No abstract

The eastern spotted skunk (Spilogale putorius) is a poorly understood mesocarnivore species that suffered a range‐wide decline in the mid‐1900s. Little is known about its current distribution or habitat needs, and in the southern Appalachians, where the Carolinas and Georgia converge, eastern spotted skunks were only recently discovered to persist. From January–April in 2016 and 2017, we used camera trap surveys to monitor eastern spotted skunks and used occupancy modeling to evaluate factors we hypothesized would influence the probability of spotted skunk detection and occurrence at the landscape scale. We detected spotted skunks at 55.6% of our sites and on 18.5% of sampling occasions. Our results suggest that detection probability was influenced by predation risk, camera setup, and the type of scent‐based attractant used. Eastern spotted skunk occupancy probability had a negative relationship with elevation, such that the probability of occupancy on average increased 7% for every 100‐m decrease in elevation. These results differ from previous findings from the northern Appalachian region, and suggest spotted skunks in the southern Appalachians may be more widely distributed than previously thought. To inform management, there remains a critical need for finer‐scale investigations into resource selection and demographic trends. © 2019 The Wildlife Society.

Eastern spotted skunks (Spilogale putorius) have suffered a dramatic range-wide decline leading to concern that the species is likely vulnerable to extinction, but were recently discovered to persist in a portion of the southern Appalachian Mountains (United States). For 2 years we investigated habitat selection by eastern spotted skunks to develop an understanding of their habitat and conservation needs in northwestern South Carolina. We used a discrete choice modeling framework to evaluate vegetative and topographic features that we predicted would influence rest site selection by male and female spotted skunks. Using VHF telemetry, we tracked 15 spotted skunks (10 males and 5 females) to 215 day-time rest sites between the months of April and August. Spotted skunks selected rest sites in close proximity to drainage channels, where the relative probability of selection decreased 18% and 50% with every 20-m increase in distance to a drainage channel for males and females, respectively. Relative probability of selection by female spotted skunks increased 30% for every one-unit increase in coarse woody debris (CWD), and relative probability of selection by male spotted skunks increased 25% for every 10% increase in understory cover. These results are consistent with previous studies that have identified cover as important for protection from predators; however, we additionally identified CWD and drainage channels as important to habitat selection by spotted skunks. These latter attributes are likely selected based on prey availability, but alternate ecological functions of these features warrant further investigation. Preservation of understory vegetation and CWD within drainage networks might benefit conservation of eastern spotted skunks in the southern Appalachians.

1. The mesopredator release hypothesis, defined as the change in distribution, abundance or behaviour of a middle-ranking predator in response to a decrease in density or distribution of an apex predator, is an increasingly popular topic in ecology. Terrestrial mesopredators have been reported as being released in multiple systems globally, particularly in North America, over the past century. 2. We reviewed 2687 scientific articles, of which we determined that 38 met our criteria for investigating mesopredator release (MR) in terrestrial North American mammalian predators. 3. We observed no support or mixed support for MR in 46% of all relevant studies, including conflicting evidence between measures (mesopredator distribution, abundance or behaviour) within a given study and among studies of the same community in different settings. 4. To advance the study of MR, we provide a conceptual framework that 1) highlights the multiple spatial, temporal and ecological scales at which mesopredator responses can occur; 2) suggests the relative weight of evidence for MR that is provided by measures of mesopredator responses at each scale; and 3) clearly defines the threshold for determining when MR is occurring. 5. In increasingly reshuffled predator communities with declining apex predators, there is a need for future studies to assess in more detail the contexts in which mesopredator behavioural responses scale up to the population-level processes and species-level distribution changes needed to identify these responses as MR.

Precopulatory sexual cannibalism is an extreme form of sexual conflict that can entail significant costs to the cannibalized individual and a variety of costs and benefits to the cannibal itself. Characterizing these costs and benefits is fundamental to our understanding of how this behavior evolves. Using the spider Agelenopsis pennsylvanica, we tested the reproductive consequences of precopulatory sexual cannibalism by staging cannibalization events and comparing the performance of experimental cannibals against natural cannibals (i.e., those that cannibalized on their own) and non‐cannibals. We found two performance benefits associated with precopulatory sexual cannibalism: first, experimental cannibals were more likely to produce egg cases than non‐cannibals, and second, egg cases from experimental cannibals and natural cannibals were significantly more likely to hatch than those produced by non‐cannibals. We then tested whether males were more likely to approach the webs of experimental cannibals vs. non‐cannibalistic control females. Our data demonstrate that sexual cannibalism increases female attractiveness to males. Although this result seems counterintuitive, in fact, rates of precopulatory sexual cannibalism were much lower in females that had already cannibalized their first male: 38% of sexually naïve females engaged in precopulatory sexual cannibalism, whereas only 5% of females engaged in cannibalism a second time. Thus, males that approach cannibals receive two benefits: they are less likely to be cannibalized precopula, and they have the possibility of mating with females that have a higher probability of producing viable egg cases. Taken together, our data suggest that precopulatory sexual cannibalism affords females numerous benefits and may have a hand in shaping male mate choice decisions.