Ecdysteroid-Responsive Genes in a Drosophila Cell Line

SYNOPSIS. In the Drosophila Kc-H cell line ecdysteroids causerapid increases in the synthesis of two groups of polypeptideswhich we call ecdysteroid-inducible polypeptides. We have shownthat these changes occur at least in part at the level of mRNAtiters and we have isolated cDNA clones corresponding to themRNAs for these polypeptides. The increases in these mRNAs maywell be among the primary hormone effects.     

Inferring Geographic Isolation of Wolverines in California Using Historical DNA

ABSTRACT Delineating a species' geographic range using the spatial distribution of museum specimens or even contemporary detection-non-detection data can be difficult. This is particularly true at the periphery of a species range where species' distributions are often disjunct. Wolverines (Gulo gulo) are wide-ranging mammals with discontinuous and potentially isolated populations at the periphery of their range. One potentially disjunct population occurred in the Sierra Nevada Mountains, California, USA, and appears to have been extirpated by the 1930s. Many early 20th century naturalists believed that this population was connected to other populations occurring in the Cascade Range of northern California, Oregon, and Washington, USA, but a recent analysis of historical records suggests that California wolverines were isolated from other populations in North America. We used DNA extracted from museum specimens to examine whether California wolverines were isolated. Both nuclear and mitochondrial DNA data indicate that California wolverines were genetically distinct from extant populations, suggesting long-term isolation. We identified 2 new control region (mitochondrial DNA) haplotypes located only within California. We used these data and referenced sequences from the Rocky Mountains, USA, to make inferences regarding potential wolverine translocations into California. In addition, we used these genetic data to make inferences about wolverine conservation throughout western North America.     

Intraspecific versus interspecific variation in Miocene Great Basin mylagaulids: implications for systematics and evolutionary history

The Mylagaulidae are a family of burrowing rodents abundant in Miocene faunas from western North America. Recent taxonomic revisions of mylagaulids from the Great Plains suggest that their systematics may be best understood on a regional basis. Previous studies addressed the taxonomy and evolutionary history of mylagaulids from the Great Basin, but recent discoveries of specimens, new phylogenetic data, and more detailed stratigraphical information necessitate a thorough reanalysis of their relationships and occurrences. We present a revision of the systematics of the mylagaulids from the Great Basin. In addition to rare large mylagaulids of uncertain taxonomic affinity, we recognize four species of mylagaulids distributed throughout Oregon and Nevada from the late Hemingfordian through to the early late Hemphillian: Alphagaulus vetus, Hesperogaulus gazini, Hesperogaulus wilsoni, and a new species from the genus Hesperogaulus. All species are known from large sample sizes of isolated premolars, allowing consideration of ontogenetic variation in determining the key morphological differences that allow recognition of different species. Although the number of enamel lakes varies within a given taxon, the presence of some of these lakes is taxonomically significant. This result emphasizes the importance of understanding ontogeny in describing species of fossil hypsodont mammals. © 2012 The Linnean Society of London, Zoological Journal of the Linnean Society, 2012, 164 , 427–450.     

Habitat Fragmentation and the Persistence of Lynx Populations in Washington State

Abstract Lynx (Lynx canadensis) occur in the northern counties of Washington state, USA; however, current distribution and status of lynx in Washington is poorly understood. During winters 2002–2004 we snow-tracked lynx for 155 km within a 211-km² area in northern Washington, to develop a model of lynx-habitat relationships that we could use to assess their potential distribution and status in the state. We recorded movements and behaviors of lynx with a Global Positioning System and overlaid digitized lynx trails on various habitat layers using a Geographic Information System. Based on univariate analyses, lynx preferred Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) forests, with moderate canopy and understory cover, and elevations ranging from 1,525 m to 1,829 m but avoided Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa) forests, openings, recent burns, open canopy and understory cover, and steep slopes. A map of suitable lynx habitat based on a logistic regression model built using these candidate variables revealed that habitats at elevations >1,400 m where lynx historically occurred in Washington are intersected and fragmented by landscape features and forest conditions that are generally avoided by lynx. Our habitat suitability map predicts 3,800 km² of lynx habitat in Washington that could support 87 lynx, far fewer than previous estimates. Since 1985, natural fires have burned >1,000 km² of forested habitat in Okanogan County, the only region in Washington where lynx occurrence has been documented during that period. Loss of suitable habitat from natural and human-caused disturbances, and the lack of verifiable evidence of lynx occurrence in historic lynx range, suggests that fragmented landscape conditions may have impeded recolonization of these areas by lynx. Consequently, translocations may be necessary to ensure lynx persistence in Washington. We suggest that managers assess the potential for translocation by first identifying the scale and distribution of potential foraging habitats for lynx based on our or similar habitat models, survey various habitat conditions to obtain reliable estimates of snowshoe hare densities, and identify a genetically compatible source population of lynx. If habitat and source populations are adequate, reintroducing lynx to areas of their historic range may be an appropriate conservation strategy.     

Habitat Conditions Associated With Lynx Hunting Behavior During Winter in Northern Washington

Abstract Effectively managing habitat for threatened populations of Canada lynx (Lynx canadensis) requires knowledge of habitat conditions that provide for the ecological needs of lynx. We snow-tracked lynx to identify habitat conditions associated with hunting behavior and predation during winters of 2002–2003 and 2003–2004 in the northern Cascade Range in Washington state, USA. We recorded number and success of predation attempts, prey species killed, and trail sinuosity on 149 km of lynx trails. Lynx killed snowshoe hares (Lepus americanus), red squirrels (Tamiasciurus hudsonicus), and cricetids more than expected in Englemann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) forests, where snowshoe hare densities were highest. Lynx killed prey less than expected in Douglas-fir (Pseudotsuga menziesii) and ponderosa pine (Pinus ponderosa) forests and forest openings. We used the sinuosity of lynx trails as an index of quality of habitat hunted. Lynx trails that included predation attempts were more sinuous than trail segments without predation attempts. Lynx trails had greater sinuosity in forest stands with high hare densities dominated by Engelmann spruce and subalpine fir than in stands with low hare densities dominated by Douglas-fir and ponderosa pine or in forest openings. We encourage forest managers to maintain or create sufficient understory cover to support high densities of snowshoe hares as foraging habitat for lynx.     

A Theft-Resistant Adjustable Security Box for Digital Cameras

Abstract: Remote camera traps are becoming an increasingly popular, affordable, and valuable tool for wildlife research. However, theft and vandalism of these camera systems can result in substantial financial loss and loss of valuable data. We developed an adjustable steel camera security box to protect our Cuddeback® (Non Typical, Inc., Park Falls, WI) digital scouting cameras. Our cameras were deployed for 160 days and experienced no theft or vandalism during that time. Our armored camera box successfully protected our equipment and data, can be sized to accommodate any brand of camera, and can be used in a variety of field situations.     

Estimating consumable biomass from body length and order in insects and spiders

1. Current models used to estimate insect prey biomass for diet studies use whole weight. However, a large proportion of an arthropod's body is taken up by an indigestible exoskeleton, leading to erroneous estimation of the food intake of insectivorous animals. 2. Linear mixed effect models were used to obtain equations to predict consumable biomass from body length for a variety of Neotropical insects and spiders. These data were obtained by feeding taxa of various orders to groups of 100 social spiders and comparing pre‐ and post‐consumption weights using size‐matched controls. 3. Significant linear relationships were found relating body size to consumed biomass for all orders, with slopes ranging from 1.276 to 4.011 and R² values from 0.476 to 0.929. For orders other than spiders and Orthoptera, the increase in weight with size exhibited negative allometric scaling, suggesting a decrease in tissue density, or an increase in internal air space, with size. 4. Although there were significant differences across taxonomic orders in the proportion of biomass consumed, within most orders the proportion consumed did not differ significantly with body size. The estimated regression coefficients may be used by other workers to estimate consumable biomass of arthropod prey for studies requiring large sample sizes or non‐lethal sampling of rare or endangered species.     

The Roles of Cell Division and Cell Expansion in the Growth of Alfalfa Leaf Mesophyll

Leaf mesophyll of Medicago sativa (L.) was investigated to determinethe roles of cell division and cell expansion in tissue growth.Samples of leaf tissue were macerated, stained, and squashed.The slides were studied under a phase microscope to determinethe percentage of recently divided cells and the average celldiameter for leaflets of varying lengths. Cell division wasgreatest in young leaflets and virtually ceased as a leaf lengthof 12 mm was attained. For leaflets less than 12 mm in length,the rate of increase in cell size appeared to be inversely associatedto the degree of cell division. For alfalfa leaflets greaterthan 12 mm in length, the mean cell size increased in proportionto leaf length since cell division had virtually ceased.     

Intra‐ and interclonal phenotypic and genetic variability of the trematode Maritrema novaezealandensis

Explaining the origin and maintenance of phenotypic variation remains a central challenge in evolutionary biology. Using the trematode parasite Maritrema novaezealandensis, we examined variability in several morphological, behavioural, and physiological phenotypic traits at the same time as controlling for genotype by using genetically identical parasite clonal lineages. We measured several morphological traits, photoreactive responses, and survivorship to quantify the amount of phenotypic variation within and among 42 clonal parasite lines. Additionally, we tested Lerner's hypothesis that homozygotes are more variable than heterozygotes and assessed correlations between heterozygosity and phenotypic variation among clones. We found substantial differences among clones in morphology, photoreactive behaviour, and survivorship, yet no significant differences among clones in levels of intraclonal phenotypic variability were seen. Although the results demonstrate that conspecific trematode clones have significantly different levels of phenotypic variability, consistent differences over time were not always apparent. Finally, no correlation was found between heterozygosity and phenotypic variation among clones and the pattern of highly variable homozygotes, as observed by Lerner, was not evident in the present study. © 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2011, 103 , 106–116.