Strategies to contain the spread of disease often are developed with incomplete knowledge of the possible outcomes but are intended to minimize the risks associated with delaying control. Culling of game species by government agencies is one approach to control disease in wild populations but is unpopular with hunters and wildlife enthusiasts, politically unpalatable, and erodes public support for agencies responsible for wildlife management. We addressed the functional differences between hunting and government culling programs for managing chronic wasting disease (CWD) in white-tailed deer by comparing prevalence over a 10-year period in Illinois and Wisconsin. When both Illinois and Wisconsin were actively culling from 2003 - 2007, there were no statistical differences between state CWD prevalence estimates. Wisconsin government culling concluded in 2007 and average prevalence over the next five years was 3.09 ± 1.13% with an average annual increase of 0.63%. During that same time period, Illinois continued government culling and there was no change in prevalence throughout Illinois. Despite its unpopularity among hunters, localized culling is a disease management strategy that can maintain low disease prevalence while minimizing impacts on recreational deer harvest.

We are developing a novel method using non-invasive skin swabs to measure stress in several amphibians from terrestrial, semi-aquatic and fully aquatic species both at the zoo and in the wild. Upon further testing, this technique will allow future studies to understand how the environment is impacting amphibian health and susceptibility to disease.

The few studies that have looked at genital allometry in mammals have typically shown a positively allometric relationship with body size and high coefficients of variation. Cryptic female choice, sexual conflict or sperm competition are mechanisms underlying genital evolution and as these are not mutually exclusive, they are often difficult to disentangle. In addition, these mechanisms are affected by both male and female social structure and/or mating strategies and, as such, pre-and post-copulatory behaviours have been shown to alter selection on genitalia. We examined genital traits and allometry in a polygynandrous and social ground squirrel Xerus inauris. We found that male testes are positively allometric and account for 1.5% of their body weight, one of the highest percentages known for sciurids. The penis, at 42.4% of head/body length, was isometric while the female reproductive tract, 22.4% head/body length, demonstrated no such relationship. Based on the allometric relationships of both males and females presented here, in conjunction with high levels of competition for females and lack of male aggression and territoriality, we suggest that sperm competition is the most likely mechanism for the evolution of the extremely large genitalia in this species.

Little is known about the behaviors river otters (Lontra canadensis) commonly exhibit when visiting latrine sites. By use of video data we constructed an ethogram to describe and quantify latrine behaviors. The most common behaviors were standing (20.5 %) and sniffing (18.6 %), lending support to the hypothesis that latrines are used for olfactory communication. Surprisingly, defecation was rarely observed (1.4 %); body rubbing occurred more than defecation (10.5 %). It is possible that, in addition to feces, urine, and anal jelly, river otters use body rubbing to scent mark. To monitor site use, we determined seasonal, monthly, and daily visitation rates and calculated visit duration. River otters most frequently visited the latrine in the winter (December and January) but the longest visits occurred in the fall. Very few visits were recorded during the summer. Latrines were most often visited at night, but nocturnal and diurnal visit durations were not different. River otters were more likely to visit the latrine and engage in a specific behavior rather than travel straight through the site. Our data supported the idea that river otters are primarily solitary mammals, with most latrine visits by single otters. However, we documented groups of up to 4 individuals using the area, and group visits lasted longer than solitary visits. Therefore, whether visits are solitary or social, latrine sites are likely to act as communication stations to transmit information between individuals.

Knowledge of reproductive characteristics of wild populations is necessary to inform responsible management decisions that promote herd health. As management, goals, and free-ranging populations change over time and landscapes, updated knowledge of reproductive characteristics are needed to inform responsible management practices. We estimated reproductive characteristics of female white-tailed deer in Illinois, including pregnancy rate, litter size, fetal growth and fetal sex ratio. We found maternal age to have an important influence on several reproductive factors. Approximately 66% of tested females (n = 3884) were pregnant and pregnancy rates increased with increasing maternal age, from 20.5% in fawns to 85.8% in adult deer. Litter size ranged from 1 to 5 fetuses per pregnant female. The average litter size was 1.9 ± 0.54 fetuses per pregnant female and also increased with age, from 1.2 in fawns to 2.0 in adults, respectively. Breeding season peaked in November with the mean estimated conception dates of fetuses varying with maternal age. Fawns conceived fetuses later in the breeding season (December 2) compared to yearlings and adults (November 11 and 8, respectively). We measured the body mass index (BMI) of all fetuses and found that litter size and female age influence fetal size. We found no bias in fetal sex ratio (average 1.0:1.0, male:female) but we observed a sex bias in fetal size (mean BMI male = 0.71, female 0.67) across all maternal age classes. A comparison of the current study and previous reports indicate that variation in maternal age within a population is an important driver of reproductive metrics, likely because maternal age and body size or condition are related. Furthermore, variation in resource availability will influence reproductive rates, especially among fawn females.

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Many rodent species are currently under conservation threat. However, population monitoring and status assessment are extremely challenging because of small body size, low abundance and elusive behavior of rodents. Furthermore, invasive methods of capture and tissue collection commonly used to address such studies can induce an unacceptable amount of stress to sensitive species. As a result, noninvasive techniques have become more widely used, but relatively few studies have applied noninvasive techniques to rodents. Here we present two noninvasive alternatives for the collection of DNA from Franklin's ground squirrels (Poliocitellus franklinii). We compared the quantity, purity and degradation of DNA extracted from plucked hair and fecal pellets to tail snip tissues. We recovered more DNA from tail snips than either plucked hair or fecal pellets. Both hair and fecal pellets recovered DNA with purity ratios similar to tail snips. As expected, DNA recovered from fecal pellets exhibited a high degree of degradation compared to hair and tail tissues. Careful planning of field and laboratory protocols is therefore necessary to compensate for challenges associated with noninvasive tissue types. While there is no tissue that can universally be applied to all research projects, both hair and feces are viable alternatives to traditional invasive procedures and can be applied to threatened and endangered rodent species.

Differences in how males and females respond to foreign antigens are common across taxa. Such sexual differences in the immune system are predicted to be greater in species with high promiscuity and sociality as these factors increase the likelihood of disease transmission. Intense sperm competition is thought to further this sexual dichotomy as increased investment in spermatogenesis likely incurs additional immunological costs. Xerus inauris, a ground squirrel found throughout southern Africa, is extremely social and promiscuous with one of the highest male reproductive investments among rodents. These life-history attributes suggest males and females should demonstrate a large dichotomy in immunity. Contrary to our prediction, we found no difference in spleen mass between the sexes. However, we did find significant biases in leukocyte types and red blood cell counts, possibly reflecting responses to parasite types. Among males, we predicted greater investments in spermatogenesis would result in reduced immunological investments. We found a negative association between testes and spleen size and a positive relationship between testes and number of lice suggesting trade-offs in reproductive investment possibly due to the costs associated with spermatogenesis and immunity. We suggest when measuring sexual differences in immunity it is important to consider the effects of reproductive pressures, parasite types, and life history costs.