How do ectotherms perform in cold environments? Physiological and life-history traits in an Andean viviparous lizard

Material complementario: https://www.frontiersin.org/articles/10.3389/fevo.2022.974968/full#supplementary-materialBoth the mean and the variation in environmental temperature are increasing globally. Indeed, the predicted increases in temperature range from 2 to 4°C in the next 50 years. Ectotherms control body temperature by means of behavior selecting microsites with different temperatures, which makes them more susceptible to changes in climate. Nevertheless, lizards living in high mountain environments have developed several mechanisms to inhabit and colonize variable environments with extreme temperatures. These mechanisms include a high metabolism to be active at lower temperatures and viviparity to improve embryonic development. Despite behavioral thermoregulation acting as a buffer to changes in environmental temperature, other traits such as lifehistory traits may be less flexible. Consequently, in an attempt to understand how lizards cope with harsh habitats, we evaluated some physiological traits and responses of females of Liolaemus bellii from two contrasting slope sites with differences in environmental temperature and humidity, but at the same altitude in the southern Andes range. We collected pregnant females from opposite slopes and maintained them until parturition in a commongarden experiment. Females from the south-facing slope (S-slope) had higher preferred body temperature (Tpref) values before and after parturition and exhibited higher daily energy expenditure before parturition. Nevertheless, no difference in Tpref was shown by their offspring, suggesting a developmental plastic response or adaptation to lower environmental temperature. For instance, the higher metabolism during pregnancy could be associated with a shorter activity period on the snowy S-slope. Additionally, females from the S-slope had larger kidneys and gave birth later than N-slope females, likely due to developmental plasticity or genetic differentiation. How fixed these traits are, in individuals from the contrasting slopes, will determine the response capacity of the L. bellii population to climate change

Diet of Phytotoma rutila (Passeriformes: Cotingidae) in the central Monte desert, Argentina

Artículo de publicación SciELOSe determinó la composición botánica de la dieta del Cortarramas Phytotoma rutila en el desierto del Monte central, Argentina, mediante análisis microhistológico de las heces. En ambos sexos, la dieta estuvo compuesta por una importante proporción de frutos (26.8%) y hojas (35.6%) del arbusto Lycium tenuispinosum (Solanaceae) y hojas del árbol Prosopis flexuosa (Fabaceae) (26.8%). P. rutila es una ave predominantemente folívora con un alto consumo de frutos durante el verano, cuando estos ítems son abundantes, lo que refleja su comportamiento oportunista.FONDECYT N°3130429 (JM Ríos

Epigenetic and phenotypic changes result from a continuous pre and post natal dietary exposure to phytoestrogens in an experimental population of mice

Background: Developmental effects of exposure to endocrine disruptors can influence adult characters in mammals, but could also have evolutionary consequences. The aim of this study was to simulate an environmental exposure of an experimental population of mice to high amounts of nutritional phytoestrogens and to evaluate parameters of relevance for evolutionary change in the offspring. The effect of a continuous pre- and post-natal exposure to high levels of dietary isoflavones was evaluated on sexual maturity, morphometric parameters and DNA methylation status in mice. Adult mice male/female couples were fed ad libitum either with control diet (standard laboratory chow) or ISF diet (control diet plus a soy isoflavone extract at 2% (w/w) that contained the phytoestrogens genistein and daidzein). In the offspring we measured: i) the onset of vaginal opening (sexual maturation) in females, ii) weight and size in all pups at 7, 14, 21 and 42 days post-natal (dpn) and iii) DNA methylation patterns in skeletal α-actin (Acta1), estrogen receptor- α and c-fos in adults (42 dpn). Results: Vaginal opening was advanced in female pups in the ISF group, from 31.6 ± 0.75 dpn to 25.7 ± 0.48. No differences in size or weight at ages 7, 14 or 21 dpn were detected between experimental groups. Nevertheless, at age 42 dpn reduced size and weight were observed in ISF pups, in addition to suppression of normal gender differences in weight seen in the control group (males heavier that females). Also, natural differences seen in DNA methylation at Acta1 promoter in the offspring originated in the control group were suppressed in the ISF group. Acta1 is known to be developmentally regulated and related to morphomotric features. Conclusion: This study demonstrates in mammals that individuals from a population subjected to a high consumption of isoflavones can show alterations in characters that may be of importance from an evolutionary perspective, such as epigenetic and morphometric characters or sexual maturation, a life history character.We greatly appreciate the linguistic revision of the manuscript by Renée Hill and critical review of the manuscript by Dr. Anders Lindroth. We are very thankful for funding by FONDECYT projects 1010647 to PS and 1030309 to LV, CONICYT fellowship for graduate studies and MECESUP grant for overseas training to CG, and NH&MRC project grant funding to SJC

Temperature variability and thermal performance in ectotherms: acclimation, behaviour, and experimental considerations

ABSTRACT Background: Among the predictions of the effect of future climate change, the impact of thermal conditions at local levels on the performance of individuals and their acclimation capacities is key to understanding animals' responses to global warming. Woodlice (the terrestrial isopod Porcellio laevis) exhibit a readily observed behaviour that may reflect their acclimation capacities. When they find themselves on their back, they sometimes roll over (i.e. right themselves). Whether they do, and how fast they do it, are measures of their behaviour and performance that vary with ambient temperature. Goal: Measure experimentally the effect of acclimation to environmental thermal variability on the rollover behaviour of Porcellio laevis. Methods: Maintain woodlice in 24ЊC laboratory environments. Each individual lived in one of three thermal treatments: constant temperature regime (δ = 0); a regime with alternating temperatures of 27ЊC during daytime and 21ЊC at night (δ = 3); and a regime with alternating temperatures of 32ЊC during daytime and 16ЊC at night (δ = 8). After 3 months, measure the rollover behaviour (percentage that rolled over) and rollover speed of the woodlice at 5, 15, 25, 32, and 38ЊC. Rollover speed is the inverse of the time it took an individual to right itself. Results: At 5 and 38ЊC, most woodlice seemed to be in thermal coma and had very slow rollover speed. At 15, 25, and 32ЊC, rollover speed was in the range 0.12-0.18 rollovers per second. At 15, 25, and 32ЊC, 52% of individuals righted themselves in ∼4 s. At these temperatures, most individuals either rolled quickly or remained inactive for the entire 10-min test period. When we examined rollover speed in the cooler (night) and warmer (daytime) periods, individuals subjected to the three regimes of temperature variation differed: woodlice acclimated to δ = 8 roll over very fast when temperature (T ) is low and very slowly when T is high; woodlice acclimated to δ = 3 roll over fairly fast when T is low and somewhat slowly when T is high; and woodlice acclimated to δ = 0 roll over quite quickly when T is low and quit

¿Resulta realmente eficaz la oxitocina intraumbilical para el alumbramiento de placenta retenida en contra de otros métodos?

La extracción manual de la placenta consiste en una extracción digital en la cual se introduce la mano en el útero, provocando el desprendimiento de la placenta y su salida al exterior. A continuación, se realiza una limpieza de la cavidad uterina. En casos graves de placenta retenida, como placenta percreta, se deberá realizar una extracción parcial o completa del útero. La inyección de oxitocina en la vena umbilical influye directamente sobre la placenta y el miometrio, con el fin de aumentar las contracciones uterinas y, de esta forma, provocar o facilitar la expulsión de la placenta. La carbetocina es una opción novedosa para tratar los casos de retención de placenta. Su uso en la actualidad no está muy extendido, debido a la falta de investigación de esta aplicación del fármaco. Sin embargo, su innovadora variante termoestable podría resultar muy interesante para sustituir a la oxitocina

Triple Oxygen Isotope Measurements (Δ\u27\u3csup\u3e17\u3c/sup\u3eO) of Body Water Reflect Water Intake, Metabolism, and δ\u3csup\u3e18\u3c/sup\u3eO of Ingested Water in Passerines

Understanding physiological traits and ecological conditions that influence a species reliance on metabolic water is critical to creating accurate physiological models that can assess their ability to adapt to environmental perturbations (e.g., drought) that impact water availability. However, relatively few studies have examined variation in the sources of water animals use to maintain water balance, and even fewer have focused on the role of metabolic water. A key reason is methodological limitations. Here, we applied a new method that measures the triple oxygen isotopic composition of a single blood sample to estimate the contribution of metabolic water to the body water pool of three passerine species. This approach relies on Δ\u2717O, defined as the residual from the tight linear correlation that naturally exists between δ17O and δ18O values. Importantly, Δ\u2717O is relatively insensitive to key fractionation processes, such as Rayleigh distillation in the water cycle that have hindered previous isotope-based assessments of animal water balance. We evaluated the effects of changes in metabolic rate and water intake on Δ\u2717O values of captive rufous-collared sparrows (Zonotrichia capensis) and two invertivorous passerine species in the genus Cinclodes from the field. As predicted, colder acclimation temperatures induced increases in metabolic rate, decreases in water intake, and increases in the contribution of metabolic water to the body water pool of Z. capensis, causing a consistent change in Δ\u2717O. Measurement of Δ\u2717O also provides an estimate of the δ18O composition of ingested pre-formed (drinking/food) water. Estimated δ18O values of drinking/food water for captive Z. capensis were ~ −11‰, which is consistent with that of tap water in Santiago, Chile. In contrast, δ18O values of drinking/food water ingested by wild-caught Cinclodeswere similar to that of seawater, which is consistent with their reliance on marine resources. Our results confirm the utility of this method for quantifying the relative contribution of metabolic versus pre-formed drinking/food water to the body water pool in birds