Updated: 2009-09-30 12:51:53
Physiological and Biochemical Zoology, Volume 0, Issue 0, Page 000, Latest Articles. Abstract Stable isotopes are an important tool for physiological and behavioral ecologists, although their usefulness depends on a thorough understanding of the dynamics of isotope incorporation into tissue(s) over time. In contrast to hair, claws, and feathers, most animal tissues continuously incorporate carbon (and other elements), and so carbon isotope values may change over time, depending on resource use and tissue‐specific metabolic rates. Here we report the carbon turnover rate for 12 tissues from a passerine bird, the zebra finch (Taeniopygia guttata). We measured average carbon retention time (τ) for 8 d for small intestine; 10-13 d for gizzard, kidney, liver, pancreas, and proventricu... #187; riginal news
Updated: 2009-09-30 12:51:24
There may be plenty of fish in the sea but the medaka knows what it likes. A new study shows how a single gene mutation that turns Japanese Killifish a drab gray color renders them significantly less attractive to more colorful members of the opposite sex. #187; riginal news
Updated: 2009-09-30 12:50:20
A fossil of a bird-like dinosaur with four wings has been discovered in northeastern China. The specimen bridges a critical gap in the transition from dinosaurs to birds, and reveals new insights into the origin evolution of feathers. #187; riginal news
Updated: 2009-09-30 12:49:52
When pondering the demise of a famous dinosaur such as 'Sue,' the mighty Tyrannosaurus rex whose fossilized remains are a star attraction of the Field Museum in Chicago, it is hard to avoid the image of clashing Cretaceous titans engaged in bloody, mortal combat. But a new study provides evidence that Sue, perhaps the most famous dinosaur in the world, was felled in more mundane fashion by a lowly parasite that still afflicts modern birds. #187; riginal news
Updated: 2009-09-30 12:48:55
The American Naturalist, Volume 0, Issue 0, Page 000, Latest Articles. Abstract: Widespread recognition of the importance of biological studies at large spatial and temporal scales, particularly in the face of many of the most pressing issues facing humanity, has fueled the argument that there is a need to reinvigorate such studies in physiological ecology through the establishment of a macrophysiology. Following a period when the fields of ecology and physiological ecology had been regarded as largely synonymous, studies of this kind were relatively commonplace in the first half of the twentieth century. However, such large‐scale work subsequently became rather scarce as physiological studies concentrated on the biochemical and molecular mechanisms underlying the capacities and to... #187; original news
Updated: 2009-09-30 12:48:43
The American Naturalist, Volume 0, Issue 0, Page 000, Latest Articles. Abstract: Populations living in a spatially and temporally changing environment can adapt to the changing optimum and/or migrate toward favorable habitats. Here we extend previous analyses with a static optimum to allow the environment to vary in time as well as in space. The model follows both population dynamics and the trait mean under stabilizing selection, and the outcomes can be understood by comparing the loads due to genetic variance, dispersal, and temporal change. With fixed genetic variance, we obtain two regimes: (1) adaptation that is uniform along the environmental gradient and that responds to the moving optimum as expected for panmictic populations and when the spatial gradient is sufficiently stee...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources. #187; riginal news
Updated: 2009-09-30 12:48:12
Scientists have found new evidence to explain how female insects can influence the father of their offspring, even after mating with up to ten males. A team has found that female crickets are able to control the amount of sperm that they store from each mate to select the best father for their young. The research suggests females may be using their abdominal muscles to control the amount of sperm stored from each mate. #187; riginal news
Updated: 2009-09-30 10:06:24
A new genetic tool will enable scientists to study vocal learning and neurogenesis at the molecular level in songbirds. #187; riginal news
Updated: 2009-09-30 09:51:06
New research by a team of leading scientists working with the UK's national Synchrotron, Diamond Light Source, could have a significant impact on the development and refinement of new eco-friendly pest control methods for worldwide agriculture. #187; riginal news
Updated: 2009-09-30 01:39:01
New research announced recently, Wednesday 30th September, by a team of leading researchers working with the UK's national Synchrotron, Diamond Light Source, could have a significant impact on the development and refinement of new eco-friendly pest control methods for worldwide agriculture. Reported in the Journal of Molecular Biology, the study was carried out by Dr Jing-Jiang Zhou and his colleagues at the world's oldest agricultural research centre and the largest UK facility, Rothamsted Research, in collaboration with Professor Nick Keep's group from the Institute of Structural and Molecular Biology at Birkbeck, University of London........
Updated: 2009-09-29 18:48:30
Scientist have revealed the first stage of the European eels mysterious migration to the Sargasso Sea by attaching pop up satellite tags to eels. #187; riginal news
Updated: 2009-09-29 18:43:55
Spotted hyenas may not be smarter than chimpanzees, but a new study shows that they outperform the primates on cooperative problem-solving tests. #187; riginal news
Updated: 2009-09-29 18:41:26
SURFBIRDS.COMConservationists trying to prevent the extinction of Northern Bald Ibis Geronticus ere #187; riginal news
Updated: 2009-09-29 15:53:41
Just as people plug in to computers, smart phones and electric outlets to communicate, electric fish communicate by quickly plugging special channels into their cells to generate electrical impulses, researchers have discovered. #187; riginal news
Updated: 2009-09-29 15:52:53
Lowers blood pressure, encourages exercise, improves psychological health -- these may sound like the effects of a miracle drug, but they are actually among the benefits of owning a four-legged, furry pet. #187; riginal news
Updated: 2009-09-29 15:48:52
The American Naturalist, Volume 0, Issue 0, Page 000, Latest Articles.
Abstract: Widespread recognition of the importance of biological studies at large spatial and temporal scales, particularly in the face of many of the most pressing issues facing humanity, has fueled the argument that there is a need to reinvigorate such studies in physiological ecology through the establishment of a macrophysiology. Following a period when the fields of ecology and physiological ecology had been regarded as largely synonymous, studies of this kind were relatively commonplace in the first half of the twentieth century. However, such large‐scale work subsequently became rather scarce as physiological studies concentrated on the biochemical and molecular mechanisms underlying the capacities and to...
Updated: 2009-09-29 02:34:16
Conclusions:Our results show that a mismatch between the sensitivity and directionality tuning is not uncommon in crickets, and an observed match (T. commodus) appears to be the exception rather than the rule. The data suggests that independent variation of both filters is possible. During evolution each sensory task may have been driven by independent constraints, and may have evolved towards its own respective optimum. (Source: Frontiers in Zoology)MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources. #187; riginal news
Updated: 2009-09-28 22:37:31
Physiological and Biochemical Zoology, Volume 0, Issue 0, Page 000, Latest Articles.
Abstract Stable isotopes are an important tool for physiological and behavioral ecologists, although their usefulness depends on a thorough understanding of the dynamics of isotope incorporation into tissue(s) over time. In contrast to hair, claws, and feathers, most animal tissues continuously incorporate carbon (and other elements), and so carbon isotope values may change over time, depending on resource use and tissue‐specific metabolic rates. Here we report the carbon turnover rate for 12 tissues from a passerine bird, the zebra finch (Taeniopygia guttata). We measured average carbon retention time (τ) for 8 d for small intestine; 10–13 d for gizzard, kidney, liver, pancreas, and proventricu...
Updated: 2009-09-28 12:33:24
. : , , Zoology : Journals , Blogs , News and Stories Login Register Most Popular Most Recent Shopping Jobs Pictures Videos Submit a Story Back to NewsBeet Home Two matched filters and the evolution of mating signals in four species of . cricket Two matched filters and the evolution of mating signals in four species of . cricket Posted from Frontiers in Zoology Late . 2 days ago Zoology Zoology Journals Background : Male field crickets produce pure-tone calling songs to attract females . Receivers are expected to have evolved a matched filter in the form of a tuned sensitivity for this frequency . In addition , the peripheral directionality of field crickets is sharply tuned as a result of a pressure . original story Discuss Add this link Tell a friend 6 views Add to : Bookmarks Recent News Carbon Turnover in Tissues of a Passerine Bird : Allometry , Isotopic Clocks , and Phenotypic Flexibility in Organ Size Feathery Four-winged Dinosaur Fossil Found In China Bridges Transition To Birds Was Mighty T . Rex Sue' Felled By A Lowly Parasite Macrophysiology : A Conceptual Reunification Unlocking The Mystery Of European Eel Migrations Related News Two matched filters and the evolution of
Updated: 2009-09-28 11:04:21
PRESS RELEASE – SCIENCE DAILY and WWFScienceDaily (Sep. 28, 2009) - A bird-eating fanged frog #187; riginal news
Updated: 2009-09-28 10:22:12
Kate closed down Radula, and moved all her blogging to Adventures of a Free Range Urban Primate.Did #187; riginal news
Updated: 2009-09-28 04:13:23
25, 1866, Lexington, Ky., U.S. died Dec. 4, 1945, Pasadena, Calif. Main American zoologist and geneticist, famous for his experimental research with the fruit fly by which he established the chromosome theory of heredity. #187; riginal news
Updated: 2009-09-28 04:12:31
I decided to wait until now to get back in the swing of things for the blog. I will try to keep it #187; riginal news
Updated: 2009-09-28 04:09:35
The retroviruses which gave rise to HIV have been battling it out with mammal immune systems since mammals first evolved around 100 million years ago -- about 85 million years earlier than previously thought, scientists now believe. #187; riginal news
Updated: 2009-09-28 04:06:25
A bird-eating fanged frog, a gecko that looks like it's from another planet, and a bird which would rather walk than fly -- these are among the 163 new species discovered in the Greater Mekong region last year that are now at risk of extinction due to climate change, says a new report. #187; riginal news
Updated: 2009-09-28 04:06:13
Conservationists trying to prevent the extinction of Northern Bald Ibis are distraught that one of the last remaining wild birds in the Middle East has been shot by a hunter in Saudi Arabia, bringing the known wild Middle Eastern population of this critically endangered species to just four individuals. #187; riginal news
Updated: 2009-09-27 15:51:27
The large group of segmented worms known as annelids, which includes earthworms, leeches and bristle worms, evolved millions of years ago and can be found in every corner of the world. Eventhough annelids are one of the most abundant animal groups on the planet, researchers have struggled to understand how the different species of this biologically diverse group relate to each other in terms of their evolutionary history. Now a team of researchers from Yale University and Dartmouth College has used a groundbreaking method to untangle some of that history........
Updated: 2009-09-27 15:51:27
Since the human response to infection is highly complex, research to understand how people fight infection is facilitated by studying how similar processes occur in simpler organisms. Zebrafish are becoming an important model for human disease, since they are easily handled, maintained and manipulated and a number of fundamental processes between zebrafish and humans are conserved. In addition, the small zebrafish embryo is highly amenable to drug screening assays. The functional similarity between the initial responses of zebrafish embryo and humans to infection suggests that the zebrafish embryo appears to be a valuable model for understanding early immune responses and identifying potential therapeutics for infection or immune mediated disease. However, the initial response of zebrafish to infection and how it compares to the human response is not well understood........
Updated: 2009-09-27 15:51:27
Conservation geneticists who study sea turtles have a new tool to help track this highly migratory and endangered group of marine animals: DNA barcodes. DNA barcodes are short genetic sequences that efficiently distinguish species from each othereven if the samples from which the DNA is extracted are minute or degraded. Now, a recently published research paper by researchers from the American Museum of Natural History and the University of Canberra, among other organizations, demonstrates that this technology can be applied to all seven sea turtle species and can provide insight into the genetic structure of a widely-dispersed and ancient group of animals........
Updated: 2009-09-27 15:29:36
THE AUSTRALIANCONSERVATIONISTS say koalas are on the brink of extinction in southeast Queensland an #187; riginal news
Updated: 2009-09-27 08:38:37
Necessity is the mother of invention: Great Tits eat hibernating common pipistrelle bats under harsh conditions of snow cover. This remarkable newly-acquired behaviour was observed by researchers in a cave in Hungary. When the researchers offered the birds alternative feed, they ate it and showed little or no interest in flying into the cave again. #187; riginal news
Updated: 2009-09-26 23:52:33
P. Rosengrave, R. Montgomerie, V. J. Metcalf, K. McBride, and N. J. Gemmell - Sperm traits of externally fertilizing fish species are typically measured in fresh (or salt) water, even though the spawning environment of their ova contains ovarian... (Source: Canadian Journal of Zoology)MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources. #187; riginal news
Updated: 2009-09-26 23:47:01
Dogs Canis familiaris are the world's most common carnivore and are known to interact with wildlife as predators, prey, competitors, and disease reservoirs or vectors. Despite these varied roles in the community, the interaction of dogs with sympatric wild carnivore species is poorly understood. We review how dogs have been classified in the literature, and illustrate how the location and ranging behaviour of dogs are important factors in predicting their interactions with wild prey and carnivores. We detail evidence of dogs as intraguild competitors with sympatric carnivores in the context of exploitative, interference and apparent competition. Dogs can have localized impacts on prey populations, but in general they are not exploitative competitors with carnivores. Rather, most dog popula... #187; riginal news
Updated: 2009-09-26 21:31:14
Here’s another longer TV news story on the incident: #187; riginal news
Updated: 2009-09-26 16:33:31
Diane Blackwood, wife of my friend Wesley Elsberry, was attacked by an alligator in a park in St. Pe #187; riginal news
Updated: 2009-09-26 16:32:44
PRNEWSWIREToday the International Fund for Animal Welfare (IFAW www.ifaw.org) filed a petition with #187; riginal news
Updated: 2009-09-26 06:44:52
J. Gibbens and J.P.Y. Arnould - Postsealing population recovery rates of fur seals and sea lions have differed markedly, perhaps owing to habitat type. Australian fur seals (Arctocephalus pusillus doriferus Wood... (Source: Canadian Journal of Zoology) #187; riginal news
Updated: 2009-09-26 06:44:04
The American Naturalist, Volume 0, Issue 0, Page 000, Latest Articles. Abstract: Maternal effects are environmental components of phenotypes that complicate relationships between natural selection and evolution because they often affect phenotypes and fitness simultaneously. We studied the effects of egg size variation on juvenile survival in a population of American coots (Fulica americana). We experimentally evaluated egg size variation at three levels: across the population, within natal nests, and within foster nests. Natal nests accounted for the most variation in population egg size. Within clutches, early‐laid eggs were larger than later‐laid eggs, with the exception of first‐laid eggs, which were small. In the fostering experiment, posthatching survival was most strongl...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources. #187; riginal news
Updated: 2009-09-26 06:43:53
Ulf Marquard-Petersen - Abundance, social organization, and population trend of the arctic wolf (Canis lupus arctos Pocock, 1935) in north and east Greenland, 1978 - 1998, were determined from 353... (Source: Canadian Journal of Zoology) #187; riginal news
Updated: 2009-09-26 06:41:33
Veronica, a resident of Sugar Grove and a 15-year-old Kaneland High School sophomore, joined 130 other high school students who participated in the Youth Volunteer Corps at the Brookfield Zoo this year. #187; riginal news
Updated: 2009-09-26 06:38:44
#187; riginal news
Updated: 2009-09-26 06:38:34
William E. Cooper, Jr., Dror Hawlena, and Valentín Pérez-Mellado - Prey often exhibit reduced escape behavior on islands where predators are absent or scarce. Models of escape and refuge use predict that prey from populations... (Source: Canadian Journal of Zoology)MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources. #187; riginal news
Updated: 2009-09-26 06:38:17
Julieta Pedrana, Alejandro Rodríguez, Javier Bustamante, Alejandro Travaini, and Juan I. Zanón Martínez - The guanaco (Lama guanicoe (Müller, 1776)) is a monomorphic polygynous mammal whose adult sex ratio is expected to be balanced or biased towards females. Remarkably... (Source: Canadian Journal of Zoology) #187; riginal news
Updated: 2009-09-26 06:38:13
Physiological and Biochemical Zoology, Volume 0, Issue 0, Page 000, Latest Articles. Abstract Two populations of homing sockeye salmon (Oncorhynchus nerka; Adams and Chilko) were intercepted in the marine approaches around the northern and southern ends of Vancouver Island (British Columbia, Canada) en route to a natal river. More than 500 salmon were nonlethally biopsied for blood plasma, gill filament tips, and gross somatic energy (GSE) and were released with either acoustic or radio transmitters. At the time of capture, GSE, body length, and circulating testosterone ([T]) differed between populations, differences that reflected known life‐history variations. Within‐population analyses showed that in Adams sockeye salmon, plasma glucose ([glu]), lactate ([lactate]), and ion co... #187; riginal news
Updated: 2009-09-25 16:47:47
Physiological and Biochemical Zoology, Volume 0, Issue 0, Page 000, Latest Articles.
Abstract Two populations of homing sockeye salmon (Oncorhynchus nerka; Adams and Chilko) were intercepted in the marine approaches around the northern and southern ends of Vancouver Island (British Columbia, Canada) en route to a natal river. More than 500 salmon were nonlethally biopsied for blood plasma, gill filament tips, and gross somatic energy (GSE) and were released with either acoustic or radio transmitters. At the time of capture, GSE, body length, and circulating testosterone ([T]) differed between populations, differences that reflected known life‐history variations. Within‐population analyses showed that in Adams sockeye salmon, plasma glucose ([glu]), lactate ([lactate]), and ion co...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.
Updated: 2009-09-25 16:37:19
BARCELONA REPORTERBats are one of the endangered species that is begin to lose it place in the Medi #187; riginal news
Updated: 2009-09-25 05:02:49
Authors: Müller CA Tool use and the associated need to choose appropriate objects for a particular task are thought to have selected for specialized cognitive abilities such as means-end comprehension. Several studies on large-brained tool-using primates and birds have demonstrated understanding of causal relationships to some extent. However, a comprehensive appraisal of this hypothesis requires testing for means-end comprehension also in non-tool-users as well as in small-brained tool users. Moreover, the results of captive studies do not answer the question whether such cognitive abilities are relevant to an animal in its natural environment. Here I presented wild banded mongooses Mungos mungo, small-brained carnivores that regularly use anvils to open food items with a hard sh... #187; riginal news
Updated: 2009-09-21 20:41:12
Physiological and Biochemical Zoology, Volume 0, Issue 0, Page 000, Latest Articles.
Abstract In female mate choice, a female chooses a reproductive partner based on direct or indirect benefits to the female. While sexual selection theory regarding female mate choice is well developed, there are few mechanistic studies of the process by which females evaluate reproductive partners. Using paternal‐care‐providing smallmouth bass (Micropterus dolomieu) as a model, the purpose of this study was to determine the relationship between female mate choice and the morphological and physiological status of chosen males. This was accomplished by locating nests within 1 d of spawning and categorizing brood size (indicator of female mate choice). This was followed by capture of parental males,...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.
Updated: 2009-09-21 02:12:55
Scientists at Uppsala University has succeeded in extracting long DNA fragments from dried, pressed plant material collected in the 1700s by Linnaeus' apprentice Adam Afzelius. It is hoped that the study, led by Associate Professor Katarina Andreasen, will shed light on whether plants growing today at Linnaeus' Hammarby estate outside Uppsala reflect the species cultivated by Linnaeus himself........
Updated: 2009-09-21 02:12:55
The ability of plants to tell the time, a mechanism common to all living beings, enables them to survive, grow and reproduce. As per a research findings reported in the latest issue of the prestigious journal Ecology Letters, an international team has studied this circadian clock from a molecular viewpoint and has found an ecological implication: it makes climate change scenarios and CO2 level figures more accurate........
Updated: 2009-09-16 19:27:27
Physiological and Biochemical Zoology, Volume 0, Issue 0, Page 000, Latest Articles.
Abstract Aggression is an important component of behavior in many animals and may be crucial to providing individuals with a competitive advantage when resources are limited. Although much is known about the effects of catecholamines and hormones on aggression, relatively few studies have examined the effects of physical performance on aggression. Here we use a large, sexually dimorphic teiid lizard to test whether individuals that show high levels of physical performance (bite force) are also more aggressive toward a potential threat (i.e., a human approaching the lizard). Our results show that independent of their sex, larger individuals with higher bite forces were indeed more aggressive. Moreover...
Updated: 2009-09-16 19:25:58
Physiological and Biochemical Zoology, Volume 0, Issue 0, Page 000, Latest Articles.
Abstract To evaluate whether decreases in muscle metabolic capacities and increases in plasma cortisol explain the effects of neighboring conspecifics on male three‐spine sticklebacks Gasterosteus aculeatus, we housed mature males alone, with a mature female, or with a rival mature male. The neighbors were separated from the focal male by a partition that allowed him to smell, see, and hear his neighbor. In the first experiment, focal males were allowed to reproduce, whereas in the second experiment, no reproduction occurred. Coloration and behaviors were monitored while the males tended their nests (or for the same period in the second experiment). The presence of a neighbor markedly affected the ...
Updated: 2009-09-16 19:25:35
We examined the effect of tail loss on locomotory costs in the Cape dwarf gecko Lygodactylus capensis (∼0.9 g) using a novel method for collecting data on small lizards, a method previously used for arthropods. We measured CO2 production during 5–10 min of exhaustive exercise (in response to stimulus) and during a 45‐min recovery period. During exercise, we measured speed (for each meter moved) as well as total distance traveled. Contrary to our expectations, tailless geckos overall expended less effort in escape running, moving both slower and for a shorter distance, compared with when they were intact. Tailless geckos also exhibited lower excess CO2 production (CO2 production in excess of normal resting metabolic rate) during exercising. This may be due to reduced metabolically act...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.
Updated: 2009-09-16 19:25:06
Physiological and Biochemical Zoology, Volume 0, Issue 0, Page 000, Latest Articles.
Abstract To better understand intraspecific variation in basal metabolic rate (BMR), we examined environmental, physiological, and/or cellular bases for residual variation in BMR in big brown bats, Eptesicus fuscus. We measured BMR and plasma levels of thyroid hormone (T3) and leptin in bats captured in maternity colonies in eastern Massachusetts (MA; northern population) and in Alabama and Georgia (ALGA; southern population) to assess macrogeographic (between‐ or among‐population) and microgeographic (within‐population) variation in those traits. After accounting for effects of body mass, stage of pregnancy, and within‐population variation, bats from the northern population did not differ si...
Updated: 2009-09-16 16:44:44
The American Naturalist, Volume 0, Issue 0, Page 000, Latest Articles.
Abstract: Both males and females vary in fitness. While high‐fitness males typically have greater siring success, it is not clear whether these males sire an equal fraction of offspring from all females or a disproportionately large fraction with high‐fitness females. The latter nonrandom reproductive pattern can arise as the result of sexual selection and creates a positive correlation in fitness between mates. Such a correlation, if it reflects a positive genetic correlation between mates with respect to fitness, increases the efficiency of selection, reducing mutation load and speeding adaptation. While there is evidence from many taxa that assortative mating for fitness may occur, these studies typically f...
Updated: 2009-09-04 20:35:21
Physiological and Biochemical Zoology, Volume 0, Issue 0, Page 000, Latest Articles.
Abstract Behavioral thermoregulation can allow ectotherms to buffer the effects of changes in environmental temperature, and thus an organism’s preferred temperature is thought to be under strong selection. However, this contention has seldom been tested. We used common killifish Fundulus heteroclitus from high‐latitude (northern) and low‐latitude (southern) populations to investigate intraspecific variation in thermal preference and its relationship to habitat temperature. We quantified the preferred temperatures of northern and southern killifish populations acclimated to three temperatures (5°, 15°, and 25°C) to evaluate two alternative hypotheses for the evolution of differences in therm...
Updated: 2009-09-04 16:38:19
In this study, we provide the first evidence of the presence of a glass transition during heating in an anhydrobiotic tardigrade through the use of differential scanning calorimetry. (Source: Physiological and Biochemical Zoology)
Updated: 2009-09-04 16:36:29
Physiological and Biochemical Zoology, Volume 0, Issue 0, Page 000, Latest Articles.
Abstract Energy metabolism is fundamental for animal fitness because it fuels locomotion, growth, and reproduction. Mitochondrial capacities often acclimate to compensate for negative thermodynamic effects. Our aim was to determine the importance of transcriptional regulation and membrane fatty acid composition in modulating oxidative capacities at body temperatures selected in a cold and a warm environment by a reptile (Crocodylus porosus). In the cool environment (mean selected Tb = 21°C), mRNA concentrations of the transcription factor peroxisome proliferator–activated receptor gamma (PPARγ) and its coactivator PPARγ coactivator 1 alpha (PGC‐1α), as well as of the cytochrome c oxidase (COX...MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.
Updated: 2009-09-04 15:36:53
From frolicking bears to fleeing rabbits – the pick of this week's images from the natural world
Updated: 2009-08-12 22:19:55
In this study, we used surgical castration and replacement of exogenous testosterone in adult male brown anoles (Anolis sagrei) to simultaneously examine the effects of testosterone on a suite of morphological (dewlap area, body size), physiological (immune function), behavioral (dewlap, head bob, and push‐up displays), and performance (stamina, sprint speed, bite force) traits. We show that testosterone increases (or castration reduces) growth rate, dewlap area, and bite force. Treatment effects on bite force may simply reflect underlying treatment differences in growth combined with allometry of bite force. Other traits, such as stamina, sprint speed, and rate of behavioral displays, were largely independent of circulating testosterone levels. Although we did not observe significant tr...
Updated: 2009-08-12 14:00:59
Christopher Turbill - Volume 57(2) (Source: Australian Journal of Zoology)
Updated: 2009-08-12 14:00:58
Laura Ruykys, David A. Taggart, William G. Breed, David Schultz - Volume 57(2) (Source: Australian Journal of Zoology)MedWorm Message: Get the very latest Swine Flu news via the MedWorm Swine Flu RSS news feed - updated hourly from thousands of authoritative health and news sources.
Updated: 2009-08-12 14:00:57
Steve Smith, Peter McRae, Jane Hughes - Volume 57(2) (Source: Australian Journal of Zoology)
Updated: 2009-08-07 20:17:49
Physiological and Biochemical Zoology, Volume 0, Issue 0, Page 000, Latest Articles.
Abstract Previous experiments showed reduction of basal metabolic rate (BMR) in birds facing energetic challenges. We alternately exposed two groups of red knots (Calidris canutus) to either 6 h or 22 h of food availability for periods of 22 d. Six h of access to food led to a 6%–10% loss of body mass over the first 8 d, with nearly all of the birds' daily energy expenditures supported by body nutrient stores during the first 2 d. Birds responded by increasing feeding behavior and food intake, but the response was slow. There were no gains of mass before day 15, which suggests a digestive bottleneck and a period of physiological adjustment. Food‐restricted birds exhibited decreases in pectoral‐...
Updated: 2009-08-06 23:45:09
In this study, we investigate the interpopulation and intersex variation in oxidative damage and plasma antioxidant capacity in the Galápagos land iguana, Conolophus subcristatus, over a 3‐yr study to evaluate what factors (e.g., season, food availability, reproductive activity) can explain levels and patterns of oxidative damage and of plasma antioxidant capacity. Our results indicate that (1) males showed lower levels of oxidative damage, higher levels of plasma antioxidant capacity, and better body condition than females and (2) significant interactions exist among patterns of oxidative damage across sexes, sampling localities, body condition, and season. These results suggest that reproductive activity and food abundance might act as determinants shaping levels and patterns of oxida...
