Seaward Migration and Larval Release Coincide with Lunar and Light-dark Cycles in Supratidal Land Crabs Cardisoma carnifex and Epigrapsus notatus.

Herein we investigated the synchronous breeding migration and larval release of ovigerous females in two dominant supratidal land crabs Cardisoma carnifex and Epigrapsus notatus in the mixed semidiurnal tidal regime in Taijiang National Park (Tainan, Taiwan). We mainly focused on the monthly and daily rhythms during the breeding season of migration and larval release for these two crabs. We also sought to understand what the main environmental cues were for these monthly and diel rhythms. Both lunar and tidal amplitude cycles are potential proximate causes for the monthly lunar/semilunar reproductive rhythm in crabs. Likewise, either the 24-hour (diel) light cycle or tidal cycle can act as the proximate cause for diel reproduction rhythm, and we investigated which one was the main factor that entrains the diel rhythm for these two species. We found that the season of migration and larval release in C. carnifex occured mainly between June and September during the rainy season while those of E. notatus occurred mainly between September and October, near the end of the rainy season. Regarding the rhythm of migration and larval release in monthly time scale, C. carnifex exhibited a semilunar rhythm following the syzygies and E. notatus exhibited a lunar rhythm following the full moon. However, these rhythms did not occur with the maximum amplitude nocturnal and diurnal high tides. This implies that the lunar cycle is a more important environmental cue than the tidal amplitude in the entrainment of the synchronous monthly breeding rhythm for these two species. This pattern is different from other intertidal crabs, most of which use the tidal amplitude cycle as the main environmental cue for larval release. In addition to Chiromantes haematocheir (a supratidal crab), our study provided two more species that live in the supratidal zone time their reproduction with respect to the lunar light cycle and independent of the tide amplitude cycles. For the diel rhythm, both species migrated to the shore and released larvae in the first half of the night during the flood tide. This suggests that the diel light cycle is a dominant cue for the determination of larval release timing for these two species. Larval release does not track the high slack tides, since larvae are only released during the first half of the night and these high slack tides occur only after midnight (0000-0600H) during the days of larval release for these two crab species.

Seasonal differences in hair growth rates of captive aye-aye, red ruffed, and black-and-white ruffed lemurs.

Hair can be an important source of biological information, providing a record of such things as pollutant exposure, hormonal levels, and stable isotope ratios. Hair as a biological sample is easily accessible, easily stored, and resists degradation. Analysis of hair is particularly useful when studying rare and endangered species, such as lemurs, since it can be sampled noninvasively. However, to better interpret the results of stable isotope or other analyses, it is important to understand hair growth rates. We measured hair growth rates in captive aye-ayes (Daubentonia madagascariensis), red ruffed lemurs (Varecia rubra), and black-and-white ruffed lemurs (Varecia variegata), both in winter (December 23, 2013, to January 13, 2014) and summer (July 10-31, 2013) at the Duke Lemur Center. Hair growth per week in all three species of lemurs differed significantly between the boreal summer and boreal winter. The aye-aye, black-and-white ruffed lemur, red ruffed lemur had a mean weekly hair growth of 0.195, 0.209, and 0.232 cm, respectively, in the summer. While the aye-aye, black-and-white ruffed lemur, and red ruffed lemur had a mean weekly hair growth of 0.239, 0.464, and 0.479 cm, respectively, in winter. We found no effect of age on hair growth rates, neither in the boreal summer, nor in the boreal winter for black-and-white ruffed lemurs and red ruffed lemurs. A pregnant black-and-white ruffed female displayed negligible hair growth during the northern winter, suggesting that pregnancy may affect the partitioning of resources away from such things as hair growth.

Roosting Site Usage, Gregarious Roosting and Behavioral Interactions During Roost-assembly of Two Lycaenidae Butterflies.

Lycaenidae is one of the larger of the world's butterfly families, based on number and diversity of species, but knowledge of roosting in this group is sparse. Zizina otis riukuensis and Zizeeria maha okinawana are two small lycaenids that are commonly found in urban settings and widely distributed across much of Asia. We conducted experiments on a university campus to determine the plant species and plant structures commonly used by these two blues when roosting. We also tested the hypothesis that gregarious roosting exists in these two blues by demonstrating the non-random distribution of roosting blues and the tight mapping of their roosts to the spatial distribution of specific plant species and/or specific plant structures, as well as by demonstrating behavioral interactions among individuals during roosting-assembly. We found that both Z. otis and Z. maha roosted primarily on flowers and fruits of Tridax procumbens and Vernonia cinerea. We also found that these blues formed conspicuous roosting aggregations with significant positive associations between the flowers and fruits of both T. procumbens and V. cinerea and the blues. Moreover, our behavioral observations showed that these blues expressed various levels of interaction during roosting gatherings. Based on these findings, we conclude that gregarious roosting exists in both Z. otis and Z. maha. To our knowledge, this paper represents one of the first demonstration of nocturnal gregarious roosting in lycaenids. This study also highlights the importance of institutional estates in providing roosting resources for butterflies in urban ecosystems.

The effect of sex, age, and location on carnivory in Utah black bears (Ursus americanus).

Ungulates are important to the diet of bears because they are high in protein, and the level of dietary protein strongly influences bear size. The size a bear obtains as an adult influences important life history characteristics, such as age of reproduction and reproductive success; therefore, it is important to know what foods are available to bears and how they are utilizing them. We tested hypotheses concerning the effect of age, sex, and location on black bear carnivory. We collected hair and vestigial premolar teeth from 49 Utah black bears, Ursus americanus according to the Utah Division of Wildlife Resources hunt unit. Hunt units differed in habitat quality and local ungulate density. We analyzed a vestigial premolar for the age of the bears and used analysis of the δ13C and δ15N values of the hairs of each bear to infer the degree of carnivory. δ15N of black bear hairs was positively correlated with increased availability of ungulates. There was a positive relationship between the δ15N of bear hairs and age in hunt units with the highest ungulate densities only. The δ15N and δ13C of black bear hairs were positively correlated, suggesting that bears are more carnivorous at higher altitudes. This study demonstrates the value of stable isotope analysis in understanding the feeding ecology of bears over broad geographic ranges. It demonstrates that ungulate availability is important to the feeding ecology of black bears in the Intermountain West.

Carbon stable-isotope tracking in breath for comparative studies of fuel use.

Almost half a century ago, researchers demonstrated that the ratio of stable carbon isotopes in exhaled breath of rats and humans could reveal the oxidation of labeled substrates in vivo, opening a new chapter in the study of fuel use, the fate of ingested substrates, and aerobic metabolism. Until recently, the combined use of respirometry and stable-isotope tracer techniques had not been broadly employed to study fuel use in other animal groups. In this review, we summarize the history of this approach in human and animal research and define best practices that maximize its utility. We also summarize several case studies that use stable-isotope measurements of breath to explore the limits of aerobic metabolism and substrate turnover among several species and various physiological states. We highlight the importance of a comparative approach in revealing the profound effects that phylogeny, ecology, and behavior can have in shaping aerobic metabolism and energetics as well as the fundamental biological principles that underlie fuel use and metabolic function across taxa. New analytical equipment and refinement of methodology make the combined use of respirometry and stable-isotope tracer techniques simpler to perform, less costly, and more field ready than ever before.

Regional scale high resolution δ18O prediction in precipitation using MODIS EVI.

The natural variation in stable water isotope ratio data, also known as water isoscape, is a spatiotemporal fingerprint and a powerful natural tracer that has been widely applied in disciplines as diverse as hydrology, paleoclimatology, ecology and forensic investigation. Although much effort has been devoted to developing a predictive water isoscape model, it remains a central challenge for scientists to generate high accuracy, fine scale spatiotemporal water isoscape prediction. Here we develop a novel approach of using the MODIS-EVI (the Moderate Resolution Imagining Spectroradiometer-Enhanced Vegetation Index), to predict δ(18)O in precipitation at the regional scale. Using a structural equation model, we show that the EVI and precipitated δ(18)O are highly correlated and thus the EVI is a good predictor of precipitated δ(18)O. We then test the predictability of our EVI-δ(18)O model and demonstrate that our approach can provide high accuracy with fine spatial (250×250 m) and temporal (16 days) scale δ(18)O predictions (annual and monthly predictabilities [r] are 0.96 and 0.80, respectively). We conclude the merging of the EVI and δ(18)O in precipitation can greatly extend the spatial and temporal data availability and thus enhance the applicability for both the EVI and water isoscape.

Using stable isotopes to unravel and predict the origins of great cormorants (Phalacrocorax carbo sinensis) overwintering at Kinmen.

The Food and Agricultural Organization of the United Nations and the World Organization for Animal Health have called for a better understanding of the role that migrating birds may play in spreading H5N1 highly pathogenic avian influenza (HPAI). Bird banding, traditionally used in studies of migration, is limited by low recapture rates. Telemetry can only be applied to larger species and a limited number of birds. We show that analyses of multiple stable isotopes (delta(13)C, delta(15)N, delta(18)O and deltaD) can provide an understanding of the number of breeding populations represented at large congregations of wintering birds, probable locations of these breeding populations, and which breeding populations do not contribute migrants to a wintering site. As Asia is thought to be the origin of many HPAI strains and the center of their evolution, and as bird migration is poorly understood in this part of the world, we recommend that, in addition to banding, satellite, and VHF telemetry, the stable isotope analysis of migration patterns should become a part of long-term surveillance studies.

Towards a physiologically based diagnosis of anorexia nervosa and bulimia nervosa.

Diagnosis of anorexia nervosa (AN) and bulimia nervosa (BN), while including such physiological data as weight and the reproductive status of the individual, are primarily based on questionnaires and interviews that rely on self-report of both body-related concerns and eating-related behaviors. While some key components of eating disorders are psychological and thus introspective in nature, reliance on self-report for the assessment of eating-related behaviors and nutritional status lacks the objectivity that a physiologically based measure could provide. The development of a more physiologically informed diagnosis for AN and BN would provide a more objective means of diagnosing these disorders, provide a sound physiological basis for diagnosing subclinical disorders and could also aid in monitoring the effectiveness of treatments for these disorders. Empirically supported, physiologically based methods for diagnosing AN and BN are reviewed herein as well as promising physiological measures that may potentially be used in the diagnosis of AN and BN.

Fasting increases delta15N-values in the uric acid of Anolis carolinensis and Uta stansburiana as measured by nondestructive sampling.

Previous studies suggest that a nutritional/energetic state may be determined from the delta(15)N-values of an animal's tissues. It has been hypothesized that if an animal is in a negative nutritional/energetic balance, (15)N will be retained by the tissues preferentially and (14)N preferentially excreted. Over time, this should cause enrichment of the delta(15)N-values of the tissues. Tests of this hypothesis have met with mixed results. To date, these studies have focused on endotherms. Few studies have considered the effects of fasting on the (15)N/(14)N ratios of substrates from ectotherms. We hypothesized that the delta(15)N-values of tail tissue and uric acid of fasted lizards would increase over time, while that of the fed lizards would remain the same. We fasted five side-blotched lizards (Uta stansburiana) and five green anoles (Anolis carolinensis) for 14 days. At the same time we fed six side-blotched and four green anoles ad libitum. All lizards were given water ad libitum. During this period, we collected uric acid from each lizard daily and tail tissue on the first day of the study and on the last day of the study. We found the the delta(15)N-values of uric acid of fasted lizards at the end of the study were (15)N-enriched compared with that of the control lizards in both species, probably due to a shift in amino acid source pools during fasting. However, we found no difference between treatment and controls in the delta(15)N-values of the tails.

An objective means of diagnosing anorexia nervosa and bulimia nervosa using 15N/14N and 13C/12C ratios in hair.

An objective means based on the carbon and nitrogen stable isotope analysis of five hairs per individual is presented for distinguishing between individuals with anorexia nervosa and/or bulimia nervosa from non-clinical individuals (i.e. clinically normal controls). Using discriminant analysis, an algorithm has been developed that provides both sensitivity and specificity of 80% in making diagnoses of individuals with these eating disorders. With further refinements, the results suggest that it may be also possible to distinguish between individuals with anorexia or bulimia. Finally, the study shows the value of conducting blind tests and using larger sample sizes of both control and treatment groups. Both groups are needed to validate the diagnostic value of a method and to provide measures of sensitivity and specificity of any diagnostic test.

Stable isotopes in breath, blood, feces and feathers can indicate intra-individual changes in the diet of migratory songbirds.

We used stable isotopes of C in breath, blood, feces and feathers to identify intra-individual changes in diet and the timescale of diet changes in free-living songbirds at a stopover site. Because accurate interpretation of differences between the delta13C of breath, plasma, and red blood cells (RBCs) relative to diet requires knowing the turnover rate of C within them, we determined the rate of change of C in breath, plasma and RBCs for yellow-rumped warblers (Dendroica coronata). Half-lives of C in breath, plasma, and RBCs were 4.4+/-2.1 h, 24.8+/-12.3 h and 10.9+/-3.2 days, respectively, for yellow-rumped warblers. delta13C of breath, plasma, RBCs and feces from wild-caught golden-crowned kinglets (Regulus satrapa), ruby-crowned kinglets (R. calendula) and gray catbirds (Dumetella carolinensis) indicated that they had maintained an isotopically consistent diet for an extended period of time. However, delta13C of breath and plasma indicated that white-throated sparrows (Zonotrichia albicollis) had recently expanded their diet to include a C4 dietary component. Likewise, delta13C of breath, plasma, RBCs and feces indicated that some wild-caught yellow-rumped warblers had consumed foods with a more enriched protein signature prior to their arrival on Block Island, and since arrival, they had consumed mostly northern bayberry (Myrica pensylvanica). Therefore, comparisons of the delta13C of breath, plasma, RBCs, feces and feathers from individual songbirds can indicate changes in diet and provide an estimate of the timescale of the diet change.

The Analysis of 13C/12C Ratios in Exhaled CO2: Its Advantages and Potential Application to Field Research to Infer Diet, Changes in Diet Over Time, and Substrate Metabolism in Birds.

Stable isotopes are becoming an increasingly powerful tool for studying the physiological ecology of animals. The (13)C/(12)C ratios of animal tissues are frequently used to reconstruct the diet of animals. This usually requires killing the subjects. While there is an extensive medical literature on measuring the (13)C/(12)C ratio of exhaled CO(2) to determine substrate digestion and oxidation, we found little evidence that animal physiologists or physiological ecologists have applied (13)C/(12)C breath analysis in their studies. The analysis breath (13)C/(12)C ratios has the advantage of being non-invasive and non-destructive and can be repeatedly used on the same individual. Herein we briefly discuss the medical literature. We then discuss research which shows that, not only can the breath(13)C/(12)C ratio indicate what an animal is currently eating, but also the animal's diet in the past, and any changes in diet have occurred over time. We show that naturally occurring (13)C/(12)C ratios in exhaled CO(2) provides quantitative measure of the relative contribution of carbohydrates and lipids to flight metabolism. This technique is ripe for application to field research, and we encourage physiological ecologists to add this technique to their toolbox.