A new species of Eimeria Schneider, 1885 (Apicomplexa: Eimeriidae) from the eastern gray squirrel,Sciurus carolinensis (Rodentia: Sciuridae: Sciurinae: Sciurini) from Oklahoma,USA

Systematic Parasitology - A new species of Eimeria Schneider, 1885 is described from an eastern gray squirrel (Sciurus carolinensis) from McCurtain County, Oklahoma, USA. Oöcysts of Eimeria...     

Experimental transmission of Eimeria confusa Joseph 1969 to the fox squirrel.

Eimeria confusa Joseph, 1969 from the gray squirrel Sciurus carolinensis was transmitted to the fox squirrel Sciurus niger rufiventer. This is the first report of the successful cross-transmission of a gray squirrel coccidium to the fox squirrel.     

Comparison of the ITS1 and ITS2 rDNA in Eimeria callospermophili (Apicomplexa:Eimeriidae) from sciurid rodents

The taxonomy of the coccidia has historically been morphologically based. The purpose of this study was to establish if conspecificity of isolates of Eimeria callospermophili from 4 ground-dwelling squirrel hosts (Rodentia: Sciuridae) is supported by comparison of rDNA sequence data and to examine how this species relates to eimerian species from other sciurid hosts. Eimeria callospermophili was isolated from 4 wild-caught hosts, i.e., Urocitellus elegans, Cynomys leucurus, Marmota flaviventris , and Cynomys ludovicianus . The ITS1 and ITS2 genomic rDNA sequences were PCR generated, sequenced, and analyzed. The highest intraspecific pairwise distance values of 6.0% in ITS1 and 7.1% in ITS2 were observed in C. leucurus. Interspecific pairwise distance values > 5% do not support E. callospermophili conspecificity. Generated E. callospermophili sequences were compared to Eimeria lancasterensis from Sciurus niger and Sciurus niger cinereus and to Eimeria ontarioensis from S. niger. A single, well-supported clade was formed by E. callospermophili amplicons in neighbor joining and maximum parsimony analyses. However, within the clade, there was little evidence of host or geographic structuring of the species.     

Phylogeny and zoogeography of six squirrel species of the genus sciurus (mammalia, rodentia), inferred from cytochrome B gene sequences

To investigate the phylogenetic relationships between the New World Sciurus and the Old World Sciurus and their biogeographic history, the partial mitochondrial cytochrome b gene sequences (1,040 base pairs) were analyzed on six Sciurus species: S. aberti, S. carolinensis, S. lis, S. niger, S. stramineus, and S. vulgaris. Phylogenetic trees (maximum parsimony, neighbor-joining, and maximum likelihood methods) commonly showed two groups with high bootstrap values (73-100%): one consisting of the New World Sciurus and the other consisting of the Old World Sciurus. Genetic distances among the New World Sciurus species were remarkably larger than that between two Sciurus species of the Old World, suggesting the earlier radiation of the New World Sciurus than the Old World Sciurus.     

A genetic analysis of grey squirrel (Sciurus carolinensis) populations in Ireland

Biological Invasions - The grey squirrel (Sciurus carolinensis) is an invasive rodent in Ireland that has had detrimental impacts on the native Irish red squirrel (S. vulgaris) as well as on...     

Eastern gray squirrel (Sciurus carolinensis) color morphs do not differ in aggressiveness

acta ethologica - Eastern gray squirrels (Sciurus carolinensis) exhibit a variety of color morphs, including black. In the USA and UK, a common folk belief is that black squirrels are more...     

Cryptococcus gattii in wildlife of Vancouver Island, British Columbia, Canada

Although Cryptococcus gattii has emerged as an important pathogen of humans and domestic animals on Vancouver Island, Canada since 1999; its distribution in regional wildlife species is largely unknown. Opportunistic sampling methods were employed to obtain nasal swabs for fungal culture from wild mammal species residing within the coastal Douglas fir biogeoclimatic zone on the southeast coast of the island. Samples were collected from 91 animals representing 14 species. Cryptococcus gattii was isolated from the nasal swabs of two eastern gray squirrels (Sciurus carolinensis) trapped in Duncan, British Columbia. The relative proportion of nasal colonization in wild mammal species is consistent with findings in domestic animals, suggesting that animals may be good indicators of environmental organisms.     

Bartonella and Rickettsia in fleas and lice from mammals in South Carolina, U.S.A.

Species in the genera Bartonella and Rickettsia are vector-borne pathogens of humans and domestic animals. The natural reservoirs and enzootic transmission cycles of these bacteria are poorly known in South Carolina. Thirteen species of lice and fleas were collected from urban animals and screened for the presence of Bartonella and Rickettsia by PCR amplification using genus-specific primers. Bartonella henselae was present in cat fleas (Ctenocephalides felis) from Virginia opossums (Didelphis virginiana) and a novel genotype of Bartonella was detected in Orchopeas howardi from an eastern gray squirrel (Sciurus carolinensis). We detected R. typhi and three novel genotypes Rickettsia in other species of fleas and lice. Rickettsia typhi, the causative agent of murine typhus, was detected in two pools of lice (Enderleinellus marmotae) from the woodchuck (Marmota monax). Cat fleas harbored one of two novel genotypes of Rickettsia. A third novel Rickettsia was detected in Orchopeas howardi from an eastern gray squirrel.     

Immunocytochemistry of luteinizing hormone-releasing hormone in brains of breeding eastern narrow-mouthed toads (Gastrophryne carolinensis)

Unlabeled antibody-enzyme immunocytochemistry was used to localize mammalian-like immunoreactive luteinizing hormone-releasing hormone in brains of breeding eastern narrow-mouthed toads (Gastrophryne carolinensis). Intense immunostaining occurred over the infundibular floor and the median eminence, yet staining of few perikarya in the anterior preoptic area was minimal. This pattern of markedly regional immunostaining differs from that reported for other anurans.     

Preparing for winter: divergence in the summer-autumn hematological profiles from representative species of the squirrel family

We examined hematological parameters in four related sciurid species in the late summer-autumn to assess the role of habitat, elevation, body size, and behavior in shaping these parameters. Red squirrels (Tamiasciurus hudsonicus) and Arctic ground squirrels (Spermophilus parryii) were sampled in southwestern Yukon, yellow-pine chipmunks (Tamias amoenus) in southern Alberta, and the eastern grey squirrel (Sciurus carolinensis) in southern Ontario. We obtained whole blood samples from each species and compared glucose levels, red blood cell characteristics (hematocrit, red blood cell count, hemoglobin concentration, mean corpuscular volume, mean corpuscular hemoglobin, and mean corpuscular hemoglobin concentration), and white blood cell counts (neutrophils, lymphocytes, monocytes, eosinophils, basophils) across species. We found species differences in glucose and red blood cell characteristics that may be a function of activity levels, phylogeny, or elevation, but not of body size, body condition, or adaptations to a semi-fossorial habitat. We also found species differences in white blood cell counts that remain unexplained by any single simple explanation and may be more useful for comparison of individuals within a given species than for interspecies comparisons.     

Molecular phylogeny of short-tailed shrews, Blarina (Insectivora: Soricidae)

Phylogenetic relationships among the three described species of short-tailed shrews (genus Blarina) were inferred based on mitochondrial DNA sequences of 16S rRNA (506 bp) and cytochrome b (1137 bp) from 38 specimens representing B. brevicauda, B. hylophaga, and B. carolinensis, from across their range in North America. Phylogenetic analyses of both data sets combined followed tests showing lack of incongruence between these fragments. Analysis of substitution patterns indicated saturation of transitions at third codon positions in cytochrome b when Blarina sequences were compared to those of Sorex and Cryptotis, used as outgroups. Maximum-likelihood and weighted parsimony supported the monophyly of the genus and placed B. hylophaga as its basal branch, sister to B. brevicauda + B. carolinensis. Phylogeographic analysis revealed a significant partition between eastern and western populations of B. carolinensis and B. brevicauda, on either side of the Mississippi basin. These results are discussed in relation to cytogenetic, morphological, and fossil data.     

Bone assessment of free-living red squirrels (Sciurus vulgaris) from the United Kingdom

Metabolic bone disease has been reported in free-living red squirrels (Sciurus vulgaris) in the United Kingdom but the prevalence of this disease is unknown. In this study the bone quality of free-living red squirrels in the UK was assessed by radiology and bone densitometry. The study comprised 20 red squirrels found dead and submitted to the Zoological Society of London (UK) between 1997 and 1998, 10 were from the Isle of Wight (IoW), where gray squirrels (Sciurus carolinensis) are absent, and 10 were from Cumbria (Cu), where gray squirrels are present. Gray squirrels are considered potential competitors for red squirrels. Radiologic evaluation of humerus, femur, tibia, radius, and ilium revealed a slightly lower bone density and thinner cortices in red squirrels from the IoW when compared with those from Cu. Dual-energy X-ray absorptiometry was used to measure bone mineral content and density of the isolated right humerus and femur of 19 of the 20 red squirrels. The bone densitometry study reinforced the radiographic findings. The IoW specimens had lower bone mineral density values, although statistical significance (P<0.05) between animals from the IoW and Cu was only reached for the proximal epiphysis of the femur and between males from the IoW and males from Cu for the proximal epiphysis of the humerus. A highly positive correlation (r>0.94) was found when the bone mineral content and density between the femur and the humerus among groups and within each group were compared, showing a uniform level of mineralization between upper and lower limbs. These findings suggested generalized bone loss for the IoW red squirrels that may be compatible with some degree of osteopenia. Within the wide range of causes that lead to osteopenia, malnutrition (especially protein deficiency), calcium and copper deficiencies, and genetic factors remain as possible etiologies.     

Observations on the Endogenous Stages of Eimeria confusa Joseph, 1969 from the Grey Squirrel Sciurus carolinensis*

SYNOPSIS. Stages in the endogenous cycle of Eimeria confusa from the grey squirrel, Sciurus carolinensis, are described from mixed infections with another species, Eimeria lancasterensis. All corresponding stages were markedly different in the 2 species. In E. confusa infections, the parasites were located below the host cell nuclei of the epithelial cells of the villi of the jejunum and ileum. Mature schizonts were ellipsoidal, averaged 20.9 × 18.6 μm and had 18–30 merozoites. The mature microgamonts measured 34.3 × 24.7 μm and had hundreds of microgametes. Mature macrogametes were ovoid, averaged 31.3 × 25.6 μm, and contained 2 kinds of plastic granules.     

Implications of raccoon latrines in the epizootiology of baylisascariasis.

Raccoons (Procyon lotor) frequently establish defecation sites, termed latrines, on large logs, stumps, rocks, and other horizontally oriented structures/surfaces. These latrines are important foci of infective eggs of Baylisascaris procyonis, a nematode parasite of raccoons which is pathogenic to numerous species of mammals and birds. To examine the role of raccoon latrines in this animal-parasite interaction, we documented animal visitations to raccoon latrines in two large forested tracts and two woodlots in Indiana (USA) during 1994 and 1995. Species richness of vertebrate visitors did not differ between sites or years, but species composition differed by site and year. Fourteen mammal and 15 bird species were documented visiting raccoon latrines. Small granivorous mammals, including white-footed mice (Peromyscus leucopus), eastern chipmunks (Tamias striatus), and tree squirrels (Sciurus carolinensis, S. niger, Tamiasciurus hudsonicus) were the most common visitors to latrine sites. White-footed mice, chipmunks, white-breasted nuthatches (Sitta carolinensis), and opossums (Didelphis virginiana) were photographed foraging on undigested seeds in raccoon feces. Active foraging at latrines also was shown experimentally; seeds embedded in raccoon feces were removed at a greater rate at latrine sites than at nonlatrines. We conclude that raccoon latrines are visited routinely by a variety of vertebrates, especially small granivorous rodents and birds which forage for seeds in raccoon feces, and that raccoon latrines are probable sites of transmission of B. procyonis to susceptible mammals and birds.     

Seasonal changes in the testis and epididymis of the American Grey squirrel, Sciurus carolinensis

The histological changes in the testis and epididymis of the American Grey squirrel, Sciurus carolinensis (Gmelin) during development and the testicular cycle are described. It was observed that male Grey squirrels, as a population, did not undergo a pronounced seasonal reproductive cycle, however, individual males did experience periods of reproductive inactivity which were asynchronous and not related to seasonal changes in the environment. It is suggested that the individual sexual cycles are due to an endogenous rhythm of gonadotrophin secretion by the pituitaries of these animals.     

Alternative reproductive tactics in male eastern gray squirrels: "making the best of a bad job"

Male eastern gray squirrels (Sciurus carolinensis) congregatearound and pursue a female on her single day of estrus. Thetactics of uniquely marked adult males were monitored duringwinter mating bouts from 1986 to 1990 to examine variation inmale copulatory success. Two tactics were chosen by males: activepursuit or satellite. Active-pursuit males were dominant anddefended proximity to females. Satellite males were subordinateand remained dispersed in the female's home range. Active pursuitwas used only by males 2.75 years old. The switch point betweenthe tactics is about 3 years. Copulations were not distributedevenly among males, with about 30% of all adult males failingto copulate during a breeding season. Active pursuit was themost successful strategy, with male success attributed to theability to defend access to the female. However, satellite malessuccessfully copulated due to the escape of females from dominantmales. Females appear to avoid the overt aggression characteristicof the competition among active-pursuit males by running fromthe group of males. Male success after a female's breakawaywas evenly distributed between the two tactics and accountedfor all copulations by satellite males. The activepursuit andsatellite tactics appear to be a conditional evolutionarilystable strategy where young, subordinate males are "making thebest of a bad job".     

What can we learn about the behaviour of red and grey squirrels from YouTube?

Citizen science has emerged as an important tool in biology, ecology, and conservation studies. In this paper, we examined YouTube (YT) videos featuring the behaviour of red (Sciurus vulgaris) and grey (Sciurus carolinensis) squirrels in Europe, in both urban and forest habitats. Our study shows that specific behaviours of these squirrels, such as aggression, grooming and calling, have frequently been recorded on YT videos. The present paper uses this open data for the first time to compare differences between the frequency of some types of behaviour in two habitats. Based on detrended correspondence analysis, we show a significant difference in sets of behaviours between two squirrel species. Our investigation show that YT can be a source for monitoring the behaviour of wild species, especially in urban habitats, thus affording insights into the species plasticity of urban individuals. YT, as part of citizen science, is a potential source of information in behavioural ecology.     

An epizootic of fibromatosis in gray squirrels (Sciurus carolinensis) in Florida

Beginning in the fall of 1998 and extending into the spring and early summer of 1999 there was a large epizootic of squirrel fibromatosis in squirrels in seven counties in peninsular Florida. Hundreds of gray squirrels (Sciurus carolinensis) with multiple cutaneous tumors were submitted or reported to biologists, veterinary hospitals, and private wildlife rehabilitators. Most squirrels died or were euthanized soon after submission. Twenty squirrels were submitted for necropsy. The majority of the squirrels examined were adults (12/20) and male (15/20). The number and location of tumors varied widely among the affected squirrels; however, a consistent finding was involvement of the eyelids (20/20). Histopathology revealed a proliferative population of mesenchymal cells within the dermis and marked ballooning degeneration of keratinocytes in the overlying epidermis. Intracytoplasmic viral inclusions were present in the neoplastic mesenchymal cell population and the degenerating keratinocytes. Ulceration and necrosis of the surface of the tumors or associated tissues was present in 14 of the 20 squirrels. Virions consistent with poxvirus were observed via electron microscopy in samples collected from a representative tumor. Death of the squirrels was attributed to emaciation, tissue damage, and severe negative energy balance associated with poxvirus infection and massive tumor growth. The underlying cause of this unusual epizootic of fibromatosis in gray squirrels remains unknown.     

Occurrence of Myrmicinosporidium durum in red imported fire ant, Solenopsis invicta, and other new host ants in eastern United States

Myrmicinosporidium durum, a parasitic fungus in several ant species, is reported from seven new hosts collected in the eastern United States, including Solenopsis invicta, Solenopsis carolinensis, Paratrechina vividula, Pheidole tysoni, Pheidole bicarinata, Pyramica membranifera, and Pogonomyrmex badius. Spores can be found in most ant body parts, are dark brown when mature, and clear to light brown while immature. Ants infected with mature spores appear darker than normal. Spores from different hosts were 47-57 microm in diameter. Prevalence in host populations varied between 2 and 67% of the ants, and 3-100% of the colonies. Infection was most common in S. carolinensis with prevalence rates between 22 and 67%. Prevalence rates for S. invicta individuals were lower than for other ants, however, prevalence rates within the infected colonies were as high as 31%. Observations of disease were recorded mostly from late summer and fall. Possible implications of this new disease in red imported fire ants are discussed.     

Eavesdropping squirrels reduce their future value of food under the perceived presence of cache robbers

Caching behavior frequently occurs within a social context that may include heterospecific cache pilferers. All else equal, the value of cacheable food should decline as the probability of cache recovering declines. We manipulated gray squirrels' (Sciurus carolinensis) estimate of the probability of cache recovery using experimental playbacks of the vocalizations of a potential cache robber, the blue jay (Cyanocitta cristata). We used giving-up densities (GUDs) to quantify relative changes in squirrels' valuation of cacheable and noncacheable foods. We collected GUDs during playback experiments to test whether squirrels (1) eavesdrop on vocalizations to detect jay presence, (2) devalue cacheable food in the (perceived) presence of jays (i.e., perceive jays as cache pilferers), and (3) are sensitive to distant effects (i.e., lower devaluation of cacheable food at sites far from the perceived location of jays). Consistent with our predictions, squirrels decreased the value of cacheable hazelnuts by two nuts, on average, during jay playbacks, but only at foraging stations near the jay playback sites. We conclude that through eavesdropping, squirrels assess site-specific risks of cache pilfering and alter their caching behavior to reduce the likelihood of pilferage. Evidence suggests that tree seed consumers in eastern deciduous forests exist within a complex communication network.