Body-coiling Behavior in the Three-toed Amphiuma (Amphiuma tridactylum)

Salamanders coil their bodies for a variety of reasons, but primarily as a response to predators. For the aquatic salamander Amphiuma, all reports on coiling are associated with nest attendance, although another notion has made it into the literature, that Amphiuma coils its body to reduce evaporative water loss of the adult. We inadvertently tested this notion via another study on temperature preference in an aquatic thermal gradient. Because nearly half of our observations were of tightly coiled individuals underwater, we conclude that this behavior is not for reducing evaporative water loss, but more likely a defensive posture

Body-coiling Behavior in the Three-toed Amphiuma (Amphiuma tridactylum)

Salamanders coil their bodies for a variety of reasons, but primarily as a response to predators. For the aquatic salamander Amphiuma, all reports on coiling are associated with nest attendance, although another notion has made it into the literature, that Amphiuma coils its body to reduce evaporative water loss of the adult. We inadvertently tested this notion via another study on temperature preference in an aquatic thermal gradient. Because nearly half of our observations were of tightly coiled individuals underwater, we conclude that this behavior is not for reducing evaporative water loss, but more likely a defensive posture

Helminth Parasites of Two Species of Lepomis (Osteichthyes: Centrarchidae) from an Urban Watershed and their Potential Use in Environmental Monitoring

We provide a checklist of the common parasites of bluegill (Lepomis macrochirus) and redbreast sunfish (Lepomis auritus) collected from eight creeks within an urban watershed located in Columbus, Georgia. A total of 12 parasite species were observed from 427 fish dissected. Bluegill (n = 222) were infected with 11 species, which included five species of larval helminths (Proteocephalus sp., Bothriocephalus sp., Posthodiplostomum minimum, Diplostomulum sp. and Clinostomum complanatum), one adult trematode (Pisciamphistoma stunkardi), four adult nematodes (Philometra sp., Philometra intraoculus, Spinetectus carolini and Camallanus oxycephalus) and one adult acanthocephalan (Neochinorhynchus cylindratus). Redbreast sunfish (n = 205) were infected with the same parasite species, except for the absence of larval Bothriocephalus sp. and the presence of an adult trematode (Crepidostomum cooperi). Metacercariae of the trematode P. minimum were the most common parasite in both fish species. Similar parasite communities in these sunfishes suggest that these species share similar microhabitats within the watershed, food resources and foraging sites. Seasonal comparison between the number of summer and winter parasites indicate a greater mean number of parasites per host in summer. We discuss the utility of such baseline parasite data in the potential environmental monitoring of the Bull and Upatoi Creeks watershed

Observed shifts in the contact zone between two forms of the diving beetle Hydroporus memnonius are consistent with predictions from sexual conflict.

Sexual conflict drives both inter- and intrasexual dimorphisms in many diving beetles, where male persistence and female resistance traits co-evolve in an antagonistic manner. To date most studies have focussed on species where rough and smooth females and their associated males typically co-occur within populations, where phenotype matching between morphs may maintain forms as stable polymorphisms. The Palaearctic diving beetle Hydroporus memnonius is characterised by having dimorphic (rough var. castaneus and smooth, shining) females and associated males which differ in persistence traits; the two forms being largely distributed parapatrically. In this species, instead of mating trade-offs between morphs, males associated with castaneus females should have a mating advantage with both this form and shining females, due to their increased persistence abilities on either cuticular surface. This may be expected to lead to the replacement of the shining form with castaneus in areas where the two come into contact. Using data collected over a thirty year period, we show that this process of population replacement is indeed occurring, castaneus having expanded significantly at the expense of the shining female form. Whilst populations of both forms close to the contact zone appear to differ in their thermal physiology, these differences are minor and suggest that the expansion of castaneus is not linked to climatic warming in recent decades. Instead we argue that the observed spread of castaneus and its associated male may result from the dynamics of sexually antagonistic coevolution in this beetle

Transient Receptor Potential Ion Channels Control Thermoregulatory Behaviour in Reptiles

Biological functions are governed by thermodynamics, and animals regulate their body temperature to optimise cellular performance and to avoid harmful extremes. The capacity to sense environmental and internal temperatures is a prerequisite for the evolution of thermoregulation. However, the mechanisms that enable ectothermic vertebrates to sense heat remain unknown. The recently discovered thermal characteristics of transient receptor potential ion channels (TRP) render these proteins suitable to act as temperature sensors. Here we test the hypothesis that TRPs are present in reptiles and function to control thermoregulatory behaviour. We show that the hot-sensing TRPV1 is expressed in a crocodile (Crocodylus porosus), an agamid (Amphibolurus muricatus) and a scincid (Pseudemoia entrecasteauxii) lizard, as well as in the quail and zebrafinch (Coturnix chinensis and Poephila guttata). The TRPV1 genes from all reptiles form a unique clade that is delineated from the mammalian and the ancestral Xenopus sequences by an insertion of two amino acids. TRPV1 and the cool-sensing TRPM8 are expressed in liver, muscle (transversospinalis complex), and heart tissues of the crocodile, and have the potential to act as internal thermometer and as external temperatures sensors. Inhibition of TRPV1 and TRPM8 in C. porosus abolishes the typically reptilian shuttling behaviour between cooling and heating environments, and leads to significantly altered body temperature patterns. Our results provide the proximate mechanism of thermal selection in terrestrial ectotherms, which heralds a fundamental change in interpretation, because TRPs provide the mechanism for a tissue-specific input into the animals' thermoregulatory response

LIVE COLOR PATTERNS DIAGNOSE SPECIES: A TALE OF TWO HERICHTHYS

The Rio Grande Cichlid, Herichthys cyanoguttatus, is native to the drainages of the Gulf Coast of northern Mexico and southern Texas and has been introduced at several sites in the US. Previous observations have suggested that non-native populations in Louisiana that are currently recognized as H. cyanoguttatus resemble another species, the Lowland Cichlid, H. carpintis. Traditional morphological and genetic techniques have been insufficient to differentiate these species, but H. carpintis has been reported to differ from H. cyanoguttatus in color pattern, so we turned to novel electronic photo archives to determine the identity of the species introduced in Louisiana. First, we used the public databases Nonindigenous Aquatic Species Database and Fishes of Texas to infer the historical distributions of these species in the US. We then used museum specimens, live specimens, and two additional databases, The Cichlid Room Companion and iNaturalist, to compare morphology and color patterns among individuals obtained from their native and introduced ranges in Mexico, Texas, and Louisiana. Our general observations found that H. cf. cyanoguttatus from Louisiana tended to have an obliquely oriented mouth and a more rounded ventral profile than H. cyanoguttatus from Texas, consistent with previous descriptions of H. carpintis, but our morphological analyses were unable to identify any significant differences among populations. Our analyses of color patterns found that H. cf. cyanoguttatus from Louisiana had larger iridescent spots than H. cyanoguttatus from Texas as well as black breeding coloration that extended anteriorly to the tip of the mouth, characters consistent with H. carpintis. Our observations indicate that at least some of the cichlids introduced in Louisiana are not H. cyanoguttatus but are instead H. carpintis, and that their presence there is likely due to release by humans. This is the first record of H. carpintis establishing a population in the US. Understanding the biology of not one, but two, species of Herichthys will be necessary to predict and mitigate their continued colonization of new environments in the US.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/167241/1/UMMZ MP 209.pdfDescription of UMMZ MP 209.pdf : Main ArticleSEL

Forecasting the combined effects of urbanization and climate change on stream ecosystems: from impacts to management options

Streams collect runoff, heat, and sediment from their watersheds, making them highly vulnerable to anthropogenic disturbances such as urbanization and climate change. Forecasting the effects of these disturbances using process-based models is critical to identifying the form and magnitude of likely impacts. Here, we integrate a new biotic model with four previously developed physical models (downscaled climate projections, stream hydrology, geomorphology, and water temperature) to predict how stream fish growth and reproduction will most probably respond to shifts in climate and urbanization over the next several decades.The biotic submodel couples dynamics in fish populations and habitat suitability to predict fish assemblage composition, based on readily available biotic information (preferences for habitat, temperature, and food, and characteristics of spawning) and day-to-day variability in stream conditions.We illustrate the model using Piedmont headwater streams in the Chesapeake Bay watershed of the USA, projecting ten scenarios: Baseline (low urbanization; no on-going construction; and present-day climate); one Urbanization scenario (higher impervious surface, lower forest cover, significant construction activity); four future climate change scenarios [Hadley CM3 and Parallel Climate Models under medium-high (A2) and medium-low (B2) emissions scenarios]; and the same four climate change scenarios plus Urbanization.Urbanization alone depressed growth or reproduction of 8 of 39 species, while climate change alone depressed 22 to 29 species. Almost every recreationally important species (i.e. trouts, basses, sunfishes) and six of the ten currently most common species were predicted to be significantly stressed. The combined effect of climate change and urbanization on adult growth was sometimes large compared to the effect of either stressor alone. Thus, the model predicts considerable change in fish assemblage composition, including loss of diversity.Synthesis and applications. The interaction of climate change and urban growth may entail significant reconfiguring of headwater streams, including a loss of ecosystem structure and services, which will be more costly than climate change alone. On local scales, stakeholders cannot control climate drivers but they can mitigate stream impacts via careful land use. Therefore, to conserve stream ecosystems, we recommend that proactive measures be taken to insure against species loss or severe population declines. Delays will inevitably exacerbate the impacts of both climate change and urbanization on headwater systems

Oxygen-limited thermal tolerance is seen in a plastron-breathing insect and can be induced in a bimodal gas exchanger.

Thermal tolerance has been hypothesized to result from a mismatch between oxygen supply and demand. However, the generality of this hypothesis has been challenged by studies on various animal groups, including air-breathing adult insects. Recently, comparisons across taxa have suggested that differences in gas exchange mechanisms could reconcile the discrepancies found in previous studies. Here, we test this suggestion by comparing the behaviour of related insect taxa with different gas exchange mechanisms, with and without access to air. We demonstrate oxygen-limited thermal tolerance in air-breathing adults of the plastron-exchanging water bug Aphelocheirus aestivalis. Ilyocoris cimicoides, a related, bimodal gas exchanger, did not exhibit such oxygen-limited thermal tolerance and relied increasingly on aerial gas exchange with warming. Intriguingly, however, when denied access to air, oxygen-limited thermal tolerance could also be induced in this species. Patterns in oxygen-limited thermal tolerance were found to be consistent across life-history stages in these insects, with nymphs employing the same gas exchange mechanisms as adults. These results advance our understanding of oxygen limitation at high temperatures; differences in the degree of respiratory control appear to modulate the importance of oxygen in setting tolerance limits

Effects of a novel climate on stress response and immune function in painted turtles (Chrysemys picta)

Climate change may subject animals to increasingly stressful environmental conditions, which could have negative physiological consequences if stress levels are elevated for long periods. We conducted a manipulative experiment to determine the effects of a novel climate on stress levels and immune function in a model reptile species, the painted turtle. We collected turtles from four populations across the species' geographic range and housed them in a common-garden in one population's local climate. We measured levels of the stress hormone corticosterone and tested two aspects of innate immune function, bactericidal capacity and natural antibody agglutination, at the time of capture (baseline) and three additional time points over 1 year. The four populations did not differ in corticosterone levels over the course of 1 year, and corticosterone levels were also similar at each sampling period except that post-hibernation corticosterone levels were significantly lower than the previous three time points. Furthermore, we found no evidence that elevated corticosterone depressed immune function in the painted turtle. Our study suggests that turtles exposed to novel climatic conditions did not display a detectable stress response, nor did the novel climate depress immune function in the transplanted populations. Therefore, in terms of innate immune function, turtles may be relatively resilient to at least small changes in climatic conditions.Fil: Refsnider, Jeanine M.. University Of California Berkeley; Estados UnidosFil: Palacios, María Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico.; ArgentinaFil: Reding, Dawn M.. Luther College. Department of Biology; Estados UnidosFil: Bronikowski, Anne M.. Iowa State University. Department of Ecology, Evolution and Organismal Biology.; Estados Unido

Hormones and Reproductive Cycles in Snakes

The study of the hormonal regulation of reproduction in snakes is in its infancy. Studies have disproportionately examined temperate zone viperid and colubrid snakes, especially the red-sided garter snake (Thamnophis sirtalis parietalis). Indeed, extensive observational and experimental studies on T. s. parietalis form the basis for our understanding of the hormonal regulation of reproduction in snakes. This review focuses on seasonal hormone concentrations in snakes in relation to events in the reproductive cycle; the limited data available on hypothalamic hormones, gonadotropins (GTHs), hormone receptors, and binding globulins; the neuroendocrinology of reproduction; and the environmental, social, physiological, and embryonic aspects of hormonal regulation of reproduction in snakes. The review ends with suggestions for future research, including studies of a more diverse ecological and taxonomic representation of snakes, experimental studies on the effects of hormones on reproductive tissues and behaviors, and further research into the neuroendocrinology of reproduction in this highly diverse group of animals