Heritability and genetic correlations of personality traits in a wild population of yellow‐bellied marmots (Marmota flaviventris)

Describing and quantifying animal personality is now an integral part of behavioural studies because individually distinctive behaviours have ecological and evolutionary consequences. Yet, to fully understand how personality traits may respond to selection, one must understand the underlying heritability and genetic correlations between traits. Previous studies have reported a moderate degree of heritability of personality traits, but few of these studies have either been conducted in the wild or estimated the genetic correlations between personality traits. Estimating the additive genetic variance and covariance in the wild is crucial to understand the evolutionary potential of behavioural traits. Enhanced environmental variation could reduce heritability and genetic correlations, thus leading to different evolutionary predictions. We estimated the additive genetic variance and covariance of docility in the trap, sociability (mirror image stimulation), and exploration and activity in two different contexts (open‐field and mirror image simulation experiments) in a wild population of yellow‐bellied marmots (Marmota flaviventris). We estimated both heritability of behaviours and of personality traits and found nonzero additive genetic variance in these traits. We also found nonzero maternal, permanent environment and year effects. Finally, we found four phenotypic correlations between traits, and one positive genetic correlation between activity in the open‐field test and sociability. We also found permanent environment correlations between activity in both tests and docility and exploration in the MIS test. This is one of a handful of studies to adopt a quantitative genetic approach to explain variation in personality traits in the wild and, thus, provides important insights into the potential variance available for selection.     

Serosurveillance for Livestock Pathogens in Free-Ranging Mule Deer (Odocoileus hemionus)

Routine disease surveillance has been conducted for decades in mule deer (Odocoileus hemionus) in California for pathogens shared between wildlife and domestic ruminants that may have implications for the animal production industry and wildlife health. Deer sampled from 1990 to 2007 (n = 2,619) were tested for exposure to six pathogens: bluetongue virus (BTV), epizootic hemorrhagic disease virus (EHDV), bovine viral diarrhea virus (BVDV), Leptospira spp., Anaplasma spp. and Brucella spp. We evaluated the relationship between exposure to these pathogens and demographic risk factors to identify broad patterns in seroprevalence across a large temporal and spatial scale. The overall seroprevalence for the entire study period was 13.4% for BTV, 16.8% for EHDV, 17.1% for BVDV, 6.5% for Leptospira spp., 0.2% for Brucella spp., and 17% for Anaplasma spp. Antibodies against BTV and EHDV were most prevalent in the deer populations of southern California. Antibodies against Leptospira spp. and Anaplasma spp. were most prevalent in coastal and central northern California whereas antibodies against BVDV were most prevalent in central-eastern and northeastern California. The overall seroprevalence for Anaplasma spp. was slightly lower than detected in previous studies. North and central eastern California contains large tracts of federal land grazed by livestock; therefore, possible contact between deer and livestock could explain the high BVDV seroprevalence found in these areas. Findings from this study will help to establish baseline values for future comparisons of pathogen exposure in deer, inform on long-term trends in deer population health and provide relevant information on the distribution of diseases that are shared between wildlife and livestock.     

Demodicosis in a mule deer (Odocoileus hemionus hemionus) from Saskatchewan, Canada

Infestation of deer with Demodex spp. mites has been described in white-tailed deer (Odocoileus virginianus) and in Columbian black-tailed deer (Odocoileus hemionus columbianus) in North America, as well as in four species of deer in Europe. We describe Demodex sp. infestation in an adult female mule deer (Odocoileus hemionus hemionus) with skin lesions found dead near Saskatoon, Saskatchewan, Canada. This is believed to be the first report of demodicosis in mule deer.     

Hybrid swarm between divergent lineages of mule deer (Odocoileus hemionus)

Studies of hybrid zones have revealed an array of evolutionary outcomes, yet the underlying structure is typically characterized as one of three types: a hybrid zone, a hybrid swarm or a hybrid taxon. Our primary objective was to determine which of these three structures best characterizes a zone of hybridization between two divergent lineages of mule deer (Odocoileus hemionus), mule deer and black-tailed deer. These lineages are morphologically, ecologically and genetically distinct, yet hybridize readily along a zone of secondary contact between the east and west slopes of the Cascade Mountains (Washington and Oregon, USA). Using microsatellite and mitochondrial DNA, we found clear evidence for extensive hybridization and introgression between lineages, with varying degrees of admixture across the zone of contact. The pattern of hybridization in this region closely resembles a hybrid swarm; based on data from 10 microsatellite loci, we detected hybrids that extend well beyond the F1 generation, did not detect linkage disequilibrium at the centre of the zone and found that genotypes were associated randomly within the zone of contact. Introgression was characterized as bidirectional and symmetric, which is surprising given that the zone of contact occurs along a sharp ecotone and that lineages are characterized by large differences in body size (a key component of mating success). Regardless of the underlying mechanisms promoting hybrid swarm maintenance, it is clear that the persistence of a hybrid swarm presents unique challenges for management in this region.     

Seasonal changes in critical enzymes of lipogenesis and triacylglycerol synthesis in the marmot (Marmota flaviventris)

Fatty acid metabolism and triacylglycerol synthesis are critical processes for the survival of hibernating mammals that undergo a prolonged fasting period. Fatty acid synthase, fatty-acid-CoA ligase, diacylglycerol acyltransferase, and monoacylglycerol acyltransferase activities were measured in liver and in white and brown adipose tissue, in order to determine whether enzymes of lipogenesis and triacylglycerol synthesis vary seasonally during hibernation in the yellow-bellied marmot (Marmota flaviventris). Compared with mid-winter hibernation, fatty acid synthase activity was higher in all three tissues during early spring when marmots emerged from hibernation and in mid-summer when they were feeding, consistent with the synthesis of fatty acids from the carbohydrate-rich summer diet. Fatty-acid-CoA ligase and diacylglycerol acyltransferase activities were highest in summer in white adipose tissue when triacylglycerol synthesis would be expected to be high; diacylglycerol acyltransferase activity was also high in brown adipose tissue during spring and summer. In liver, however, diacylglycerol acyltransferase specific activity was highest during hibernation, suggesting that triacylglycerol synthesis may be prominent in liver in winter. Monoacylglycerol acyltransferase activity, which may aid in the retention of essential fatty-acids, was 80-fold higher in liver than in white or brown adipose tissue, but did not vary seasonally. Its dependence on palmitoyl-CoA suggests that a divalent cation might play a role in enzyme activation. The high hepatic diacylglycerol acyltransferase activity during hibernation suggests that the metabolism of very low density lipoprotein may be important in the movement of adipose fatty acids to brown adipose tissue and muscle during the rewarming that occurs periodically during hibernation. These studies suggest that enzymes of lipid metabolism vary seasonally in the marmot, consistent with requirements of this hibernator for triacylglycerol synthesis and metabolism.Abbreviations BAT brown adipose tissue - DGAT diacylglycerol acyltransferase - FAS fatty acid synthase - K _m Michaelis constant - MGAT monoacylglycerol acyltransferase - RQ respiratory quotiant - VLDL very low density lipoprotein - WAT white adipose tissue     

Effect of predation risk on the presence and persistence of yellow-bellied marmot (Marmota flaviventris) colonies

Habitat selection may have population level consequences and ultimately may influence a population's local persistence or extinction. We capitalized on a long-term study (1962–2004) of yellow-bellied marmots Marmota flaviventris in and around the Rocky Mountain Biological Laboratory, Gothic, Colorado, USA, and compared habitat characteristics associated with food availability and predation risk to explain variation in persistence of marmots at 27 sites, and their absence at 22 additional, randomly selected sites. We classified sites as persistent, intermittent or null based on whether there was a history of extinction; intermittent sites periodically went extinct and null sites never had marmots. Logistic regression analyses revealed that environmental variables associated with visibility and safety, rather than food, correctly classified sites as persistent or non-persistent as well as persistent or intermittent. Discriminant function analysis that included the null sites revealed that the same visibility-related characteristics predicted where marmots were found. These results highlight the importance of variation in safety among sites in predicting long-term population persistence, as well as a species' distribution.     

A review of the population dynamics of mule deer and black‐tailed deer Odocoileus hemionus in North America

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Ocular plague (Yersinia pestis) in mule deer (Odocoileus hemionus) from Wyoming and Oregon

Although plague is relatively rare in wild ungulates, this report describes ocular lesions associated with Yersinia pestis infection in three free-ranging mule deer (Odocoileus hemionus) from Wyoming and Oregon, USA. All deer were observed antemortem and seemed to be blind. Post-mortem examination revealed gross lesions of bilateral keratoconjunctivitis and/or panophthalmitis in the first two deer, but only partial retinal detachment in the third deer. Microscopically, all deer had moderate-to-severe necrotizing and fibrinopurulent endophthalmitis and varying degrees of keratoconjunctivitis with abundant intralesional coccobacilli. The lesions in the first (D1) and third deer (D3) suggested an acute course, whereas those in the second deer (D2) were subacute to chronic. Yersinia pestis was isolated from ocular tissue swabs or ocular fluids of D1 and D2, and it was demonstrated by immunohistochemistry within ocular lesions of D1 and D3. Although plague does not seem to be a major cause of morbidity or mortality in free-ranging mule deer, keratoconjunctivitis or pinkeye is relatively common in these animals and plague should be considered as a differential diagnosis in such cases, with appropriate precautions taken to protect the human and animal health.     

Detection and Avoidance of Predators in White-Tailed Deer (Odocoileus virginianus) and Mule Deer (O. hemionus)

In this paper, we investigate the relationship between early detection of predators and predator avoidance in white-tailed deer ( Odocoileus virginianus ) and mule deer ( O. hemionus ), two closely related species that differ in their habitat preferences and in their anti-predator behavior. We used observations of coyotes ( Canis latrans ) hunting deer to test whether the distance at which white-tails and mule deer alerted to coyotes was related to their vulnerability to predation. Coyote encounters with both species were more likely to escalate when deer alerted at shorter distances. However, coyote encounters with mule deer progressed further than encounters with white-tails that alerted at the same distance, and this was not due to species differences in group size or habitat. We then conducted an experiment in which a person approached groups of deer to compare the detection abilities and the form of alert response for white-tails and mule deer, and for age groups within each species. Mule deer alerted to the approacher at longer distances than white-tails, even after controlling for variables that were potentially confounding. Adult females of both species alerted sooner than conspecific juveniles. Mule deer almost always looked directly at the approacher as their initial response, whereas white-tails were more likely to flee or to look in another direction with no indication that they pinpointed the approacher during the trial. Mule deer may have evolved the ability to detect predators earlier than white-tails as an adaptation to their more open habitats, or because they need more time to coordinate subsequent anti-predator defenses.     

Fertility in an F1 male hybrid of white-tailed deer (Odocoileus virginianus) x mule deer (O. hemionus)

The fecundity of an F1 male hybrid deer, from a cross between a male Odocoileus virginianus (white-tailed deer) and a female O. hemionus (mule deer), was assessed by cytogenetic and flow cytometric techniques. Analysis of chromosome morphology, nucleolus organizer expression, meiotic chromosome pairing, sperm production, and nuclear gene inheritance revealed no genetic anomalies that could potentially impair normal fertility. These observations are discussed in relation to recent reports of hybridization between natural populations of these two species.     

Bot fly larvae (Cephenemyia spp., Oestridae) in mule deer (Odocoileus hemionus) from Utah

Ninety-nine mule deer (Odocoileus hemionus) from four Utah counties (Cache, Utah, Sanpete and Sevier) were examined for larvae of Cephenemyia spp. in 1985 and 1986. Numbers of first, second and third stage bot fly instars were related to age, sex, year and geographic location of the mule deer. Fawns and adult deer greater than or equal to 5.5 yr had a significantly (P less than or equal to 0.05) higher intensity (means = 37 and means = 68, respectively) of infection than the 1.5- and 2.5-yr-old age groups (means = 19 and means = 26, respectively). Infection by larvae was not significantly different between sexes. Infection was 100% in both years, but the mean intensity was significantly lower in 1986 (P less than 0.05). The decline may be related to differences in soil moisture between the 2 years. In 1985, 82% of the deer examined were infected with all three instars. Seventy-seven percent of all first instar larvae were observed in the trachea, usually in the fold immediately posterior to the epiglottis and corniculate cartilages. This new site of attachment for first instar larvae has not previously been recognized.     

Prevalence of agglutinating antibodies to Toxoplasma gondii in adult and fetal mule deer (Odocoileus hemionus) from Nebraska

Toxoplasma gondii is an apicomplexan parasite of mammals and birds. Herbivores acquire postnatal infection by ingesting oocysts from contaminated food or water. Toxoplasma gondii infection is common in white-tailed deer, Odocoileus virginianus, but little is known about the prevalence of infection in mule deer, O. hemionus. We examined sera from 89 mule deer from Nebraska for agglutinating antibodies to T. gondii using the modified direct agglutination test (MAT) with formalin-fixed tachyzoites as antigen. Thirty-one (35%) of the samples were positive at dilutions of > or = 1:25. Samples were examined from 29 fetuses from these mule deer and none were positive in the MAT. Sera from 14 white-tailed deer from Nebraska were also examined and 6 (43%) were positive for T. gondii. Samples were examined from 5 fetuses from these white-tailed deer and none was positive in the MAT. Our results in both deer species from Nebraska are similar to studies conducted in white-tailed deer from other regions of the United States. Our findings indicate that mule deer are frequently infected with T. gondii and that mule-deer meat may be a source of human infection.     

Failure of fallow deer (Dama dama) to develop chronic wasting disease when exposed to a contaminated environment and infected mule deer (Odocoileus hemionus)

We monitored a herd of fallow deer (Dama dama) for evidence of prion infection for 7 yr by periodic postmortem examination of animals from the herd. The fallow deer were exposed to the chronic wasting disease (CWD) agent from mule deer by living in a paddock considered contaminated with infectivity from its history of housing CWD infected deer and, after the first year of the study, by comingling with infected mule deer (Odocoileus hemionus). At least 8 of 12 mule deer serving as sentinels for prion transmission and 25 additional mule deer serving as sources of infectivity developed clinical CWD or were otherwise confirmed to be infected with CWD via lymphoid tissue immunohistochemistry (IHC). In contrast, none of the 41 exposed fallow deer showed clinical signs suggestive of CWD, IHC staining of disease-associated prion in lymphoid or brain tissues, or evidence of spongiform degeneration in sections of brain stem at the level of the obex when sampled 18 mo to 7 yr after entering the mule deer paddock. The absence of clinical disease and negative IHC results in fallow deer housed in the same contaminated paddock for up to 7 yr and almost continuously exposed to CWD-infected mule deer for up to 6 yr suggests a species barrier or other form of resistance preventing fallow deer infection by the CWD agent or delaying progression of the disease in this species.