Peromyscus boylii (Rodentia: Cricetidae)

Peromyscus boylii (Baird, 1855), the brush deermouse, is a common cricetid rodent in the southwestern United States and Mexico. It is a member of the Peromyscus boylii species group and has had a complicated taxonomic history because many former subspecies have been elevated to species. It is a medium-sized Peromyscus with small ears and a long, slightly bicolored and slightly haired tail that ends in a tuft of long hairs. It prefers brushy habitat, showing an affinity for oak–scrub oak and canyon–creek bottoms. It is not of special conservation concern

Elephants, woodlands and biodiversity in southern Africa.

When elephant densities exceed approximately 0.5 per km[2], savanna woodlands are generally converted to shrub-lands or grasslands. The impact of such elephant-mediated habitat change on biodiversity in African game reserves has seldom been measured. We examined species richness of woody plants, birds, bats, mantises and ants in reserves where elephants had destroyed the miombo woodland and in adjacent but intact miombo woodlands outside the reserves. Species richness of woodland birds and ants was significantly lower where elephants had removed the tree canopy. Our findings may have important policy implications for conserving biodiversity in many African reserves in the face of rapidly growing elephant populations (approximately 5% per annum). The problem is further compounded by international public pressures against reducing elephant densities within game reserves while, outside these protected areas, savanna woodlands and their associated faunas are being lost to agriculture. Where then will refugia for habitat-sensitive species exist if not within the region's largest protected areas

Tree roost selection by bats: an empirical synthesis using meta-analysis.

Over the past 2 decades, we have begun to accumulate a basic understanding of the roosting and foraging ecology of temperate insectivorous bats in forests. As our understanding improves, it is not surprising there should be attempts at synthesizing our knowledge to prioritize future research directions (e.g., Hayes 2003, Miller et al. 2003). Miller et al. (2003) reviewed results of 56 papers (1980-2001) and concluded that current data were unreliable because of small sample sizes, the short-term nature of studies, pseudoreplication, inferences beyond the scale of data collected, study design, and limitations of bat detectors and statistical analyses. Our concern is that this type of narrative synthesis that highlights limitations ignores any quantitative patterns that may exist. in this study we assess whether general patterns in North American bat use of roost trees and stand characteristics are robust enough to distill from the published literature. We used a series of meta-analyses on the same set of studies cited by Miller et al. (2003) to assess whether limitations of the current data warrant exclusion of bats from management recommendations. We used a second series of meta-analyses incorporating more recent data to determine the best current synthesis of knowledge on bat use of forests for roosting. In a third and fourth series of meta-analyses, we separated studies done on bats roosting in cavities versus roosting in foliage. in general, we found that, relative to other trees in the forest, the roost trees of bats were tall with large DBH in stands with open canopy and high snag density. In contrast, roost trees of bats did not differ from random trees with respect to live-tree density. The main differences we detected between foliage- and cavity-roosting bats were in percent canopy cover and distance to water. The roost trees of cavity-roosting species had more open canopies and were closer to water than random trees. Our results clearly show that significant patterns can be detected from the literature when data sets are combined using a meta-analytic approach

Influence of Intensive Pine Management on Dipteran Community Structure in Coastal North Carolina

Intensive pine (Pinus spp.) management is a primary land use in the southeastern United States. In eastern North Carolina, intensively managed pine stands often occur on land previously ditched and drained. Because modification of natural vegetation and water sources are known to affect dipteran community structure, we studied effects of intensive pine management on abundance and diversity of dipteran families in the northern coastal plain of North Carolina during 2006 and 2007. We used malaise traps and emergence traps to sample different types of forest stands (n = 143 sample nights) and water sources (n = 147 sample nights) in a managed pine forest and a natural forested wetland. Cecidomyiids were more abundant in stands with canopy cover, chironomids were more abundant at edges between forested stands and open canopy stands, and chloropids were more abundant in open canopy stands. Families Ceratopogonidae, Dolichopodidae, Ephydridae, Muscidae, Psychodidae, and Tipulidae were more abundant in the natural forested wetland than in all types of modified water sources. Dipteran diversity and evenness were highest in stands with open canopy and at forest edges, and highest in the natural forested wetland. Unmanaged, natural stands on the intensively managed landscape did not support a higher abundance or diversity of dipteran families than intensively managed stands. Restoration of natural wetlands may increase dipteran diversity in unmanaged stands. Heliponds, a modified water source, supported a comparable dipteran abundance to that of the natural forested wetland. Increased numbers of heliponds may facilitate higher dipteran abundance in managed pine landscapes

Ultrasonic vocalizations of male mice differ among species and females show assortative preference for male calls

Male house mice (Mus musculus) emit ultrasonic vocalizations (USVs) during courtship, which attract females, and we aimed to test whether females use these vocalizations for species or subspecies recognition of potential mates. We recorded courtship USVs of males from different Mus species, Mus musculus subspecies, and populations (F1 offspring of wild-caught Mus musculus musculus, Mus musculus domesticus (and F1 hybrid crosses), and Mus spicilegus), and we conducted playback experiments to measure female preferences for male USVs. Male vocalizations contained at least seven distinct syllable types, whose frequency of occurrence varied among species, subspecies, and populations. Detailed analyses of multiple common syllable types indicated that Mus musculus and Mus spicilegus could be discriminated based on spectral and temporal characteristics of their vocalizations, and populations of Mus musculus were also distinctive regardless of the classification model used. Females were able to discriminate USVs from different species, and showed assortative preferences for conspecific males. We found no evidence that females discriminate USVs of males from a different subspecies or separate populations of the same species, even though our spectral analyses identified acoustic features that differ between species, subspecies, and populations of the same species. Our results provide the first comparison of USVs between Mus species or between Mus musculus subspecies, and the first evidence that male USVs potentially facilitate species recognition

Production of ultrasonic vocalizations by Peromyscus mice in the wild.

Background: There has been considerable research on rodent ultrasound in the laboratory and these sounds have been well quantified and characterized. Despite the value of research on ultrasound produced by mice in the lab, it is unclear if, and when, these sounds are produced in the wild, and how they function in natural habitats. Results: We have made the first recordings of ultrasonic vocalizations produced by two free-living species of mice in the genus Peromyscus (P. californicus and P. boylii) on long term study grids in California. Over 6 nights, we recorded 65 unique ultrasonic vocalization phrases from Peromyscus. The ultrasonic vocalizations we recorded represent 7 different motifs. Within each motif, there was considerable variation in the acoustic characteristics suggesting individual and contextual variation in the production of ultrasound by these species. Conclusion: The discovery of the production of ultrasonic vocalizations by Peromyscus in the wild highlights an underappreciated component in the behavior of these model organisms. The ability to examine the production of ultrasonic vocalizations in the wild offers excellent opportunities to test hypotheses regarding the function of ultrasound produced by rodents in a natural context

Intraspecific Variation in Roost-site Selection by Little Brown Bats (<i>Myotis lucifugus</i>)

Although many species of bats select roost sites in large trees that are in open areas, intraspecific variation in roost-site selection may exist. We collected data on the roosting behaviour of little brown bats in the Cypress Hills, Saskatchewan, to determine the extent of intraspecific variation in roost-site selection. In addition, we examined the thermal microclimate of the tree-roosts selected by bats, to determine if roost-microsite variation can explain why certain cavities are selected over others. We found little brown bats roosting in trees as well as buildings. With the exception of a male who roosted in a spruce (Picea glauca) stump, tree-roosts selected by male and female little brown bats were all in trembling aspen (Populus tremuloides) trees. We found variation in roost-site fidelity and differential use of torpor by male bats. Temperatures within conifer snag cavities differed from aspen cavities during the day, and mirrored ambient temperature, which tended to be warmer than aspen cavities. We propose that bats select cavities in aspens because they are susceptible to heart rot. Aspen trees with heart rot provide cavities with an intact sapwood shell that protects bats against harsh ambient conditions as well as predators, and provides a unique thermal microclimate. Our results suggest that the origin of a roost site may be unimportant to a bat, provided certain other requirements are met

Hard forest edges act as conduits, not filters, for bats

High levels of bat activity have been reported at forest edges worldwide, but few studies have examined the ecological function of edges as a linear landscape feature. Patterns of association of bats at edges between old and young forest stands (hard edges) could be a result of edges acting as either a semi-permeable barrier or a filter to movement into the forest between different-aged forest stands for bats (or their insect prey), causing an accumulation of bat activity along the edge. Alternatively, edges may be a linear landscape feature similar to roads and riparian corridors that bats use as flight conduits as they move from one place to another. Using ultrasound microphone arrays and recording equipment, we were able to determine flight patterns of bats at hard edges within a landscape of intensively managed loblolly pine (Pinus taeda) plantation in eastern North Carolina, USA, during 2009. Across edges and species sampled, bats consistently flew parallel to edges, suggesting that edges act as conduits for bats. Feeding rates of bats at edges were low, further supporting use of edges as conduits for bats that are either flying along edges to move to and from roosting and foraging habitat patches or moving among foraging patches. Continuous edges should be maintained between linear and nonlinear landscape features, especially where known roosting and foraging areas are being connected by an edge

Impact of predation risk on emergence by little brown bats, Myotis lucifugus (Chiroptera: Vespertilionidae), from a maternity colony.

When bats emerge from their roosts in the evening to forage and drink, it appears as though their departure involves brief periods when many individuals emerge interspersed with periods during which few individuals emerge. Clustering is seen in many species of animals and probably has an anti-predator or information-transfer function. Regardless of its function, clustering in the emergence of bats may intensify as a result of large numbers of individuals trying to pass through a small exit hole in a short period of time. A total of 31 observations of emergence were made from May to Aug. 1992 and 1993 at a maternity colony of little brown bats (Myotis lucifugus), in Cypress Hills, Saskatchewan, Canada. To determine the effects of a predator on clustering in the emergence, a plastic great horned owl (Bubo virginianus) was used as a predator model and mounted close to roost exits on 8 nights. Recorded calls of a great horned owl were played back towards the roost. The predator model and associated calls did not affect the number of bats that emerged, the median time of emergence, or the degree of clustering in the emergence. There was a significant positive relationship between the extent of clustering in the emergence and the number of bats that emerged. Emergences of more than 25 bats were clustered. Thus, we found no evidence to support clustering during emergence as being an anti-predator response. However, clustering may be intensified with increased numbers of individuals trying to pass through a narrow space in a short period of time

Female and male adult brush mice (Peromyscus boylii) use ultrasonic vocalizations in the wild

We examined the individual context of ultrasonic vocalizations (USVs) produced by free-living wild male and female adult brush mice (Peromyscus boylii). We tested the hypothesis that USV production is dependent on behavioral context, and is important during both adult male and female interactions. Our methods included a 12-channel microphone array, radio-telemetry and thermal imaging that allowed us to determine: (1) who produced USVs, (2) characteristics of USVs, (3) type of USVs, (4) behavioral context of USVs and (5) the identity of the second mouse if an individual was not alone when a USV was produced. Females vocalized as much as males and produced the same types of USVs as males. There were no differences between spectral characteristics of male and female USVs. Females and males vocalized in the presence of one another. Importantly, when females were together they vocalized more than expected based on the proportion of time they spent together. Our results suggest that, in addition to facilitating courtship and mating, USVs are general territorial calls for neighbors because females vocalized in the presence of their neighbors. Despite a large literature on laboratory mouse (Mus musculus) USVs, studies are heavily biased towards males. Our results on brush mice, a species with a similar breeding system to the lab mouse and other rodents, suggest that female-female communication is an important and underappreciated component of the evolution and maintenance of mouse USVs