Relatedness-based mate choice and female philopatry: inbreeding trends of wolf packs in a human-dominated landscape.

Inbreeding can reduce offspring fitness and has substantial implications for the genetic diversity and long-term viability of populations. In social cooperative canids, inbreeding is conditioned by the geographic proximity between opposite-sex kin outside natal groups and the presence of related individuals in neighbouring groups. Consequently, challenges in moving into other regions where the species is present can also affect inbreeding rates. These can be particularly problematic in areas of high human density, where movement can be restricted, even for highly vagile species. In this study, we investigate the socio-ecological dynamics of Iberian wolf packs in the human-dominated landscape of Alto Minho, in northwest Portugal, where wolves exhibit a high prevalence of short-distance dispersal and limited gene flow with neighbouring regions. We hypothesise that mating occurs regardless of relatedness, resulting in recurrent inbreeding due to high kin encounter rates. Using data from a 10-year non-invasive genetic monitoring programme and a combination of relatedness estimates and genealogical reconstructions, we describe genetic diversity, mate choice, and dispersal strategies among Alto Minho packs. In contrast with expectations, our findings reveal relatedness-based mate choice, low kin encounter rates, and a reduced number of inbreeding events. We observed a high prevalence of philopatry, particularly among female breeders, with the most common breeding strategy involving the pairing of a philopatric female with an unrelated immigrant male. Overall, wolves were not inbred, and temporal changes in genetic diversity were not significant. Our findings are discussed, considering the demographic trend of wolves in Alto Minho and its human-dominated landscape.

North African fox genomes show signatures of repeated introgression and adaptation to life in deserts.

Elucidating the evolutionary process of animal adaptation to deserts is key to understanding adaptive responses to climate change. Here we generated 82 individual whole genomes of four fox species (genus Vulpes) inhabiting the Sahara Desert at different evolutionary times. We show that adaptation of new colonizing species to a hot arid environment has probably been facilitated by introgression and trans-species polymorphisms shared with older desert resident species, including a putatively adaptive 25 Mb genomic region. Scans for signatures of selection implicated genes affecting temperature perception, non-renal water loss and heat production in the recent adaptation of North African red foxes (Vulpes vulpes), after divergence from Eurasian populations approximately 78 thousand years ago. In the extreme desert specialists, Rueppell's fox (V. rueppellii) and fennec (V. zerda), we identified repeated signatures of selection in genes affecting renal water homeostasis supported by gene expression and physiological differences. Our study provides insights into the mechanisms and genetic underpinnings of a natural experiment of repeated adaptation to extreme conditions.

Hair cortisol concentration reflects the life cycle and management of grey wolves across four European populations.

The grey wolf (Canis lupus) persists in a variety of human-dominated landscapes and is subjected to various legal management regimes throughout Europe. Our aim was to assess the effects of intrinsic and methodological determinants on the hair cortisol concentration (HCC) of wolves from four European populations under different legal management. We determined HCC by an enzyme-linked immune assay in 259 hair samples of 133 wolves from the Iberian, Alpine, Dinaric-Balkan, and Scandinavian populations. The HCC showed significant differences between body regions. Mean HCC in lumbar guard hair was 11.6 ± 9.7 pg/mg (range 1.6-108.8 pg/mg). Wolves from the Dinaric-Balkan and Scandinavian populations showed significantly higher HCC than Iberian wolves, suggesting that harvest policies could reflected in the level of chronic stress. A significant negative relationship with body size was found. The seasonal, sex and age patterns are consistent with other studies, supporting HCC as a biomarker of chronic stress in wolves for a retrospective time frame of several weeks. Our results highlight the need for standardization of sampling and analytical techniques to ensure the value of HCC in informing management at a continental scale.

Non-Invasive Molecular Survey of Sarcoptic Mange in Wildlife: Diagnostic Performance in Wolf Faecal Samples Evaluated by Multi-Event Capture-Recapture Models.

Sarcoptic mange is globally enzootic, and non-invasive methods with high diagnostic specificity for its surveillance in wildlife are lacking. We describe the molecular detection of Sarcoptes scabiei in non-invasively collected faecal samples, targeting the 16S rDNA gene. We applied this method to 843 Iberian wolf Canis lupus signatus faecal samples collected in north-western Portugal (2006-2018). We further integrated this with serological data (61 samples from wolf and 20 from red fox Vulpes vulpes, 1997-2019) in multi-event capture-recapture models. The mean predicted prevalence by the molecular analysis of wolf faecal samples from 2006-2018 was 7.2% (CI95 5.0-9.4%; range: 2.6-11.7%), highest in 2009. The mean predicted seroprevalence in wolves was 24.5% (CI95 18.5-30.6%; range: 13.0-55.0%), peaking in 2006-2009. Multi-event capture-recapture models estimated 100% diagnostic specificity and moderate diagnostic sensitivity (30.0%, CI95 14.0-53.0%) for the molecular method. Mange-infected individually identified wolves showed a tendency for higher mortality versus uninfected wolves (ΔMortality 0.150, CI95 -0.165-0.458). Long-term serology data highlights the endemicity of sarcoptic mange in wild canids but uncovers multi-year epidemics. This study developed and evaluated a novel method for surveying sarcoptic mange in wildlife populations by the molecular detection of S. scabiei in faecal samples, which stands out for its high specificity and non-invasive character.

Protein metabolism and physical fitness are physiological determinants of body condition in Southern European carnivores.

The physiological significance of biometric body condition indices (bBCI) is poorly understood. We hypothesized that bBCI are composite metrics of nutritional physiology, physical fitness and health. To test this hypothesis, we first compared the performance of eight bBCI, using 434 Southern European carnivores from six species as a model system; and then identified, by non-destructive methods, the hematology and serum biochemistry correlates of three selected bBCI. Fulton's K Index, Major Axis Regression Residuals and Scaled Mass Index were the only bBCI insensitive to the effect of sex and age. The most informative physiological parameters in explaining the variation of these bBCI were the albumin (Effect Size (ES) = - 1.66 to - 1.76), urea (ES = 1.61 to 1.85) and total bilirubin (ES = - 1.62 to - 1.79). Hemoglobin and globulins (positive) and cholesterol (negative) were moderately informative (0.9 <|ES|< 1.5). This study shows that most bBCI do not control for the effect of age and sex in Southern European carnivores. Our results support that bBCI are composite measures of physiologic processes, reflecting a positive gradient from protein-poor to protein-rich diets, accompanied by increased physical fitness. Biometric body condition indices allow the integration of ecologically relevant physiological aspects in an easily obtained metric.

Characterization and minimization of the stress response to trapping in free-ranging wolves (Canis lupus): insights from physiology and behavior.

OBJECTIVES: Wildlife capture is an essential management tool that induces a reactive homeostasis response in the captured animals. The aim of this study was to characterize the reactive homeostatic response to trapping in free-ranging wolves and assess the mitigation achieved by reducing the duration of restraint. MATERIALS AND METHODS: Making use of wolves captured for ecological research as a model for wildlife acute stress, we characterize 25 reactive homeostasis mediators and we assess the effect on these mediators of reducing the duration of restraint in trap by using remote trap activation alarms. RESULTS: Free-ranging wolves trapped by leg-hold snares (n = 15) showed higher stress leukogram, tissue injury and hematocrit; while lower glucose, ions and cardiac rate compared with captive wolves. They also showed higher leukocyte count and creatine kinase; but lower hematocrit, cardiac rate and rectal body temperature compared to wolves captured by darting from a helicopter. Daily distance travelled was significantly lower up to day 12 post-capture compared to the remainder of the telemetry follow-up and this effect was more noticeable on the nocturnal distance travelled. Reducing the duration of restraint on trap significantly lowered the stress leukogram and dehydration. Daily distance travelled during the night by wolves captured using trap-alarms was significantly lower only up to day 4 post-capture compared to up to day 28 for wolves captured without trap-alarms. DISCUSSION: The capture method and duration of restraint influence the reactive homeostasis response of free-ranging wolves. Technological solutions that reduce the duration of restraint on trap significantly dampen this influence. CONCLUSIONS: Wildlife trapping actions should strive to minimize the delay from capture to manipulation.