Ryan L Earley

Ryan L Earley
University of Alabama | UA · Department of Biological Sciences

PhD

About

178
Publications
33,160
Reads
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3,936
Citations
Additional affiliations
August 2008 - present
University of Alabama
Position
  • Professor (Associate)
August 2006 - August 2008
California State University, Fresno
Position
  • Professor (Assistant)
June 2002 - August 2006
Georgia State University
Position
  • PostDoc Position

Publications

Publications (178)
Article
Full-text available
The aim of this study was to examine the potential differences in acute hemodynamic responses and muscular performance outcomes following resistance exercise between traditional blood flow restriction (TRABFR) and a novel band tissue flossing method (BTFBFR). Methods: Fifteen healthy young adults (23.27 ± 2.69 years) visited the lab for three ses...
Article
Full-text available
Colorful traits (i.e., ornaments) that signal quality have well-established relationships with individual condition and physiology. Furthermore, ornaments expressed in females may have indirect fitness effects in offspring via the prenatal physiology associated with, and social consequences of, these signaling traits. Here we examine the influence...
Article
Full-text available
The vertebrate stress response comprises a suite of behavioural and physiological traits that must be functionally integrated to ensure organisms cope adaptively with acute stressors. Natural selection should favour functional integration, leading to a prediction of genetic integration of these traits. Despite the implications of such genetic integ...
Article
New World mangrove trees are foundation species, and their range is predicted to expand northward with climate change. Foundation species are commonly prioritized for conservation, with the goal of preserving the entire community that depends on them. However, no studies have explicitly investigated whether mangrove-dependent species' ranges will t...
Article
Full-text available
Sex differences in animal coloration often result from sex-dependent regulatory mechanisms. Still, some species exhibit incomplete sexual dimorphism as females carry a rudimentary version of a costly male trait, leading to intralocus sexual conflict. The underlying physiology and condition dependence of these traits can inform why such conflicts re...
Preprint
Fighting experiences strongly influence aggressive behavior and physiology (winner-loser effects). These effects are conserved from invertebrates to vertebrates, but the underlying mechanisms remain unclear. Recent studies indicate that the brain social decision-making network (SDN) plays a key role in guiding experience-induced behavioral change....
Preprint
Full-text available
Mixed mating strategies offer the benefits of both self-fertilizing ones own eggs (selfing) and outcrossing, while limiting the costs of both methods. The economics of mixed mating is further determined by individual self-compatibility. In gynodioecious (hermaphrodites, females) and androdioecious (hermaphrodites, males) species, the level of self-...
Preprint
Full-text available
Mate choice has the potential to drive phenotypic evolution because it can determine traits that increase an individuals likelihood to reproduce (courtship behaviors, elaborate ornamentation). These traits, however, can also be detrimental for health or survival, often antagonizing the evolution of extreme phenotypes. Mangrove rivulus fish ( Krypto...
Preprint
Full-text available
Mixed mating, a reproduction strategy utilized by many plants and invertebrates, optimizes the cost to benefit ratio of a labile mating system. One type of mixed mating includes outcrossing with conspecifics and self-fertilizing ones own eggs. The mangrove rivulus fish ( Kryptolebias marmoratus ) is one of two vertebrates known to employ both self-...
Article
Full-text available
AimCompared to other modulators of physiological strain associated with exercise heat stress, hyperthermia results in the greatest magnitude of cardiovascular (CV) drift and associated decrements in maximal oxygen uptake (\(\dot{V}{\text{O}}_{2\max }\)).PurposeTo determine if elevated core temperature in the luteal phase (LP) of the menstrual cycle...
Article
Full-text available
Steroid hormones accumulate in recirculation aquaculture systems (RAS) and may influence the reproductive physiology of farmed fish. Ozone reduces hormone concentrations in freshwater RAS used to rear Atlantic salmon, but its effect on reproductive development is unknown. Accordingly, an 8-month trial was carried out to evaluate the growth, health,...
Article
Full-text available
Carotenoid pigments have myriad functions in fish, including coloration and immunity. The “carotenoid trade-off hypothesis” posits that dietary limitation of carotenoids imposes constraints on animals to allocate to one function at the expense of another. This hypothesis rarely has been tested in fish. We quantified tissue carotenoids in breeding a...
Article
Emotions encompass cognitive and behavioural responses to reward and punishment. Using contests as a case-study, we propose that short-term emotions underpin animals' assessments, decision-making, and behaviour. Equating contest assessments to emotional "appraisals", we describe how contestants appraise more than resource value and outcome probabil...
Article
Prominent theory suggests that factor one psychopathic traits may develop from increased input from hormones in the hypothalamic pituitary gonadal axis (HPG; i.e., testosterone) and decreased input from the hypothalamic pituitary adrenal axis (HPA; i.e., cortisol). Although there are extensive findings connecting low cortisol to psychopathy, less s...
Article
Ecdysteroids are a family of insect hormones that may play a role in modulating aggressive behavior in reproductive contexts. In Hymenoptera, the few studies investigating the link between ecdysteroid titers, reproduction and aggressiveness during contests concern solely eusocial species. Here, we explored whether ecdysteroid titers influenced fema...
Article
β-N-methylamino-L-alanine (BMAA), a neurotoxin naturally produced by cyanobacteria, diatoms and dinoflagellates, constitutes a serious environmental and health threat especially during acute blooms, which are becoming more frequent. This neurotoxin is implicated in several neurodegenerative diseases (ND) in humans through contaminated water or food...
Article
We aimed to characterize cardiac-autonomic responses to a 13-day preseason camp in the heat among an American college football team. Players were categorized as linemen (n=10) and non-linemen (n=18). RHR, natural logarithm of the root-mean square of successive differences multiplied by twenty (LnRMSSD), and subjective wellbeing (LnWellness) were ac...
Article
Extreme inbreeding is expected to reduce the incidence of hybridization, serving as a prezygotic barrier. Mangrove rivulus is a small killifish that reproduces predominantly by self‐fertilization, producing highly homozygous lines throughout its geographic range. The Bahamas and Caribbean are inhabited by two highly diverged phylogeographic lineage...
Article
In heterogeneous environments, mobile species should occupy habitats in which their fitness is maximized. Mangrove rivulus fish inhabit mangrove ecosystems where salinities range from 0-65 ppt but are most often collected at ∼25 ppt. We examined rivulus' salinity preference in a lateral salinity gradient, in the absence of predators and competitors...
Article
Full-text available
Sequential hermaphroditism (sex change) is understood to be a strategy that maximizes lifetime reproduction in systems where one sex confers highest fitness early in life, and the other later in life. This strategy is evolutionarily stable despite costs to growth, survival, or current reproduction. Few studies have examined advantages of sex change...
Article
Metabolic rate and life history traits vary widely both among and within species reflecting trade-offs in energy allocation, but the proximate and ultimate causes of variation are not well understood. We tested the hypothesis that these trade-offs are mediated by environmental heterogeneity, using isogenic strains of the amphibious fish Kryptolebia...
Thesis
Full-text available
Within the animal kingdom, individuals of the same species are often in conflict for access to certain resources. In solitary parasitoids, females can compete directly for access to a host that is an essential resource for their reproductive success. During this thesis, we investigated the factors that influence the display of agonistic behaviour a...
Article
Full-text available
Understanding the ecological pressures that generate variation in body shape is important because body shape profoundly affects physiology and overall fitness. Using Fundulus, a genus of fish that exhibits considerable morphological and physiological variation with evidence of repeated transitions between freshwater and saltwater habitats, we teste...
Preprint
Full-text available
The vertebrate stress response comprises a suite of behavioural and physiological traits that must be functionally integrated to ensure organisms cope adaptively with acute stressors. The expectation that natural selection has favoured functional integration leads to a prediction of genetic integration: genetic variation in the stress response shou...
Article
Full-text available
Prior experience of fighting affects the outcome of subsequent contests, with prior winners being more likely to win and prior losers being more likely to lose a future encounter. These winner and loser effects have been shown in numerous species but have usually been tested in only one set of conditions. However, if such effects are not fixed but...
Article
During gametogenesis and embryonic development, precise regulation of gene expression, across cell/tissue types and over time, is crucial. In vertebrates, transcription is partly regulated by histone lysine acetylation/deacetylation, an epigenetic mechanism mediated by lysine acetyltransferases (KAT) and histone deacetylases (HDAC). Well characteri...
Article
In vertebrates, titers of androgens such as testosterone are known to upregulate aggressive behaviors associated with reproduction. In insects, juvenile hormone (JH) is a good candidate for studying the flexibility of insect endocrine responses because it has important effects on both reproductive processes and behavior. JH has a gonadotropic effec...
Article
The electromyographical-threshold (EMGT) has been previously validated as a means to predict the work rate at which lactate-threshold (LT) occurs. The reliability of these measures has yet to be examined after a bout of exercise. The purpose was to determine the agreement between EMG and LT after a 30-minute bout of steady-state aerobic exercise. P...
Article
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Figure 3 legend has been corrected to state: “Difference matrices for pairwise-trait phenotypic correlations (rP, below diagonal) and pairwise-trait genetic correlations (rG, above diagonal) from 1, 15, and 100 DPH. Differences are color coded by strength and direction. Differences shown in gray are positive and differences shown in black are negat...
Article
For many species, behaviors such as territory defense and parental care are energetically costly, but are nonetheless can provide substantial fitness gains. In systems in which both parents provide parental care, each of the parents benefits from exhibiting (or having their partner exhibit) these behaviors. However, in many cases, costs and benefit...
Article
Alternative male phenotypes exist in many species and impact mating system dynamics, population genetics, and mechanisms of natural and sexual selection that operate within a population. We report on the discovery of a cryptic male phenotype in the mangrove rivulus fish (Kryptolebias marmoratus), one of only two self-fertilizing hermaphroditic vert...
Article
Full-text available
When confronted with social challenge, animals extract information from their environment to make adaptive behavioural decisions. The size of an individual relative to its opponent is a decisive factor that could influence contest decisions and the outcome of social competition. Animals may determine whether or not to engage in fights by assessing...
Article
Full-text available
Understanding how the brain processes social information and generates adaptive behavioural responses is a major goal in neuroscience. We examined behaviour and neural activity patterns in socially relevant brain nuclei of hermaphroditic mangrove rivulus fish (Kryptolebias marmoratus) provided with different types of social stimuli: stationary mode...
Article
We have demonstrated that genetic (co)variance structures among performance-related morphological traits are age dependent. This multivariate G x A can be conceptualized in two alternative ways: as shifting patterns of evolutionary constraint for responses to selection on age-specific morphology; or as the presence of genetic variance in the multiv...
Article
Full-text available
Early life environments have important effects on phenotype development, but it can be difficult to disentangle the relative influences of genotype and environment on phenotypic variation within and among populations. Mangrove rivulus fish (Kryptolebias marmoratus) reproduce by self-fertilization and can generate isogenic lineages, which provides o...
Article
Full-text available
The vertebrate stress response enables individuals to react to and cope with environmental challenges. A crucial aspect of the stress response is the elevation of circulating glucocorticoids. However, continued activation of the stress response under repeated exposure to stressors can be damaging to fitness. Under certain circumstances it may there...
Article
Hormones play a prominent role in animal development, mediating the expression of traits and coordinating phenotypic responses to the environment. Their role as physiological integrators has implications for how populations respond to natural selection and can impact the speed and direction of evolutionary change. However, many emerging and establi...
Preprint
Full-text available
The vertebrate stress response enables individuals to react to and cope with environmental challenges. A crucial aspect of the stress response is the elevation of circulating glucocorticoids. However, continued activation of the stress response under repeated (or chronic) stress can be damaging to fitness. Under certain circumstances it may therefo...
Article
By definition, mating between individuals is infrequent in highly selfing organisms, and so too, therefore, hybridization should be rare between genetically divergent lineages in predominantly self-fertilizing species. Notwithstanding these expectations, here we report a remarkable case of natural hybridization between highly diverged phylogeograph...
Article
Full-text available
In many species, males tend to behave more aggressively than females and female aggression often occurs during particular life stages such as maternal defence of offspring. Though many studies have revealed differences in aggression between the sexes, few studies have compared the sexes in terms of their neuroendocrine responses to contest experien...
Article
Full-text available
To survive, animals must respond appropriately to stress. Stress responses are costly, so early-life experiences with potential stressors could adaptively tailor adult stress responses to local conditions. However, how multiple stressors influence the development of the stress response remains unclear, as is the role of sex. Trinidadian guppies (Po...
Article
Establishing links between morphology and performance is important for understanding the functional, ecological, and evolutionary implications of morphological diversity. Relationships between morphology and performance are expected to be age dependent if, at different points during ontogeny, animals must perform in different capacities to achieve...
Article
Full-text available
Fishes acclimated to hypoxic environments often increase gill surface area to improve O2uptake. In some species, surface area is increased via reduction of an interlamellar cell mass (ILCM) that fills water channels between gill lamellae. Amphibious fishes, however, may not increase gill surface area in hypoxic water because these species can inste...
Article
Full-text available
The mangrove rivulus fish (Kryptolebias marmoratus) is an emerging model for research in the biological sciences. The species is androdioecious, with populations consisting predominantly of self-fertilizing hermaphrodites and a low abundance of males, but no females. Males arise either through environmental sex determination at the embryonic stage...
Article
Full-text available
Despite having to endure a rigorous in-season training schedule, research evaluating daily physiological recovery status markers among American football players is limited. The purpose of this study was to determine if recovery of cardiac-autonomic activity to resting values occurs between consecutive-day, in-season training sessions among college...
Article
Full-text available
Mirror image stimulation has a long history of being used to quantify aggressive behaviour but its suitability has recently been questioned because behavioural responses towards a mirror image and towards a real opponent are not always correlated, and are associated with different physiological responses. These discrepancies might result from later...
Article
Individuals vary in their baseline levels of stress hormones (predictive homeostasis) and in their stress responses (reactive homeostasis). Variation in normal reactive scope, both predictive and reactive homeostasis, may be important for understanding how endocrine traits respond to selection. Reactive homeostasis is the increase in glucocorticoid...
Article
The mangrove rivulus, Kryptolebias marmoratus, is one of only two self-fertilizing hermaphroditic fish and inhabits mangrove forests. While selfing can be advantageous, it reduces heterozygosity and decreases genetic diversity. Studies using microsatellites found that there are variable levels of selfing among populations of K. marmoratus but overa...
Article
Full-text available
In addition to genetic variation, epigenetic mechanisms such as DNA methylation might make important contributions to heritable phenotypic diversity in populations. However, it is often difficult to disentangle the contributions of genetic and epigenetic variation to phenotypic diversity. Here, we investigated global DNA methylation and mRNA expres...
Article
Full-text available
We use extensive geographical sampling and surveys of nuclear microsatellite and mitochondrial DNA loci to investigate the phylogeographic structure of the only recognized self-fertilizing vertebrates, the mangrove killifishes, currently thought to comprise two cryptic species, Kryptolebias marmoratus and Kryptolebias hermaphroditus. All genetic ma...
Article
Full-text available
The purpose of this study was to determine if recovery of cardiac-autonomic activity to baseline occurs between consecutive-day training sessions among positional groups of a collegiate football team during Spring camp. A secondary aim was to evaluate relationships between chronic (i.e., 4-week) HRV and training load parameters. Baseline HRV (lnRMS...
Article
Full-text available
Steroid hormones have been shown to accumulate in recirculation aquaculture system (RAS) water over time; however, their influence on the reproductive physiology of fish within RAS remains unknown. Whether ozonation impacts waterborne hormone levels in RAS has likewise not been fully evaluated. To this end, a controlled 3-month study was conducted...
Poster
Full-text available
Vagally-mediated heart rate variability (lnRMSSD) reflects cardiac-parasympathetic modulation and is commonly used as recovery status marker among athletes. Fitness level, body mass and physiological responses to training vary among positional groups in football. Thus, we hypothesize that lnRMSSD responses to training may also differ among position...
Article
Full-text available
We present evidence suggesting that some male convict cichlids (Amatitlania siquia) in Lake Xiloá, Nicaragua engage in alternative reproductive tactics (ARTs). These putative ART males were smaller than typical parental males, displayed coloration similar to breeding females, and possessed enlarged gonads. Gonadosomatic indices in these males were...
Article
Aquatic organisms living adjacent to roads face many challenges posed by exposure to toxic runoff. The use of de-icing road salt across northern latitudes has salinized nearby freshwater habitats. Freshwater amphibians exposed to road salt at early life stages typically experience reduced survival; however, few studies address later-life effects. O...
Article
The mangrove rivulus, Kryptolebias marmoratus, is one of two known vertebrate species with preferentially self-fertilizing hermaphrodites. Males also exist, and can outcross with hermaphrodites. Outcrossing events vary across wild populations and occur infrequently in laboratory settings. This study sought to add dimension to our understanding of m...