Distribution of the Eastern Gray Squirrel (Sciurus carolinensis) within California as of 2015

Abstract - The goals of this study were to map the distribution of the invasive eastern gray squirrel, Sciurus carolinensis, in California as of 2015 and to assess range expansion since the first documented sightings within the state. Range maps exist, but the last update by the California Department of Fish and Wildlife was in 2007. An assessment of the rate of range expansion over time has not been conducted, but comparisons between the locations of initial sightings and the current distribution are included. Location data were obtained from museum specimens, wildlife rehabilitation centers, a roadkill database, and research-grade citizen observations. Range maps were produced with ArcGIS software. Populations of eastern gray squirrels are currently concentrated around Sacramento and Davis, the western side of San Francisco Bay, within as well as north and east of Santa Cruz, within Monterey, north of the Golden Gate Bridge through Marin County as well as around Santa Rosa, and around the Bellota / Stockton area. Isolated populations on the eastern side of San Francisco Bay occur around Berkeley, Hayward, and Pleasanton. Observations extend into the foothills of the Sierra Nevada Mountain Range from north of the American River to south of the San Antonio River. We suggest that the eastern gray squirrel might become more damaging to the two native diurnal species of tree squirrels in California (Sciurus griseus and Tamiasciurus douglasii) than the introduced eastern fox squirrel (Sciurus niger)

Food Selection of Coexisting Western Gray Squirrels and Eastern Fox Squirrels in a Native California Botanic Garden in Claremont, California

The Eastern Fox Squirrel (Sciurus niger) has been introduced to many areas within California. Over time, the fox squirrel has expanded its geographic range and has displaced the native Western Gray Squirrel (Sciurus griseus) in many urban/suburban habitats. Reasons for displacement could be similarities in habitat, space, and/or resource use by each species. A food preferences study was conducted in Claremont, CA at a native California botanic garden. Food items consumed by each species were recorded for one year. Species ate different food items with fox squirrels utilizing more natural foods totaling to 22 items. The gray squirrel utilized 18 food items with 11 of those overlapping with the fox squirrel. The fox squirrel also utilized several plant and tree species whereas the gray squirrel remained with only 3 plant/tree species yet consumed many different reproductive structures such as fruits, catkins, and buds. This study provides information on coexistence of gray and fox squirrels and potential reasons for gray squirrel displacement

De novo formation of an aggregation pheromone precursor by an isoprenyl diphosphate synthase-related terpene synthase in the harlequin bug.

Insects use a diverse array of specialized terpene metabolites as pheromones in intraspecific interactions. In contrast to plants and microbes, which employ enzymes called terpene synthases (TPSs) to synthesize terpene metabolites, limited information from few species is available about the enzymatic mechanisms underlying terpene pheromone biosynthesis in insects. Several stink bugs (Hemiptera: Pentatomidae), among them severe agricultural pests, release 15-carbon sesquiterpenes with a bisabolene skeleton as sex or aggregation pheromones. The harlequin bug, Murgantia histrionica, a specialist pest of crucifers, uses two stereoisomers of 10,11-epoxy-1-bisabolen-3-ol as a male-released aggregation pheromone called murgantiol. We show that MhTPS (MhIDS-1), an enzyme unrelated to plant and microbial TPSs but with similarity to trans-isoprenyl diphosphate synthases (IDS) of the core terpene biosynthetic pathway, catalyzes the formation of (1S,6S,7R)-1,10-bisaboladien-1-ol (sesquipiperitol) as a terpene intermediate in murgantiol biosynthesis. Sesquipiperitol, a so-far-unknown compound in animals, also occurs in plants, indicating convergent evolution in the biosynthesis of this sesquiterpene. RNAi-mediated knockdown of MhTPS mRNA confirmed the role of MhTPS in murgantiol biosynthesis. MhTPS expression is highly specific to tissues lining the cuticle of the abdominal sternites of mature males. Phylogenetic analysis suggests that MhTPS is derived from a trans-IDS progenitor and diverged from bona fide trans-IDS proteins including MhIDS-2, which functions as an (E,E)-farnesyl diphosphate (FPP) synthase. Structure-guided mutagenesis revealed several residues critical to MhTPS and MhFPPS activity. The emergence of an IDS-like protein with TPS activity in M. histrionica demonstrates that de novo terpene biosynthesis evolved in the Hemiptera in an adaptation for intraspecific communication

Eye Size at Birth in Prosimian Primates: Life History Correlates and Growth Patterns

Abstract Background: Primates have large eyes relative to head size, which profoundly influence the ontogenetic emergence of facial form. However, growth of the primate eye is only understood in a narrow taxonomic perspective, with information biased toward anthropoids

Comparing vibrissal morphology and infraorbital foramen area in pinnipeds

Pinniped vibrissae are well-adapted to sensing in an aquatic environment, by being morphologically diverse and more sensitive than those of terrestrial species. However, it is both challenging and time-consuming to measure vibrissal sensitivity in many species. In terrestrial species, the infraorbital foramen (IOF) area is associated with vibrissal sensitivity and increases with vibrissal number. While pinnipeds are thought to have large IOF areas, this has not yet been systematically measured before. We investigated vibrissal morphology, IOF area, and skull size in 16 species of pinniped and 12 terrestrial Carnivora species. Pinnipeds had significantly larger skulls and IOF areas, longer vibrissae, and fewer vibrissae than the other Carnivora species. IOF area and vibrissal number were correlated in Pinnipeds, just as they are in terrestrial mammals. However, despite pinnipeds having significantly fewer vibrissae than other Carnivora species, their IOF area was not smaller, which might be due to pinnipeds having vibrissae that are innervated more. We propose that investigating normalized IOF area per vibrissa will offer an alternative way to approximate gross individual vibrissal sensitivity in pinnipeds and other mammalian species. Our data show that many species of pinniped, and some species of felids, are likely to have strongly innervated individual vibrissae, since they have high values of normalized IOF area per vibrissa. We suggest that species that hunt moving prey items in the dark will have more sensitive and specialized vibrissae, especially as they have to integrate between individual vibrissal signals to calculate the direction of moving prey during hunting

Eye Size at Birth in Prosimian Primates: Life History Correlates and Growth Patterns

BACKGROUND: Primates have large eyes relative to head size, which profoundly influence the ontogenetic emergence of facial form. However, growth of the primate eye is only understood in a narrow taxonomic perspective, with information biased toward anthropoids.\ud \ud METHODOLOGY/PRINCIPAL FINDINGS: We measured eye and bony orbit size in perinatal prosimian primates (17 strepsirrhine taxa and Tarsius syrichta) to infer the extent of prenatal as compared to postnatal eye growth. In addition, multiple linear regression was used to detect relationships of relative eye and orbit diameter to life history variables. ANOVA was used to determine if eye size differed according to activity pattern. In most of the species, eye diameter at birth measures more than half of that for adults. Two exceptions include Nycticebus and Tarsius, in which more than half of eye diameter growth occurs postnatally. Ratios of neonate/adult eye and orbit diameters indicate prenatal growth of the eye is actually more rapid than that of the orbit. For example, mean neonatal transverse eye diameter is 57.5% of the adult value (excluding Nycticebus and Tarsius), compared to 50.8% for orbital diameter. If Nycticebus is excluded, relative gestation age has a significant positive correlation with relative eye diameter in strepsirrhines, explaining 59% of the variance in relative transverse eye diameter. No significant differences were found among species with different activity patterns.\ud \ud CONCLUSIONS/SIGNIFICANCE: The primate developmental strategy of relatively long gestations is probably tied to an extended period of neural development, and this principle appears to apply to eye growth as well. Our findings indicate that growth rates of the eye and bony orbit are disassociated, with eyes growing faster prenatally, and the growth rate of the bony orbit exceeding that of the eyes after birth. Some well-documented patterns of orbital morphology in adult primates, such as the enlarged orbits of nocturnal species, mainly emerge during postnatal development.\ud \u

Navigating New Landscapes: The Contribution of Socio-Legal Scholarship in Mapping the Plurality of International Economic Law and Locating Power in International Economic Relations

The evolution of international economic law in the past two decades has been characterised by the growth and diversification of international economic actors, the expansion in the substantive areas governed by international law, and, crucially, the proliferation of multiple sites of international economic governance. This web of multi-layered international economic governance is, in turn, underpinned by complex dynamics of power which structure the legal and economic relations between the subjects of international economic law and other actors impacted by international legal rules and regulation. The challenge for international legal scholarship lay not only in mapping the multiple sites of international economic governance but also in unmasking the power dynamics inherent in international economic relations. Locating and analysing power relations underlying international economic law is to crucial to understanding the cause and effect of international economic rules and institutions for rulemaking. Conventional legal scholarship with its doctrinal focus, while useful in providing the foundational basis for analysis, cannot adequately capture the complexity of contemporary international economic law. Socio-legal approaches may be able to overcome these epistemological limitations by supplying: a) the methodologies to study international economic law beyond a focus on rules and institutions; and b) the critical theoretical lens to understand the power dynamics inherent in international legal relations. The objective of this paper is twofold: firstly, it will seek to identify the contributions of socio-legal approaches to the study of international economic law; and secondly, it will explore how socio-legal scholarship can provide a methodological and theoretical framework to construct an understanding of the pluralistic nature of international economic regulatory regimes and their underlying dynamics of power. In doing so, the paper will also consider the value of juxtaposing an empirical methodology for mapping legal regimes with a critical normative approach for analysing power relations in international economic law

What can whiskers tell us about mammalian evolution, behaviour, and ecology?

Most mammals have whiskers; however, nearly everything we know about whiskers derives from just a handful of species, including laboratory rats Rattus norvegicus and mice Mus musculus, as well as some species of pinniped and marsupial. We explore the extent to which the knowledge of the whisker system from a handful of species applies to mammals generally. This will help us understand whisker evolution and function, in order to gain more insights into mammalian behaviour and ecology. This review is structured around Tinbergen’s four questions, since this method is an established, comprehensive, and logical approach to studying behaviour. We ask: how do whiskers work, develop, and evolve? And what are they for? While whiskers are all slender, curved, tapered, keratinised hairs that transmit vibrotactile information, we show that there are marked differences between species with respect to whisker arrangement, numbers, length, musculature, development, and growth cycles. The conservation of form and a common muscle architecture in mammals suggests that early mammals had whiskers. Whiskers may have been functional even in therapsids. However, certain extant mammalian species are equipped with especially long and sensitive whiskers, in particular nocturnal, arboreal species, and aquatic species, which live in complex environments and hunt moving prey. Knowledge of whiskers and whisker use can guide us in developing conservation protocols and designing enriched enclosures for captive mammals. We suggest that further comparative studies, embracing a wider variety of mammalian species, are required before one can make large-scale predictions relating to evolution and function of whiskers. More research is needed to develop robust techniques to enhance the welfare and conservation of mammals