Beyond the encounter: Predicting multi‐predator risk to elk (Cervus canadensis) in summer using predator scats

1. There is growing evidence that prey perceive the risk of predation and alter their behavior in response, resulting in changes in spatial distribution and potential fitness consequences. Previous approaches to mapping predation risk across a landscape quantify predator space use to estimate potential predator‐prey encounters, yet this approach does not account for successful predator attack resulting in prey mortality. An exception is a prey kill site that reflects an encounter resulting in mortality, but obtaining information on kill sites is expensive and requires time to accumulate adequate sample sizes.
2. We illustrate an alternative approach using predator scat locations and their contents to quantify spatial predation risk for elk (Cervus canadensis) from multiple predators in the Rocky Mountains of Alberta, Canada. We surveyed over 1300 km to detect scats of bears (Ursus arctos/U. americanus), cougars (Puma concolor), coyotes (Canis latrans), and wolves (C. lupus). To derive spatial predation risk, we combined predictions of scat‐based resource selection functions (RSFs) weighted by predator abundance with predictions that a predator‐specific scat in a location contained elk. We evaluated the scat‐based predictions of predation risk by correlating them to predictions based on elk kill sites. We also compared scat‐based predation risk on summer ranges of elk following three migratory tactics for consistency with telemetry‐based metrics of predation risk and cause‐specific mortality of elk.
3. We found a strong correlation between the scat‐based approach presented here and predation risk predicted by kill sites and (r = .98, p < .001). Elk migrating east of the Ya Ha Tinda winter range were exposed to the highest predation risk from cougars, resident elk summering on the Ya Ha Tinda winter range were exposed to the highest predation risk from wolves and coyotes, and elk migrating west to summer in Banff National Park were exposed to highest risk of encountering bears, but it was less likely to find elk in bear scats than in other areas. These patterns were consistent with previous estimates of spatial risk based on telemetry of collared predators and recent cause‐specific mortality patterns in elk.
4. A scat‐based approach can provide a cost‐efficient alternative to kill sites of quantifying broad‐scale, spatial patterns in risk of predation for prey particularly in multiple predator species systems.

     

Integrative analysis of clinical and epigenetic biomarkers of mortality

DNA methylation (DNAm) has been reported to be associated with many diseases and with mortality. We hypothesized that the integration of DNAm with clinical risk factors would improve mortality prediction. We performed an epigenome‐wide association study of whole blood DNAm in relation to mortality in 15 cohorts (n = 15,013). During a mean follow‐up of 10 years, there were 4314 deaths from all causes including 1235 cardiovascular disease (CVD) deaths and 868 cancer deaths. Ancestry‐stratified meta‐analysis of all‐cause mortality identified 163 CpGs in European ancestry (EA) and 17 in African ancestry (AA) participants at p < 1 × 10⁻⁷, of which 41 (EA) and 16 (AA) were also associated with CVD death, and 15 (EA) and 9 (AA) with cancer death. We built DNAm‐based prediction models for all‐cause mortality that predicted mortality risk after adjusting for clinical risk factors. The mortality prediction model trained by integrating DNAm with clinical risk factors showed an improvement in prediction of cancer death with 5% increase in the C‐index in a replication cohort, compared with the model including clinical risk factors alone. Mendelian randomization identified 15 putatively causal CpGs in relation to longevity, CVD, or cancer risk. For example, cg06885782 (in KCNQ4) was positively associated with risk for prostate cancer (Beta = 1.2, P _MR = 4.1 × 10⁻⁴) and negatively associated with longevity (Beta = −1.9, P _MR = 0.02). Pathway analysis revealed that genes associated with mortality‐related CpGs are enriched for immune‐ and cancer‐related pathways. We identified replicable DNAm signatures of mortality and demonstrated the potential utility of CpGs as informative biomarkers for prediction of mortality risk.     

Vital rates of two small populations of brown bears in Canada and range‐wide relationship between population size and trend

Identifying mechanisms of population change is fundamental for conserving small and declining populations and determining effective management strategies. Few studies, however, have measured the demographic components of population change for small populations of mammals (<50 individuals). We estimated vital rates and trends in two adjacent but genetically distinct, threatened brown bear (Ursus arctos) populations in British Columbia, Canada, following the cessation of hunting. One population had approximately 45 resident bears but had some genetic and geographic connectivity to neighboring populations, while the other population had <25 individuals and was isolated. We estimated population‐specific vital rates by monitoring survival and reproduction of telemetered female bears and their dependent offspring from 2005 to 2018. In the larger, connected population, independent female survival was 1.00 (95% CI: 0.96–1.00) and the survival of cubs in their first year was 0.85 (95% CI: 0.62–0.95). In the smaller, isolated population, independent female survival was 0.81 (95% CI: 0.64–0.93) and first‐year cub survival was 0.33 (95% CI: 0.11–0.67). Reproductive rates did not differ between populations. The large differences in age‐specific survival estimates resulted in a projected population increase in the larger population (λ = 1.09; 95% CI: 1.04–1.13) and population decrease in the smaller population (λ = 0.84; 95% CI: 0.72–0.95). Low female survival in the smaller population was the result of both continued human‐caused mortality and an unusually high rate of natural mortality. Low cub survival may have been due to inbreeding and the loss of genetic diversity common in small populations, or to limited resources. In a systematic literature review, we compared our population trend estimates with those reported for other small populations (<300 individuals) of brown bears. Results suggest that once brown bear populations become small and isolated, populations rarely increase and, even with intensive management, recovery remains challenging.     

Risky movements? Natal dispersal does not decrease survival of a large herbivore

Natal dispersal is assumed to be a particularly risky movement behavior as individuals transfer, often long distances, from birth site to site of potential first reproduction. Though, because this behavior persists in populations, it is assumed that dispersal increases the fitness of individuals despite the potential for increased risk of mortality. The extent of dispersal risk, however, has rarely been tested, especially for large mammals. Therefore, we aimed to test the relationship between dispersal and survival for both males and females in a large herbivore. Using a radio‐transmittered sample of 398 juvenile male and 276 juvenile female white‐tailed deer (Odocoileus virginianus), we compared survival rates of dispersers and nondispersers. We predicted that dispersing deer would experience greater overall mortality than philopatric deer due to direct transfer‐related risks (e.g., vehicular collision), indirect immigration‐related mortality attributable to colonization of unfamiliar habitat, and increased overwinter mortality associated with energetic costs of movement and unfamiliarity with recently colonized habitat. For both male and female yearlings, survival rates of dispersers (male = 49.9%, female = 64.0%) did not differ from nondispersers (male = 51.6%, female = 70.7%). Only two individuals (both female) were killed by vehicular collision during transfer, and overwinter survival patterns were similar between the two groups. Although dispersal movement likely incurs energetic costs on dispersers, these costs do not necessarily translate to decreased survival. In many species, including white‐tailed deer, dispersal is likely condition‐dependent, such that larger and healthier individuals are more likely to disperse; therefore, costs associated with dispersal are more likely to be borne successfully by those individuals that do disperse. Whether low‐risk dispersal of large mammals is the rule or the exception will require additional research. Further, future research is needed to evaluate nonsurvival fitness‐related costs and benefits of dispersal (e.g., increased reproductive opportunities for dispersers).     

Camera trap reveals the co‐occurrence patterns of two sympatric muntjac species in southern Anhui Province,China: No spatial segregation

The competitive relationship and coexistence pattern among close related species have long been one of the hot issues in ecological research. Interspecies interactions can exert important influences on the local distribution of rare species. Black muntjac Muntiacus crinifrons is an endemic species to eastern China, currently restricted to limited regions. In contrast, Chinese muntjac Muntiacus reevesi is the most common and widespread deer in southern China. Both species co‐occur in southern Anhui and western Zhejiang Province. Little is known about the interaction of these two sympatric‐related species. In this study, to investigate the site use determinants and co‐occurrence pattern of the two sympatric muntjac species, we conducted a camera trap survey across about 250 km² in mountainous area of southern Anhui Province, China. We adopted a multistep approach to incorporate habitat preferences while modeling occupancy and detection. We found that the two species did not separate along elevation gradient (range from 400 m to 1,400 m) as described in previous studies. Results of single‐species occupancy models indicated that elevation had positive effects on the site use of both species, while slope had an opposite influence on their site use. Positive effects of elevation on the site use implied that both species try to avoid human interference at low elevations. Significant negative effect of slope on the site use of black muntjac suggested that the species prefer habitat with gentle slope and avoided steep. Co‐occurrence models and species interaction factors provided evidence that the two muntjac species had an independent occupancy (ψ ^{BM CM} = ψ ^{BM cm}, SIF = 1) and exhibited a positive species interaction in detection probability (p ^BM < r ^{BM CM}). Combined with the results of previous studies, we suggested that it was fine differentiation in microhabitats and food resources utilization rather spatial or temporal segregation that allowed the two species co‐occurrence. The site use determinants revealed in our study would be useful for the habitat conservation and restoration for the rare black muntjac, and the co‐occurrence pattern of the two sympatric muntjac species could provide useful information for deep understanding of the coexistence mechanism among forest‐dwelling ungulates.     

Capture method affects survival estimates and subsequent interpretation of ecological covariates for a long‐lived cervid

Understanding what variables affect ungulate neonate survival is imperative to successful conservation and management of the species. Predation is commonly cited as a cause‐specific source of mortality, and ecological covariates often influence neonate survival. However, variation in survival estimates related to capture methodology has been documented with opportunistically captured neonates generally displaying greater survival than those captured via aid of vaginal implant transmitters (VITs), likely because of increased left truncation observed in the opportunistically captured datasets. Our goal was to assess whether 3‐ and 6‐month survival estimates varied by capture method while simultaneously assessing whether capture method affected model selection and interpretation of ecological covariates for white‐tailed deer neonates captured from three study sites from 2014 to 2015 in North Dakota and South Dakota, USA. We found survival varied by capture method for 3‐month neonate survival with opportunistically captured neonates displaying up to 26% greater survival than their counterparts captured via VITs; however, this relationship was not present for 6‐month survival. We also found model selection and subsequent interpretation of ecological covariates varied when analyzing datasets comprised of neonates captured via VITs, neonates captured opportunistically, and all neonates combined regardless of capture method. When interpreting results from our VIT‐only analysis for 3‐month survival, we found survival varied by three time intervals and was lowest in the first two weeks of life. Capture method did not affect 6‐month survival, which was most influenced by total precipitation occurring during 3 – 8 weeks of a neonate''s life and percent canopy cover found at a neonate''s capture site. Our results support previous research that capture method must be accounted for when deriving survival estimates for ungulate neonates as it can impact derived estimates and subsequent interpretation of results.     

Hot stuff in the bushes: Thermal imagers and the detection of burrows in vegetated sites

1. Thermal imaging technology is a developing field in wildlife management. Most thermal imaging work in wildlife science has been limited to larger ungulates and surface‐dwelling mammals. Little work has been undertaken on the use of thermal imagers to detect fossorial animals and/or their burrows. Survey methods such as white‐light spotlighting can fail to detect the presence of burrows (and therefore the animals within), particularly in areas where vegetation obscures burrows. Thermal imagers offer an opportunity to detect the radiant heat from these burrows, and therefore the presence of the animal, particularly in vegetated areas. Thermal imaging technology has become increasingly available through the provision of smaller, more cost‐effective units. Their integration with drone technology provides opportunities for researchers and land managers to utilize this technology in their research/management practices.
2. We investigated the ability of both consumer (<AUD$20,000) and professional imagers (>AUD$65,000) mounted on drones to detect rabbit burrows (warrens) and entrances in the landscape as compared to visual assessment.
3. Thermal imagery and visual inspection detected active rabbit warrens when vegetation was scarce. The presence of vegetation was a significant factor in detecting entrances (p < .001, α = 0.05). The consumer imager did not detect as many warren entrances as either the professional imager or visual inspection (p = .009, α = 0.05). Active warren entrances obscured by vegetation could not be accurately identified on exported imagery from the consumer imager and several false‐positive detections occurred when reviewing this footage.
4. We suggest that the exportable frame rate (Hz) was the key factor in image quality and subsequent false‐positive detections. This feature should be considered when selecting imagers and suggest that a minimum export rate of 30 Hz is required. Thermal imagers are a useful additional tool to aid in identification of entrances for active warrens and professional imagers detected more warrens and entrances than either consumer imagers or visual inspection.

     

How do King Cobras move across a major highway? Unintentional wildlife crossing structures may facilitate movement

1. Global road networks continue to expand, and the wildlife responses to these landscape‐level changes need to be understood to advise long‐term management decisions. Roads have high mortality risk to snakes because snakes typically move slowly and can be intentionally targeted by drivers.
2. We investigated how radio‐tracked King Cobras (Ophiophagus hannah) traverse a major highway in northeast Thailand, and if reproductive cycles were associated with road hazards.
3. We surveyed a 15.3 km stretch of Highway 304 to determine if there were any locations where snakes could safely move across the road (e.g., culverts and bridges). We used recurse analyses to detect possible road‐crossing events, and used dynamic Brownian Bridge Movement Models (dBBMMs) to show movement pathways association with possible unintentional crossing structures. We further used Integrated Step Selection Functions (ISSF) to assess seasonal differences in avoidance of major roads for adult King Cobras in relation to reproductive state.
4. We discovered 32 unintentional wildlife crossing locations capable of facilitating King Cobra movement across the highway. While our dBBMMs broadly revealed underpasses as possible crossing points, they failed to identify specific underpasses used by telemetered individuals; however, the tracking locations pre‐ and post‐crossing and photographs provided strong evidence of underpass use. Our ISSF suggested a lower avoidance of roads during the breeding season, although the results were inconclusive. With the high volume of traffic, large size of King Cobras, and a 98.8% success rate of crossing the road in our study (nine individuals: 84 crossing attempts with one fatality), we strongly suspect that individuals are using the unintentional crossing structures to safely traverse the road.
5. Further research is needed to determine the extent of wildlife underpass use at our study site. We propose that more consistent integration of drainage culverts and bridges could help mitigate the impacts of roads on some terrestrial wildlife.

     

Quantifying anthropogenic wolf mortality in relation to hunting regulations and landscape attributes across North America

Understanding the types and magnitude of human‐caused mortality is essential for maintaining viable large carnivore populations. We used a database of cause‐specific mortality to examine how hunting regulations and landscape configurations influenced human‐caused mortality of North American gray wolves (Canis lupus). Our dataset included 21 studies that monitored the fates of 3564 wolves and reported 1442 mortalities. Human‐caused mortality accounted for 61% of mortality overall, with 23% due to illegal harvest, 16% due to legal harvest, and 12% the result of management removal. The overall proportion of anthropogenic wolf mortality was lowest in areas with an open hunting season compared to areas with a closed hunting season or mixed hunting regulations, suggesting that harvest mortality was neither fully additive nor compensatory. Proportion of mortality from management removal was reduced in areas with an open hunting season, suggesting that legal harvest may reduce human‐wolf conflicts or alternatively that areas with legal harvest have less potential for management removals (e.g., less livestock depredation). Proportion of natural habitat was negatively correlated with the proportion of anthropogenic and illegal harvest mortality. Additionally, the proportion of mortality due to illegal harvest increased with greater natural habitat fragmentation. The observed association between large patches of natural habitat and reductions in several sources of anthropogenic wolf mortality reiterate the importance of habitat preservation to maintain wolf populations. Furthermore, effective management of wolf populations via implementation of harvest may reduce conflict with humans. Effective wolf conservation will depend on holistic strategies that integrate ecological and socioeconomic factors to facilitate their long‐term coexistence with humans.     

Age patterns of intra‐pair DNA methylation discordance in twins: Sex difference in epigenomic instability and implication on survival

Aging is a biological process linked to specific patterns and changes in the epigenome. We hypothesize that age‐related variation in the DNA methylome could reflect cumulative environmental modulation to the epigenome which could impact epigenomic instability and survival differentially by sex. To test the hypothesis, we performed sex‐stratified epigenome‐wide association studies on age‐related intra‐pair DNA methylation discordance in 492 twins aged 56–80 years. We identified 3084 CpGs showing increased methylation variability with age (FDR < 0.05, 7 CpGs with p < 1e‐07) in male twins but no significant site found in female twins. The results were replicated in an independent cohort of 292 twins aged 30–74 years with 37% of the discovery CpGs successfully replicated in male twins. Functional annotation showed that genes linked to the identified CpGs were significantly enriched in signaling pathways, neurological functions, extracellular matrix assembly, and cancer. We further explored the implication of discovery CpGs on individual survival in an old cohort of 224 twins (220 deceased). In total, 264 CpGs displayed significant association with risk of death in male twins. In female twins, 175 of the male discovery CpGs also showed non‐random correlation with mortality. Intra‐pair comparison showed that majority of the discovery CpGs have higher methylation in the longer‐lived twins suggesting that loss of DNA methylation during aging contributes to increased risk of death which is more pronounced in male twins. In conclusion, age‐related epigenomic instability in the DNA methylome is more evident in males than in females and could impact individual survival and contribute to sex difference in human lifespan.     

Association between IGF‐1 levels ranges and all‐cause mortality: A meta‐analysis

The association between IGF‐1 levels and mortality in humans is complex with low levels being associated with both low and high mortality. The present meta‐analysis investigates this complex relationship between IGF‐1 and all‐cause mortality in prospective cohort studies. A systematic literature search was conducted in PubMed/MEDLINE, Scopus, and Cochrane Library up to September 2019. Published studies were eligible for the meta‐analysis if they had a prospective cohort design, a hazard ratio (HR) and 95% confidence interval (CI) for two or more categories of IGF‐1 and were conducted among adults. A random‐effects model with a restricted maximum likelihood heterogeneity variance estimator was used to find combined HRs for all‐cause mortality. Nineteen studies involving 30,876 participants were included. Meta‐analysis of the 19 eligible studies showed that with respect to the low IGF‐1 category, higher IGF‐1 was not associated with increased risk of all‐cause mortality (HR = 0.84, 95% CI = 0.68–1.05). Dose–response analysis revealed a U‐shaped relation between IGF‐1 and mortality HR. Pooled results comparing low vs. middle IGF‐1 showed a significant increase of all‐cause mortality (HR = 1.33, 95% CI = 1.14–1.57), as well as comparing high vs. middle IGF‐1 categories (HR = 1.23, 95% CI = 1.06–1.44). Finally, we provide data on the association between IGF‐1 levels and the intake of proteins, carbohydrates, certain vitamins/minerals, and specific foods. Both high and low levels of IGF‐1 increase mortality risk, with a specific 120–160 ng/ml range being associated with the lowest mortality. These findings can explain the apparent controversy related to the association between IGF‐1 levels and mortality.     

Integrating growth and survival models for flexible estimation of size‐dependent survival in a cryptic,endangered snake

Estimates of demographic rates for animal populations and individuals have many applications for ecological and conservation research. In many animals, survival is size‐dependent, but estimating the form of the size–survival relationship presents challenges. For elusive species with low recapture rates, individuals’ size will be unknown at many points in time. Integrating growth and capture–mark–recapture models in a Bayesian framework empowers researchers to impute missing size data, with uncertainty, and include size as a covariate of survival, capture probability, and presence on‐site. If there is no theoretical expectation for the shape of the size–survival relationship, spline functions can allow for fitting flexible, data‐driven estimates. We use long‐term capture–mark–recapture data from the endangered San Francisco gartersnake (Thamnophis sirtalis tetrataenia) to fit an integrated growth–survival model. Growth models showed that females reach longer asymptotic lengths than males and that the magnitude of sexual size dimorphism differed among populations. The capture probability and availability of San Francisco gartersnakes for capture increased with snout–vent length. The survival rate of female snakes exhibits a nonlinear relationship with snout–vent length (SVL), with survival flat between 300 mm and 550 mm SVL before decreasing for females between 550 mm and 700 mm SVL. For male snakes, survival decreased for adult males >550 mm SVL. The survival rates of the smallest and largest San Francisco gartersnakes were highly uncertain because recapture rates were very low for these sizes. By integrating growth and survival models and using penalized splines, we found support for size‐dependent survival in San Francisco gartersnakes. Our results have applications for devising management activities for this endangered subspecies, and our methods could be applied broadly to the study of size‐dependent demography among animals.     

No effect of passive integrated transponder tagging method on survival or body condition in a northern population of Black‐capped Chickadees (Poecile atricapillus)

Passive integrated transponder (PIT) tags allow a range of individual‐level data to be collected passively and have become a commonly used technology in many avian studies. Although the potential adverse effects of PIT tags have been evaluated in several species, explicit investigations of their impacts on small (<12 g) birds are limited. This is important, because it is reasonable to expect that smaller birds could be impacted more strongly by application of PIT tags. In this study, we individually marked Black‐capped Chickadees (Poecile atricapillus), a small (circa 10 g) passerine, at the University of Alberta Botanic Garden to evaluate potential lethal and sublethal effects of two PIT tagging methods: attachment to leg bands or subcutaneous implantation. We used a Cox proportional hazards model to compare the apparent survival of chickadees with leg band (N = 79) and implanted PIT tags (N = 77) compared with control birds that received no PIT tags (N = 76) over the subsequent 2 years based on mist net recaptures. We used radio‐frequency identification (RFID) redetections of leg band PIT tags to evaluate sex‐specific survival and increase the accuracy of our survival estimates. We also used a generalized linear regression model to compare the body condition of birds recaptured after overwintering with leg band PIT tags, implanted PIT tags, or neither. Our analysis found no evidence for adverse effects of either PIT tagging method on survival or body condition. While we recommend carefully monitoring study animals and evaluating the efficacy of different PIT tagging methods, we have shown that both leg band and subcutaneously implanted PIT tags ethical means of obtaining individualized information in a small passerine.     

Age‐related DNA methylation on Y chromosome and their associations with total mortality among Chinese males

In view of the sex differences in aging‐related diseases, sex chromosomes may play a critical role during aging process. This study aimed to identify age‐related DNA methylation changes on Y chromosome (ChrY). A two‐stage study design was conducted in this study. The discovery stage contained 419 Chinese males, including 205 from the Wuhan‐Zhuhai cohort panel, 107 from the coke oven workers panel, and 107 from the Shiyan panel. The validation stage contained 587 Chinese males from the Dongfeng‐Tongji sub‐cohort. We used the Illumina HumanMethylation BeadChip to determine genome‐wide DNA methylation in peripheral blood of the study participants. The associations between age and methylation levels of ChrY CpGs were investigated by using linear regression models with adjustment for potential confounders. Further, associations of age‐related ChrY CpGs with all‐cause mortality were tested in the validation stage. We identified the significant associations of 41 ChrY CpGs with age at false discovery rate (FDR) <0.05 in the discovery stage, and 18 of them were validated in the validation stage (p < 0.05). Meta‐analysis of both stages confirmed the robust positive associations of 14 CpGs and negative associations of 4 CpGs with age (FDR<0.05). Among them, cg03441493 and cg17816615 were significantly associated with all‐cause mortality risk [HR(95% CI) = 1.37 (1.04, 1.79) and 0.70 (0.54, 0.93), respectively]. Our results highlighted the importance of ChrY CpGs on male aging.     

Molecular approaches reveal weak sibship aggregation and a high dispersal propensity in a non‐native fish parasite

Inferring parameters related to the aggregation pattern of parasites and to their dispersal propensity are important for predicting their ecological consequences and evolutionary potential. Nonetheless, it is notoriously difficult to infer these parameters from wildlife parasites given the difficulty in tracking these organisms. Molecular‐based inferences constitute a promising approach that has yet rarely been applied in the wild. Here, we combined several population genetic analyses including sibship reconstruction to document the genetic structure, patterns of sibship aggregation, and the dispersal dynamics of a non‐native parasite of fish, the freshwater copepod ectoparasite Tracheliastes polycolpus. We collected parasites according to a hierarchical sampling design, with the sampling of all parasites from all host individuals captured in eight sites spread along an upstream–downstream river gradient. Individual multilocus genotypes were obtained from 14 microsatellite markers, and used to assign parasites to full‐sib families and to investigate the genetic structure of T. polycolpus among both hosts and sampling sites. The distribution of full‐sibs obtained among the sampling sites was used to estimate individual dispersal distances within families. Our results showed that T. polycolpus sibs tend to be aggregated within sites but not within host individuals. We detected important upstream‐to‐downstream dispersal events of T. polycolpus between sites (modal distance: 25.4 km; 95% CI [22.9, 27.7]), becoming scarcer as the geographic distance from their family core location increases. Such a dispersal pattern likely contributes to the strong isolation‐by‐distance observed at the river scale. We also detected some downstream‐to‐upstream dispersal events (modal distance: 2.6 km; 95% CI [2.2–23.3]) that likely result from movements of infected hosts. Within each site, the dispersal of free‐living infective larvae among hosts likely contributes to increasing genetic diversity on hosts, possibly fostering the evolutionary potential of T. polycolpus.     

Thalassaemia is paradoxically associated with a reduced risk of in‐hospital complications and mortality in COVID‐19: Data from an international registry

Although numerous patient‐specific co‐factors have been shown to be associated with worse outcomes in COVID‐19, the prognostic value of thalassaemic syndromes in COVID‐19 patients remains poorly understood. We studied the outcomes of 137 COVID‐19 patients with a history of transfusion‐dependent thalassaemia (TDT) and transfusion independent thalassaemia (TIT) extracted from a large international cohort and compared them with the outcomes from a matched cohort of COVID‐19 patients with no history of thalassaemia. The mean age of thalassaemia patients included in our study was 41 ± 16 years (48.9% male). Almost 81% of these patients suffered from TDT requiring blood transfusions on a regular basis. 38.7% of patients were blood group O. Cardiac iron overload was documented in 6.8% of study patients, whereas liver iron overload was documented in 35% of study patients. 40% of thalassaemia patients had a history of splenectomy. 27.7% of study patients required hospitalization due to COVID‐19 infection. Amongst the hospitalized patients, one patient died (0.7%) and one patient required intubation. Continuous positive airway pressure (CPAP) was required in almost 5% of study patients. After adjustment for age‐, sex‐ and other known risk factors (cardiac disease, kidney disease and pulmonary disease), the rate of in‐hospital complications (supplemental oxygen use, admission to an intensive care unit for CPAP therapy or intubation) and all‐cause mortality was significantly lower in the thalassaemia group compared to the matched cohort with no history of thalassaemia. Amongst thalassaemia patients in general, the TIT group exhibited a higher rate of hospitalization compared to the TDT group (p = 0.001). In addition, the rate of complications such as acute kidney injury and need for supplemental oxygen was significantly higher in the TIT group compared to the TDT group. In the multivariable logistic regression analysis, age and history of heart or kidney disease were all found to be independent risk factors for increased in‐hospital, all‐cause mortality, whereas the presence of thalassaemia (either TDT or TIT) was found to be independently associated with reduced all‐cause mortality. The presence of thalassaemia in COVID‐19 patients was independently associated with lower in‐hospital, all‐cause mortality and few in‐hospital complications in our study. The pathophysiology of this is unclear and needs to be studied in vitro and in animal models.     

Patterns of testosterone in male white‐tailed deer (Odocoileus virginianus): Seasonal and lifetime variation

Testosterone is strongly associated with the annual development of antlers in cervids, but endocrine research on wild, freely breeding ungulates is often done without repeated capture of known‐aged individuals. As a result, our knowledge on how testosterone fluctuates over the course of a lifetime and variation in lifetime patterns among individuals is limited. We investigated patterns of testosterone in a freely breeding population of white‐tailed deer (Odocoileus virginianus) in Alabama, USA, that breeds in January. Testosterone peaked during the height of the breeding season, despite this period occurring approximately 2 months later than in most temperate‐region white‐tailed deer populations. Age‐related differences in testosterone were only prevalent during the breeding season, with bucks ≥3.5 years old having greater testosterone (853 ng/dl ± 96 SE; p = 0.012) than bucks 1.5–2.5 years old (364 ng/dl ± 100 SE). Additionally, an individual''s testosterone level as a yearling was not positively associated with their lifetime maximum testosterone level (p = 0.583), and an individual''s mean testosterone level was positively associated with lifetime testosterone variation (p < 0.001). To our knowledge, our study is one of the first to assess how testosterone early in life might relate to individual testosterone later in life. We believe these data provide insight into lifetime hormonal patterns in cervids, and that these patterns may indicate intraspecific variation of lifetime reproductive strategies.     

Spotted hyaena Crocuta crocuta feeding ecology and selectivity of large herbivorous prey in the Namib desert

We have investigated the relationship between spotted hyaenas in the south Namib Desert and large herbivorous prey and have summarized an updated overview of predator‐prey relationships in this resource‐limited arid environment. Over the 52‐month study, we recorded the densities (#/km⁻², ±SE) of the four local large herbivorous prey species: gemsbok (1.229, ±0.50), springbok (1.352, ±0.48), ostrich (0.648, ±0.23), and greater kudu (0.343, ±0.00). A fecal analysis was performed on 146 collected spotted hyaena scats, and prey items were identified and hairs cross‐follicle analyzed to the species level. Spotted hyaena diet at the study area remained opportunistic with 240 identified prey items representing eight differing prey species being recorded, ranging from ostrich eggs to large ungulates. The Ivlev''s Electivity Index was used to determine which large herbivorous prey was most selected for. Although gemsbok had a higher representation of prey items in the sampled scats, all sampled large herbivorous prey species scored below 0 and are thus generally avoided in relation to their availability in the environment. If any prey preferences are expressed by spotted hyaena in the Namib, it can be presumed to be a nonsampled prey species. We therefore promote further detailed investigations into all other prey species present, and seasonal variations of prey densities and scat sampling, within the study environment.     

Home‐site fidelity and homing behavior of the big‐headed turtle Platysternon megacephalum

Site fidelity refers to the restriction of dispersal distance of an animal and its tendency to return to a stationary site. To our knowledge, the homing ability of freshwater turtles and their fidelity is reportedly very low in Asia. We examined mark–recapture data spanning a 4‐year period in Diaoluoshan National Nature Reserve, Hainan Province, China, to investigate the site fidelity and homing behavior of big‐headed turtles Platysternon megacephalum. A total of 11 big‐headed turtles were captured, and all individuals were used in this mark–recapture study. The site fidelity results showed that the adult big‐headed turtles (n = 4) had a 71.43% recapture rate in the original site after their release at the same site, whereas the juveniles (n = 1) showed lower recapture rates (0%). Moreover, the homing behavior results showed that the adults (n = 5) had an 83.33% homing rate after displacement. Adult big‐headed turtles were able to return to their initial capture sites (home) from 150 to 2,400 m away and precisely to their home sites from either upstream or downstream of their capture sites or even from other streams. However, none of the juveniles (n = 4) returned home, despite only being displaced 25–150 m away. These results indicated that the adult big‐headed turtles showed high fidelity to their home site and strong homing ability. In contrast, the juvenile turtles may show an opposite trend but further research is needed.