| mortality in red-sided garter snakes, thamnophis sirtalis parietalis, due to larval nematode, eustrongylides sp. | garter snakes, thamnophis sirtalis parietalis, that had been fed wild-caught banded killifish, fundulus diaphanus, and laboratory-bred leopard frogs, rana pipiens, were infected by larval nematode, eustrongylides sp; 7 of the 25 snakes died. signs of infection in 20 snakes included subcutaneous "lumps," violent contortions, and bloody exudate, apparently from the nares. nemotodes were collected at necropsy from beneath the skin, in the lungs, in the body cavity, and along the spinal column. nema ... | 1976 | 940307 |
| role of the anterior hypothalamus-preoptic area in the regulation of courtship behavior in the male canadian red-sided garter snake (thamnophis sirtalis parietalis): intracranial implantation experiments. | testosterone (t) was administered intracranially to intact adult male canadian red-sided garter snakes (thamnophis sirtalis parietalis) in the fall and in the summer. implants in the anterior hypothalamus-preoptic area (ah-poa) as well as other regions of the brain, including the medial and basal hypothalamus, thalamus, medial cortex, and third ventricle, failed to elicit courtship behavior. the spermatogenic stage was more advanced, and the circulating level of androgens was significantly highe ... | 1985 | 4007796 |
| differential effects of courtship and mating on receptivity and brain metabolism in female red-sided garter snakes (thamnophis sirtalis parietalis). | in the female red-sided garter snake (thamnophis sirtalis parietalis), the loss of receptivity following intromission during mating can be prevented by injection of a local anesthetic (tetracaine) in the cloacal region prior to courtship and mating. females that were courted and then mated had significantly higher uptake of radio-labeled [14c]2-fluoro-2-deoxyglucose (2-dg) in the preoptic area (25%) and significantly lower uptake in the ventromedial hypothalamus (-20%) compared with females that ... | 2003 | 12619917 |
| alaria mesocercariae in the tails of red-sided garter snakes: evidence for parasite-mediated caudectomy. | trematodes of the genus alaria develop into an arrested stage, known as mesocercariae, within their amphibian second intermediate host. the mesocercariae are frequently transmitted to a non-obligate paratenic host before reaching a definitive host where further development and reproduction can occur. snakes are common paratenic hosts for alaria spp. with the mesocercariae often aggregating in the host's tail. in the current study, we used morphological examination and molecular analyses based on ... | 2015 | 26337267 |
| mating increases plasma levels of prostaglandin f2 alpha in female garter snakes. | plasma levels of prostaglandin f2 alpha (pgf2 alpha) in female red-sided garter snakes (thamnophis sirtalis parietalis) were measured at intervals after mating or exposure to males. pgf2 alpha levels increased significantly within 15 minutes of mating and peaked 6-24 hr after mating. females that did not mate, but received similar amounts of male courtship, had levels of pgf2 alpha significantly lower than those of females that mated. these results extend previous findings that unmated female ga ... | 2009 | 2748917 |
| how to make a sexy snake: estrogen activation of female sex pheromone in male red-sided garter snakes. | vertebrates indicate their genetic sex to conspecifics using secondary sexual signals, and signal expression is often activated by sex hormones. among vertebrate signaling modalities, the least is known about how hormones influence chemical signaling. our study species, the red-sided garter snake (thamnophis sirtalis parietalis), is a model vertebrate for studying hormonal control of chemical signals because males completely rely on the female sex pheromone to identify potential mates among thou ... | 2012 | 22323194 |
| behavioral and physiological control of yolk synthesis and deposition in the female red-sided garter snake (thamnophis sirtalis parietalis). | ovarian recrudescence in female garter snakes, thamnophis sirtalis parietalis, follows spring emergence from hibernation and mating. in the laboratory, courtship and mating stimuli significantly increased the proportion of female garter snakes becoming pregnant, although some noncourted nonmated controls also became pregnant. females given artificial mating stimuli under anesthetic, without courtship stimuli, were no more likely than either noncourted, nonmated or anesthetized controls to become ... | 2014 | 3924812 |
| chronobiology of reproduction in garter snakes: neuroendocrine mechanisms and geographic variation. | the majority of studies on reproductive neuroendocrinology in snakes have focused on one particular snake population in manitoba, canada, the red-sided garter snake (thamnophis sirtalis parietalis). although traditionally these studies have emphasized its unusual temporal dissociation between mating behavior and peak gonadal activity, current evidence suggests that reproductive regulation in this population may be more similar to the norm than previously thought. like other ectotherms, temperatu ... | 2012 | 22210163 |
| structural flexibility of the small intestine and liver of garter snakes in response to feeding and fasting. | garter snakes thamnophis sirtalis parietalis feed frequently but also tolerate extended periods of fasting when food is unavailable. we studied the dynamics, reversibility and repeatability of size changes of the small intestine and liver using ultrasonography. we employed light and transmission electron microscopy and flow cytometry to study the tissue mechanism that drives this flexibility. we compared garter snakes that fed every other day, snakes that fed once a week and fasting snakes. in a ... | 2002 | 11976350 |
| neuroanatomical distribution of chicken-i gonadotropin-releasing hormone (cgnrh-i) in the brain of the male red-sided garter snake. | immunocytochemistry was used to investigate the neuroanatomical distribution of the chicken-i form of gonadotropin-releasing hormone (cgnrh-i) in reproductively active, male, red-sided garter snakes (thamnophis sirtalis parietalis). cell bodies with cgnrh-i immunoreactivity (ir) were found in the terminal nerve ganglion, nucleus of the diagonal band of broca, medial preoptic area, and the hypothalamus. fibers containing cgnrh-iir were distributed in the following brain areas. within the olfactor ... | 1997 | 9063592 |
| gonadotropin antagonist modulates courtship behavior in male red-sided garter snakes, thamnophis sirtalis parietalis. | behavioral studies were used to investigate the central effects of chicken-i gnrh, chicken-ii gnrh, and d-phe2,6,pro3-gnrh, a gnrh antagonist, on the courtship behavior of male red-sided garter snakes, thamnophis sirtalis parietalis. intracerebroventricular (i.c.v.) injections of chicken-i or chicken-ii gnrh had no effect on time spent courting or latency to court when experimental males were exposed to unmated females, or when experimental males were exposed to the female sex attractiveness phe ... | 1997 | 8976544 |
| seasonal fluctuations in brain nuclei in the red-sided garter snake and their hormonal control. | in many vertebrates, breeding seasons are protracted and mating behavior is temporally associated with gonadal growth and increased sex steroid hormone secretion. in the red-sided garter snake (thamnophis sirtalis parietalis), mating behavior is restricted to the 2-4 weeks immediately following emergence from winter dormancy. during this period mating behavior is sex-specific: chin-rubbing is exhibited only by males and receptivity to chin-rubbing is exhibited only by females. it is remarkable t ... | 1993 | 8254379 |
| temperature activation of courtship behavior in the male red-sided garter snake (thamnophis sirtalis parietalis): role of the anterior hypothalamus-preoptic area. | adult male red-sided garter snakes (thamnophis sirtalis parietalis) received radio-frequency lesions prior to 17 weeks of low-temperature hibernation. animals found to have bilateral lesions of the anterior hypothalamus-preoptic area (ah-poa) failed to exhibit courtship behavior on emergence from hibernation. those individuals in which the major portion of the destruction was centered in the anterior poa also exhibited deficits in thermoregulatory behavior. animals that received unilateral lesio ... | 1987 | 3580125 |
| gonadotropin-releasing hormone from brains of reptiles: turtles (pseudemys scripta) and snakes (thamnophis sirtalis parietalis). | gonadotropin-releasing hormone (gnrh)-like peptides were present in whole brain extracts of turtle (pseudemys scripta) and snake (thamnophis sirtalis parietalis) with higher content and concentration in the turtle brain. the peptides were identified by cross-reactivity profiles with four gnrh antisera and by retention times on reverse-phase high-pressure liquid chromatography (hplc) compared with synthetic gnrh standards. turtle brain extracts contained two hplc peaks that cross-reacted with gnr ... | 1988 | 3282979 |
| immunorecognition of estrogen receptors by monoclonal antibody h222 in reproductive tissues of the red-sided garter snake. | a study was conducted to determine if a monoclonal antibody (mab), h222, prepared against human breast cancer estrogen receptors (er) would recognize er in the oviduct and liver of garter snakes (thamnophis sirtalis parietalis). using sucrose gradient analysis of antibody-er complexes bound to [3h]estradiol we have determined that the mab h222 binds to an er in the cytosolic and nuclear extracts of snake tissues. the snake er is not bound by nonspecific mabs in the sucrose gradient analysis. fur ... | 1991 | 2026308 |
| responses to capture stress and exogenous corticosterone vary with body condition in female red-sided garter snakes (thamnophis sirtalis parietalis). | this study examined whether hormonal and behavioral responses to capture stress and exogenous corticosterone (cort) vary with body condition in female red-sided garter snakes (thamnophis sirtalis parietalis). female snakes were collected during the spring mating season and treated with 4 h of capture stress. we measured plasma cort and estradiol before, during and after capture stress treatment followed by latency to copulate, a measure of female receptivity. body condition was determined as the ... | 2013 | 24075831 |
| sex or candy? neuroendocrine regulation of the seasonal transition from courtship to feeding behavior in male red-sided garter snakes (thamnophis sirtalis parietalis). | this article is part of a special issue "energy balance". seasonal modulation of glucocorticoids plays an important role in supporting critical life-history events, and probably facilitates transitions between different life-history stages. in a well-studied population of red-sided garter snakes (thamnophis sirtalis parietalis), glucocorticoids are elevated during the mating season, but males dispersing to summer feeding grounds have significantly lower baseline glucocorticoids than courting mal ... | 2014 | 24508620 |
| a novel mechanism regulating a sexual signal: the testosterone-based inhibition of female sex pheromone expression in garter snakes. | vertebrates communicate their sex to conspecifics through the use of sexually dimorphic signals, such as ornaments, behaviors and scents. furthermore, the physiological connection between hormones and secondary sexual signal expression is key to understanding their dimorphism, seasonality and evolution. the red-sided garter snake (thamnophis sirtalis parietalis) is the only reptile for which a described pheromone currently exists, and because garter snakes rely completely on the sexual attractiv ... | 2014 | 25058443 |
| seasonal variation in cell proliferation and cell migration in the brain of adult red-sided garter snakes (thamnophis sirtalis parietalis). | plasticity in the adult central nervous system has been described in all vertebrate classes as well as in some invertebrate groups. however, the limited taxonomic diversity represented in the current neurogenesis literature limits our ability to assess the functional significance of adult neurogenesis for natural behaviors as well as the evolution of its regulatory mechanisms. in the present study, we used free-ranging red-sided garter snakes (thamnophis sirtalis parietalis) to test the hypothes ... | 2014 | 25301175 |
| size dependence in non-sperm ejaculate production is reflected in daily energy expenditure and resting metabolic rate. | the non-sperm components of an ejaculate, such as copulatory plugs, can be essential to male reproductive success. but the costs of these ejaculate components are often considered trivial. in polyandrous species, males are predicted to increase energy allocation to the production of non-sperm components, but this allocation is often condition dependent and the energetic costs of their production have never been quantified. red-sided garter snakes (thamnophis sirtalis parietalis) are an excellent ... | 2015 | 25954044 |
| female behaviour and the interaction of male and female genital traits mediate sperm transfer during mating. | natural selection and post-copulatory sexual selection, including sexual conflict, contribute to genital diversification. fundamental first steps in understanding how these processes shape the evolution of specific genital traits are to determine their function experimentally and to understand the interactions between female and male genitalia during copulation. our experimental manipulations of male and female genitalia in red-sided garter snakes (thamnophis sirtalis parietalis) reveal that cop ... | 2016 | 26809830 |
| seasonal and sex differences in responsiveness to adrenocorticotropic hormone contribute to stress response plasticity in red-sided garter snakes (thamnophis sirtalis parietalis). | as in many vertebrates, hormonal responses to stress vary seasonally in red-sided garter snakes (thamnophis sirtalis parietalis). for example, males generally exhibit reduced glucocorticoid responses to a standard stressor during the spring mating season. we asked whether variation in adrenal sensitivity to adrenocorticotropic hormone (acth) explains why glucocorticoid responses to capture stress vary with sex, season and body condition in red-sided garter snakes. we measured glucocorticoids at ... | 2016 | 26896543 |
| counter-perfume: using pheromones to prevent female remating. | strong selection to secure paternity in polyandrous species leads to the evolution of numerous chemicals in the male's seminal content. these include antiaphrodisiac pheromones, which are transmitted from the male to the female during mating to render her unattractive to subsequent males. an increasing number of species have been shown to use these chemicals. herein, i examine the taxonomic distribution of species using antiaphrodisiac pheromones, the selection pressures driving their evolution ... | 2017 | 27554169 |
| patterns of stress responses shift during seasonal life-history transitions: an analysis comparing baseline, maximal and integrated corticosterone in female red-sided garter snakes (thamnophis sirtalis parietalis). | glucocorticoids often rise and fall with a variety of external and internal cues and frequently vary among life-history stages. this suggests that changing glucocorticoids may coordinate life-history transitions. to explore this hypothesis, we asked if the time-course of stress-induced glucocorticoid levels differ between two life-history transitions (i.e., spring and fall migration) in female red-sided garter snakes (thamnophis sirtalis parietalis). we collected non-migratory females from a com ... | 2017 | 28322762 |
| age-related sex differences in body condition and telomere dynamics of red-sided garter snakes. | life-history strategies vary dramatically between the sexes, which may drive divergence in sex-specific senescence and mortality rates. telomeres are tandem nucleotide repeats that protect the ends of chromosomes from erosion during cell division. telomeres have been implicated in senescence and mortality because they tend to shorten with stress, growth and age. we investigated age-specific telomere length in female and male red-sided garter snakes,thamnophis sirtalis parietaliswe hypothesized t ... | 2017 | 28381620 |
| arginine vasotocin and neuropeptide y vary with seasonal life-history transitions in garter snakes. | transitions between life-history stages are often accompanied by dramatic behavioral switches that result from a shift in motivation to pursue one resource over another. while the neuroendocrine mechanisms that regulate such behavioral transitions are poorly understood, arginine vasotocin (avt) and neuropeptide y (npy) are excellent candidates because they modulate reproductive and feeding behavior, respectively. we asked if seasonal changes in avt and npy are concomitant with the seasonal migra ... | 2017 | 28992226 |
| physiological correlates of reproductive decisions: relationships among body condition, reproductive status, and the hypothalamus-pituitary-adrenal axis in a reptile. | when opportunities to feed and reproduce are limited, females are often unable to recover sufficient energy stores to reproduce in consecutive years. body condition has been used as a proxy for recent reproductive history in such species. we previously found that glucocorticoid responses to capture stress vary with body condition in female red-sided garter snakes (thamnophis sirtalis parietalis), a species with limited seasonal breeding opportunities. because variation in glucocorticoid receptor ... | 2018 | 29452075 |
| pheromonal mediation of intraseasonal declines in the attractivity of female red-sided garter snakes, thamnophis sirtalis parietalis. | during the breeding season, female red-sided garter snakes (thamnophis sirtalis parietalis) produce and express a sexual attractiveness pheromone that elicits male courtship behavior. composed of a homologous series of saturated and monounsaturated methyl ketones, this pheromone is expressed in female skin lipids. recent studies have shown that the sexual attractivity of unmated female garter snakes declines as the breeding season progresses. here, we investigated whether temporal changes in the ... | 2012 | 22231473 |
| brain nuclei in actively courting red-sided garter snakes: a paradigm of neural trimorphism. | during the breeding season, two distinct male phenotypes are exhibited by red-sided garter snakes (thamnophis sirtalis parietalis), with courtship behavior being directed not only toward females, but also toward a sub-population of males called she-males. she-males are morphologically identical to other males except for a circulating androgen level three times that of normal males and their ability to produce a female-like pheromone. as in other vertebrates, limbic nuclei in the red-sided garter ... | 2011 | 21195723 |
| temporally distinct effects of stress and corticosterone on diel melatonin rhythms of red-sided garter snakes (thamnophis sirtalis). | circadian and circannual rhythms in physiology and behavior are temporally organized via hormonal signals that reflect changing environmental cues. interactions between endocrine signals are in turn important for integrating multiple physiological and behavioral rhythms. in the present study, we examined interactions between melatonin, the hypothalamus-pituitary-adrenal (hpa) axis, and corticosterone in a well-studied population of red-sided garter snakes (thamnophis sirtalis parietalis). we dem ... | 2010 | 20603122 |
| low temperature dormancy affects the quantity and quality of the female sexual attractiveness pheromone in red-sided garter snakes. | low temperature dormancy is a necessary requirement of the annual cycle of most nonmigratory, temperate vertebrates. the red-sided garter snake, thamnophis sirtalis parietalis, overwinters in communal dens during its prolonged winter dormancy (8 mo), and upon emergence, reproductive behavior of both sexes is maximal. previous work on this species showed that male courtship behavior is maximally induced after simulated low temperature dormancy. the purpose of this study was to determine whether l ... | 2009 | 19904571 |
| endocrine mechanisms mediating temperature-induced reproductive behavior in red-sided garter snakes (thamnophis sirtalis parietalis). | we investigated the mechanisms by which temperature induces seasonal reproductive behavior in red-sided garter snakes (thamnophis sirtalis parietalis). specifically, we addressed whether elevated temperatures during winter dormancy influence (1) diel melatonin and corticosterone rhythms; (2) sex steroid hormone and corticosterone profiles; and (3) the expression of reproductive behavior following emergence. elevated hibernation temperatures (i.e. 10 degrees c versus 5 degrees c) significantly in ... | 2009 | 19749103 |
| geographic variation in timekeeping systems among three populations of garter snakes (thamnophis sirtalis) in a common garden. | transduction of environmental cues into endocrine signals that synchronize physiology and behavior with optimal environmental conditions is central to an animal's timekeeping system. using a common garden approach, we investigated possible geographic variation in timekeeping systems by comparing 24-h melatonin and corticosterone rhythms and reproductive behavior among three populations of garter snakes with very different life histories: red-sided garter snakes (thamnophis sirtalis parietalis) f ... | 2013 | 18937566 |
| do female garter snakes evade males to avoid harassment or to enhance mate quality? | females of many species behave in ways that make it difficult for males to locate, court, and inseminate them. two hypotheses have been advanced to explain such behavior: either a female thereby minimizes costs of harassment (sexual conflict model) or by playing "hard to get" she discourages inferior suitors (indirect mate choice model). our studies of garter snakes (thamnophis sirtalis parietalis) at a communal den in manitoba support an interpretation of sexual conflict rather than indirect ma ... | 2005 | 15937746 |
| a serotonin receptor antagonist, but not melatonin, modulates hormonal responses to capture stress in two populations of garter snakes (thamnophis sirtalis parietalis and thamnophis sirtalis concinnus). | hormonal and behavioral responses to a stressor depend on many factors, including the influence of other hormones. we examined the role of melatonin in modulating hormonal responses to capture stress in two populations of male garter snakes, thamnophis sirtalis. studies of red-sided (t. sirtalis parietalis) and red-spotted (t. sirtalis concinnus) garter snakes were conducted in the field with free-living snakes. populations of red-sided garter snakes in south-central manitoba, canada undergo a p ... | 2005 | 15804513 |
| effects of melatonin on the behavioral and hormonal responses of red-sided garter snakes (thamnophis sirtalis parietalis) to exogenous corticosterone. | we investigated possible interactions between melatonin and corticosterone in modulating the reproductive behavior of male red-sided garter snakes (thamnophis sirtalis parietalis) following spring emergence. we also examined whether melatonin's modulatory actions could be explained by its potential properties as a serotonin receptor antagonist. exogenous corticosterone significantly reduced courtship behavior of male snakes in a dose-dependent manner. melatonin also significantly reduced courtsh ... | 2004 | 15555513 |
| the male red-sided garter snake (thamnophis sirtalis parietalis): reproductive pattern and behavior. | among the small group of species (e.g., some temperate zone turtles, snakes, and bats) that exhibit a dissociated reproductive pattern, the red-sided garter snake (thamnophis sirtalis parietalis) is probably the most well studied. for these species, courtship and mating occur immediately upon emergence from winter dormancy; the gonads remain essentially inactive. male red-sided garter snakes are a particularly informative animal model for examining the role of neuroendocrine factors associated w ... | 2004 | 14756156 |
| pheromonally mediated sexual isolation among denning populations of red-sided garter snakes, thamnophis sirtalis parietalis. | utilizing behavioral experiments and chemical analyses, we examined whether pheromonally mediated sexual isolation exists between denning populations of red-sided garter snakes (thamtnophis sirtalis parietalis) in manitoba, canada. simultaneous choice tests conducted during the breeding season revealed that adult males from a hibernaculum in central manitoba displayed a strong courtship preference for females from their own population over females from a hibernaculum in western manitoba, whereas ... | 2003 | 12775159 |
| variation in a female sexual attractiveness pheromone controls male mate choice in garter snakes. | male red-sided garter snakes (thamnophis sirtalis parietalis) display a courtship preference for larger females during the breeding season. utilizing behavioral experiments and chemical analyses, we tested the hypothesis that males can discriminate among females of varying size solely by means of the sexual attractiveness pheromone, a previously characterized sex pheromone composed of a homologous series of long-chain saturated and omega-9 cis-unsaturated methyl ketones contained in the skin lip ... | 2002 | 12184402 |
| behavioral and hormonal responses to corticosterone in the male red-sided garter snake, thamnophis sirtalis parietalis. | stress and glucocorticoids are generally thought to suppress reproductive function at multiple levels. we tested the hypotheses that exogenous corticosterone would suppress sexual behavior in a dose-dependent manner, as well as drive a decrease in plasma testosterone levels in the male red-sided garter snake, thamnophis sirtalis parietalis. we examined this by challenging individual males with intraperitoneal injections of exogenous corticosterone, and subsequently exposing them to sexually attr ... | 2001 | 11336998 |
| conflicts between courtship and thermoregulation: the thermal ecology of amorous male garter snakes (thamnophis sirtalis parietalis, colubridae). | thermoregulatory behavior is an important component of daily activities for many reptiles, especially for small heliothermic (sun-basking) species that inhabit cold climates. however, the relative costs and benefits of thermoregulation depend on numerous factors, such that reptiles may sometimes accord a low priority to precise control of body temperatures. we observed and radio tracked garter snakes (thamnophis sirtalis parietalis) in central manitoba during the mating season (spring). previous ... | 2006 | 11009405 |
| behavioural and hormonal responses to capture stress in the male red-sided garter snake, thamnophis sirtalis parietalis. | we measured the behavioural and hormonal responses to capture stress in male red-sided garter snakes. four hours of capture stress resulted in no suppression of mating behaviour relative to control individuals. in contrast, the same stress resulted in a significant increase in plasma levels of corticosterone and a significant decrease in plasma levels of testosterone. there was a significant negative correlation between plasma levels of corticosterone and testosterone in both control and capture ... | 2000 | 10715174 |
| the transvestite serpent: why do male garter snakes court (some) other males? | in large mating aggregations of red-sided garter snakes, thamnophis sirtalis parietalis, in manitoba, male courtship is directed not only to females, but also to other males with female-like skin lipids ('she-males'). we show that 'she-maleness' is an intrinsic property of a male rather than an artefact of lipid transfer from females, and that male-male courtship is very common in the field. she-males were distinctive in terms of appearance (they were heavier than other males and more often cove ... | 2000 | 10675257 |
| courting and noncourting male red-sided garter snakes, thamnophis sirtalis parietalis: plasma melatonin levels and the effects of pinealectomy. | previous studies found that pinealectomy of male canadian red-sided garter snakes (thamnophis sirtalis parietalis) in the autumn, before prolonged exposure to low temperatures (hibernation), significantly impaired the expression of courtship behavior upon emergence in the spring. additionally, pinealectomized animals with a disrupted diel cycle of plasma melatonin did not court while those exhibiting a more typical diel pattern did. these results suggested that the pineal gland functions in the ... | 1996 | 8797027 |
| plasma triglyceride and beta-hydroxybutyric acid levels in red-sided garter snakes (thamnophis sirtalis parietalis) at emergence from hibernation. | measurement of plasma levels of triglycerides and beta-hydroxybutyric acid in females and males of the red-sided garter snake (thamnophis sirtalis parietalis) suggest that the former may provide a useful physiological marker of condition. levels of triglycerides at emergence from hibernation during a month of natural aphagia were significantly greater in females than in males and she-males, a subset of the male population that mimics females. higher levels of triglycerides in the females may be ... | 1996 | 8608816 |
| bumpus in the snake den: effects of sex, size, and body condition on mortality of red-sided garter snakes. | huge breeding aggregations of red-sided garter snakes (thamnophis sirtalis parietalis) at overwintering dens in manitoba provide a unique opportunity to identify sources of mortality and to clarify factors that influence a snake's vulnerability to these factors. comparisons of sexes, body sizes, and body condition of more than 1000 dead snakes versus live animals sampled at the same time reveal significant biases. three primary sources of mortality were identified. predation by crows, corvus bra ... | 2001 | 11327166 |
| metabolic adaptations supporting anoxia tolerance in reptiles: recent advances. | animal survival during severe hypoxia and/or anoxia is enhanced by a variety of biochemical adaptations including adaptations of fermentative pathways of energy production and, most importantly, the ability to sharply reduce metabolic rate by 5-20 fold and enter a hypometabolic state. the biochemical regulation of metabolic arrest is proving to have common molecular principles that extend across phylogenetic lines and that are conserved in different types of arrested states (not only anaerobiosi ... | 1996 | 8936040 |
| effects of ovariectomy and estrogen replacement on attractivity and receptivity in the red-sided garter snake (thamnophis sirtalis parietalis). | activation of courtship behavior in male red-sided garter snakes, thamnophis sirtalis parietalis, is independent of the presence of sex steroids. the only consistent treatment that stimulates courtship behavior in males is prolonged exposure to low temperature followed by subsequent warming, mimicking the emergence from hibernation. we investigated whether attractivity and receptivity in female red-sided garter snakes is similarly steriod independent. female red-sided garter snakes are attractiv ... | 1996 | 8583424 |
| an airborne sex pheromone in snakes. | most reptile sex pheromones so far described are lipid molecules too large to diffuse through the air; instead, they are detected via direct contact (tongue-flicking) with another animal's body or substrate-deposited trails, using the vomeronasal system. the only non-lipid pheromone reported in snakes involves courtship termination in red-sided gartersnakes (thamnophis sirtalis parietalis): males that encounter copulatory fluids cease courtship, presumably reflecting the futility of courting an ... | 2012 | 21992822 |
| pinealectomy, melatonin, and courtship behavior in male red-sided garter snakes (thamnophis sirtalis parietalis). | activation of courtship behavior in male red-sided garter snakes is independent of androgens. only exposure to extended periods of low temperature with subsequent warming stimulates courtship in males. the pineal gland is thought to transduce temperature as well as photoperiodic information in reptiles. therefore, we explored the relationship of the pineal and melatonin to sexual behavior in this species. pinealectomy of male garter snakes disrupted sexual behavior upon emergence from a 17-week ... | 1996 | 8583209 |
| seasonal changes and annual variability in daily plasma melatonin in the red-sided garter snake (thamnophis sirtalis parietalis). | we report seasonal and annual variation in the daily cycle of plasma melatonin levels in male red-sided garter snakes, thamnophis sirtalis parietalis. in autumn of 1989 and 1990, levels averaged a maximum of 210 pg/ml during scotophase and a minimum of 45 pg/ml during photophase and had a similar diel pattern. under hibernation conditions (4 degrees, 0:24 l:d), melatonin was undetectable and a diel cycle could not be determined. in spring 1990, melatonin levels rose rapidly and precipitously wit ... | 1995 | 8582604 |
| corticosterone and the transition from courtship behavior to dispersal in male red-sided garter snakes (thamnophis sirtalis parietalis). | seasonal modulation of baseline glucocorticoid concentrations as well as the sensitivity of the hypothalamic-pituitary-adrenal (hpa) axis plays an important role in supporting critical life-history events such as seasonal reproduction and migration. despite numerous studies on adrenocortical modulation, little is known about the exact timing of this seasonal modulation with respect to critical life-history stages. we tested the hypothesis that seasonal modulation of the hpa axis during the sprin ... | 2007 | 16989831 |
| does large body size in males evolve to facilitate forcible insemination? a study on garter snakes. | a trend for larger males to obtain a disproportionately high number of matings, as occurs in many animal populations, typically is attributed either to female choice or success in male-male rivalry; an alternative mechanism, that larger males are better able to coercively inseminate females, has received much less attention. for example, previous studies on garter snakes (thamnophis sirtalis parietalis) at communal dens in manitoba have shown that the mating benefit to larger body size in males ... | 2005 | 16396183 |
| chemical ecology of the red-sided garter snake, thamnophis sirtalis parietalis. | the red-sided garter snake, thamnophis sirtalis parietalis is an ideal model for the study of chemical or pheromonal communication in vertebrates. results of long-term field and laboratory investigations of the chemical ecology of these unusual animals is summarized. these studies include a description of the characterization of the female attractiveness pheromone that serves to induce male courtship behavior. the male sex recognition pheromone system that identifies males as inappropriate indiv ... | 1993 | 8477349 |
| odorized air current trailing by garter snakes, thamnophis sirtalis. | the response of adult red-sided garter snakes, thamnophis sirtalis parietalis, to airborne odor trails was studied. an airtight t-maze was used, through which a constant airflow was drawn by a vacuum pump. the arms of the 't' provided a choice between earthworm extract and distilled water. experiment 1 tested the snake's responses to varying concentrations of earthworm extract. snakes accurately trailed the extract at tested concentrations (0.0, 0.01, 0.1, 1, 10, 100%). at ten percent concentrat ... | 1993 | 8477343 |
| sexual behavior and 2-deoxyglucose uptake in male red-sided garter snakes (thamnophis sirtalis parietalis). | the [14c]2-deoxyglucose (2-dg) technique was used to study patterns of neural activity associated with the species-typical courtship behavior of male red-sided garter snakes (thamnophis sirtalis parietalis). males in this species court females intensely during the first month following spring emergence from their prolonged winter hibernation. autoradiographic methods were used to measure the accumulation of radioactive label in various regions through the brains of male garter snakes that courte ... | 1992 | 1393517 |
| prostaglandin f2 alpha, sexual behavior and ovarian estrogen synthesis in garter snakes (thamnophis sirtalis parietalis). | 1. high levels of prostaglandin f2 alpha (pgf2 alpha; 10-18 ng) were detected in copulatory material removed from the cloacae of female thamnophis sirtalis parietalis immediately after mating. 2. in vitro, ovarian fragments treated with pgf2 alpha secreted significantly more estrogen than control fragments. 3. together these results suggest that a post-mating surge in estrogen secretion that occurs in this species may be influenced by a substantial rise in pgf2 alpha that occurs after mating. 4. ... | 1991 | 1685380 |
| the effects of exogenous neuropeptide y on feeding and sexual behavior in the red-sided garter snake (thamnophis sirtalis parietalis). | actively courting adult male red-sided garter snakes were injected with one of two dosages of neuropeptide y (npy) or saline into the third cerebral ventricle. courtship and feeding responses were assessed prior to surgery, 4-5 h and 24 h post-surgery. feeding behavior was tested by the presentation of a favored food, an earthworm. npy significantly reduced courtship behavior scores at both low (0.16 nmol) and high (0.77 nmol) doses 4-5 h after surgery. snakes also took much longer to reach the ... | 1990 | 2265362 |
| characterization, synthesis, and behavioral responses to sex attractiveness pheromones of red-sided garter snakes (thamnophis sirtalis parietalis). | the sex attractiveness pheromone of the red-sided garter snake,thamnophis sirtalis parietalis, has been characterized as a mixture of 13 long-chain (c29-c37) saturated and monounsaturated methyl ketones. samples of the major unsaturated ketones in the mixture, (z)-24-tritriaconten-2-one (7) and (z)-26-pentatriaconten-2-one (10), and their saturated analogs, 2-tritriacontanone (8) and 2-pentatriacontanone (11) were prepared by unambiguous synthesis. in field bioassay tests, male garter snakes wer ... | 1990 | 24264099 |
| mating-induced ovarian recrudescence in the red-sided garter snake. | in the female red-sided garter snake (thamnophis sirtalis parietalis) mating initiates a neuroendocrine reflex that has both a short-term (within hours) effect on circulating estrogen concentrations and a long-term (6-7 weeks) effect on ovarian development. the perception of mating appears at least facultative, if not obligatory, for the initiation and maintenance of vitellogenesis and hence successful reproduction. | 1990 | 2341988 |
| effect of fall mating on ovarian development in the red-sided garter snake. | although spring mating is an important factor in initiating vitellogenesis in female red-sided garter snakes (thamnophis sirtalis parietalis), some females can become vitellogenic without having mated in the spring. two hypotheses have been proposed to explain this phenomenon: 1) long-term storage of copulatory stimuli from mating the previous fall, or 2) additional cue(s) overcoming the lack of mating to stimulate vitellogenesis. through oviductal biopsy, the presence of sperm in females return ... | 1989 | 2604010 |
| sex pheromones in snakes. | the majority of pheromones identified to date are insect pheromones, which are volatile in nature. identification of nonvolatile pheromones have been relatively rare, especially in vertebrates. male and female garter snakes use pheromones to mediate sexual behavior. the female sex attractiveness pheromone of the canadian red-sided garter snake, thamnophis sirtalis parietalis, consists of a novel series of nonvolatile saturated and monounsaturated long-chain methyl ketones, whereas the male sex r ... | 1989 | 2749261 |
| annual reproductive cycle in the male red-sided garter snake, thamnophis sirtalis parietalis: field and laboratory studies. | the reproductive cycle of male red-sided garter snakes (thamnophis sirtalis parietalis) was studied in a laboratory-maintained population and in nature. both populations exhibited a dissociated reproductive pattern in which spermatogenesis was initiated after the breeding season and sperm were stored in the vas deferens over winter. although animals in both the laboratory and the field exhibited a dissociated reproductive pattern, temporal differences were evident in the two populations. animals ... | 1987 | 3666424 |
| plasma steroid hormone levels of female red-sided garter snakes, thamnophis sirtalis parietalis: relationship to mating and gestation. | plasma levels of progesterone (p), testosterone (t), estradiol (e2), and corticosterone (b) of female red-sided garter snakes were measured during the period of ovarian development. differences in hormone levels were analyzed with respect to three factors: whether the female mated in the spring, ovarian condition, and time after emergence from hibernation. the influence of these three factors on steroid hormone levels of two groups of females were then compared. in experiment i, females were obt ... | 1987 | 3623067 |
| pinealectomy blocks vernal courtship behavior in red-sided garter snakes. | male red-sided garter snakes (thamnophis sirtalis parietalis) court only on emergence from winter dormancy. the salient proximate factor responsible for the initiation of courtship behavior appears to be warm ambient temperatures subsequent to sustained exposure to cold temperatures. in the present study, autumn-captured garter snakes were pinealectomized or sham-pinealectomized 1-2 weeks prior to hibernation. after 17 weeks of maintenance in several ambient lighting and temperature conditions, ... | 1987 | 3575458 |
| facilitation of courtship behavior in the male red-sided garter snake (thamnophis sirtalis parietalis) following lesions of the septum or nucleus sphericus. | courtship behavior in male red-sided garter snakes is limited to the period immediately following spring emergence. lesions of the septum or nucleus sphericus prior to hibernation facilitate courtship behavior upon emergence the following spring. these lesions also had a significant effect on the reproductive physiology of the male snake. snakes with lesions in the nucleus sphericus had a significantly higher concentration of circulating androgens compared to the control group. while animals wit ... | 1987 | 3313451 |
| hibernation in garter snakes (thamnophis sirtalis parietalis): seasonal cycles of cold tolerance. | 1. the red-sided garter snake hibernates for about six months each year in manitoba, canada, where winter temperatures are often as low as -40 degrees c. mammalian hibernators typically undergo profound changes in preparation for hibernation, but little is known about corresponding changes in reptiles. 2. we tested the importance of seasonal changes in the ability of red-sided garter snakes to hibernate successfully by exposing them to winter conditions at different times of year. 3. animals tha ... | 1987 | 2887376 |
| effects of prostaglandin f2 alpha on sexual behavior and ovarian function in female garter snakes (thamnophis sirtalis parietalis). | sexual behavior, plasma steroid hormone levels, and ovarian growth of female red-sided garter snakes (thamnophis sirtalis parietalis) treated with prostaglandin f2 alpha (pgf2 alpha; 0.5-5.0 micrograms/g bw) were observed. the largest dose of pgf2 alpha significantly inhibited receptivity (mating) within 0.5 h of treatment and resulted in a significant decrease in sexual attractively 24 h later. these changes precisely parallel those seen in females that have mated. lower doses of pgf2 alpha sig ... | 1986 | 3460798 |
| ovarian development in red-sided garter snakes, thamnophis sirtalis parietalis: relationship to mating. | female red-sided garter snakes (thamnophis sirtalis parietalis) exhibit a complex array of behavioral patterns. females may mate once, more than once, or not at all in the spring of the year, and a high percentage of females may mate in late summer before returning to winter hibernacula. the role of mating in the induction of ovarian growth in this species is complicated by this pattern of spring and late summer mating. females hibernated in the laboratory that mate on emergence in the spring ex ... | 1986 | 3940930 |
| effects of early sex steroid hormone treatment on courtship behavior and sexual attractivity in the red-sided garter snake, thamnophis sirtalis parietalis. | previous research has shown that exogenous androgen fails to elicit courtship (chin-rubbing) behavior in adult male or female red-sided garter snakes (thamnophis sirtalis parietalis). however, gonadectomized and intact newborn male and female red-sided garter snakes given silastic capsules containing testosterone exhibit chin-rubbing behavior; gonadectomized and untreated animals do not show this behavior. both males and females also exhibit chin-rubbing behavior when treated with testosterone a ... | 1985 | 4070432 |
| role of the anterior hypothalamus-preoptic area in the regulation of courtship behavior in the male canadian red-sided garter snake (thamnophis sirtalis parietalis): lesion experiments. | lesions of the medial preoptic area and/or the ventromedial hypothalamus resulted in an abrupt and immediate decline in courtship behavior in adult male canadian red-sided garter snakes (thamnophis sirtalis parietalis). lesions of the more anterior portions of the preoptic area resulted in a more gradual, delayed decline in courtship behavior. male snakes sustaining lesions dorsal, ventral, or caudal to the anterior hypothalamus-preoptic area exhibited no change in courtship behavior relative to ... | 1985 | 3843310 |
| female mimicry in garter snakes. | in many diverse taxa, males of the same species often exhibit multiple mating strategies. one well-documented alternative male reproductive pattern is 'female mimicry', whereby males assume a female-like morphology or mimic female behaviour patterns. in some species males mimic both female morphology and behaviour. we report here female mimicry in a reptile, the red-sided garter snake (thamnophis sirtalis parietalis). this form of mimicry is unique in that it is expressed as a physiological femi ... | 2007 | 4010782 |
| small male body size in garter snake depends on testes. | in the red-sided garter snake (thamnophis sirtalis parietalis) adult females are larger than adult males; this difference is apparent within 3 wk of birth, a time coinciding with high circulating levels of androgens. to study the ontogeny and regulation of this sexual dimorphism, male neonates were either castrated, castrated and given silastic capsules containing testosterone or estradiol, or given a sham operation at 8, 9, or 10 wk of age. female neonates were either given a silastic capsule c ... | 1985 | 4014497 |
| responses of the aorta of the garter snake (thamnophis sirtalis parietalis) to purines. | 1. isolated aortic rings from the garter snake (thamnophis sirtalis parietalis) were investigated in order to identify and classify responses to adenosine and adenosine 5'-triphosphate (atp) and their analogues as part of a comparative study of vertebrate purinoceptors. 2. adenosine, d-5'-(n-ethylcarboxamide) adenosine (neca), r- and s-n6-(2-phenylisopropyl) adenosine (r- and s-pia) and 2-chloroadenosine (2-ca) all concentration-dependently relaxed aorta preconstricted with noradrenaline (na). t ... | 1995 | 7712027 |
| antioxidant defenses in the tolerance of freezing and anoxia by garter snakes. | the garter snake thamnophis sirtalis parietalis can readily tolerate several hours of freezing or anoxia exposure. both stresses halt oxygen availability to tissues and to endure these stresses snakes must cope with potential oxidative stress arising as a result of the ischemic/anoxic condition followed by reperfusion of aerated blood during recovery. to determine whether antioxidant defenses are important for freezing and anoxia survival, we monitored the activities of antioxidant enzymes and t ... | 1993 | 8214160 |
| in vitro oxidative inactivation of glutathione s-transferase from a freeze tolerant reptile. | we have previously reported that when garter snakes. thamnophis sirtalis parietalis, a freeze tolerant species, were exposed to 5 h freezing at -2.5 degrees c organs showed increases in the activities of anti-oxidant enzymes, especially catalase in skeletal muscle. this was interpreted to be an adaptation to deal with the potentially injurious postischemic situation of thawing. the present work analyzes in vitro oxidative inactivation of a possible target of postischemic-induced free radical dam ... | 1993 | 8232286 |
| social dynamics of group courtship behavior in male red-sided garter snakes (thamnophis sirtalis parietalis). | mating in red-sided garter snakes is characterized by the formation of mating balls. up to 100 males simultaneously court single females. the social dynamics of the formation of these mating balls was examined to determine whether the mating balls are formed simply because of a common attraction to the female or whether males are stimulated by the mating balls themselves. a sexually attractive female garter snake appears to be even more attractive to a male when she is being courted by other mal ... | 1985 | 4006433 |
| female sex pheromone in the skin and circulation of a garter snake. | serums and extracts of tissues from the female garter snake (thamnophis sirtalis parietalis) each act as a pheromone and elicit male courtship behavior when applied to the back of another male. since pheromonal activity is present in yolk and liver tissue of untreated females and can be induced with estrogen treatment in the serums and livers of males, the pheromone may be associated with the circulating yolk lipoprotein, vitellogenin. | 1981 | 7292007 |
| antioxidant defenses and metabolic depression. the hypothesis of preparation for oxidative stress in land snails. | the roles of enzymatic antioxidant defenses in the natural tolerance of environmental stresses that impose changes in oxygen availability and oxygen consumption on animals is discussed with a particular focus on the biochemistry of estivation and metabolic depression in pulmonate land snails. despite reduced oxygen consumption and po2 during estivation, which should also mean reduced production of oxyradicals, the activities of antioxidant enzymes, such as superoxide dismutase and catalase, incr ... | 1998 | 9787804 |
| animal response to drastic changes in oxygen availability and physiological oxidative stress. | oxygen is essential for most life forms, but it is also inherently toxic due to its biotransformation into reactive oxygen species (ros). in fact, the development of many animal and plant pathological conditions, as well as natural aging, is associated with excessive ros production and/or decreased antioxidant capacity. however, a number of animal species are able to tolerate, under natural conditions, situations posing a large potential for oxidative stress. situations range from anoxia in fish ... | 2002 | 12458182 |
| 2-deoxyglucose uptake following visual stimulation in squamate reptiles. | unilateral visual stimulation following 2-deoxyglucose injection was used to delineate functional visual pathways in red-sided garter snakes (thamnophis sirtalis parietalis) and whiptail lizards (cnemidophorus inornatus and c. uniparens). stimulation enhanced both overall uptake and particularly uptake in visual pathways contralateral to the side of stimulation. bilaterally symmetrical uptake was observed in retinae, septum, nucleus sphericus, and brainstem nuclei. overall uptake and lateralizat ... | 1989 | 2611637 |
| effects of castration and androgen replacement on male courtship behavior in the red-sided garter snake (thamnophis sirtalis parietalis). | | 1980 | 7216186 |
| integumentary bloodvascular system in garter snakes (thamnophis sirtalis parietalis and thamnophis rasix). | | 1978 | 647530 |
| the influence of photoperiod and temperature on seasonal testicular recrudescence in the red-sided garter snake (thamnophis sirtalis parietalis). | | 1976 | 2423 |
| effects of temperature, photoperiod and season on in vitro metabolic rates of tissues from thamnophis sirtalis parietalis, a cold climate reptile. | | 1973 | 4147926 |
| effects of temperature on the kinetics of malate dehydrogenase from a cold climate reptile, thamnophis sirtalis parietalis. | | 1973 | 4712869 |
| temperature-dependent shifts in the metabolism of a cool temperate reptile, thamnophis sirtalis parietalis. | | 1971 | 4150231 |
| the effects of in vivo light and temperature acclimation on in vitro responses of heart rate to temperature in a cold-climate reptile, thamnophis sirtalis parietalis. | | 1970 | 5503023 |
| hormonal independence of courtship behavior in the male garter snake. | garter snakes exhibit a dissociated reproductive tactic in which gonadal activity is minimal at the time of mating, increasing only after the breeding season has ended. experiments are presented demonstrating that neither short-term nor longterm castration affects courtship behavior in adult male red-sided garter snakes (thamnophis sirtalis parietalis). so long as males have passed through a low-temperature dormancy period (hibernation), castration either shortly after emergence in the spring, o ... | 1984 | 6706317 |