Energyscapes and prey fields shape a North Atlantic seabird wintering hotspot under climate change.

There is an urgent need for a better understanding of animal migratory ecology under the influence of climate change. Most current analyses require long-term monitoring of populations on the move, and shorter-term approaches are needed. Here, we analysed the ecological drivers of seabird migration within the framework of the energyscape concept, which we defined as the variations in the energy requirements of an organism across geographical space as a function of environmental conditions. We compared the winter location of seabirds with their modelled energy requirements and prey fields throughout the North Atlantic. Across six winters, we tracked the migration of 94 little auks (Alle alle), a key sentinel Arctic species, between their East Greenland breeding site and wintering areas off Newfoundland. Winter energyscapes were modelled with Niche Mapper™, a mechanistic tool which takes into account local climate and bird ecophysiology. Subsequently, we used a resource selection function to explain seabird distributions through modelled energyscapes and winter surface distribution of one of their main prey, Calanus finmarchicus. Finally, future energyscapes were calculated according to IPCC climate change scenarios. We found that little auks targeted areas with high prey densities and moderately elevated energyscapes. Predicted energyscapes for 2050 and 2095 showed a decrease in winter energy requirements under the high emission scenario, which may be beneficial if prey availability is maintained. Overall, our study demonstrates the great potential of the energyscape concept for the study of animal spatial ecology, in particular in the context of global change.

Outbreak of pathogenic Escherichia coli in an outdoor-housed non-human primate colony.

BACKGROUND: Pathogenic Escherichia coli has been identified as an etiologic agent in humans causing acute diarrhea or even death but has been rarely reported in non-human primates (NHP). An outbreak of diarrhea occurred in an outdoor-housed NHP colony over a period of 2 months with an attack rate of 29%. METHODS: Bacterial culture and PCR were performed on the fecal specimens to identify enteroinvasive E. coli (EIEC) and Enterohemorrhagic E. coli (EHEC) in the NHPs. RESULTS: By random sampling of 10% of fecal samples of diarrheal cases, four cases of EIEC in rhesus macaques and two cases of EHEC in cynomolgus macaques were confirmed. CONCLUSION: This is the first time EIEC and EHEC have been reported in NHPs associated with diarrhea. The primary source of infection could not be determined.

Breath carbon stable isotope ratios identify changes in energy balance and substrate utilization in humans.

Rapid detection of shifts in substrate utilization and energy balance would provide a compelling biofeedback tool for individuals attempting weight loss. As a proof of concept, we tested whether the natural abundance of exhaled carbon stable isotope ratios (breath δ(13)C) reflects shifts between negative and positive energy balance. Volunteers (n=5) consumed a 40% energy-restricted diet for 6 days followed by 50% excess on day 7. Breath was sampled immediately before and 1 h and 2 h after breakfast, lunch and dinner. Exhaled breath δ(13)C values were measured by cavity ring-down spectroscopy. Using repeated measures analysis of variance (ANOVA) followed by Dunnett's contrasts, pre-breakfast breath values on days 2-6 were compared with day 1, and postprandial day 7 time points were compared with pre-breakfast day 7. Energy restriction diminished pre-breakfast breath δ(13)C by day 3 (P<0.05). On day 7, increased energy intake was first detected immediately before dinner (-23.8±0.6 vs -21.9±0.7‰, P=0.002 (means±s.d.)), and breath δ(13)C remained elevated at least 2 h post dinner. In conclusion, when shifting between negative and positive energy balance, breath δ(13)C showed anticipated isotopic changes. Although additional research is needed to determine specificity and repeatability, this method may provide a biomarker for marked increases in caloric intake.

NMR-based metabolomics and breath studies show lipid and protein catabolism during low dose chronic T(1)AM treatment.

OBJECTIVE: 3-Iodothyronamine (T1 AM), an analog of thyroid hormone, is a recently discovered fast-acting endogenous metabolite. Single high-dose treatments of T1 AM have produced rapid short-term effects, including a reduction of body temperature, bradycardia, and hyperglycemia in mice. DESIGN AND METHODS: The effect of daily low doses of T1 AM (10 mg/kg) for 8 days on weight loss and metabolism in spontaneously overweight mice was monitored. The experiments were repeated twice (n = 4). Nuclear magnetic resonance (NMR) spectroscopy of plasma and real-time analysis of exhaled (13) CO2 in breath by cavity ring down spectroscopy (CRDS) were used to detect T1 AM-induced lipolysis. RESULTS: CRDS detected increased lipolysis in breath shortly after T1 AM administration that was associated with a significant weight loss but independent of food consumption. NMR spectroscopy revealed alterations in key metabolites in serum: valine, glycine, and 3-hydroxybutyrate, suggesting that the subchronic effects of T1 AM include both lipolysis and protein breakdown. After discontinuation of T1 AM treatment, mice regained only 1.8% of the lost weight in the following 2 weeks, indicating lasting effects of T1 AM on weight maintenance. CONCLUSIONS: CRDS in combination with NMR and (13) C-metabolic tracing constitute a powerful method of investigation in obesity studies for identifying in vivo biochemical pathway shifts and unanticipated debilitating side effects.

Modeling animal landscapes.

There is an increasing need to assess the effects of climate and land-use change on habitat quality, ideally from a mechanistic basis. The symposium "Molecules to Migration: Pressures of Life" at the Fourth International Conference in Africa for Comparative Physiology and Biochemistry, Maasai Mara National Reserve, Kenya, 2008, illustrated how the principles of biophysical ecology can capture the mechanistic links between organisms, climate, and other habitat features. These principles provide spatially explicit assessments of habitat quality from a physiological perspective (i.e., "animal landscapes") that can be validated independently of the data used to derive and parameterize them. The contents of this symposium showcased how the modeling of animal landscapes can be used to assess key issues in applied and theoretical ecology. The presentations included applications to amphibians, reptiles, birds, and mammals. The rare Arabian oryx on the Arabian Peninsula is used as an example for energetic calculations and their implications for behavior on the landscape.

Po'ouli landscape bioinformatics models predict energetics, behavior, diets, and distribution on Maui.

This study uses a spatially explicit microclimate/biophysical approach to examine the potential distribution of the Po'ouli on Maui to find either new habitats to search for existence or refine search efforts in previously occupied areas. We used specific physiological and behavioral ecology bird data, and Po'ouli morphological and spectral data obtained from museum specimens to address ecological and conservation-related questions about the Po'ouli that are otherwise very difficult to quantify. Laboratory and field tested microclimate and biophysical-behavioral animal computer models were integrated with remote sensing technologies. To show that the generic microclimate and endotherm models can predict metabolic and water loss requirements of Hawaiian Honeycreepers, we used the 2 species with known physiological properties, the Hawaiian Amakihi, Hemignathus virens, and the Hawaiian Anianiau, Hemignathus parvus. Predictions were within experimental measurement error of the laboratory measurements. Then using field rather than laboratory conditions as input data, we predict the field distribution of the Amakihi on Maui as the first spatial test of the models applied to birds. Results are consistent with Amakihi field distribution data. Fossils show that the Po'ouli once lived on Maui at low elevations in dry/mesic habitats on a likely diet of native tree snails and insects. The arrival of lethal mosquito-borne avian malaria in Hawaii exterminated low elevation Po'ouli forcing a population shift to mountain rainforests and possibly a snail diet instead of insects. To explore the maximum consequences of such a diet shift we assumed exclusive diets of snails versus insects at both low and high elevations. Snail diets require ∼4 times higher foraging rates than do insect diets, making a predominantly snail diet an unlikely prospect for the Po'ouli. Landscape scale simulations suggest that a snail diet would force a Po'ouli distribution inconsistent with observations. A predominantly insect diet is consistent with distribution observations. We show that as local environmental conditions change across the landscape in space and diurnal/seasonal time it is possible to quantify animal physiological and behavioral consequences of those variations in their local environment. This enables quantification of the requisite spatial and temporal distribution and amount or availability of resources that may affect species' potential for survival, growth, reproduction and distribution.

Endocrine, immune, and behavioral effects of aldicarb (carbamate), atrazine (triazine) and nitrate (fertilizer) mixtures at groundwater concentrations.

This paper describes the results of 5 years of research on interactive effects of mixtures of aldicarb, atrazine, and nitrate on endocrine, immune, and nervous system function. The concentrations of chemicals used were the same order of magnitude as current maximum contaminant levels (MCLs) for all three compounds. Such levels occur in groundwater across the United States. Dosing was through voluntary consumption of drinking water. We used fractional and full factorial designs with center replicates to determine multifactor effects. We used chronic doses in experiments that varied in duration from 22 to 103 days. We tested for changes in thyroid hormone levels, ability to make antibodies to foreign proteins, and aggression in wild deer mice, Peromyscus maniculatus, and white outbred Swiss Webster mice, Mus musculus, ND4 strain. Endocrine, immune, and behavior changes occurred due to doses of mixtures, but rarely due to single compounds at the same concentrations. Immune assay data suggest the possibility of seasonal effects at low doses. We present a multiple-level model to help interpret the data in the context of human health and biological conservation concerns. We discuss six testing deficiencies of currently registered pesticides, and suggest areas of human health concerns if present trends in pesticide use continue.

Early detection of catabolic state via change in 13C/12C ratios of blood proteins.

We find that induction of catabolic state changes the ratios of carbon 13 to carbon 12 in blood proteins. Diet can be inferred in growing chicks by feather carbon isotope ratios. This suggests an approach for early detection of catabolic state induced in patients with HIV, cancers that induce catabolism, infection onset, sepsis, kidney and liver disease, malnutrition and dietary problems. The technique would also be useful in animal husbandry.

Prediction of forced ventilation in animal fur from a measured pressure distribution.

A model and computation scheme are given for predicting forced ventilation in the fur on an animal limb or torso, modelled here as a fur-covered cylinder with the hairs erect. The intra-fur flow is described by an anisotropic Darcy model, and pressure distribution measured previously for flow past a solid cylinder at Reynolds number 1.29 x 10(5) is used for the outer flow. Calculations from the model are presented for five mammalian species.

A time-course study of airway hyperresponsiveness in conscious parainfluenza virus type 3-infected guinea pigs.

The study of virus-induced airway hyperresponsiveness may provide insight into mechanisms that contribute to respiratory diseases such as asthma. We examined changes induced by parainfluenza virus type 3 (PI-3) in lung lesions, tissue weights, and airway responsiveness to aerosols of histamine, methacholine, or citric acid in conscious guinea pigs, using modified whole body plethysmography. During the first week after inoculation, infected lung tissue had peribronchiolitis and airway hyperresponsiveness to various agents when dyspnea and significant respiratory events were measured; these effects persisted throughout postinoculation weeks 2 and 3. Airway hyperresponsiveness was defined by reductions in the onset of dyspnea or significant respiratory events. Throughout the course of the study, PI-3 infected animals had resting respiratory patterns that reflected labored breathing and may have been related to the edema indicated by increased lung weights. Furthermore, increased numbers of inflammatory cells were observed in lung tissue as well as bronchoalveolar lavage fluid of infected animals at these times. Unlike PI-3 infection, exposure to gram-negative endotoxin resulted primarily in airway hyporesponsiveness to histamine aerosol. Hence, we have shown PI-3 infection in guinea pigs causes time-dependent alterations in airway responsiveness to diverse bronchoactive agents as well as in normal breathing patterns, which may persist up to several weeks after inoculation in animals that may otherwise appear normal.

Groundwater pesticides: interactive effects of low concentrations of carbamates aldicarb and methomyl and the triazine metribuzin on thyroxine and somatotropin levels in white rats.

Using full-factorial design experiments for three variables at two levels each and center replicates, we examined the effects of common agricultural carbamate insecticides, aldicarb and methomyl, and a triazine herbicide, metribuzin, on hormone levels in Sprague-Dawley rats. Fifty-four female rats were sampled at 2 and 6 wk during a 6-wk exposure to individual chemicals or to combinations of them. Some main effects and interaction effects were significant. For example, rats treated with the herbicide (metribuzin) were hyperthyroid. The interactions of all three chemicals also significantly increased thyroxine levels. One year later, we repeated these experiments for 16 wk using 54 male rats; the results were very similar. Metribuzin alone significantly increased thyroxine throughout the second study (at 7, 13, and 16 wk). Somatotropin levels were significantly altered after 13 wk of exposure. The same concentrations and mixtures of these three pesticides have now been shown to be implicated in learning impairment and other neurological functions, immune parameter changes, and endocrine changes. These findings support the concept of the interconnectedness of the nervous, endocrine, and immune systems and raise the likelihood of impacts on all three systems if one is shown to be affected. Development, growth, and reproduction all depend on the proper function of these three systems. These results strongly suggest the need to reassess currently allowed "safe" levels of chemicals based on adult dosages that are accepted in ground-water and in our food supplies.

Temperature, activity, and lizard life histories.

Lizard life-history characteristics vary widely among species and populations. Most authors seek adaptive or phylogenetic explanations for life-history patterns, which are usually presumed to reflect genetic differences. However, lizard life histories are often phenotypically plastic, varying in response to temperature, food availability, and other environmental factors. Despite the importance of temperature to lizard ecology and physiology, its effects on life histories have received relatively little attention. We present a theoretical model predicting the proximate consequences of the thermal environment for lizard life histories. Temperature, by affecting activity times, can cause variation in annual survival rate and fecundity, leading to a negative correlation between survival rate and fecundity among populations in different thermal environments. Thus, physiological and evolutionary models predict the same qualitative pattern of life-history variation in lizards. We tested our model with published life-history data from field studies of the lizard Sceloporus undulatus, using climate and geographical data to reconstruct estimated annual activity seasons. Among populations, annual activity times were negatively correlated with annual survival rate and positively correlated with annual fecundity. Proximate effects of temperature may confound comparative analyses of lizard life-history variation and should be included in future evolutionary models.

Behavioral and neurochemical changes associated with chronic exposure to low-level concentration of pesticide mixtures.

In order to assess behavioral and neurochemical changes resulting from pesticide exposure, food-restricted male weanling rats were exposed for 90 d to low doses (1 ppb-10,000 ppb range) of individual pesticides (aldicarb, metribuzin, or methomyl) or mixtures of them. During exposure, rats were trained to run a T-maze and tested for spatial discrimination reversal learning. At sacrifice, three brain regions (cortex, hippocampus, and neostriatum) were assayed for the neurotransmitters dopamine, acetylcholine, and serotonin. Animals treated with a mixture of two insecticides and one herbicide were found to have slower speeds in maze-running (motor control) and also had altered levels of choline in their neostriatums. Rats treated with one herbicide compound (metribuzin) took longer to learn on two reversals; this group also had a significantly lower acetylcholine/choline ratio in their hippocampus.

The effect of haemolysis on certain canine serum chemistry parameters.

Haemolysis has been known to cause artefacts in certain canine serum chemistry parameters. These parameters are often used by researchers to detect toxicity in certain studies; haemolysis, therefore, can make serum chemistry interpretation very difficult. In order to determine whether a relationship existed between the level of haemolysis and certain canine serum chemistry parameters, haemolysis was artificially induced by adding a haemolysate of known haemoglobin concentration to serum specimens. A routine clinical chemistry profile was performed on each specimen. Statistical analyses were performed on the results to examine the relationship between level of haemolysis and serum chemistry results. Interpretation of serum chemistry results of haemolysed canine sera paralleled, in most cases, human historical data.

Heat loss from deer mice (Peromyscus): evaluation of seasonal limits to thermoregulation.

This paper investigates the influence of seasonal adaptations to thermoregulatory heat loss for deer mice (Peromyscus) during summer and winter. A general, mechanistic model of heat transfer through fur was evaluated for the structural properties of the fur of deer mice. The model was validated against heat production determined from mice exposed to a range of radiative (wall) temperatures (tr) at air temperatures (ta) of 15, 27 and 34 degrees C. Calculated heat loss from the appendages was subtracted from the measured heat production to yield heat loss from the furred torso. This calculated torso heat loss agreed closely with the predicted fur heat loss for all conditions, as shown by a regression slope near 1 (0.99). Simulations using models of fur and appendage heat loss reveal that the winter increase in thermogenic (heat production) capacity has a greater effect than changes in fur properties in expanding the limits to thermoregulation. Both wind and a clear night sky increase heat loss and can limit thermoregulation to air temperatures above those found in deer mice habitats during winter (-25 degrees C). Thus, despite seasonal adaptations, these simulations indicate that thermoregulation is not possible under certain winter conditions, thereby restricting deer mice to within the protected environment of the leaf litter or snow tunnels.

Critical radius of endotherms.

The critical radius effect for insulation, well known in the engineering literature, was used by other authors to explain the lack of insulation on newborn endotherms. If that effect existed in small animals, they would lose less heat if nude than if fur or feathers were present. We show 1) that the previous analysis, although incomplete, yields the same result as a solid insulation model with the required sophistication and 2) that a proper model of fur is a porous media model. Neither of two porous media versions yield a critical radius effect. No critical radius effect occurs because simultaneous heat transfer by conduction and radiation makes it impossible to obtain the required logarithmic increase in thermal resistance with increasing insulation radius in a porous medium.

Surgical correction of genital prolapse in three rhesus monkeys.

Three adult female rhesus monkeys (Macaca mulatta) in a breeding colony of approximately 75 adult females developed a clinical condition characterized by protrusion of the cervix through the vulva during pregnancy and/or following parturition. The Gilliam round-ligament uterine ventro-suspension procedure (hereafter called the Gilliam uterine suspension or uterine suspension procedure) was used to return the cervix to a normal anatomical position. Following the procedure, one female delivered a normal live infant, but reprolapsed. After a second suspension procedure, she again became pregnant and delivered a normal live infant without a reoccurrence of the prolapse. A second animal never became pregnant despite repeated breedings to different males for two years. The third animal became pregnant twice following the procedure. The first pregnancy terminated in abortion at two months of gestation, while the second pregnancy ended in an apparent dystocia, necessitating a cesarean section and delivery of a dead fetus. The animal died post-operatively. This surgical procedure successfully salvaged one of these animals which otherwise had no reproductive future.

Absence of therapeutic blood concentrations of tetracycline in rats after administration in drinking water.

Because of ease of administration and broad antibacterial spectrum, tetracycline often is administered in drinking water to control infectious diseases of rats. Assay of serum after a gavage bolus of tetracycline (300 mg/kg body weight) revealed little absorption of tetracycline by this route. Rats were given water containing tetracycline at several concentrations (400 mg/liter, 4g/liter, and 4 g tetracycline plus 50 g sucrose/liter) ad libitum and serum concentrations of tetracycline were monitored. Bioassay of serum samples from these animals, taken during 72 hours of water medication, revealed no detectable tetracycline concentrations (greater than 0.2 mcg/ml) in the 400 mg and 4 g/liter groups. Two of eighteen serum samples from the group given 4 g tetracycline with 50 g sucrose/liter had minimal therapeutic tetracycline concentrations (0.3 mcg/ml) effective for Mycoplasma pulmonis. Some of the animals given tetracycline ad libitum in drinking water drank very little and lost weight compared to control animals. These findings indicate that the practice of adding tetracycline to drinking water of rats may be ineffective in controlling systemic diseases, and also be detrimental to the treated animals.