Polymorphic microsatellite markers for the striped skunk, Mephitis mephitis, and other mephitids

We report 10 polymorphic microsatellite loci primers developed for striped skunks (Mephitis mephitis), a widespread mesocarnivore in North America. Numbers of alleles in these loci ranged from seven to 14 and the observed heterozygosity ranged from 0.76 to 1.0. These primers will be useful for studying population dynamics of skunks where rabies is endemic and will be useful to estimate genetic relatedness among females sharing winter dens. Most of these primers amplify across species within the Mephitidae.     

Contrasting landscape epidemiology of two sympatric rabies virus strains

Viral strain evolution and disease emergence are influenced by anthropogenic change to the environment. We investigated viral characteristics, host ecology, and landscape features in the rabies‐striped skunk disease system of the central Great Plains to determine how these factors interact to influence disease emergence. We amplified portions of the N and G genes of rabies viral RNA from 269 samples extracted from striped skunk brains throughout the distribution of two different rabies strains for which striped skunks were the reservoir. Because the distribution of these two strains overlapped on the landscape and were present in the same host population, we could evaluate how viral properties influenced epidemiological patterns in the area of sympatry. We found that South Central Skunk rabies (SCSK) exhibited intense purifying selection and high infectivity, which are both characteristics of an epizootic virus. Conversely, North Central Skunk rabies (NCSK) exhibited relaxed purifying selection and comparatively lower infectivity, suggesting the presence of an enzootic virus. The host population in the area of sympatry was highly admixed, and skunks among allopatric and sympatric areas had similar effective population sizes. Spatial analysis indicated that landscape features had minimal influence on NCSK movement across the landscape, but those same features were partial barriers to the spread of SCSK. We conclude that NCSK and SCSK have different epidemiological properties that interact differently with both host and landscape features to influence rabies spread in the central Great Plains. We suggest a holistic approach for future studies of emerging infectious diseases that includes studies of viral properties, host characteristics, and spatial features.     

Methods to mitigate human–wildlife conflicts involving common mesopredators: a meta-analysis

Conflicts between humans and mesopredators are frequent and widespread. Over the last decades, conflicts have led to the development and application of different mitigation methods to diminish the costs and damage caused by such conflicts. We conducted a systematic literature search and meta-analysis to assess the influence of different mitigation methods on 3 common nuisance species: raccoons (Procyon lotor), red foxes (Vulpes vulpes), and striped skunks (Mephitis mephitis). A majority of the studies, from 1963‒2022, were conducted in North America, followed by Australia and Europe. The predation of wildlife species of conservation concern by nuisance species is the main reported source of conflict in the published literature. Lethal control is the most commonly tested method and is generally effective at reducing conflicts based on the calculated effect size. Barriers have mixed effects, with electric fences and nest exclosures both being effective, whereas conventional fences seem to be less effective. Repellents mimicking predators (e.g., guard animal, predator smell) are also effective. Conditioned taste aversion is a promising approach, but no precise product or chemical has proven to be effective. Many interventions suffered from a lack of validation through experimental approach. Research on human–mesopredator conflict mitigation would benefit from repeated studies using the same methods in similar contexts, thus reducing heterogeneity in the results, and by testing new and innovative methods.     

Targeted surveillance of raccoon rabies in Québec,Canada

Data from wildlife disease surveillance programs are used to inform implementation of disease control (e.g., vaccination, population reduction) in space and time. We developed an approach to increase detection of raccoon rabies in raccoons (Procyon lotor) and skunks (Mephitis mephitis) of Québec, Canada, and we examined the implications of using this approach for targeted surveillance. First we modeled the probability of a rabid animal relative to environmental characteristics of sampling locations. Rabid animals were more likely to be found in low-lying flat landscapes that had higher proportions of corn-forest edge habitat and hay agriculture, and that were within 20 km of one or more known rabies cases. From the model, we created 2 complementary risk maps to identify areas where rabid animals were most likely to be sampled. One map accounted for habitat and known rabies case locations, and can be used to define an infection zone from which surveillance can be targeted along the periphery to determine if disease is continuing to spread. The other map only accounted for habitat and can be used to locate areas most likely to contain rabid animals when the disease is present. In a further analysis we compared the 2 most successful methods for detecting raccoon rabies in Québec, given the disease was present. Government trapping operations (active surveillance) detected more cases in the short-term, but citizen notification (passive and enhanced) was more effective after 12 trapping days from which the initial rabies case was found. Our approach can benefit wildlife and public health agencies wanting to assess the disease status of regions by targeting surveillance to habitats most likely to contain infected animals and by defining the duration over which sampling methods are effective. © 2011 The Wildlife Society.     

Common ringtail possum (Pseudocheirus peregrinus) as a management model for the Pseudocheiridae: Reproductive scope,behavior, and biomedical values on a browse-free diet

The purposes of this study were to determine 1) the life history characteristics of a captive colony of the arboreal folivore Pseudocheirus peregrinus maintained on a browse free diet under enhanced laboratory conditions, 2) the direction and magnitude of life history differences from wild population values, and 3) the feasibility of developing captive colonies of this and related species for conservation and research programs. Rates of reproduction, growth, and development; demographic trends; behavioral patterns pertinent to exhibition; and management and medical techniques are reported. Fecundity was 67% greater than that of wild populations and there was an approximate four-fold increase in the rate of offspring survival to sexual maturity. These trends were due largely to reduced post-pouch emergence mortality and the decay of reproductive seasonality. The results indicate that a properly designed “artificial” diet can support significantly enhanced reproduction in a trophic specialist. Other demographic, developmental, and behavioral measures found to be consistent with those reported from wild populations indicate that there was no significant life history distortion caused by the management regime. Empirical data are presented showing that the common ringtail is nocturnal, has low rates of activity, and has specific space and substrate preferences. These results suggest ways in which the animals' physical environment can be manipulated to improve exhibition. We conclude that the reproductive rates of other ringtail possum species might also be enhanced under comparable management conditions.     

Denning ecology of the striped skunk in the Canadian prairies: implications for waterfowl nest predation

1. From 1993 to 1995, we studied the summer denning ecology of 40 radio-collared striped skunks Mephitis mephitis (32 females, eight males) during the waterfowl nesting season in Saskatchewan, Canada.
2. Forty-seven natal dens were used by 30 females. Natal den sites were either underground burrows (55%) or holes underneath buildings (45%), and were preferably located in farmsteads.
3. Male and female striped skunks used similar resting sites which consisted of above-ground retreats (57%), underground burrows (23%), buildings (17%) and culverts (3%).
4. Habitat preferences for resting sites did not differ between males and females: both sexes preferred farmsteads and wetlands, whereas managed waterfowl nesting areas, woodland and miscellanous habitats were avoided. Cropland was avoided for both natal dens and resting sites.
5. Females did not simultaneously share natal dens or resting sites, but both types of retreats were occupied by different females over time. Natal dens were occupied for 47 ± 3 days for females using a single den vs. 60 ± 3 days for females using >1 natal dens. Den switching may have been induced by a build-up of faeces.
6. Management of natal den sites such as abandoned farmsteads and buildings may provide an avenue of non-destructive predator management that is less expensive and controversial than exclusion or control.     

Factors affecting pair compatibility in captive kangaroo rats,Dipodomys heermanni

Captive propagation is a critical component of the Morro Bay Kangaroo Rat Recovery Plan, but past attempts to breed this and other kangaroo rat species have had mixed success. In three experiments using a closely related surrogate species, the Lompoc kangaroo rat, we evaluated the effects of familiarity and long-term housing experience on the behavior of captive males and females during dyadic encounters in an attempt to devise husbandry methods most conducive to reproduction. Females exhibited less aggression with and were more likely to allow physical contact with familiar males, provided the males had had previous social experience, such as that provided by living in close sensory contact with female conspecifics. Socialized males (those housed adjacent to females, separated from them by a wire mesh screen) were cautious, rather than persistent, when interacting with unfamiliar or anestrous females. Males housed in isolation from conspecifics were persistent whether or not they were familiar to the female. Pairs with very long periods of familiarity exhibited more nonaggressive contact than newly acquainted pairs. Results suggest that housing structures allowing longterm sensory contact between potential mates may improve breeding success in kangaroo rats and other solitary, aggressive species. © 1995 Wiley-Liss, Inc.

1 This article is a US Government work and, as such, is in the public domain in the United States of America.

     

Habitat use,foraging behavior,and activity patterns in reproducing western tarsiers,Tarsius bancanus,in captivity: A managment synthesis

As the only obligatorily predatory primates, tarsiers are notoriously difficult to keep successfully in captivity. Here we report empirical and experimental results from a 5-year study of behavior and life history in captive Tarsius bancanus. Four reproducing adult tarsiers used space nonrandomly, preferring small-diameter vertical or near-vertical locomotor substrates at midlevel enclosure heights (1.2–2.1 m) for sleeping, scanning, and prey capture. The tarsiers were completely nocturnal, and spent 78% of the scotophase scanning, 13% sleeping, and 9% in prey capture and other activities. Only live crickets were eaten; prey capture rates were highest in the first hour after waking, but overall activity rates were highest later in the scotophase. Adult males and nonpregnant or lactating females ingested approximately 44.7–49.7 kJ/day. Growing and lactating individuals ingested approximately 84.4–94.1 KJ/day. An energetically conservative, sit-and-wait predatory strategy was employed, in which 88% of capture attempts were successful. Most successful prey captures involved reaching for, or leaping from, 90° or 60° supports in a horizontal or downward direction onto prey less than 0.6 m away. Virtually all prey captures were in arboreal locations, despite much higher densities of crickets on enclosure floors. Prey capture rates during the first hour of the nocturnal activity period were positively correlated with arboreal cricket densities. At constant arboreal cricket densities, capture rates were negatively correlated with ambient light intensity, with optimum levels for prey capture ranging from 0.1 to 2.0 Lux. In terms of social behavior, these T. bancanus were nongregarious. Females enforced interindividual spacing by chasing and displacing males. Chase/displacement rates increased significantly during late pregnancy and lactation, apparently in an attempt to keep males from harassing infants. There was no direct male parental care. Infants were precocial at birth, and grew at a rate of 0.35–0.5 g/day, until nutritional weaning at approximately 60 days of age. The implications of specialized predatory morphology and behavior for management are discussed. © 1993 Wiley-Liss, Inc.     

广东省主要水系罗非鱼的建群状况

【背景】罗非鱼是华南地区自然水域的常见种,是我国主要的外来鱼类之一,但对其在自然水域的分布和数量缺乏详细的描述。【方法】对广东省的主要河流珠江(西江、北江、东江)、韩江、鉴江和潭江等的多个样点进行了调查,主要对各样点渔获物中罗非鱼的比例进行了统计,并对各种群的年龄结构、性比、性腺发育和食性等进行了研究。【结果】广东省各主要水系均有罗非鱼野生个体的存在,其中,鉴江袂花江段数量最多,约占渔获物总质量的60%,西江、北江数量相对较少,不到渔获物总质量的1%;在各种群中均发现了2龄以上个体和性成熟个体,并在调查中采集到大量仔、幼鱼。【结论与意义】以上结果表明罗非鱼在广东各主要河流已能完成越冬和繁殖,并建立自然种群。     

Cage restraints for rhinoceroses

Captive breeding programs for the rhinoceros can be enhanced by studying their reproductive physiology. To do so requires repetitive manipulations under physically controlled circumstances. To facilitate these procedures, zoos throughout the world have constructed restraint devices, or chutes. Chute designs are usually determined by the space in which they are to be situated and the budget available for their construction. In this study, eight chute designs at seven institutions were compared for efficiency in controlling rhinoceroses during ultrasonography, semen collection, and blood sampling. Procedures were conducted on 16 rhinoceroses of four species: the white rhinoceros (Ceratotherium simum simum), the black (Diceros bicornis), the greater one-horned Asian (Rhinoceros unicornis), and the Sumatran (Dicerorhinus sumatrensis). Chutes were evaluated for dimensions, fabricating materials, procedures to be attempted, and structural features such as shoulder restraints. Permanent, indoor, side-adjustable, pass-through chutes were determined to be the most efficient and convenient type because they saved time and reduced stress on the animals. Zoo Biol 17:343–359, 1998. © 1998 Wiley-Liss, Inc.