Patterns of Natural and Human-Caused Mortality Factors of a Rare Forest Carnivore,the Fisher (Pekania pennanti) in California

Wildlife populations of conservation concern are limited in distribution, population size and persistence by various factors, including mortality. The fisher (Pekania pennanti), a North American mid-sized carnivore whose range in the western Pacific United States has retracted considerably in the past century, was proposed for threatened status protection in late 2014 under the United States Endangered Species Act by the United States Fish and Wildlife Service in its West Coast Distinct Population Segment. We investigated mortality in 167 fishers from two genetically and geographically distinct sub-populations in California within this West Coast Distinct Population Segment using a combination of gross necropsy, histology, toxicology and molecular methods. Overall, predation (70%), natural disease (16%), toxicant poisoning (10%) and, less commonly, vehicular strike (2%) and other anthropogenic causes (2%) were causes of mortality observed. We documented both an increase in mortality to (57% increase) and exposure (6%) from pesticides in fishers in just the past three years, highlighting further that toxicants from marijuana cultivation still pose a threat. Additionally, exposure to multiple rodenticides significantly increased the likelihood of mortality from rodenticide poisoning. Poisoning was significantly more common in male than female fishers and was 7 times more likely than disease to kill males. Based on necropsy findings, suspected causes of mortality based on field evidence alone tended to underestimate the frequency of disease-related mortalities. This study is the first comprehensive investigation of mortality causes of fishers and provides essential information to assist in the conservation of this species.     

The Effects of Ultraviolet Radiation and Nutrient Additions on Periphyton Biomass and Composition in a Sub‐Alpine Lake (Castle Lake,USA)

Rising levels of ultraviolet radiation (UVR) striking the Earth's surface have led to numerous studies assessing its inhibitory effects on phytoplankton and periphyton in aquatic systems. Mineral nutrients such as nitrogen (N) and phosphorus (P) have been shown to increase aspects of algal metabolism and compensate for UVR inhibition. An in situ substratum enrichment technique and UV shielding was used to assess the effects of nutrient additions on periphyton exposed to different levels of UVR in Castle Lake, California during July‐August, 1997. UV shielding had no effect on total periphyton biomass, but caused shifts in species composition. The dominant periphyton species, Anabaena circinalis RAB., demonstrated sensitivity to ambient levels of UV radiation possibly due to UV inhibition of N2 ‐fixation. Total diatom biovolume decreased when shielded from UVR. Phosphorus additions continually elicited an increase in periphyton biovolume at all levels of analysis. These results suggest an interaction between nutrient status/availability and UV sensitivity.     

Trap color and placement affects estimates of insect family-level abundance and diversity in a Nebraska salt marsh

Sampling programs to establish baseline ecosystem information (e.g., species abundance and diversity) often fail to consider the potential influence of sampling techniques on results. Research on sampling economically important insects has demonstrated the possible influences of trap color and trap placement on results, but few data have been collected from natural environments. Consequently, we examined the effects of color (yellow and blue) and placement (exposed and shaded by plants) of sticky traps on insect captures and diversity estimates from a Nebraska inland salt marsh community. We identified 1913 specimens from 67 insect families collected during five trapping dates in July 1996. More Cicindelidae were collected on exposed traps, and more Staphylinidae, Dolichopodidae, Cicadellidae, and Thripidae were collected on shaded traps. More Dolichopodidae were collected on yellow traps, while more Syrphidae and Thripidae were collected on blue. Shannon and alpha diversity measures were significantly higher for shaded traps than exposed traps, but were not affected by trap color. Our results highlight the importance of characterizing sampling techniques when establishing diversity estimates. These data provide the first complete accounting of community-level insect response to colored sticky traps and provide new information for color preference of non-economic insect species.     

Developmental expression of adenosine deaminase in the upper alimentary tract of mice

The distribution and localization of adenosine deaminase (ADA) was studied during postnatal development of the alimentary tract in mice. There was detectable enzyme activity in all organs examined, but a range of more than 10,000 fold in the relative levels of specific activity was observed among adult tissues. A comprehensive survey of multiple adult tissues revealed that the highest levels of ADA occur in the upper alimentary tract (tongue, esophagus, forestomach, proximal small intestine). Immunohistochemical analysis revealed that ADA was predominantly localized to the epithelial lining of the alimentary mucosa: the keratinized squamous epithelium that lines the forestomach, esophagus, and surface of the tongue; and the simple columnar epithelium of the proximal small intestine (duodenum, proximal jejunum). Biochemical analysis revealed that ADA was one of the most abundant proteins of these mucosal tissue layers, accounting for 5%-20% of the total soluble protein. Tissue-specific differences in ADA activity correlated both with levels of immunoreactive protein and RNA abundance. The level of ADA activity in the upper alimentary tissues was subject to pronounced developmental control, being low at birth and achieving very high levels within the first few weeks of postnatal life. The appearance in development of ADA-immunoreactivity coincided with maturation of the mucosal epithelium. These results suggest that ADA is subject to strong cell-specific developmental regulation during functional differentiation of certain foregut derivatives in mice.     

The genetic architecture of fitness in a seed beetle: assessing the potential for indirect genetic benefits of female choice

Background  

Quantifying the amount of standing genetic variation in fitness represents an empirical challenge. Unfortunately, the shortage of detailed studies of the genetic architecture of fitness has hampered progress in several domains of evolutionary biology. One such area is the study of sexual selection. In particular, the evolution of adaptive female choice by indirect genetic benefits relies on the presence of genetic variation for fitness. Female choice by genetic benefits fall broadly into good genes (additive) models and compatibility (non-additive) models where the strength of selection is dictated by the genetic architecture of fitness. To characterize the genetic architecture of fitness, we employed a quantitative genetic design (the diallel cross) in a population of the seed beetle Callosobruchus maculatus, which is known to exhibit post-copulatory female choice. From reciprocal crosses of inbred lines, we assayed egg production, egg-to-adult survival, and lifetime offspring production of the outbred F1 daughters (F1 productivity).     

Calcium signaling in dendrites and spines: practical and functional considerations

Changes in intracellular calcium (Ca) concentration following synaptic and suprathreshold activity are mediated by a wide range of sources and contribute to the regulation of myriad neuronal functions. The development of Ca imaging techniques has dramatically increased our understanding of the complex interactions between different Ca sources and their ability to produce spatial and temporal specificity of signaling, even within small cellular compartments such as dendrites and dendritic spines. However, as the use of Ca imaging has become more prevalent, the need to exercise care in the experimental methodology and interpretation of data has also grown. In this review, we discuss the recent progress made using imaging methods in understanding dendritic Ca signaling and also describe a quantitative framework for using fluorescent indicators to experimentally measure and interpret changes in intracellular Ca.     

Relationship between platelet-activating factor concentration in rhesus monkey (Macaca mulatta) spermatozoa and sperm motility.

Platelet-activating factor (PAF) is a potent signaling phospholipid that has been implicated in a number of biological activities. PAF concentration in primate spermatozoa has a positive correlation with fertility. While PAF is present in rhesus spermatozoa, there are no relational reports on its concentration and the cell's motility. The study objective was to determine if PAF concentration in rhesus spermatozoa was correlated with motility indices (percent motility and forward progression). Semen was collected from sexually mature males and cell counts, and percent motilities and forward progressions were recorded prior to PAF measurement by radioimmunoassay. Spermatozoa-derived PAF concentration ranged from a low of 0.9 picomoles/10(6) cells to a high of 13.0 picomoles/10(6) cells. The overall mean (+/-SEM) PAF concentration was 4.6 (+/-1.6) picomoles/10(6) spermatozoa. Regression analysis revealed a positive and significant relationship between PAF concentration in the spermatozoa and percent motility (R2 = 0.914; P < 0.01) as well as forward progression (R2 = 0.849; P < 0.05). A receiver-operator characteristic curve and the calculation of the probability that a positive forward progression will be predicted indicated a cutoff limit of 1.5 picomoles/10(6) cells for PAF concentration in rhesus sperm. Rhesus monkey spermatozoa motility was significantly greater (P < 0.01) in the high-PAF (> or =2 picomoles/10(6) cells) group (31.0 +/- 7.6) than in the low-PAF (<2 picomoles/10(6) cells) group (6.8 +/- 2.1). Rhesus monkey spermatozoa forward progression was significantly greater (P < 0.05) in the high-PAF (> or =2 picomoles/10(6) cells) group (3.0 +/- 1.0) than in the low-PAF (<2 picomoles/10(6) cells) group (0.7 +/- 0.3). The data demonstrate that PAF concentration in rhesus spermatozoa has a significant relationship with percent motility and the cell's forward progression. Determining PAF concentration in spermatozoa may be a significant predictor of fertility in the primate. Additional studies will elucidate the role of PAF in spermatozoa function and the significance PAF plays in primate fertility.