Holographic quantitative structure activity relationship(HQSAR) is an emerging QSAR technique with the combined application of molecular hologram, which encoded the frequency of occurrence of various molecular fragme...Holographic quantitative structure activity relationship(HQSAR) is an emerging QSAR technique with the combined application of molecular hologram, which encoded the frequency of occurrence of various molecular fragment types, and the subsequent partial least squares(PLS) regression analysis. In this paper, the acute toxicity data to the guppy( poecilia reticulata) for a series of 56 substituted benzenes, phenols, aromatic amines and nitro aromatics were subjected and this resulted in a model with a high predictive ability. The influence of fragment size and fragment distinction parameters on the quality of HQSAR model was investigated. The robustness and predictive ability of the model were also validated by leave one out (LOO) cross validation procedure and external testing data set.展开更多
A preliminary study was conducted to investigate the effects of the extracts of 112 medicinal plant species, collected from the southern part of Thailand, on Aedes aegypti. Studies on larvicidal properties of plant ex...A preliminary study was conducted to investigate the effects of the extracts of 112 medicinal plant species, collected from the southern part of Thailand, on Aedes aegypti. Studies on larvicidal properties of plant extracts against the fourth instar larvae revealed that extracts of 14 species showed evidence of larvicidal activity. Eight out of the 14 plant species showed 100% mosquito larvae mortality. The LC50 values were less than 100μg/mL （4.1μg/ mL-89.4μg/mL）. Six plant species were comparatively more effective against the fourth instar larvae at very low concentrations. These extracts demonstrated no or very low toxicity to guppy fish （Poecilia reticulata）, which was selected to represent most common non-target organism found in habitats ofAe. aegypti, at concentrations active to mosquito larvae. Three medicinal plants with promising larvicidal activity, having LC50 and LC50 values being 4.1 and 16.4 μg/mL for Mammea siamensis, 20.2 and 34.7 μg/mL forAnethum graveolens and 67.4 and 110.3μg/mL forAnnona muricata, respectively, were used to study the impact of the extracts on the life cycle ofAe. aegypti. These plants affected pupal and adult mortality and also affected the reproductive potential of surviving adults by reducing the number of eggs laid and the percentage of egg hatchability. When each larval stage was treated with successive extracts at the LC50 value, the first instar larvae were found to be very susceptible to A. muricata and the second instar larvae were found to be susceptible to A. graveolens, while the third and fourth instar larvae were found to be susceptible to M. siamensis. These extracts delayed larval development and inhibited adult emergence and had no adverse effects on P. reticulata at LC50 and LC50 values, except for the M. siamensis extract at its LC50 value.展开更多
The importance of predation risk as a key driver of evolutionary change is exemplified by the Northern Range in Trinidad, where research on guppies living in multiple parallel streams has pro- vided invaluable insight...The importance of predation risk as a key driver of evolutionary change is exemplified by the Northern Range in Trinidad, where research on guppies living in multiple parallel streams has pro- vided invaluable insights into the process of evolution by natural selection. Although Trinidadian guppies are now a textbook example of evolution in action, studies have generally categorized predation as a dichotomous variable, representing high or low risk. Yet, ecologists appreciate that community structure and the attendant predation risk vary substantially over space and time. Here, we use data from a longitudinal study of fish assemblages at 16 different sites in the Northern Range to quantify temporal and spatial variation in predation risk. Specifically we ask： 1） Is there evidence for a gradient in predation risk？ 2） Does the ranking of sites （by risk） change with the defi- nition of the predator community （in terms of species composition and abundance currency）, and 3） Are site rankings consistent over time？ We find compelling evidence that sites lie along a contin- uum of risk. However, site rankings along this gradient depend on how predation is quantified in terms of the species considered to be predators and the abundance currency is used. Nonetheless, for a given categorization and currency, rankings are relatively consistent over time. Our study sug- gests that consideration of predation gradients will lead to a more nuanced understanding of the role of predation risk in behavioral and evolutionary ecology. It also emphasizes the need to justify and report the definition of predation risk being used.展开更多
Objective:To determine toxicity and safety margins of trichlorofon in different species as trichlorofon toxicity has a large variation in the susceptibility of different species.Methods:In this research,four viviparou...Objective:To determine toxicity and safety margins of trichlorofon in different species as trichlorofon toxicity has a large variation in the susceptibility of different species.Methods:In this research,four viviparous aquarium fish were exposed to trichlorofon for 96 h.LC_(50)of 24 h,48 h,72 h and 96 h were attained by probit analysis software SPSS Version 16.Fish samples were exposed to different concentrations of trichlorofon(5,10,20 and 40 mg/L)for 96 h and mortality were recorded,separately.Results:The 96 h LC_(50)of Poecilia latipinna,Poecilia reticulata a,Gambusia holbrooki and Xiphophorus helleri were 9.80,9.80,9.95 and 7.99 mg/L,respectively.Conclusions:According to the results of this research,LC_(50)values indicated Xiphophorus helleri was the most resistant and Gambusia holbrooki,with a few differences,was the most sensitive species compared with the fishes examined.展开更多
The present studies describe Chromosomal aberration effects of electrofishing, which were evaluated on Poecilia latipinna, located in Shat Al-Arab river in Al-garmma city (south of Iraq). The electrofishing derive use...The present studies describe Chromosomal aberration effects of electrofishing, which were evaluated on Poecilia latipinna, located in Shat Al-Arab river in Al-garmma city (south of Iraq). The electrofishing derive used in work is simulated to that used in the commercial fishing. The apparatus generates voltage ranged from 40 to 280 volts. Nine bearers of Poecilia latipinna sailfin molly fish in chromosomal analysis were divided into three treatments. The first were a control, the fishes of the second were exposed to 110 volts (10 seconds), and final groups were exposed to 110 volts (15 seconds). Mitotic index of the electrofishing with a control for each group decreased with increasing exposed time in somatic cell kidney tissue of Poecilia latipinna. The chromosome aberration analysis revealed a significant increase in the most frequent aberration per 150 metaphase in analyzed groups (1.33 in T1 groups, 39.33 in T2 groups) was chromosome break, fragment, range chromosome, Sticky chromosome mean, were higher in comparison to non exposed electrical shock fishing groups (control groups T1). At the same time, it showed a higher positive correlation of total chromosome aberration frequencies between T1 and T2 groups, while, all fishes died in T3 groups. According to our results, we represented the first record in Iraq.展开更多
Objective:To describe the occurrence of various spinal deformations in a captive-bred wild line of Poecilia wingei(P.wingei).Methods:Fish belonging to a wild line of P.wingei caught from Laguna de Los Patos,Venezuela,...Objective:To describe the occurrence of various spinal deformations in a captive-bred wild line of Poecilia wingei(P.wingei).Methods:Fish belonging to a wild line of P.wingei caught from Laguna de Los Patos,Venezuela,were bred in an aquarium home-breeding system during a period of three years(2006-2009).The spinal curvature was observed to study spinal deformities in P.wingei.Results:Out of a total of 600 fish,22 showed different types of deformities(scoliosis,lordosis,kyphosis),with a higher incidence in females.Growth,swimming and breeding of deformed fish were generally normal.Conclusions:Possible causes for spinal curvature in fish are discussed on the basis of the current literature.While it is not possible to determine the exact cause(s)of spinal deformities observed in the present study,traumatic injuries,nutritional imbalances,genetic defects or a combination of these factors can be supposed to be involved in the pathogenesis of such lesions.展开更多
Although the majority of studies on mate choice focus on female mate choice, there is growing recognition of the role of male mate choice too. Male mate choice is tightly linked to 2 other phenomena： female competiti...Although the majority of studies on mate choice focus on female mate choice, there is growing recognition of the role of male mate choice too. Male mate choice is tightly linked to 2 other phenomena： female competition for males and ornamentation in females. In the current article, I review the existing literature on this in a group of fishes, Poeciliidae. In this group, male mate choice appears to be based on differences in female quality, especially female size, which is a proxy for fecundity. Some males also have to choose between heterospecific and conspecific females in the unusual mating system of the Amazon molly. In this case, they typically show a preference for conspecific females. Whereas male mate choice is relatively well documented for this family, female ornamentation and female competition are not.展开更多
Sensory drive predicts coevolution of mate choice signals with the sensory systems detecting those sig nals. Guppies are a classic model for sensory drive as mate preferences based on coloration differ across individu...Sensory drive predicts coevolution of mate choice signals with the sensory systems detecting those sig nals. Guppies are a classic model for sensory drive as mate preferences based on coloration differ across individuals and populations. A large body of work has identified variation in color vision, yet we lack a dir ect tie between how such variation in color vision influences variation in color preference. Here we bring together studies that have investigated guppy vision over the past 40years to： （1） highlight our current understanding of where variation occurs in the guppy color vision pathway and （2） suggest future ave nues of research into sources of visual system variation that could influence guppy color preference. This will allow researchers to design careful studies that couple measures of color preference with measures of visual system variation from the same individual or population. Such studies will finally provide im portant answers as to what sets the direction and speed of mate preference evolution via sensory drive.展开更多
Producing sperm is costly and males have been selected to strategically adjust their sperm produc- tion and/or expenditure according to the fitness return associated with a specific mating. For exam- ple, males respon...Producing sperm is costly and males have been selected to strategically adjust their sperm produc- tion and/or expenditure according to the fitness return associated with a specific mating. For exam- ple, males respond to fluctuations in the mating opportunities by adjusting the number of ＂ready＂ sperm. This phenomenon is known as ＂sperm priming＂ and is interpreted as a strategy to econo- mize the investment in sperm. The cost and benefits of the sperm priming response, however, are expected to depend on a male＇s baseline sperm production （BSP） in the absence of females, because of the different risk of sperm depletion and the nonlinearly increasing costs of sperm pro- duction. We tested this prediction in 2 replicated lines of male guppies Poecilia reticulata that were artificially selected for high and low BSP. BSP has a large genetic variance and a high sire heritabil- ity in guppies, and males respond to the perceived mating opportunities by increasing the number of ＂ready＂ sperm. We investigated whether males with a different BSP differed in their sperm pri- ming response. We found that when the perceived mating opportunities increased, males from low-sperm lines had a stronger sperm priming response than those from high-sperm lines. This result suggests that adaptive plasticity in sperm priming has the potential to evolve in response to different levels of BSP. The comparison between guppy populations with different levels of sperm production would allow to test whether the pattern reported here is also observed at the interpopulation level.展开更多
During adaptation to different habitat types, both morphological and behavioral traits can undergo divergent selection. Males often fight for status in dominance hierarchies and rank positions predict reproductive suc...During adaptation to different habitat types, both morphological and behavioral traits can undergo divergent selection. Males often fight for status in dominance hierarchies and rank positions predict reproductive success. Ecotypes with reduced fighting abilities should have low reproductive success when migrating into habitats that harbor ecotypes with superior fighting abilities. Livebearing fishes in the Poecilia mexicana-species complex inhabit not only regular freshwater environments, but also independently colonized sulfidic （H2S-containing） habitats in three river drainages. In the current study, we found fighting intensities in staged contests to be considerably lower in some but not all sulfidic surface ecotypes and the sulfidic cave ecotype compared with populations from non-sulfidic surface sites. This is perhaps due to selection imposed by H2S, which hampers oxygen uptake and transport, as well as cellular respiration. Furthermore, migrants from sulfidic habitats may lose fights even if they do not show overall reduced aggressiveness, as phys- iological performance is likely to be challenged in the non-sulfidic environment to which they are not adapted. To test this hypothesis, we simulated migration of H2S-adapted males into H2S-free waters, as well as H2S-adapted cave-dwelling males into sulfidic surface waters. We found that intruders established dominance less often than resident males, independent of whether or not they showed reduced aggressiveness overall. Our study shows that divergent evolution of male aggressive behavior may also contribute to the maintenance of genetic differentiation in this system and we call for more careful evaluation of male fighting abilities in studies on ecological speciation.展开更多
A major advantage of animal aggregations concerns cooperative antipredator strategies.Schooling behavior emerges earlier in many fish species,especially in those cannibalizing their offspring.Experience is fundamental...A major advantage of animal aggregations concerns cooperative antipredator strategies.Schooling behavior emerges earlier in many fish species,especially in those cannibalizing their offspring.Experience is fundamental for developing schooling behavior.However,the cognitive ability of naive newborn fish to aggregate remains unclear.Herein,Poecilia reticulata,was selected as model organism to investigate how combinations of biomimetic robotic agents and adult conspecific olfactory cues affect collective responses in newborns.The role of white and brown backgrounds in evoking aggregations was also assessed.Olfactory cues were sufficient for triggering aggregations in P.reticulata newborns,although robotic agents had a higher influence on the group coalescence.The combination of robotic agents and olfactory cues increased schooling behavior duration.Notably,schooling was longer in the escape compartment when robotic agents were presented,except for the combination of the male-mimicking robotic fish plus adult guppy olfactory cues,with longer schooling behavior in the exploring compartment.Regardless of the tested cues,newborn fish aggregated preferentially on the brown areas of the arena.Overall,this research provides novel insights on the early collective cognitive ability of newborn fish,paving the way to the use of biomimetic robots in behavioral ecology experiments,as substitutes for real predators.展开更多
The full length cDNA of a prion protein (PrP) encoding gene of guppy (Poecilia reticulata) and the corresponding ge-nomic DNA were cloned. The cDNA was 2245 bp in length and contained an open reading frame (ORF) of 15...The full length cDNA of a prion protein (PrP) encoding gene of guppy (Poecilia reticulata) and the corresponding ge-nomic DNA were cloned. The cDNA was 2245 bp in length and contained an open reading frame (ORF) of 1545 bp encoding a pro-tein of 515 amino acids,which held all typical structural characteristics of the functional PrP. The cloned genomic DNA fragment corresponding to the cDNA was 3720 bp in length,consisting of 2 introns and 2 exons. The 5’ untranslated region of cDNA origi-nated from the 2 exons,while the ORF originated from the second exon. Although the gene was transcribed in diverse tissues in-cluding brain,eye,liver,intestine,muscle and tail,its transcript was most abundant in the brain. In addition,the transcription of the gene was enhanced by 5 salinity,implying that it was associated with the response of guppy to saline stress.展开更多
Guppies( Poecilia reticulata) are considered a candidate model species for the identification and testing of endocrine-disrupting chemicals. Male guppies may be used to address the challenge of making potential linkag...Guppies( Poecilia reticulata) are considered a candidate model species for the identification and testing of endocrine-disrupting chemicals. Male guppies may be used to address the challenge of making potential linkages between alterations of biomarkers, both at the cellular and organ level, and adverse outcomes. In the present study, a predictive relationship between sex characteristics and reproductive output was observed in male guppies that underwent a long-term toxicity test with 0.5 μg/L 17 β-estradiol administered during the juvenile period. Radioimmunoassay and western blot analyses demonstrated that 17 β-estradiol exposure caused a significant increase in testicular 17 β-estradiol levels as well as the induction of exposure biomarkers, namely hepatic vitellogenin. Exposure to 17 β-estradiol also caused a significant decrease in testosterone levels, which consequently reduced the gonadosomatic index, sperm counts, and the coloration index. These changes of male sexual characteristics further translated into adverse influences on reproduction, as measured by a decrease in offspring production and survival rate. Our results suggest that the above-mentioned sexual characteristics of male guppies may be considered potential in vivo biomarkers of estrogen effects on reproduction.展开更多
The Muller-Lyer illusion is a well-known distortion illusion that occurs when the spatial arrangement of inducers(i.e.,inwards-or outwards-pointing arrowheads)influences a line's perceived relative length.To date,...The Muller-Lyer illusion is a well-known distortion illusion that occurs when the spatial arrangement of inducers(i.e.,inwards-or outwards-pointing arrowheads)influences a line's perceived relative length.To date,this illusion has been reported in several animal species but only in 1 teleost fish(i.e.,redtail splitfins Xenotoca eiseni),although teleost fish represent approximately 50%of vertebrate diversity.We investigated the perception of this illusion in another teleost fish:guppies Poecilia reticulata,a species that diverged from the redtail splitfin 65 million years ago.The guppies were trained to select the longer between 2 lines;after meeting the learning criterion,illusory trials were presented.Control trials were also arranged to exclude the possibility that their choices were based on potential spatial biases that relate to the illusory pattern.The guppies'overall performance indicated that they were susceptible to the Muller-Lyer illusion,perceiving the line with the inwards-pointing arrowheads as longer.The performance in the control trials excluded the possibility that the subjects used the physical differences between the 2 figures as the discriminative cue in the illusory trials.Our study suggests that sensibility to the Muller-Lyer illusion could be widespread across teleost fish and reinforces the idea that the perceptual mechanisms underlying size estimation might be similar across vertebrates.展开更多
文摘Holographic quantitative structure activity relationship(HQSAR) is an emerging QSAR technique with the combined application of molecular hologram, which encoded the frequency of occurrence of various molecular fragment types, and the subsequent partial least squares(PLS) regression analysis. In this paper, the acute toxicity data to the guppy( poecilia reticulata) for a series of 56 substituted benzenes, phenols, aromatic amines and nitro aromatics were subjected and this resulted in a model with a high predictive ability. The influence of fragment size and fragment distinction parameters on the quality of HQSAR model was investigated. The robustness and predictive ability of the model were also validated by leave one out (LOO) cross validation procedure and external testing data set.
文摘A preliminary study was conducted to investigate the effects of the extracts of 112 medicinal plant species, collected from the southern part of Thailand, on Aedes aegypti. Studies on larvicidal properties of plant extracts against the fourth instar larvae revealed that extracts of 14 species showed evidence of larvicidal activity. Eight out of the 14 plant species showed 100% mosquito larvae mortality. The LC50 values were less than 100μg/mL （4.1μg/ mL-89.4μg/mL）. Six plant species were comparatively more effective against the fourth instar larvae at very low concentrations. These extracts demonstrated no or very low toxicity to guppy fish （Poecilia reticulata）, which was selected to represent most common non-target organism found in habitats ofAe. aegypti, at concentrations active to mosquito larvae. Three medicinal plants with promising larvicidal activity, having LC50 and LC50 values being 4.1 and 16.4 μg/mL for Mammea siamensis, 20.2 and 34.7 μg/mL forAnethum graveolens and 67.4 and 110.3μg/mL forAnnona muricata, respectively, were used to study the impact of the extracts on the life cycle ofAe. aegypti. These plants affected pupal and adult mortality and also affected the reproductive potential of surviving adults by reducing the number of eggs laid and the percentage of egg hatchability. When each larval stage was treated with successive extracts at the LC50 value, the first instar larvae were found to be very susceptible to A. muricata and the second instar larvae were found to be susceptible to A. graveolens, while the third and fourth instar larvae were found to be susceptible to M. siamensis. These extracts delayed larval development and inhibited adult emergence and had no adverse effects on P. reticulata at LC50 and LC50 values, except for the M. siamensis extract at its LC50 value.
文摘The importance of predation risk as a key driver of evolutionary change is exemplified by the Northern Range in Trinidad, where research on guppies living in multiple parallel streams has pro- vided invaluable insights into the process of evolution by natural selection. Although Trinidadian guppies are now a textbook example of evolution in action, studies have generally categorized predation as a dichotomous variable, representing high or low risk. Yet, ecologists appreciate that community structure and the attendant predation risk vary substantially over space and time. Here, we use data from a longitudinal study of fish assemblages at 16 different sites in the Northern Range to quantify temporal and spatial variation in predation risk. Specifically we ask： 1） Is there evidence for a gradient in predation risk？ 2） Does the ranking of sites （by risk） change with the defi- nition of the predator community （in terms of species composition and abundance currency）, and 3） Are site rankings consistent over time？ We find compelling evidence that sites lie along a contin- uum of risk. However, site rankings along this gradient depend on how predation is quantified in terms of the species considered to be predators and the abundance currency is used. Nonetheless, for a given categorization and currency, rankings are relatively consistent over time. Our study sug- gests that consideration of predation gradients will lead to a more nuanced understanding of the role of predation risk in behavioral and evolutionary ecology. It also emphasizes the need to justify and report the definition of predation risk being used.
基金Supported by the Gorgan University of Agriculture Science and Natural Resource(Grant No.6177515-5).
文摘Objective:To determine toxicity and safety margins of trichlorofon in different species as trichlorofon toxicity has a large variation in the susceptibility of different species.Methods:In this research,four viviparous aquarium fish were exposed to trichlorofon for 96 h.LC_(50)of 24 h,48 h,72 h and 96 h were attained by probit analysis software SPSS Version 16.Fish samples were exposed to different concentrations of trichlorofon(5,10,20 and 40 mg/L)for 96 h and mortality were recorded,separately.Results:The 96 h LC_(50)of Poecilia latipinna,Poecilia reticulata a,Gambusia holbrooki and Xiphophorus helleri were 9.80,9.80,9.95 and 7.99 mg/L,respectively.Conclusions:According to the results of this research,LC_(50)values indicated Xiphophorus helleri was the most resistant and Gambusia holbrooki,with a few differences,was the most sensitive species compared with the fishes examined.
文摘The present studies describe Chromosomal aberration effects of electrofishing, which were evaluated on Poecilia latipinna, located in Shat Al-Arab river in Al-garmma city (south of Iraq). The electrofishing derive used in work is simulated to that used in the commercial fishing. The apparatus generates voltage ranged from 40 to 280 volts. Nine bearers of Poecilia latipinna sailfin molly fish in chromosomal analysis were divided into three treatments. The first were a control, the fishes of the second were exposed to 110 volts (10 seconds), and final groups were exposed to 110 volts (15 seconds). Mitotic index of the electrofishing with a control for each group decreased with increasing exposed time in somatic cell kidney tissue of Poecilia latipinna. The chromosome aberration analysis revealed a significant increase in the most frequent aberration per 150 metaphase in analyzed groups (1.33 in T1 groups, 39.33 in T2 groups) was chromosome break, fragment, range chromosome, Sticky chromosome mean, were higher in comparison to non exposed electrical shock fishing groups (control groups T1). At the same time, it showed a higher positive correlation of total chromosome aberration frequencies between T1 and T2 groups, while, all fishes died in T3 groups. According to our results, we represented the first record in Iraq.
基金Supported by a grant from University of Teramo(Research Projects 60%/2009)
文摘Objective:To describe the occurrence of various spinal deformations in a captive-bred wild line of Poecilia wingei(P.wingei).Methods:Fish belonging to a wild line of P.wingei caught from Laguna de Los Patos,Venezuela,were bred in an aquarium home-breeding system during a period of three years(2006-2009).The spinal curvature was observed to study spinal deformities in P.wingei.Results:Out of a total of 600 fish,22 showed different types of deformities(scoliosis,lordosis,kyphosis),with a higher incidence in females.Growth,swimming and breeding of deformed fish were generally normal.Conclusions:Possible causes for spinal curvature in fish are discussed on the basis of the current literature.While it is not possible to determine the exact cause(s)of spinal deformities observed in the present study,traumatic injuries,nutritional imbalances,genetic defects or a combination of these factors can be supposed to be involved in the pathogenesis of such lesions.
文摘Although the majority of studies on mate choice focus on female mate choice, there is growing recognition of the role of male mate choice too. Male mate choice is tightly linked to 2 other phenomena： female competition for males and ornamentation in females. In the current article, I review the existing literature on this in a group of fishes, Poeciliidae. In this group, male mate choice appears to be based on differences in female quality, especially female size, which is a proxy for fecundity. Some males also have to choose between heterospecific and conspecific females in the unusual mating system of the Amazon molly. In this case, they typically show a preference for conspecific females. Whereas male mate choice is relatively well documented for this family, female ornamentation and female competition are not.
文摘Sensory drive predicts coevolution of mate choice signals with the sensory systems detecting those sig nals. Guppies are a classic model for sensory drive as mate preferences based on coloration differ across individuals and populations. A large body of work has identified variation in color vision, yet we lack a dir ect tie between how such variation in color vision influences variation in color preference. Here we bring together studies that have investigated guppy vision over the past 40years to： （1） highlight our current understanding of where variation occurs in the guppy color vision pathway and （2） suggest future ave nues of research into sources of visual system variation that could influence guppy color preference. This will allow researchers to design careful studies that couple measures of color preference with measures of visual system variation from the same individual or population. Such studies will finally provide im portant answers as to what sets the direction and speed of mate preference evolution via sensory drive.
文摘Producing sperm is costly and males have been selected to strategically adjust their sperm produc- tion and/or expenditure according to the fitness return associated with a specific mating. For exam- ple, males respond to fluctuations in the mating opportunities by adjusting the number of ＂ready＂ sperm. This phenomenon is known as ＂sperm priming＂ and is interpreted as a strategy to econo- mize the investment in sperm. The cost and benefits of the sperm priming response, however, are expected to depend on a male＇s baseline sperm production （BSP） in the absence of females, because of the different risk of sperm depletion and the nonlinearly increasing costs of sperm pro- duction. We tested this prediction in 2 replicated lines of male guppies Poecilia reticulata that were artificially selected for high and low BSP. BSP has a large genetic variance and a high sire heritabil- ity in guppies, and males respond to the perceived mating opportunities by increasing the number of ＂ready＂ sperm. We investigated whether males with a different BSP differed in their sperm pri- ming response. We found that when the perceived mating opportunities increased, males from low-sperm lines had a stronger sperm priming response than those from high-sperm lines. This result suggests that adaptive plasticity in sperm priming has the potential to evolve in response to different levels of BSP. The comparison between guppy populations with different levels of sperm production would allow to test whether the pattern reported here is also observed at the interpopulation level.
文摘During adaptation to different habitat types, both morphological and behavioral traits can undergo divergent selection. Males often fight for status in dominance hierarchies and rank positions predict reproductive success. Ecotypes with reduced fighting abilities should have low reproductive success when migrating into habitats that harbor ecotypes with superior fighting abilities. Livebearing fishes in the Poecilia mexicana-species complex inhabit not only regular freshwater environments, but also independently colonized sulfidic （H2S-containing） habitats in three river drainages. In the current study, we found fighting intensities in staged contests to be considerably lower in some but not all sulfidic surface ecotypes and the sulfidic cave ecotype compared with populations from non-sulfidic surface sites. This is perhaps due to selection imposed by H2S, which hampers oxygen uptake and transport, as well as cellular respiration. Furthermore, migrants from sulfidic habitats may lose fights even if they do not show overall reduced aggressiveness, as phys- iological performance is likely to be challenged in the non-sulfidic environment to which they are not adapted. To test this hypothesis, we simulated migration of H2S-adapted males into H2S-free waters, as well as H2S-adapted cave-dwelling males into sulfidic surface waters. We found that intruders established dominance less often than resident males, independent of whether or not they showed reduced aggressiveness overall. Our study shows that divergent evolution of male aggressive behavior may also contribute to the maintenance of genetic differentiation in this system and we call for more careful evaluation of male fighting abilities in studies on ecological speciation.
基金supported by the H2020 Project"Submarine cultures perform long-term robotic exploration of unconventional environmental niches"(subCULTron)(No.640967FP7)。
文摘A major advantage of animal aggregations concerns cooperative antipredator strategies.Schooling behavior emerges earlier in many fish species,especially in those cannibalizing their offspring.Experience is fundamental for developing schooling behavior.However,the cognitive ability of naive newborn fish to aggregate remains unclear.Herein,Poecilia reticulata,was selected as model organism to investigate how combinations of biomimetic robotic agents and adult conspecific olfactory cues affect collective responses in newborns.The role of white and brown backgrounds in evoking aggregations was also assessed.Olfactory cues were sufficient for triggering aggregations in P.reticulata newborns,although robotic agents had a higher influence on the group coalescence.The combination of robotic agents and olfactory cues increased schooling behavior duration.Notably,schooling was longer in the escape compartment when robotic agents were presented,except for the combination of the male-mimicking robotic fish plus adult guppy olfactory cues,with longer schooling behavior in the exploring compartment.Regardless of the tested cues,newborn fish aggregated preferentially on the brown areas of the arena.Overall,this research provides novel insights on the early collective cognitive ability of newborn fish,paving the way to the use of biomimetic robots in behavioral ecology experiments,as substitutes for real predators.
基金the Key Laboratory of Freshwater Germplasm and Biotechnology of Chinese Ministry of Agriculture,Yangtze River Fisheries Research Institute,Chinese Academy of Fishery Sciences (LFB20070601)the Key Laboratory of Mariculture of Chinese Ministry of Education,Ocean University of ChinaNational High Technology Research and Development Program of China (2007AA09Z427)
文摘The full length cDNA of a prion protein (PrP) encoding gene of guppy (Poecilia reticulata) and the corresponding ge-nomic DNA were cloned. The cDNA was 2245 bp in length and contained an open reading frame (ORF) of 1545 bp encoding a pro-tein of 515 amino acids,which held all typical structural characteristics of the functional PrP. The cloned genomic DNA fragment corresponding to the cDNA was 3720 bp in length,consisting of 2 introns and 2 exons. The 5’ untranslated region of cDNA origi-nated from the 2 exons,while the ORF originated from the second exon. Although the gene was transcribed in diverse tissues in-cluding brain,eye,liver,intestine,muscle and tail,its transcript was most abundant in the brain. In addition,the transcription of the gene was enhanced by 5 salinity,implying that it was associated with the response of guppy to saline stress.
基金Supported by the National Natural Science Foundation of China(No.31202001)the Natural Science Foundation of Shandong Province,China(No.ZR2012CQ010)
文摘Guppies( Poecilia reticulata) are considered a candidate model species for the identification and testing of endocrine-disrupting chemicals. Male guppies may be used to address the challenge of making potential linkages between alterations of biomarkers, both at the cellular and organ level, and adverse outcomes. In the present study, a predictive relationship between sex characteristics and reproductive output was observed in male guppies that underwent a long-term toxicity test with 0.5 μg/L 17 β-estradiol administered during the juvenile period. Radioimmunoassay and western blot analyses demonstrated that 17 β-estradiol exposure caused a significant increase in testicular 17 β-estradiol levels as well as the induction of exposure biomarkers, namely hepatic vitellogenin. Exposure to 17 β-estradiol also caused a significant decrease in testosterone levels, which consequently reduced the gonadosomatic index, sperm counts, and the coloration index. These changes of male sexual characteristics further translated into adverse influences on reproduction, as measured by a decrease in offspring production and survival rate. Our results suggest that the above-mentioned sexual characteristics of male guppies may be considered potential in vivo biomarkers of estrogen effects on reproduction.
基金This study was supported by a“STARS@unipd”(ANIM_ILLUS)awarded to Christian Agrillo.
文摘The Muller-Lyer illusion is a well-known distortion illusion that occurs when the spatial arrangement of inducers(i.e.,inwards-or outwards-pointing arrowheads)influences a line's perceived relative length.To date,this illusion has been reported in several animal species but only in 1 teleost fish(i.e.,redtail splitfins Xenotoca eiseni),although teleost fish represent approximately 50%of vertebrate diversity.We investigated the perception of this illusion in another teleost fish:guppies Poecilia reticulata,a species that diverged from the redtail splitfin 65 million years ago.The guppies were trained to select the longer between 2 lines;after meeting the learning criterion,illusory trials were presented.Control trials were also arranged to exclude the possibility that their choices were based on potential spatial biases that relate to the illusory pattern.The guppies'overall performance indicated that they were susceptible to the Muller-Lyer illusion,perceiving the line with the inwards-pointing arrowheads as longer.The performance in the control trials excluded the possibility that the subjects used the physical differences between the 2 figures as the discriminative cue in the illusory trials.Our study suggests that sensibility to the Muller-Lyer illusion could be widespread across teleost fish and reinforces the idea that the perceptual mechanisms underlying size estimation might be similar across vertebrates.
