Download or read book The Effects of Predation Risk on Phenotypic and Hatching Time Variation in Fathead Minnow i pimephales Promelas i Embryos written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Predation has long been recognized as a strong selective force influencing the behaviour, morphology and life history traits of prey species. Some prey species have the ability to alter their phenotypes in response to predation threat, to decrease their chances of being detected, caught and/or consumed by predators. It has also been demonstrated that some species have control over the timing of transition between one specific life stage and the next. This ability gives the prey control over how much time it spends in a risky stage. A particularly vulnerable stage for many prey fishes is that of the embryo, as they are a major prey item for many invertebrate and vertebrate predators. As such, strong selection pressure should exist for the development of anti-predator defenses specific for this time period. In a series of four experiments I assessed the ability of fathead minnow embryos to alter their hatching time and/or phenotype in response to various predation threats. In the first three experiments injured embryo cue was used to simulate a predation threat, as it has been shown to represent a general predation risk for many aquatic animals. In the fourth experiment predator odour was used in conjunction with injured embryo cues. Results of a power analysis conducted on the first three experiments determined with 95% confidence that fathead minnow embryos do not alter their hatch time in response to injured embryo cues. However, the embryos in the predation treatment did hatch with an altered phenotype; fry were significantly smaller (total body length) when exposed to predation cues. In the fourth experiment the embryos hatched with the same altered morphology in response to injured embryo cues combined with predator cues. Moreover, in this experiment the embryos hatched faster in the predation treatment than the control treatment. This is the first empirical evidence that fish can alter their hatching time in response to predation.
Download or read book The Effects of Predation Risk on Phenotypic and Hatching Time Variation in Fathead Minnow Pimephales Promelas Embryos written by Robin Christine Kusch and published by . This book was released on 2009 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Embryonic Antipredator Defenses and Behavioral Carryover Effects in the Fathead Minnow Pimephales Promelas written by Christopher Crowder and published by . This book was released on 2021 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Most research on embryonic learning and behavior in aquatic vertebrates has focused on fitness benefits after hatching, but the ability of embryos to perceive and respond to environmental stimuli may also have immediate adaptive value. Here, we examined whether fathead minnow embryos, Pimephales promelas, detect and respond to cues indicative of predation risk, and whether the embryonic environment influences behavior after hatching. We compared the behavior of 5-dpf embryos reared in the presence or absence of olfactory alarm cue, alone or in combination with cues of a piscivorous predator (Bluegill sunfish, Lepomis macrochirus). Next, we reared larvae from the embryonic treatments to 21 dpf, and tested them in two antipredator behavioral assays varying in the degree of immediate risk (predator avoidance vs attack evasion). Embryos that developed in perceived high-risk conditions exhibited reduced activity compared to those from low-risk environments. Larvae from high-risk environments also showed enhanced antipredator behavior, and evidence for embryonic predator learning. These data provide new insight into the learning capabilities and antipredator behaviors of aquatic vertebrate embryos.
Download or read book Canadian Journal of Zoology written by and published by . This book was released on 2004 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Maternal Transfer of Dietary Methylmercury and Implications for Embryotoxicity in Fathead Minnows Pimephales Promelas written by Kristin N. Bridges and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Mercury (Hg) is a ubiquitous environmental contaminant, which is capable of global atmospheric transport. As a result, even the most pristine aquatic ecosystems are affected by atmospheric Hg deposition, following which microbial transformation yield organic Hg forms, the most concerning of which is methylmercury (MeHg). Methylmercury is capable of bioaccumulation and biomagnification in food webs, resulting in potentially toxic body burdens due to regular dietary exposure in long-lived organisms at higher trophic levels. It is also a molecular mimic of some endogenous amino acids, providing a route of transfer from mother to offspring via large amino acid transporters. Exposure during neurodevelopment can lead to serious, irreversible neurological dysfunction, associated with a variety of cognitive and motor abnormalities across species. The present studies evaluate the effects of maternally-transferred dietary MeHg, at environmentally relevant concentrations on early life stage fathead minnows (Pimephales promelas). Embryos were collected from adult fatheads exposed to one of three diets with varying concentrations of MeHg for 30 days. Adult reproductive metrics were also monitored over the course of the study, with results indicating no effects on spawning frequency, clutch size, or total egg output. In embryos, Hg concentration was a function of female diet and the duration (number of days) of female exposure. Offspring spawned in tanks administered the low Hg diet displayed altered embryonic movement patterns (hyperactivity), decreased time to hatch, decreased mean larval size, and alterations to several metabolite abundances when compared with controls. Significantly altered metabolites include those associated with cellular energetics, fatty acid metabolism, and polyamine synthesis, indicating current environmental exposure scenarios are sufficient to disrupt important cellular pathways. Dysregulation of the dopaminergic system of embryos is also characterized, and may be a possible mechanism by which hyperactive behaviors are observed in these embryos. Offspring from tanks administered the high Hg diet exhibited delayed hatching, increased mortality, and physiological abnormalities. Brain tissue of exposed adults from the low diet were dissected into regions, and also evaluated for alterations in dopamine cycling. Collectively, these results indicate current exposure scenarios in North American lakes and rivers are sufficient to cause reductions in fitness and survival of early life stage fish. The potential for community structure impacts exists, as sensitive individuals and species become disproportionately affected by chronic, low-level MeHg exposure
Download or read book Influence of Diet and Starvation on Toxicity of Endrin to Fathead Minnows Pimephales Promelas written by Göran Dave and published by . This book was released on 1981 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Prehatching Development of the Fathead Minnow pimephales Promelas Rafinesque written by United States. Environmental Protection Agency. Office of Research and Development and published by . This book was released on 1996 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: The fathead minnow, Pimephales promelas Raf., presents a classical model of teleostean embryogenesis. Its prehatching development has been divided into 32 stages, each representing an easily observed interval in the developmental continuum. Embryos were examined live and histologically under controlled laboratory conditions. Fertilization, early cleavage, epiboly, and organogenesis are very similar to that of other cyprinids except for the tiiming of the appearance of specific structures. Hatching was found to occur in approximately 120 hours post-fertilization at 25 degrees celcius. Rapid embryonic development, coupled with a short generation time of 3-6 months under laboratory conditions, make it a useful native North American species for studies in experimental embryology.
Download or read book Determinants and Consequences of Perceived Predation Risk From Individual Behavior to Transgenerational Effects written by Chiara Morosinotto and published by Frontiers Media SA. This book was released on 2022-05-27 with total page 107 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Temporal Variation in Predation Risk on Predator prey Interactions written by Matthew D. Kenworthy and published by . This book was released on 2011 with total page 112 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Photoperiod on the Reproductive Success of Fathead Minnows Pimephales Promelas written by John Buchanan Clayton and published by . This book was released on 1997 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mothers Transfer Information Via Eggs Effect of Mothers Experience with Predators on Offspring written by Eric R. Giesing and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Parents play an important role in creating phenotypic variation in their offspring through genetic and environmental mechanisms. For example, mothers can influence their offspring via hormonally-mediated maternal effects. In this study, offspring of mothers that had been exposed to a predator during oogenesis (experimental) were compared to offspring of mothers that had not been exposed to a predator (control). I measured the consequences of maternal exposure to predation risk on the number and size of eggs, egg cortisol content, metabolic rates of eggs, and the growth and behavior of juvenile threespined sticklebacks (Gasterosteus aculeatus). Exposure to a predator during oogenesis caused females to produce larger eggs and heavier clutches, but there was no effect on the number of eggs per clutch. The concentration of cortisol was higher in experimental eggs than control eggs. Experimental eggs also breathed faster soon after fertilization, but the difference between control and experimental eggs in oxygen consumption attenuated over time. Standard length of juveniles increased over the course of the experiment, but there was no effect of treatment on growth during the period when the fry were measured. Shoaling behavior, an antipredator response, was measured from photographs, and was estimated as the nearest neighbor distance between individuals in each tank. Experimental females shoaled more tightly together prior to a mild disturbance. Both control and experimental juveniles shoaled more tightly together immediately following and two minutes after a mild disturbance. Altogether, these results suggest that the effect of mothers on their offspring might depend on a mothers' experience with stressors in the environment, and that mothers might manipulate the development, growth, and behavior of their offspring to match their future environment.
Download or read book Constraints on Phenotypic Plasticity in Response to Predation Risk written by Amanda M. Bennett and published by . This book was released on 2014 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Controlled Spawning of Laboratory Reared Fathead Minnows Pimephales Promelas and Effect of Different Diets on Survival and Growth of the Fry written by Stephen W. Duda and published by . This book was released on 1989 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Timing it Right written by Kecia Kerr and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Reproductive timing often affects reproductive success. Plants and animals in a multitude of habitats time reproduction to coincide with environmental conditions that are conducive to fertilization or offspring growth and survival. Many marine organisms time the release of planktonic larvae with large amplitude nocturnal tides. These conditions sweep the newly hatched offspring away from shore, and high densities of predators, while diurnally feeding predators are inactive. Experimental work has supported the hypothesis that these strong cycles of reproduction are driven by the avoidance of predators. However, how planktonic predation risk varies across interacting environmental cycles remains unclear. I used tethered adult and larval brine shrimp to assess the risk of predation across diel, tidal amplitude and seasonal cycles (upwelling vs. nonupwelling). The proportion of prey items lost was higher during the day than at night for larvae, but showed the opposite trend for adults. On the Pacific coast of Panama, the pattern of higher diurnal predation on larvae remained consistent across seasons, but risk increased overall during upwelling. Thus, the release of larvae at night should indeed increase early larval survival. Matching reproductive timing with particular times in environmental cycles may be hampered by the inverse effect of temperature on developmental rate. For brooding organisms that reproduce across seasonal changes in temperature, changes in incubation period will result in errors in timing of larval release if adjustments to temperature are not made. Using laboratory and field experiments, I examined the effect of temperature and temperature variation on the timing of larval release of two species of fiddler crabs both of which usually release larvae during large amplitude nocturnal tides. I found that Uca terpsichores maintained timing in the field during low but constant temperature but made errors in timing when temperature varied during incubation. Uca deichmanni maintained accurate and precise timing of larval release in the field despite variable temperature but released larvae late in cold conditions in the lab. To determine whether these species reduce temperature-induced timing errors by shifting when they mate, I measured courtship intensity across seasonal temperature changes at field sites with different thermal properties. Both species exhibit strong cycles of courtship linked with tidal amplitude that result in their strong cycles of larval release. I found that courtship cycles and tidal amplitude for U. deichmanni remained strongly correlated across spatial and temporal differences in temperature. In contrast, the relationship between courtship and tidal amplitude for U. terpsichores changed across sites and with seasonal temperature variation. U. terpsichores respond to temperature variation by changing when they mate while U. deichmanni do not. Predictions for the effect of climate change on seasonal upwelling of cold water include increased variability and increased intensity in upwelling. The predictive nature of adjustment by U. terpsichores means that they may be more vulnerable to timing errors with increased temperature variability while behavioural adjustments by U. deichmanni during incubation may make them more vulnerable to increased intensity of upwelling. The combination of timing errors that result from upwelling induced temperature variation and the seasonal increase in predation risk during upwelling may have significant impacts on early larval survival." --
Download or read book Acute Toxicities of Organic Chemicals to Fathead Minnows Pimephales Promelas written by L. T. Brooke and published by Lake Superior Research Institute. This book was released on 1990 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Evaluating a Predator Induced Phenotype in a Mixed Species Context written by Ellie Anne Baker and published by . This book was released on 2021 with total page 49 pages. Available in PDF, EPUB and Kindle. Book excerpt: Phenotypic plasticity, a single genotype producing multiple phenotypes in response to environmental change, is crucical to our understanding ecological and evolutionary processes. Adaptive plasticity describes phenotypic response wherein a subsequent fitness benefit is conferred to the plastic individual. Predator-induced plasticity is a well-studied form of adaptive plasticity. For instance, numerous tadpole species exposed to aquatic predators produce more muscular and brightly colored tail fins, which have been shown to improve survival chances in subsequent predator encounters compared to noninduced individuals. However, predator-induced phenotypes can be costly when expressed in a non-lethal environment. Current understanding of the relative costs and adaptive benefits of predator-induced plasticity is based on intraspecific comparisons. However, multiple species differing in their plastic abilities often co-occur and interact with one another in nature. Few studies have evaluated whether the adaptive benefits and relative costs of predator-induced plasticity are retained in multi-species assemblages (a more ecologically-relevant setting). We conducted a two-phased experiment to evaluate the adaptive value and relative costs of a predator-induced phenotype in tadpoles of the Pine Woods Treefrog, Hyla femoralis, in the presence and absence of a congeneric species, the Squirrel Treefrog (Hyla squirella). Hyla femoralis and H. squirella share ecological settings and close evolutionary ties, yet larval H. squirella does not exhibit the same phenotypic response (changes in body/tail morphology) to predation risk as larval H. femoralis does. In Phase I (Induction), single-species assemblages were assigned to one of two predator-exposure (induction) treatments: a non-lethal treatment with a caged dragonfly nymph or a control with no predator. After four weeks, H. femoralis tadpoles from both induction treatments were photographed for morphometric analysis to quantify any plastic responses ( change in morphology) to perceived predation risk. We found that larval H. femoralis morphology significantly differed between induced and noninduced populations. In Phase II (Predation Trials), tadpoles from single (H. femoralis only) and mixed-species assemblages (H. femoralis and H. squirella) were exposed to one of two predation treatments: a lethal, free-swimming predator treatment or a no-predator control. Periodic survival estimates were determined for both assemblages in lethal treatments to quantify possible survival advantages conferred by the inducible phenotype in larval H. femoralis. Growth metrics (size at emergence) and a development metric (time to emergence) were collected for both assemblages in control treatments to quantify possible costs associated with induced plasticity. Survival data supports that the adaptive advantage of increased survival in induced H. femoralis tadpoles is retained in mixed-species assemblages. Size at emergence in larval H. femoralis was not affected by induction treatment or assemblage type. Conversely, time-to emergence was significantly impacted by induction treatment. Induced H. femoralis tadpoles in both single and mixed-species assemblages took longer to reach metamorphosis, indicating predators likely have a stronger effect on developmental timelines than the presence of another tadpole species. This study aims to contribute revelatory insights into the ecology and maintenance of adaptive plasticity in natural, complex community systems.
Download or read book Prudent Females Effects of Food Availability and Predation Risk on Female Investment in Offspring written by Nicole Elizabeth Krauss and published by . This book was released on 2018 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: Life history theory posits a trade-off between investment in self and reproduction depending on environment. Because of their increased investment in prenatal offspring, females in particular may exercise prudence if environmental conditions are unfavorable. Changes in female investment can alter offspring phenotype, resulting in non-genetic plastic changes known as maternal effects, which can have lasting effects into adulthood. We asked how predation risk and food availability alter female investment in offspring in a migratory passerine bird, the black-throated blue warbler (Setophaga caerulescens ; BTBW). In chapter 1, we used an experimental approach to assess the effect of nest predation risk on female contributions to eggs. We found no difference in mass or yolk hormones between treatment and control eggs, suggesting that nest predation risk does not affect female investment during egg formation. In chapter 2, we explored how variation in food availability during egg formation may limit or alter prenatal investment in offspring. Surprisingly, we did not find a relationship between energetic investment in clutches and food availability but did find a negative relationship between two anabolic yolk androgens, testosterone and androstenedione, and food availability. The negative relationship between yolk androgens and food availability suggests that females may decrease androgens when food is ample to avoid the costs of maintaining high levels of androgens, and instead promote increased growth of their nestlings through increased feeding. In chapter 3, we used a 14-year data set to evaluate the effect of predation risk on female investment in prenatal and postnatal offspring, as well as offspring condition. These data included surveys of nest predators in a subset of BTBW territories, as well as clutch size, female feeding rates, nestling mass, and nestling age at fledge. We found no relationship between predation risk, female investment in offspring, and nestling phenotype. Together these chapters highlight the persistent investment in reproduction of female BTBWs, as they did not decrease investment in response to increased predation risk and had limited response to changes in food availability. This may be because the probability of successfully breeding in the future is too low to decrease current investment.
