposure in higher vertebrate wildlife, principally birds and mammals, may occur. We examine whether approaches taken within existing surveillance schemes (that commonly target established classes of persistent or bioaccumulative contaminants) and the risk assessment approaches currently used for pesticides are relevant to pharmaceuticals, and we highlight where new approaches may be required to assess pharmaceutical-related risk.
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Fish represent the planet’s most diverse group of vertebrates and they can be exposed to a wide range of pharmaceuticals. For practical reasons, extrapolation of pharmaceutical effects from ‘model’ species to other fish species is adopted in risk assessment. Here, we critically assess this approach. First, we show that between 65% and 86% of human drug targets are evolutionarily conserved in 12 diverse fish species. Focusing on nuclear steroid hormone receptors, we further show that the sequence of the ligand binding domain that plays a key role in drug potency is highly conserved, but there is variation between species. This variation for the oestrogen receptor, however, does not obviously account for observed differences in receptor activation. Taking the synthetic oestrogen ethinyloestradiol as a test case, and using life-table-response experiments, we demonstrate significant reductions in population growth in fathead minnow and medaka, but not zebrafish, for environmentally relevant exposures. This finding contrasts with zebrafish being ranked as more ecologically susceptible, according to two independent life-history analyses. We conclude that while most drug targets are conserved in fish, evolutionary divergence in drug-target activation, physiology, behaviour and ecological life history make it difficult to predict population-level effects. This justifies the conventional use of at least a x10 assessment factor in pharmaceutical risk assessment, to account for differences in species susceptibility.
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One contribution of 18 to a Theme Issue 'Assessing risks and impacts of pharmaceuticals in the environment on wildlife and ecosystems'. Many wildlife species forage on sewage-contaminated food, for example, at wastewater treatment plants and on fields fertilized with sewage sludge. The resultant exposure to human pharmaceuticals remains poorly studied for terrestrial species. On the basis of predicted exposure levels in the wild, we administered the common antidepressant fluoxetine (FLUOX) or control treat-ment via prey to wild-caught starlings (Sturnus vulgaris) for 22 weeks over winter. To investigate responses to fluoxetine, birds were moved from their group aviaries into individual cages for 2 days. Boldness, exploration and activity levels showed no treatment effects but controls and FLUOX birds habi-tuated differently to isolation in terms of the concentration of corticosterone (CORT) metabolites in faeces. The controls that excreted higher concentrations of CORT metabolites on day 1 lost more body mass by day 2 of isolation than those which excreted lower levels of CORT metabolites. CORT metabolites and mass loss were unrelated in FLUOX birds. When we investigated the move-ments of birds in their group aviaries, we found the controls made a higher frequency of visits to food trays than FLUOX birds around the important fora-ging periods of sunrise and sunset, as is optimal for wintering birds. Although individual variability makes interpreting the sub-lethal endpoints measured challenging, our data suggest that fluoxetine at environmentally relevant concentrations can significantly alter behaviour and physiology.
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One contribution of 18 to a Theme Issue 'Assessing risks and impacts of pharmaceuticals in the environment on wildlife and ecosystems'. Global pharmaceutical consumption is rising with the growing and ageing human population and more intensive food production. Recent studies have revealed pharmaceutical residues in a wide range of ecosystems and organisms. Environmental concentrations are often low, but pharmaceuticals typically are designed to have biological effects at low doses, acting on physiological systems that can be evolutionarily conserved across taxa. This Theme Issue introduces the latest research investigating the risks of environmentally relevant concen-trations of pharmaceuticals to vertebrate wildlife. We take a holistic, global view of environmental exposure to pharmaceuticals encompassing terrestrial, freshwater and marine ecosystems in high-and low-income countries. Based on both field and laboratory data, the evidence for and relevance of changes to physiology and behaviour, in addition to mortality and reproductive effects, are examined in terms of the population-and community-level consequences of pharmaceutical exposure on wildlife. Studies on uptake, trophic transfer and indirect effects of pharmaceuticals acting via food webs are presented. Given the logistical and ethical complexities of research in this area, several papers focus on techniques for prioritizing which compounds are most likely to harm wildlife and how modelling approaches can make predictions about the bioavailability, metabolism and toxicity of pharmaceuticals in non-target species. This Theme Issue aims to help clarify the uncertainties, highlight opportunities and inform ongoing scientific and policy debates on the impacts of pharmaceuticals in the environment.
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The study of animal behaviour is important for both ecology and ecotoxicology, yet research in these two fields is currently developing independently. Here, we synthesize the available knowledge on drug-induced behavioural alterations in fish, discuss potential ecological consequences and report results from an experiment in whichwe quantify both uptake and behavioural impact of a psychiatric drug on a predatory fish (Perca fluviatilis) and its invertebrate prey (Coenagrion hastulatum). We show that perch became more active while damselfly behaviour was unaffected, illustrating that behavioural effects of pharmaceuticals can differ between species. Furthermore, we demonstrate that prey consumption can be an important exposure route as on average 46% of the pharmaceutical in ingested prey accumulated in the predator. This suggests that investigations of exposure through bioconcentration, where trophic interactions and subsequent bioaccumulation of exposed individuals are ignored, underestimate exposure. Wildlife may therefore be exposed to higher levels of behaviourally altering pharmaceuticals than predictions based on commonly used exposure assays and pharmaceutical concentrations found in environmental monitoring programmes.
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Individuals often show consistent differences in risk-taking behaviours; behaviours that increase resource acquisition at the expense of an increased risk of mortality. Recently, basal metabolic rate (BMR) has been suggested as a potentially important state variable underlying adaptive individual differences in a range of behaviours, including risk-taking.We tested the relationship between BMR and risk-taking in free-living great tits (Parus major) using experimental manipulations of perceived predation risk. We compared the latency of individuals to return to feeders following control (human) and predator (model sparrowhawk, Accipiter nisus) disturbances at fixed feeder locations. We predicted that if variation in risk-taking is shaped by energetic constraints, high BMR individuals should return to feeders sooner following both disturbance types and show smaller changes in risk-taking as a function of predation danger.Higher BMR tended to be associated with lower risk-taking following control disturbances but greater risk-taking following predator disturbances, resulting in a significant interaction between BMR and treatment.Within-individual changes in risk-taking as a function of ambient temperature (a proxy for within-individual changes in energetic constraints) mirrored these results. Lower temperatures tended to be associated with lower risk-taking following control disturbances, but greater risk-taking following predator disturbances, resulting in a significant interaction between temperature and treatment.The effects of BMR and temperature on variation in risk-taking as a function of perceived predation danger were qualitatively similar, suggesting that energetic constraints play a role in shaping risk-taking. However, the hypothesized mechanism (energetic requirements directly influence the optimal expression of risk-taking behaviour) is insufficient to account for the observed negative relationship between energetic constraint and risk-taking following control disturbances.We conclude that variation in risk-taking is associated with differences in energetic constraints, including BMR and temperature, but that the relationship is context-specific, here high vs. low perceived predation risk. Further studies are needed to elucidate potential mechanisms that could generate context-specific relationships between energetic constraints and risk-taking.
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We hypothesize that chemical toxicity to marine ectotherms is the lowest at an optimum temperature (OT) and it exacerbates with increasing or decreasing temperature from the OT. This study aimed to verify this hypothetical temperature-dependent chemical toxicity (TDCT) model through laboratory experiments. Acute toxicity over a range of temperatures was tested on four commonly used chemicals to three marine ectotherms. Our results confirmed that toxicities, in terms of 96-h LC50 (median lethal concentration; for the marine medaka fish Oryzias melastigma and the copepod Tigriopus japonicus) and 24-h LC50 (for the rotifer Brachionus koreanus), were highly temperature-dependent, and varied between test species and between study chemicals. The LC50 value of the fish peaked at 20 °C for copper (II) sulphate pentahydrate and triphenyltin chloride, and at 25 °C for dichlorophenyltrichloroethane and copper pyrithione, and decreased with temperature increase or decrease from the peak (i.e., OT). However, LC50 values of the copepod and the rotifer generally showed a negative relationship with temperature across all test chemicals. Both copepod and rotifer entered dormancy at the lowest temperature of 4 °C. Such metabolic depression responses in these zooplanktons could reduce their uptake of the chemical and hence minimize the chemical toxicity at low temperatures. Our TDCT model is supported by the fish data only, whereas a simple linear model fits better to the zooplankton data. Such species-specific TDCT patterns may be jointly ascribed to temperature-mediated changes in (1) the physiological response and susceptibility of the marine ectotherms to the chemical, (2) speciation and bioavailability of the chemical, and (3) toxicokinetics of the chemical in the organisms.
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Characterization of metabolic rate is critical to constructing daily and seasonal energy budgets, constructing models of individuals for use in individual based modeling, understanding patterns of resource allocation, and understanding within-and among-population variation in life-history phenotypes. We investigated the efects of mass, ambient temperature, time of day, sex, population of origin, and feeding on O₂ consumption of the canyon lizard, Sceloporus merriami. We observed strong efects of mass and ambient temperature and constructed predictive relationships for O₂ consumption on the basis of these variables for scotophase and photophase. These fundamental relationships coupled with existing field body temperature data suggest that lizards from populations exhibiting different daily body temperature profiles may significantly differ in maintenance requirement. We observed strong diel cycles in O₂ consumption that were correlated with daily activity. No main effects of sex orpopulation of origin were observed. A significant higher-order interaction involving temperature, time of day, sex, and population of origin suggests that ecologically significant variation in metabolic rate may occur between groups defined by sex and population. A plateau in O₂ consumption between 32° and 34°C was observed during scotophase. This plateau is not easily explained as a mechanism of homeostasis because scotophase body temperatures may often fall below this range. Feeding significantly increased O₂ consumption in this species; the magnitude of increase was linearly related to meal size. We estimated the total energetic cost of digestion to be between 2.9% and 4.9% of dietary metabolizable energy content.
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Eastern and Western Gambusia (i.e., Gambusia holbrooki and G. affinis, respectively) are considered together here because these two fish species are very closely related, similar in appearance, similar in biology and often confused. Widely divergent attitudes have developed with regard to these fish with some viewing them as being highly beneficial to humans through controlling mosquitoes and the diseases they harbor, and others expressing concern about the negative impacts that these fish may have on other species with which they interact. Because of the widespread distribution, high levels of abundance, ease of capture and captive maintenance, and divergent attitudes, a very large and diffuse literature has developed with regard to these species. In fact, few fish species have been studied as much as or more than these two species combined. There has, however, been no comprehensive review of their biology published to date. As it is not possible to provide a comprehensive review of Gambusia biology in one reasonably sized document, I provide here a review of aspects of their biology at the level of species and individual. In another review I focused instead on the levels of population and species communities and consider the impacts that these fish have on mosquitoes and other organisms (Pyke, unpublished). As would be expected of such widespread and abundant species, Gambusia affinis and G. holbrooki are clearly very tolerant, adaptable and variable in their biology, at both an individual and population level. Both individuals and populations can tolerate, and often thrive within, a wide range of conditions and the abilities of individuals to do this are enhanced if they have time to acclimate to any changes. Populations can adapt through genetic or evolutionary changes in response to conditions that vary in space or time, and there is significant genetic variation within and between populations.
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Behavioral responses have been applied for decades as tools for aquatic toxicity testing, but have received far less attention than studies assessing lethality, development or reproduction. With improved visual and non-visual assessment tools and increased knowledge of the importance of behavior for organism health and fitness, interest in behavioral analysis has increased in recent years. However, to our knowledge there has never been a quantitative assessment of the available techniques for organismal toxicity testing, so it is not clear whether behavioral studies represent valuable additions to environmental monitoring. We performed a meta-analysis comparing the relative sensitivities and average durations of behavioral studies to those assessing acute lethality, development and reproduction. Results demonstrate that the average duration of behavioral studies is consistently less than developmental or reproductive studies, and that behavioral endpoints are generally more sensitive than those assessing development or reproduction. We found effect sizes to be lower but power to be higher in behavioral and reproductive studies compared to studies assessing development, which likely relates to low sample sizes commonly used in developmental studies. Overall, we conclude that behavioral studies are comparatively fast and sensitive, and therefore warrant further attention as tools for assessing the toxicological effects of environmental contaminants. We suggest that research aimed at developing and optimizing techniques for behavioral analysis could prove extremely useful to the field of toxicology, but that future work must be directed at determining what specific behaviors are most sensitive to various classes of contaminants, and at understanding the relevance of changes to discrete behaviors for influencing organismal and population-level health and fitness.
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Bioaccumulation assessment is important in the scientific evaluation of risks that chemicals may pose to humans and the environment and is a current focus of regulatory effort. The status of bioaccumulation evaluations for organic chemicals in aquatic systems is reviewed to reduce uncertainty in bioaccumulation measurement, to provide quality data for assessment, and to assist in model development. A review of 392 scientific literature and database sources includes 5317 bioconcentration factor (BCF) and 1656 bioaccumulation factor (BAF) values measured for 842 organic chemicals in 219 aquatic species. A data quality assessment finds that 45% of BCF values are subject to at least one major source of uncertainty and that measurement errors generally result in an underestimation of actual BCF values. A case study of organic chemicals on the Canadian Domestic Substances List indicates that empirical data are available for less than 4% of the chemicals that require evaluation and of these chemicals, 76% have less than three acceptable quality BCF or BAF values. Field BAFs tend to be greater than laboratory BCFs emphasizing the importance of environmental measurement for reliable assessment; however, only 0.2% of current use organic chemicals have BAF measurements. Key parameters influencing uncertainty and variability in BCF and BAF data are discussed using reviewed data and models. A critical evaluation of representative BCF and BAF models in relation to existing measurements and regulatory criteria in Canada indicate the probability of Type H errors, i.e., false negatives or "misses", using BCF models for bioaccumulation assessment may be as high as 70.6% depending on the model. Recommendations for the selection of measured and modelled values used in bioaccumulation assessment are provided, and improvements for the science and regulatory criteria are proposed.
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This Perspective gives an overview of the definitions, advantages, and the importance of behavioral studies in ecotoxicology. Recent developments in automated quantitative recording technology as well as in mathematical data analysis and statistical data treatment have given rise to increased research in behavioral ecotoxicology. As an example, several studies performed with different invertebrate and vertebrate species using the non-optical impedance recorder, the Multispecies Freshwater Biomonitor™, are mentioned and discussed under the aspect of recent developments. However, some problems have still to be solved, such as (1) linking behavior to other biological test parameters on the suborganismal as well as the population level, (2) standardization of test designs and methods, and (3) creating more acceptance of these methods in the legislative framework of biomonitoring.
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The capacity of pharmaceutical pollution to alter behaviour in wildlife is of increasing environmental concern. A major pathway of these pollutants into the environment is the treatment of livestock with hormonal growth promotants (HGPs), which are highly potent veterinary pharmaceuticals that enter aquatic ecosystems via effluent runoff. Hormonal growth promotants are designed to exert biological effects at low doses, can act on physiological pathways that are evolutionarily conserved across taxa, and have been detected in ecosystems worldwide. However, despite being shown to alter key fitness-related processes (e.g., development, reproduction) in various non-target species, relatively little is known about the potential for HGPs to alter ecologically important behaviours, especially across multiple contexts. Here, we investigated the effects of exposure to a field-realistic level of the androgenic HGP metabolite 17β-trenbolone-an endocrine-disrupting chemical that has repeatedly been detected in freshwater systems-on a suite of ecologically important behaviours in wild-caught female eastern mosquitofish (Gambusia holbrooki). First, we found that 17β-trenbolone-exposed fish were more active and exploratory in a novel environment (i.e., maze arena), while boldness (i.e., refuge use) was not significantly affected. Second, when tested for sociability, exposed fish spent less time in close proximity to a shoal of stimulus (i.e., unexposed) conspecific females and were, again, found to be more active. Third, when assayed for foraging behaviour, exposed fish were faster to reach a foraging zone containing prey items (chironomid larvae), quicker to commence feeding, spent more time foraging, and consumed a greater number of prey items, although the effect of exposure on certain foraging behaviours was dependent on fish size. Taken together, these findings highlight the potential for exposure to sub-lethal levels of veterinary pharmaceuticals to alter sensitive behavioural processes in wildlife across multiple contexts, with potential ecological and evolutionary implications for exposed populations.
Book
Human-induced environmental change currently represents the single greatest threat to global biodiversity. Species are typically adapted to the local environmental conditions in which they have evolved. Changes in environmental conditions initially influence behaviour, which in turn affects species interactions, population dynamics, evolutionary processes and, ultimately, biodiversity. How animals respond to changed conditions, and how this influences population viability, is an area of growing research interest. Yet, despite the vital links between environmental change, behaviour, and population dynamics, surprisingly little has been done to bridge these areas of research. This is the first book of its kind devoted to understanding behavioural responses to environmental change. The volume is comprehensive in scope, discussing impacts on both the mechanisms underlying behavioural processes, as well as the longer-term ecological and evolutionary consequences. Drawing on international experts from across the globe, the book covers topics as diverse as endocrine disruption, learning, reproduction, migration, species interactions, and evolutionary rescue.
Article
Despite the pivotal role sexual selection plays in population dynamics and broader evolutionary processes, the impact of chemical pollution on female mate choice is poorly understood. One group of chemical contaminants with the potential to disrupt the mechanisms of female mate choice is endocrine disrupting chemicals (EDCs); a broad class of environmental pollutants that can interfere with the endocrinology of organisms at extremely low concentrations. Recent research has revealed that estrogenic EDCs can affect female mate choice in fish, but the impact of androgenic EDC exposure is yet to be studied. To address this, we investigated the effects of an environmentally relevant concentration of trenbolone - an androgenic steroid used as a growth promoter in the cattle industry - on female mate choice in wild-caught guppies (Poecilia reticulata). We exposed male and female guppies to 17β-trenbolone for 21 days (measured concentration 4ng/L) via a flow-through system, and found that trenbolone-exposed female guppies spent less time associating with males, and were less choosy, compared to unexposed females. In contrast, trenbolone had no impact on male reproductive behavior or morphology. This is the first study to show that androgenic EDC exposure can disrupt female mate choice, highlighting the need for studies to investigate the behavioral impacts of environmental contaminants on both sexes.
Article
Chemical pollution is a pervasive and insidious agent of environmental change. One class of chemical pollutant threatening ecosystems globally are the endocrine disrupting chemicals (EDCs). The capacity of EDCs to disrupt development 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 reproductive behaviour following exposure to an environmentally realistic concentration of 17β-trenbolone, demonstrating the possibility of widespread disruption of mating systems of aquatic organisms by common agricultural contaminants. Copyright © 2015. Published by Elsevier Inc.
Article
1. The importance of body size and growth rate in ecological interactions is widely recognized, and both are frequently used as surrogates for fitness. However, if there are significant costs associated with rapid growth rates then its fitness benefits may be questioned. 2. In replicated whole-lake experiments, we show that a domestic strain of rainbow trout (artificially selected for maximum intrinsic growth rate) use productive but risky habitats more than wild trout. Consequently, domestic trout grow faster in all situations, experience greater survival in the absence of predators, but have lower survival in the presence of predators. Therefore, rapid growth rates are selected against due to increased foraging effort (or conversely, lower antipredator behaviour) that increases vulnerability to predators. In other words, there is a behaviourally mediated trade-off between growth and mortality rates. 3. Whereas rapid growth is beneficial in many ecological interactions, our results show the mortality costs of achieving it are large in the presence of predators, which can help explain the absence of an average phenotype with maximized growth rates in nature.
Article
Veterinary use of the non-steroidal anti-inflammatory drug diclofenac on domesticated ungulates caused populations of resident Gyps vultures in the Indian sub-continent to collapse. The birds died when they fed on carrion from treated animals. Veterinary diclofenac was banned in 2006 and meloxicam was advocated as a 'vulture-safe' alternative. We examine the effectiveness of the 2006 ban, whether meloxicam has replaced diclofenac, and the impact of these changes on vultures. Drug residue data from liver samples collected from ungulate carcasses in India since 2004 demonstrate that the prevalence of diclofenac in carcasses in 2009 was half of that before the ban and meloxicam prevalence increased by 44%. The expected vulture death rate from diclofenac per meal in 2009 was one-third of that before the ban. Surveys at veterinary clinics show that diclofenac use in India began in 1994, coinciding with the onset of rapid Gyps declines ascertained from measured rates of declines. Our study shows that one pharmaceutical product has had a devastating impact on Asia's vultures. Large-scale research and survey were needed to detect, diagnose and quantify the problem and measure the response to remedial actions. Given these difficulties, other effects of pharmaceuticals in the environment may remain undetected. © 2014 The Author(s) Published by the Royal Society. All rights reserved.
Article
Animal waste from livestock farming operations (LFOs) can contain varying levels of natural and synthetic androgens and/or estrogens, which can contaminate surrounding waterways. In the present study, surface stream water was collected from six basins containing LFOs. Aqueous concentrations of 12 hormones were determined via chemical analyses. Relative androgenic and estrogenic activity was measured using in vitro cell assays (MDA-kb2 and T47D-Kbluc assays, respectively). In parallel, 48-h static-renewal in vivo exposures were conducted to examine potential endocrine-disrupting effects in fathead minnows. Mature fish were exposed to surface water dilutions (0%, 25%, 50%, and 100%) and 10-ng/L of 17α-ethynylestradiol or 50-ng/L of 17β-trenbolone as positive controls. Hepatic expression of vitellogenin and estrogen receptor-α mRNA, gonadal ex vivo testosterone and 17β-estradiol production, and plasma vitellogenin concentrations were examined. Potentially estrogenic and androgenic steroids were detected at low ng/L concentrations. In vitro estrogenic activity was detected in all samples, while androgenic activity was detected in only one sample. In vivo exposures to the surface water had no significant dose-dependent effect on any of the biological endpoints, with the exception of increased male testosterone production in one exposure. The current study, which combines analytical chemistry measurements, in vitro bioassays, and in vivo fish exposures, highlights the integrated value and future use of a combination of techniques to obtain a comprehensive characterization of an environmental chemical mixture. Environ Toxicol Chem. © 2014 SETAC
Article
Freshwater environments are common repositories for the discharge of large volumes of domestic and industrial waste, particularly through wastewater effluent. One common group of chemical pollutants present in wastewater are endocrine disrupting chemicals (EDCs), which can induce morphological and behavioural changes in aquatic organisms. The aim of this study was to compare the reproductive behaviour and morphology of a freshwater fish, the mosquitofish (Gambusia holbrooki), collected from two sites (wastewater treatment plant (WWTP) and a putative pristine site). The mosquitofish is a sexually dimorphic livebearer with a coercive mating system. Males inseminate females using their modified anal fin as an intromittent organ. Despite this, females are able to exert some control over the success of male mating attempts by selectively associating with, or avoiding, certain males over others. Using standard laboratory assays of reproductive behaviour, we found that mosquitofish males living in close proximity to WWTP showed increased mating activity compared to those inhabiting a pristine site. More specifically, during behavioural trials in which males were allowed to interact with females separated by a transparent divider, we found that WWTP-males spent more time associating with females. Concordant with this, when males and females were subsequently allowed to interact freely, WWTP-males also spent more time chasing and orienting towards the females. As a result, females from both sites showed more interest towards the WWTP-site males. Male anal fin morphology, however, did not differ between sites. Our study illustrates that lifetime exposure to WWTP-effluents can greatly affect male behaviour. The results underscore the importance of behaviour as a potential tool for investigating unknown contaminants in the environment.
Article
The bioconcentration factors (BCF's) of various types of organic chemicals in several fish species reported by Veith and Kosian were utilized to verify the applicability of ∑i and ∑o to describe their bioconcentration potentials quantitatively. A good linear correlation between logBCF and ∑i and ∑o was established over the 107 chemicals by a multiple regression: logBCF = −0.00458 ± (0.00089) · ∑i + 0.00991 ± (0.00036) · ∑o (n = 107, r2 = 0.936, s = 0.735). The results suggest that ∑i and ∑o can be a good predictor of bioconcentration of organic chemicals in fish and broaden its applicability in this particular field.
Article
When animals can choose from a range of feeding options, often those options with a higher energetic gain carry a higher risk of predation. This paper analyses the optimal trade-off between food and predation. We are primarily interested in how an animal's decisions and its state change over time. Our models are very general. They can be applied to growth decisions, such as choice of habitat, in which case we might consider how the state variable size changes over an animal's lifetime. Equally our models are applicable to short-term foraging decisions, such as vigilance level, in which case we might consider how energy reserves vary over a day. We concentrate on two cases: (i) the animal must reach a fixed state, its fitness depending on when this is attained; (ii) the animal must survive to a fixed time, its fitness depending on its final state. In case (i) minimization of mortality per unit increase of state is optimal under certain baseline conditions. In case (ii) behaviour is constant over time under baseline conditions (the `Risk-spreading Theorem'). We analyse how these patterns are modified by complicating factors, e.g. time penalties, premature termination of the food supply, stochasticity in food supply or in metabolic expenditure, and state-dependence in the ability to obtain food, in metabolic expenditure and in predation risk. From this analysis we obtain a variety of possible explanations for why an animal should reduce its intake rate over time (i.e. show satiation). We show how earlier work can be viewed as special cases of our results.
Article
This research evaluates the effect of temperature on the sensitivity of food web organisms to selected chemicals. Test organisms included planktonic algae, zooplankton, microbenthos, macrobenthos, and fishes. The chemicals used were copper, zinc, chromate, chlorine, cyanide, and phenol. The sensitivity of the test organisms to these chemicals was studied over a temperature range of 5 to 35C. The specific temperatures studied varied with each species. Results indicate considerable variation in the sensitivity of each species, depending on the chemical and the test temperature. Generally, the algal responses to the temperature and chemicals varied depending on the thermal sensitivity of the algal species in question. The invertebrates usually exhibited the classic response of increased sensitivity to chemicals at higher temperatures.
Article
Activity is an important behavioral trait that in most animals mediates a trade-off between obtaining food for growth and avoiding predation. Active individuals usually experience a higher encounter rate with food items and predators and, as a consequence, grow faster and suffer higher predation pressure than less active individuals. We investigated how predator-induced mortality and growth of the damselfly Coenagrion haxtulatum depend on activity at the level of the genotype. Larvae from six different C. hastulatum families were reared in two different predator treatments: predator present or absent. Families differed in activity, and active families grew to a significantly larger size than less-active families. Within families there was a plastic response to predators. Larvae reared without predators were more active and grew larger than larvae reared with a non-lethal predator. In the presence of a lethal predator the active families experienced higher mortality than the less active families. The results illustrate that the growth/predation-risk trade-off was mediated by activity and clearly show a cost of antipredator behavior. They also suggest that variation in activity level might be genetically regulated and could explain why C. hastulatum are abundant in aquatic systems both with and without potential predators.