Testing Global Positioning System Telemetry to Study Wolf Predation on Deer Fawns

ABSTRACT We conducted a pilot study to test the usefulness of Global Positioning System (GPS) collars for investigating wolf (Canis lupus) predation on white-tailed deer (Odocoileus virginianus) fawns. Using GPS collars with short location-attempt intervals on 5 wolves and 5 deer during summers 2002–2004 in northeastern Minnesota, USA, demonstrated how this approach could provide new insights into wolf hunting behavior of fawns. For example, a wolf traveled ≥1.5–3.0 km and spent 20–22 hours in the immediate vicinity of known fawn kill sites and ≥0.7 km and 8.3 hours at scavenging sites. Wolf travel paths indicated that wolves intentionally traveled into deer summer ranges, traveled ≥0.7–4.2 km in such ranges, and spent <1–22 hours per visit. Each pair of 3 GPS-collared wolf pack members were located together for ≤6% of potential locations. From GPS collar data, we estimated that each deer summer range in a pack territory containing 5 wolves ≥1 year old and hunting individually would be visited by a wolf on average every 3–5 days. This approach holds great potential for investigating summer hunting behavior of wolves in areas where direct observation is impractical or impossible.     

Molecular cloning and structural analysis of human norepinephrine transporter gene（NETHG）

A cDNA molecule encoding a major part of the human Norepinephrine transporter(hNET) was synthesized by means of Polymerase Chain Reaction(PCR) technique and used as a probe for selecting the human genomic NET gene.A positive clone harbouring the whole gene was obtained from a human lymphocyte genomic library through utilizing the “genomic walking” technique.The clone,designated as phNET,harbours a DNA fragment of about 59 kd in length inserted into BamH I site in cosmid pWE15.The genomic clone contains 14 exons encoding all amino acid residues in the protein.A single exon encodes a distinct transmembrane domain,except for transmembrane domain 10 and 11,which are encoded by part of two exons respectively,and exon 12,which encodes part of domain 11 and all of domain 12.These results imply that there is a close relationship between exon splicing of a gene and structureal domains of the protein,as is the case for the human γ－aminobutyric acid transporter(hGAT) and a number of other membrane proteins.     

Separating physical disturbance and nutrient enrichment caused by Pacific salmon in stream ecosystems

1. Pacific salmon (Oncorhynchus spp.) deliver marine‐derived nutrients to the streams in which they spawn and die, and these resource subsidies can increase the abundance of stream biota. In strong contrast, physical disturbance from salmon spawning activity can reduce the abundance of benthic organisms. Previous experimental designs have not established the relative effects of these two contrasting processes on stream organisms during a salmon run. 2. We combined manipulative and observational field studies to assess the degree of nutrient enrichment, physical disturbance, and the net effect of salmon on the abundance of benthic periphyton. Related salmon‐mediated processes were also evaluated for benthic macroinvertebrates. Mesh exclosures (2 × 2 m plots) prevented salmon from disturbing areas of the stream channel, which were compared with areas to which salmon had access. Sampling was conducted both before and during the late‐summer spawning run of pink (O. gorbushca) and chum (O. keta) salmon. 3. Streamwater nitrogen and phosphorus concentrations increased sharply with the onset of the salmon run, and highly significant positive relationships were observed between the numbers of salmon present in the stream and these dissolved nutrients. Before the salmon run, periphyton biomass (as chlorophyll a) and total macroinvertebrate abundance were very similar between control and exclosure plots. During the salmon run, exclosures departed substantially from controls, suggesting significant disturbance imparted on benthic biota. 4. Comparing exclosures before and during the salmon run enabled us to estimate the effects of salmon in the absence of direct salmon disturbance. This ‘nutrient enrichment potential’ was significant for periphyton biomass, as was a related index for macroinvertebrate abundance (although enhanced invertebrate drift into exclosures during the salmon run could also have been important). Interestingly, however, the net effect of salmon, evaluated by comparing control plots before and during the salmon run, was relatively modest for both periphyton and macroinvertebrates, suggesting that nutrient enrichment effects were largely offset by disturbance. 5. Our results illustrate the importance of isolating the specific mechanisms via which organisms affect ecosystems, and indicate that the relative magnitude of salmon nutrient enrichment and benthic disturbance determines the net effect that these ecologically important fish have on stream ecosystems.     

Coyote Habitat Selection and Management Implications for the Gaspésie Caribou

ABSTRACT Anthropogenic disturbances can promote establishment and growth of predator populations in areas where secondary prey can then become threatened. In this study, we investigated habitat selection of eastern coyotes (Canis latrans), a relatively new predator in the vicinity of an endangered population of caribou (Rangifer tarandus caribou). We hypothesized that coyotes in the boreal forest depend mainly on disturbed habitat, particularly that of anthropogenic origin, because these habitats provide increased food accessibility. Coyotes would likely take advantage of moose (Alces alces) carcasses, berries, and snowshoe hares (Lepus americanus) found in open habitats created by logging. To test these predictions, we described coyote diet and habitat selection at different spatial and temporal levels and then compared resource availability between habitats. To do so, we installed Global Positioning System radiocollars on 23 individual coyotes in the Gaspésie Peninsula, eastern Québec, Canada. Coyotes selected clear-cuts of 5–20 years and avoided mature coniferous forests both at the landscape and home-range levels. Clear-cuts of 5–20 years were found to contain a high availability of moose carcasses and berries, and vulnerability of snowshoe hares is known to increase in clear-cuts. The importance of these 3 food resources was confirmed by the characteristics of core areas used by coyotes and diet analysis. Moose remains were found at 45% of core areas and coyote diet comprised 51% moose on an annual basis. Anthropogenic disturbances in the boreal forest thus seem to benefit coyotes. Our results indicated that the relationship between coyotes and caribou likely involves spillover predation. This knowledge allows managers to consider spillover predation by coyotes as a possible threat for endangered caribou population when the predator depends mainly on habitat of anthropogenic origin and to suggest methods to alleviate it when developing management plans.     

Fine Structure of Differentiating Oocysts and Mature Sporozoites of Haemoproteus metchnikovi in its Intermediate Host Chrysops callidus*

The fine structure of the sporogonic stages of Haemoproteus metchnikovi has been investigated by electron microscopy. Young oocysts are found beneath the basement membrane of midgut epithelial cells. These eventually protrude outward into the haemocoel space and are surrounded by a distinct oocyst capsule. Sporozoite formation begins with a subcapsular vacuolation. Evagination of the oocyst cytoplasm occurs in regions of membrane thickenings and 100–200 sporozoites are formed about a single sporoblastoid body. Remnants of the ookinete pellicle can be observed in maturing oocysts and always are found in the residual body. The fine structure of the mature sporozoite is essentially similar to that which has been described for other haemosporidia and a spherical body is described in association with the mitochondrion of the sporozoite. The sporogonic stages of H. metchnikovi have features common to the sporogonic stages of Plasmodium and Leucocytozoon that are not held in common by the latter 2 genera, including pattern of sporozoite formation and number of sporozoites formed, the presence of a cytostome and of “crystalloid” in the sporozoite.     

THE WINDOW OF OPPORTUNITY: DECISION THEORY AND THE TIMING OF PROGNOSTIC TESTS FOR NEWBORN INFANTS

In many forms of severe acute brain injury there is an early phase when prognosis is uncertain, followed later by physiological recovery and the possibility of more certain predictions of future impairment. There may be a window of opportunity for withdrawal of life support early, but if decisions are delayed there is the risk that the patient will survive with severe impairment. In this paper I focus on the example of neonatal encephalopathy and the question of the timing of prognostic tests and decisions to continue or to withdraw life‐sustaining treatment. Should testing be performed early or later; and how should parents decide what to do given the conflicting values at stake? I apply decision theory to the problem, using sensitivity analysis to assess how different features of the tests or different values would affect a decision to perform early or late prognostic testing. I draw some general conclusions from this model for decisions about the timing of testing in neonatal encephalopathy. Finally I consider possible solutions to the problem posed by the window of opportunity. Decision theory highlights the costs of uncertainty. This may prompt further research into improving prognostic tests. But it may also prompt us to reconsider our current attitudes towards the palliative care of newborn infants predicted to be severely impaired.     

Development of the foetal membranes in the cane rat (Thryonomys swinderianus): a re-interpretation

The morphogenesis of the foetal membranes of the African cane rat (Thryonomys swinderianus, Temminck) was studied and compared with that of the caviomorphs from South America. Like the guinea pig and chinchilla, implantation in the cane rat is interstitial, amniogenesis is by cavitation, there is very early and complete inversion of yolk sac endoderm, there is a well-developed subplacenta which persists throughout gestation, and the interhaemal membrane is haemomonochorial in nature. The phylogenetic significance of these findings are discussed in the light of long geographical and temporal separation between the continents.     

Species richness estimates of Blattodea s.s. (Insecta: Dictyoptera) from northern Guyana vary depending upon methods of species delimitation

Cockroaches (Order: Blattodea) comprise a taxon that, although very abundant in tropical forests, remains largely unstudied. Making sense of the diversity of species is a challenging task hindered by the large numbers of species and the abundance of cryptic or polymorphic forms. Here, we estimated species richness of cockroaches (s.s.) from northern Guyana while applying a method to deal with these confounding factors. We utilized two interpretations of abundance data, the first using only morphological information, and the second using both morphological and genetic barcode information. The two methods of species delimitation greatly influenced the resulting estimates of species richness. When incorporating genetic barcodes, our total species richness estimate decreased by 26%. Our results emphasize the importance of using independent datasets to delimit species boundaries and expert identification of specimens when possible.