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Heiko L Schoenfuss - One of the best experts on this subject based on the ideXlab platform.
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antidepressants at environmentally relevant concentrations affect Predator Avoidance behavior of larval fathead minnows pimephales promelas
Environmental Toxicology and Chemistry, 2009Co-Authors: Meghan M Painter, Megan A Buerkley, Matthew L Julius, Alan M Vajda, David O Norris, Larry B Barber, Edward T Furlong, Melissa M Schultz, Heiko L SchoenfussAbstract:The effects of embryonic and larval exposure to environmentally relevant (ng/L) concentrations of common antidepressants, fluoxetine, sertraline, venlafaxine, and bupropion (singularly and in mixture) on C-start escape behavior were evaluated in fathead minnows (Pimephales promelas). Embryos (postfertilization until hatching) were exposed for 5 d and, after hatching, were allowed to grow in control well water until 12 d old. Similarly, posthatch fathead minnows were exposed for 12 d to these compounds. High-speed (1,000 frames/s) video recordings of escape behavior were collected and transferred to National Institutes of Health Image for frame-by-frame analysis of latency periods, escape velocities, and total escape response (combination of latency period and escape velocity). When tested 12 d posthatch, fluoxetine and venlafaxine adversely affected C-start performance of larvae exposed as embryos. Conversely, larvae exposed for 12 d posthatch did not exhibit altered escape responses when exposed to fluoxetine but were affected by venlafaxine and bupropion exposure. Mixtures of these four antidepressant pharmaceuticals slowed Predator Avoidance behaviors in larval fathead minnows regardless of the exposure window. The direct impact of reduced C-start performance on survival and, ultimately, reproductive fitness provides an avenue to assess the ecological relevance of exposure in an assay of relatively short duration.
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Predator Avoidance performance of larval fathead minnows pimephales promelas following short term exposure to estrogen mixtures
Aquatic Toxicology, 2009Co-Authors: Meghan R Mcgee, Matthew L Julius, Alan M Vajda, David O Norris, Larry B Barber, Heiko L SchoenfussAbstract:Aquatic organisms exposed to endocrine disrupting compounds (EDCs) at early life-stages may have reduced reproductive fitness via disruption of reproductive and non-reproductive behavioral and physiological pathways. Survival to reproductive age relies upon optimal non-reproductive trait expression, such as adequate Predator Avoidance responses, which may be impacted through EDC exposure. During a Predator-prey confrontation, larval fish use an innate C-start escape behavior to rapidly move away from an approaching threat. We tested the hypotheses that (1) larval fathead minnows exposed to estrogens, a primary class of EDCs, singularly or in mixture, suffer a reduced ability to perform an innate C-start behavior when faced with a threat stimulus; (2) additive effects will cause greater reductions in C-start behavior; and (3) effects will differ among developmental stages. In this study, embryos (post-fertilization until hatching) were exposed for 5 days to environmentally relevant concentrations of estrone (E1), 17beta-estradiol (E2), and 17alpha-ethinylestradiol (EE2) singularly and in mixture. Exposed embryos were allowed to hatch and grow in control well water until 12 days old. Similarly, post-hatch fathead minnows were exposed for 12 days to these compounds. High-speed (1000frames/s) video recordings of escape behavior were collected and transferred to National Institutes of Health Image for frame-by-frame analysis of latency period, escape velocity, and total escape response (combination of latency period and escape velocity). When tested 12 days post-hatch, only E1 adversely affected C-start performance of larvae exposed as embryos. Conversely, larvae exposed for 12 days post-hatch did not exhibit altered escape responses when exposed to E1, while adverse responses were seen in E2 and the estrogen mixture. Ethinylestradiol exposure did not elicit changes in escape behaviors at either developmental stage. The direct impact of reduced C-start performance on survival, and ultimately, reproductive fitness provides an avenue to assess the ecological relevance of exposure in an assay of relatively short duration.
Douglas P. Chivers - One of the best experts on this subject based on the ideXlab platform.
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learning threat sensitive Predator Avoidance how do fathead minnows incorporate conflicting information
Animal Behaviour, 2006Co-Authors: Maud C O Ferrari, Douglas P. ChiversAbstract:For prey species, the costs associated with antiPredator behaviours should drive the development of efficient risk assessment systems. According to the threat-sensitive Predator Avoidance hypothesis, prey match the intensity of their antiPredator responses with the degree of threat posed. Evidence of threat sensitivity exists for a variety of taxa, but little is known about how such responses develop. We investigated the effect of multiple conditioning events on the development of threat-sensitive antiPredator responses of fathead minnows, Pimephales promelas . In experiment 1, we conditioned Predator-naive minnows with brook charr, Salvelinus fontinalis , odour paired with either a high or low concentration of conspecific alarm cues. Fish were conditioned twice (low/low, low/high, high/low, high/high), then tested for learned recognition of charr odour alone. Results suggest that minnows learn the relative risk associated with the Predator based on the highest alarm cue concentration experienced during the conditioning trials. In experiment 2, Predator-naive minnows were conditioned six times with charr odour paired with either a high or low concentration of alarm cues (6 low, 5 low/1 high, 1 high/5 low, 6 high). The intensity of the minnows' antiPredator response to charr odour was not an averaging of the intensity of responses during the six conditioning trials. Instead, they used their last conditioning experience to adjust the intensity of their response to the predation cues. Predation fluctuates in space and time. Thus, the best way to adaptively respond to Predator cues is to constantly update information regarding the relative risk associated with a given Predator.
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Making sense of Predator scents: investigating the sophistication of Predator assessment abilities of fathead minnows
Behavioral Ecology and Sociobiology, 2004Co-Authors: Robin C. Kusch, Reehan S. Mirza, Douglas P. ChiversAbstract:According to the threat-sensitive Predator Avoidance hypothesis, selection favors prey that accurately assess the degree of threat posed by a Predator and adjust their anti-Predator response to match the level of risk. Many species of animals rely on chemical cues to estimate predation risk; however, the information content conveyed in these chemical signatures is not well understood. We tested the threat-sensitive Predator Avoidance hypothesis by determining the specificity of the information conveyed to prey in the chemical signature of their Predator. We found that fathead minnows ( Pimephales promelas ) could determine the degree of threat posed by northern pike ( Esox lucius ) based on the concentration of chemical cues used. The proportion of minnows that exhibited an anti-Predator response when exposed to a Predator cue increased as the concentration of the pike cue used increased. More surprisingly, the prey could also distinguish large pike from small pike based on their odor alone. The minnows responded more intensely to cues of small pike than to cues of large pike. In this Predator–prey system small pike likely represent a greater threat than large pike.
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Threat-sensitive Predator Avoidance by slimy sculpins: understanding the importance of visual versus chemical information
Canadian Journal of Zoology, 2001Co-Authors: Douglas P. Chivers, Reehan S. Mirza, Pamela J. Bryer, Joseph M. KieseckerAbstract:The supposition that prey animals assess and behave flexibly in response to different degrees of predation threat is known as the threat-sensitive Predator Avoidance hypothesis. We completed a series of field and laboratory experiments to examine whether slimy sculpins (Cottus cognatus) exhibit threat-sensitive Predator Avoidance when exposed to sympatric Predatory brook trout (Salvelinus fontinalis). In a field experiment we caged small and large trout in similar habitats and found that sculpins avoided areas containing trout that were large enough to pose a threat to them, but did not avoid areas containing trout that were small and hence not a threat. In a series of laboratory experiments we found that sculpins showed threat-sensitive Predator Avoidance when they could assess the Predator visually. However, when only chemical cues from the Predator were presented, sculpins responded to the Predator regardless of its size. Chemical cues seem to function to warn the sculpin that the Predator is in the vi...
Timothy M Eppley - One of the best experts on this subject based on the ideXlab platform.
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Predator Avoidance and dietary fibre predict diurnality in the cathemeral folivore hapalemur meridionalis
Behavioral Ecology and Sociobiology, 2017Co-Authors: Julia Watzek, Timothy M Eppley, Jorg U Ganzhorn, Giuseppe DonatiAbstract:Though numerous mammalian taxa exhibit cathemerality (i.e. activity distributed across the 24-h cycle), this includes very few primates, exceptions being species from Aotinae and Lemuridae. Four non-mutually exclusive hypotheses have been proposed to explain the ultimate determinants for cathemeral activity in lemurs: thermoregulatory benefits, anti-Predator strategy, competition Avoidance and metabolic dietary-related needs. However, these have only been explored in the frugivorous genus Eulemur, with some species increasing nocturnality as a possible response to avoid diurnal raptors and to increase their ability to digest fibre during resource-scarce periods. Since Eulemur lack specializations for digesting bulk food, this strategy would allow for processing fibres over the full 24-h. The folivorous lemurids, i.e. genus Hapalemur, provide a divergent model to explore these hypotheses due to gastrointestinal adaptations for digesting dietary fibre and small body size compared to Eulemur. We linked continuous activity data collected from archival tags with observational behaviour and feeding data from three groups of adult Hapalemur meridionalis from January to December 2013. We tested the effects of thermoregulation, Predator Avoidance and the weighted proportion of digestible dietary fibre on the daily diurnal/nocturnal activity ratio using a Linear Mixed-Model. Our best-fit model revealed that increased canopy exposure and dietary fibre predicted greater diurnality. Our findings partly contrast with previous predictions for frugivorous lemurids. We propose a divergent adaptive explanation for folivorous lemurids. We suggest that the need to avoid terrestrial Predators, as well as longer digestive bouts during bulk food periods, may override cathemerality in favour of diurnality in these bamboo lemurs. Southern bamboo lemurs are active throughout the 24-h day, with high proportions of dietary fibre increasing diurnality, in contrast to other cathemeral primates. They also increase diurnality on days when using areas with greater canopy exposure, potentially avoiding nocturnal Predators in risky foraging areas. We suggest that folivorous lemurids may require long periods of inactivity to conserve energy and digest dietary fibre, thus limiting activity to periods of optimal foraging efficiency over the 24-h cycle.
Luis A Bezarescalderon - One of the best experts on this subject based on the ideXlab platform.
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neural circuitry of a polycystin mediated hydrodynamic startle response for Predator Avoidance
eLife, 2018Co-Authors: Luis A Bezarescalderon, Jurgen Berger, Sanja Jasek, Csaba Veraszto, Sara Mendes, Martin Guhmann, Rodrigo AlmedaAbstract:Startle responses triggered by aversive stimuli including Predators are widespread across animals. These coordinated whole-body actions require the rapid and simultaneous activation of a large number of muscles. Here we study a startle response in a planktonic larva to understand the whole-body circuit implementation of the behaviour. Upon encountering water vibrations, larvae of the annelid Platynereis close their locomotor cilia and simultaneously raise the parapodia. The response is mediated by collar receptor neurons expressing the polycystins PKD1-1 and PKD2-1. CRISPR-generated PKD1-1 and PKD2-1 mutant larvae do not startle and fall prey to a copepod Predator at a higher rate. Reconstruction of the whole-body connectome of the collar-receptor-cell circuitry revealed converging feedforward circuits to the ciliary bands and muscles. The wiring diagram suggests circuit mechanisms for the intersegmental and left-right coordination of the response. Our results reveal how polycystin-mediated mechanosensation can trigger a coordinated whole-body effector response involved in Predator Avoidance.
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neural circuitry of a polycystin mediated hydrodynamic startle response for Predator Avoidance
bioRxiv, 2018Co-Authors: Luis A Bezarescalderon, Sanja Jasek, Csaba Veraszto, Sara Mendes, Rodrigo Almeda, Juergen Berger, Martin Guehmann, Reza Shahidi, Gaspar JekelyAbstract:Startle responses triggered by aversive stimuli including Predators are widespread across animals. These coordinated whole-body actions require the rapid and simultaneous activation of a large number of muscles. Here we study a startle response in a planktonic larva to understand the whole-body circuit implementation of the behavior. Upon encountering water vibrations, larvae of the annelid Platynereis close their locomotor cilia and simultaneously contract the body and raise the parapodia. The startle response is mediated by collar receptor neurons expressing the polycystins PKD1-1 and PKD2-1. CRISPR-generated PKD1-1 and PKD2-1 mutant larvae do not startle and fall prey to a copepod Predator at a higher rate. Reconstruction of the whole-body connectome of the collar-receptor-cell circuitry revealed converging feedforward circuits to the ciliary bands and muscles. The wiring diagram suggests circuit mechanisms for the intersegmental and left-right coordination of the response. Our results reveal how polycystin-mediated mechanosensation can trigger a coordinated whole-body effector response involved in Predator Avoidance.
Larry B Barber - One of the best experts on this subject based on the ideXlab platform.
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antidepressants at environmentally relevant concentrations affect Predator Avoidance behavior of larval fathead minnows pimephales promelas
Environmental Toxicology and Chemistry, 2009Co-Authors: Meghan M Painter, Megan A Buerkley, Matthew L Julius, Alan M Vajda, David O Norris, Larry B Barber, Edward T Furlong, Melissa M Schultz, Heiko L SchoenfussAbstract:The effects of embryonic and larval exposure to environmentally relevant (ng/L) concentrations of common antidepressants, fluoxetine, sertraline, venlafaxine, and bupropion (singularly and in mixture) on C-start escape behavior were evaluated in fathead minnows (Pimephales promelas). Embryos (postfertilization until hatching) were exposed for 5 d and, after hatching, were allowed to grow in control well water until 12 d old. Similarly, posthatch fathead minnows were exposed for 12 d to these compounds. High-speed (1,000 frames/s) video recordings of escape behavior were collected and transferred to National Institutes of Health Image for frame-by-frame analysis of latency periods, escape velocities, and total escape response (combination of latency period and escape velocity). When tested 12 d posthatch, fluoxetine and venlafaxine adversely affected C-start performance of larvae exposed as embryos. Conversely, larvae exposed for 12 d posthatch did not exhibit altered escape responses when exposed to fluoxetine but were affected by venlafaxine and bupropion exposure. Mixtures of these four antidepressant pharmaceuticals slowed Predator Avoidance behaviors in larval fathead minnows regardless of the exposure window. The direct impact of reduced C-start performance on survival and, ultimately, reproductive fitness provides an avenue to assess the ecological relevance of exposure in an assay of relatively short duration.
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Predator Avoidance performance of larval fathead minnows pimephales promelas following short term exposure to estrogen mixtures
Aquatic Toxicology, 2009Co-Authors: Meghan R Mcgee, Matthew L Julius, Alan M Vajda, David O Norris, Larry B Barber, Heiko L SchoenfussAbstract:Aquatic organisms exposed to endocrine disrupting compounds (EDCs) at early life-stages may have reduced reproductive fitness via disruption of reproductive and non-reproductive behavioral and physiological pathways. Survival to reproductive age relies upon optimal non-reproductive trait expression, such as adequate Predator Avoidance responses, which may be impacted through EDC exposure. During a Predator-prey confrontation, larval fish use an innate C-start escape behavior to rapidly move away from an approaching threat. We tested the hypotheses that (1) larval fathead minnows exposed to estrogens, a primary class of EDCs, singularly or in mixture, suffer a reduced ability to perform an innate C-start behavior when faced with a threat stimulus; (2) additive effects will cause greater reductions in C-start behavior; and (3) effects will differ among developmental stages. In this study, embryos (post-fertilization until hatching) were exposed for 5 days to environmentally relevant concentrations of estrone (E1), 17beta-estradiol (E2), and 17alpha-ethinylestradiol (EE2) singularly and in mixture. Exposed embryos were allowed to hatch and grow in control well water until 12 days old. Similarly, post-hatch fathead minnows were exposed for 12 days to these compounds. High-speed (1000frames/s) video recordings of escape behavior were collected and transferred to National Institutes of Health Image for frame-by-frame analysis of latency period, escape velocity, and total escape response (combination of latency period and escape velocity). When tested 12 days post-hatch, only E1 adversely affected C-start performance of larvae exposed as embryos. Conversely, larvae exposed for 12 days post-hatch did not exhibit altered escape responses when exposed to E1, while adverse responses were seen in E2 and the estrogen mixture. Ethinylestradiol exposure did not elicit changes in escape behaviors at either developmental stage. The direct impact of reduced C-start performance on survival, and ultimately, reproductive fitness provides an avenue to assess the ecological relevance of exposure in an assay of relatively short duration.
