The Experts below are selected from a list of 1083 Experts worldwide ranked by ideXlab platform
Caitlin R Gabor - One of the best experts on this subject based on the ideXlab platform.
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an acute increase in the stress hormone corticosterone is associated with mating behavior in both male and female red spotted newts notophthalmus viridescens
General and Comparative Endocrinology, 2014Co-Authors: Aaron M Reedy, Alex Edwards, Chloe Pendlebury, Laura Murdaugh, Ryan Avery, Jake Seidenberg, Andrea S Aspbury, Caitlin R GaborAbstract:Hormones play key, functional roles in mediating the tradeoff between survival and reproduction. Glucocorticoid hormones can inhibit reproduction and improve chances of survival during periods of stress. However, glucocorticoid hormones are, at times, also associated with successfully engaging in energetically costly courtship and mating behaviors. Corticosterone (CORT), a primary glucocorticoid hormone in amphibians, reptiles and birds, may be important in activating or sustaining energetically costly mating behaviors. We used a non-invasive, water-borne hormone assay to measure CORT release rates of male and female red-spotted newts (Notophthalmus viridescens) collected when either engaged in Amplexus or when not engaged in Amplexus. Because Amplexus is energetically costly for males, we predicted that males would have higher CORT release rates than females. We also predicted that females in Amplexus would have elevated CORT release rates because the restraint of Amplexus prevents foraging and breathing and may be costly. Here we show that an acute increase in CORT is associated with Amplexus behavior in both male and female red-spotted newts. Additionally we demonstrate that males have higher overall CORT release rates both in and out of Amplexus than do females. Our results support the hypothesis that glucocorticoid hormones are associated with energetically costly courtship and mating behaviors for both sexes.
Richard Shine - One of the best experts on this subject based on the ideXlab platform.
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may the selective force be with you spatial sorting and natural selection exert opposing forces on limb length in an invasive amphibian
Journal of Evolutionary Biology, 2019Co-Authors: Gregory S Clarke, Richard Shine, Benjamin L PhillipsAbstract:: Spatial sorting on invasion fronts drives the evolution of dispersive phenotypes, and in doing so can push phenotypes in the opposite direction to natural selection. The invasion of cane toads (Rhinella marina) through tropical Australia has accelerated over recent decades because of the accumulation of dispersal-enhancing traits at the invasion front, driven by spatial sorting. One such trait is the length of the forelimbs: invasion-front toads have longer arms (relative to body length) in comparison with populations 10-20 years after invasion. Such a shift likely has fitness consequences: an increase of forearm length would decrease the strength with which a male could cling to a female during Amplexus and so render such a male less competitive in competition for mates, compared to short-armed conspecifics. Our laboratory trials of attachment strength confirmed that males with relatively longer arms were easier to displace, and competition trials show higher duration of Amplexus for males with shorter arms. Together with the sharp cline in limb length observed behind the invasion front, these results imply an opposition of selective forces: spatial sorting optimizes dispersal, but as this force wanes behind the invasion front, we see the primacy of natural selection reassert itself.
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whispers on the wind male cane toads modify mate searching and Amplexus tactics based on calls from other males
Animal Behaviour, 2019Co-Authors: Gregory S Clarke, Richard Shine, Benjamin L PhillipsAbstract:In many species of anurans, males produce advertisement calls that function to attract reproductively active females. Rival males may use the public information in these calls to optimize their own tactics for acquiring mates. To see whether male cane toads, Rhinella marina, modify their mate-searching and Amplexus behaviours in response to conspecific calls, we monitored toads in outdoor enclosures while playing recordings of advertisement calls, a biologically irrelevant stimulus with similar acoustic properties or silence. Male toads were seven times more likely to engage in Amplexus and moved twice as much during a toad chorus than during the control sound or silence. Nonacoustic cues also influenced propensity to initiate Amplexus, with males five to 16 times more likely to amplect a moving target than a stationary one (regardless of the sex of the animal being amplexed). Our study shows that male toads dramatically alter their behaviour in response to acoustic and visual information from conspecifics, suggesting that this public information holds substantial value to them as they seek to fine-tune their own reproductive tactics.
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sexual selection in cane toads rhinella marina a male s body size affects his success and his tactics
Current Zoology, 2013Co-Authors: Haley Bowcock, Gregory P Brown, Richard ShineAbstract:Male body size can play an important role in the mating systems of anuran amphibians. We conducted labora- tory-based trials with cane toads Rhinella (Bufo) marina from an invasive population in the wet-dry tropics of northern Australia, to clarify the effects of a male's body size on his reproductive success and behavior (mate choice). Males were stimulated with a synthetic hormone to induce reproductive readiness. Larger body size enhanced a male toad's ability to displace a smaller rival from Amplexus, apparently because of physical strength: more force was required to dislodge a larger than a smaller amplectant male. A male's body size also affected his mate-choice criteria. Males of all body sizes were as likely to attempt Amplexus with another male as with a female of the same size, and preferred larger rather than smaller sexual targets. However, this size prefe- rence was stronger in larger males and hence, Amplexus was size-assortative. This pattern broke down when males were given access to already-amplectant male-female pairs: males of all body sizes readily attempted Amplexus with the pair, with no size discrimination. An amplectant pair provides a larger visual stimulus, and prolonged Amplexus provides a strong cue for sex iden- tification (one of the individuals involved is almost certainly a female). Thus, a male cane toad's body size affects both his ability to defeat rivals in physical struggles over females, and the criteria he uses when selecting potential mates, but the impacts of that selectivity depend upon the context in which mating occurs (Current Zoology 59 (6): 747-753, 2013).
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beastly bondage the costs of Amplexus in cane toads bufo marinus
Copeia, 2009Co-Authors: Haley Bowcock, Gregory P Brown, Richard ShineAbstract:Reproductive activities can impose fitness costs as well as benefits. In most anuran species, males clasp females for prolonged periods prior to gamete release, and intuition suggests that the male’s presence may impair the female’s ability to move about and to feed. We tested the prediction that female locomotion and feeding would be reduced during Amplexus in laboratory experiments with Cane Toads, Bufo marinus. Amplexus reduced the female’s locomotor (sprint and swim) performance, with the degree of locomotor impairment (speed and distance per hop) dependent upon the body size of the amplectant male for trials of terrestrial locomotion, but not for aquatic locomotion. Amplexus also reduced feeding rates in females; amplectant males did not feed at all. Overall, our data confirm that Amplexus imposes locomotor and feeding costs to female Cane Toads, and suggest that this distinctive posture may generate sexual conflict in at least some anuran species.
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sexual communication in cane toads chaunus marinus what cues influence the duration of Amplexus
Animal Behaviour, 2008Co-Authors: Haley Bowcock, Gregory P Brown, Richard ShineAbstract:Successful reproduction often involves complex communication, but signalling capabilities frequently differ between the sexes. Research on sexual communication in anuran amphibians has focused heavily on the advertisement call made by reproductive males, with less attention paid to the release signal that males (and some females) give in response to misdirected attempts at Amplexus. In the cane toad the release signal consists of a mechanical component (vibrations of the body wall, given by both sexes) as well as an auditory call (apparently given by males alone). We investigated the cane toad release signal to ask: (1) do females call in a manner similar to that of males but at a frequency inaudible to human ears? and (2) what stimuli (acoustic or otherwise) induce males to terminate Amplexus? Analysis of calls over a wide (4–100 000 Hz) frequency range confirmed that female toads are indeed mute. Acoustic playback experiments revealed that males were less likely to dismount if we prevented an otherwise vocal target animal from making a release call. However, adding a release call to an otherwise mute target did not initiate dismount. Instead, the cue eliciting male dismount appears to involve synchrony between the release call and some other factor (probably, vibration of the clasped animal). Sexual dimorphism in skin rugosity also may play a role in Amplexus termination.
Aaron M Reedy - One of the best experts on this subject based on the ideXlab platform.
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an acute increase in the stress hormone corticosterone is associated with mating behavior in both male and female red spotted newts notophthalmus viridescens
General and Comparative Endocrinology, 2014Co-Authors: Aaron M Reedy, Alex Edwards, Chloe Pendlebury, Laura Murdaugh, Ryan Avery, Jake Seidenberg, Andrea S Aspbury, Caitlin R GaborAbstract:Hormones play key, functional roles in mediating the tradeoff between survival and reproduction. Glucocorticoid hormones can inhibit reproduction and improve chances of survival during periods of stress. However, glucocorticoid hormones are, at times, also associated with successfully engaging in energetically costly courtship and mating behaviors. Corticosterone (CORT), a primary glucocorticoid hormone in amphibians, reptiles and birds, may be important in activating or sustaining energetically costly mating behaviors. We used a non-invasive, water-borne hormone assay to measure CORT release rates of male and female red-spotted newts (Notophthalmus viridescens) collected when either engaged in Amplexus or when not engaged in Amplexus. Because Amplexus is energetically costly for males, we predicted that males would have higher CORT release rates than females. We also predicted that females in Amplexus would have elevated CORT release rates because the restraint of Amplexus prevents foraging and breathing and may be costly. Here we show that an acute increase in CORT is associated with Amplexus behavior in both male and female red-spotted newts. Additionally we demonstrate that males have higher overall CORT release rates both in and out of Amplexus than do females. Our results support the hypothesis that glucocorticoid hormones are associated with energetically costly courtship and mating behaviors for both sexes.
David J Able - One of the best experts on this subject based on the ideXlab platform.
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scramble competition selects for greater tailfin size in male red spotted newts amphibia salamandridae
Behavioral Ecology and Sociobiology, 1999Co-Authors: David J AbleAbstract:Darwin predicted that scramble competition for access to reproductive females would result in sexual dimorphism of locomotory structures, but direct evidence for this is extremely rare. I examined the relationship between variation in tailfin size and mating success in a field and laboratory study of red-spotted newts, Notophthalmus viridescens. Over three breeding seasons, male tailfin size was positively correlated with variation in male Amplexus frequency, and indirectly correlated with male insemination frequency. In a laboratory study, I confirmed that males' ability to capture females is affected by variation in tailfin size. This is the first study to show that naturally occurring variation in male locomotory structures affects male mating success. It corroborates the prediction that scramble competition leads to sexual selection on locomotory structures and, potentially, to dimorphism in these structures.
Chloe Pendlebury - One of the best experts on this subject based on the ideXlab platform.
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an acute increase in the stress hormone corticosterone is associated with mating behavior in both male and female red spotted newts notophthalmus viridescens
General and Comparative Endocrinology, 2014Co-Authors: Aaron M Reedy, Alex Edwards, Chloe Pendlebury, Laura Murdaugh, Ryan Avery, Jake Seidenberg, Andrea S Aspbury, Caitlin R GaborAbstract:Hormones play key, functional roles in mediating the tradeoff between survival and reproduction. Glucocorticoid hormones can inhibit reproduction and improve chances of survival during periods of stress. However, glucocorticoid hormones are, at times, also associated with successfully engaging in energetically costly courtship and mating behaviors. Corticosterone (CORT), a primary glucocorticoid hormone in amphibians, reptiles and birds, may be important in activating or sustaining energetically costly mating behaviors. We used a non-invasive, water-borne hormone assay to measure CORT release rates of male and female red-spotted newts (Notophthalmus viridescens) collected when either engaged in Amplexus or when not engaged in Amplexus. Because Amplexus is energetically costly for males, we predicted that males would have higher CORT release rates than females. We also predicted that females in Amplexus would have elevated CORT release rates because the restraint of Amplexus prevents foraging and breathing and may be costly. Here we show that an acute increase in CORT is associated with Amplexus behavior in both male and female red-spotted newts. Additionally we demonstrate that males have higher overall CORT release rates both in and out of Amplexus than do females. Our results support the hypothesis that glucocorticoid hormones are associated with energetically costly courtship and mating behaviors for both sexes.