scholarly journals Patterns and potential drivers of intraspecific variability in the body elemental composition of a terrestrial consumer, the snowshoe hare (Lepus americanus)

2019 ◽  
Author(s):  
Matteo Rizzuto ◽  
Shawn J. Leroux ◽  
Eric Vander Wal ◽  
Yolanda F. Wiersma ◽  
Travis R. Heckford ◽  
...  
Keyword(s):  
Body Size ◽  
Chemical Composition ◽  
Intraspecific Variability ◽  
Lepus Americanus ◽  
The Body ◽  
Whole Body ◽  
Snowshoe Hare ◽  
Weak Relationship ◽  
Snowshoe Hares ◽  
P Content

AbstractIntraspecific variability in ecological traits is widespread in nature. Recent evidence, mostly from aquatic ecosystems, shows individuals differing at the most fundamental level, that of their chemical composition. Age, sex, or body size may be key drivers of intraspecific variability in the body concentrations of carbon (C), nitrogen (N), and phosphorus (P). However, we still have a rudimentary understanding of the patterns and drivers of intraspecific variability in chemical composition of terrestrial consumers, particularly vertebrates.Here, we investigate the whole-body chemical composition of snowshoe hare Lepus americanus, providing one of the few studies of patterns of stoichiometric variability and its potential drivers for a terrestrial vertebrate. Based on snowshoe hare ecology, we expected higher P and N concentrations in females, as well as in larger and older individuals.We obtained whole-body C, N, and P concentrations and C:N, C:P, N:P ratios from a sample of 50 snowshoe hares. We then used general linear models to test for evidence of a relationship between age, sex, or body size and stoichiometric variability in hares.We found considerable variation in the C, N, and P concentrations and elemental ratios within our sample. Contrary to our predictions, we found evidence of N content decreasing with age. As expected, we found evidence of P content increasing with body size. As well, we found no support for a relationship between sex and N or P content, nor for variability in C content and any of our predictor variables.Despite finding considerable stoichiometric variability in our sample, we found no substantial support for age, sex, or body size to relate to this variation. The weak relationship between body N concentration and age may suggest varying nutritional requirements of individuals at different ages. Conversely, P’s weak relationship to body size appears in line with recent evidence of the potential importance of P in terrestrial systems. Snowshoe hares are a keystone herbivore in the boreal forest of North America. The substantial stoichiometric variability we find in our sample could have important implications for nutrient dynamics in both boreal and adjacent ecosystems.

scholarly journals Patterns and potential drivers of intraspecific variability in the body C, N, and P composition of a terrestrial consumer, the snowshoe hare ( Lepus americanus )

2019 ◽  
Vol 9 (24) ◽  
pp. 14453-14464
Author(s):  
Matteo Rizzuto ◽  
Shawn J. Leroux ◽  
Eric Vander Wal ◽  
Yolanda F. Wiersma ◽  
Travis R. Heckford ◽  
...  
Keyword(s):  
Intraspecific Variability ◽  
Lepus Americanus ◽  
The Body ◽  
Snowshoe Hare

Decay and preservation of polychaetes: taphonomic thresholds in soft-bodied organisms

Paleobiology ◽  
1993 ◽  
Vol 19 (1) ◽  
pp. 107-135 ◽  
Author(s):  
Derek E. G. Briggs ◽  
Amanda J. Kear
Keyword(s):  
Chemical Composition ◽  
Soft Tissues ◽  
Lipid Fraction ◽  
Relative Proportion ◽  
Two Dimensions ◽  
The Body ◽  
Whole Body ◽  
Fluid Loss ◽  
Preservation Potential ◽  
Grès À Voltzia

A series of experiments was carried out to investigate the nature and controls (oxygen, microbial populations, agitation) on the degradation of soft tissues. Decay was monitored in terms of morphological change, weight loss, and change in chemical composition in the polychaete Nereis virens. Polychaetes include a range of tissue types of differing chemical composition and preservation potential: muscle, cuticle, setae, and jaws. Regardless of conditions, all the muscle had broken down and fluid loss through the ruptured cuticle had reduced the carcass to two dimensions within 8 days at 20°C. In most cases some cuticle, in addition to the jaws and setae, remained after 30 days. Where oxygen was completely eliminated, the rate of decay of the more volatile issues was significantly reduced. The degree of both osmotic uptake of water by the carcass and changes in water pH differed depending on whether the system was open or closed to oxygen diffusion. Autolytic and chemical processes are not sufficient to fully degrade the carcass in the absence of bacteria. Where internal bacteria are present, the presence or absence of water column bacteria made little difference to decay rate. Initial degradation (in the first 3 days) affects mainly the lipid fraction and the collagen of the cuticle. Later decay reduces the nonsoluble protein and increases the relative proportion of refractory structural components (tanned chitin and collagen) to more than 95% by day 30. Thus, only the sclerotized tissues are likely to survive beyond 30 days in the absence of early diagenetic mineralization. The sequence of degradation predicted from the relative decay resistance of macromolecules in the sedimentary record (protein → carbohydrate → lipid) is not, therefore, a consistent indicator of the preservation potential of structural tissues which incorporate them.The experiments reveal five stages in the decay of polychaete carcasses; whole/shriveled, flaccid, unsupported gut, cuticle sac, jaws and setae. All are represented in the fossil record. This allows an estimation of how far decay proceeded before it was halted by the fossilization process. The most complete preservations occur in the Cambrian where the Burgess Shale preserves evidence of muscle tissues. Traces of the gut and cuticle are more widely preserved, as at Mazon Creek, Grès à Voltzia, Solnhofen, and Hakel. Preservation varies within Konservat-Lagerstätten. The most common whole body preservation includes only the more recalcitrant tissues, jaws (where present) and setae, with an impression of the body outline. The stage of decay can be used as a taphonomic threshold, to provide an indication of how significantly the diversity of an exceptionally preserved biota is likely to have been reduced by taphonomic loss.

The control of somitogenesis in mouse embryos

Development ◽  
1981 ◽  
Vol 65 (Supplement) ◽  
pp. 103-128
Author(s):  
P. P. L. Tam
Keyword(s):  
Body Size ◽  
Primitive Streak ◽  
Mouse Embryos ◽  
The Body ◽  
Whole Body ◽  
Axis Formation ◽  
Presomitic Mesoderm ◽  
Tail Bud ◽  
Somite Formation ◽  
Somitic Mesoderm

Somitogenesis in the mouse embryo commences with the generation of presumptive somitic mesoderm at the primitive streak and in the tail-bud mesenchyme. The presumptive somitic mesoderm is then organized into somite primordia in the presomitic mesoderm. These primordia undergo morphogenesis leading to the segmentation of somites at the cranial end of the presomitic mesoderm. Somite sizes at the time of segmentation vary according to the position of the somite in the body axis: the size of lumbar and sacral somites is nearly twice that of upper trunk somites and of tail somites. The size of the presomitic mesoderm, which is governed by the balance between the addition of cells at the caudal end and the removal of somites at the cranial end, changes during embryonic development. Somitogenesis is disturbed during the compensatory growth of mouse embryos which have suffered a drastic size reduction at the primitive-streak and early-organogenesis stages. The formation of somites is retarded and the upper trunk somites are formed at a smaller size. The embryo also follows an entirely different growth profile, but a normal body size is restored by the early foetal stage. The somite number is regulated to normal and this is brought about by an altered rate of somite formation and the adjustment of somite size in proportion to the whole body size. It is proposed that axis formation and somitogenesis are related morphogenetic processes and that embryonic growth controls the kinetics of somitogenesis, namely by regulating the number of cells allocated to each somite and the rate of somite formation.

What factors determine cyclic amplitude in the snowshoe hare (Lepus americanus) cycle?

2014 ◽  
Vol 92 (12) ◽  
pp. 1039-1048 ◽  
Author(s):  
Charles J. Krebs ◽  
John Bryant ◽  
Knut Kielland ◽  
Mark O’Donoghue ◽  
Frank Doyle ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Forest Succession ◽  
Monitoring Program ◽  
Lepus Americanus ◽  
Snowshoe Hare ◽  
Amplitude Variation ◽  
Regional Monitoring ◽  
Snowshoe Hares ◽  
Existing Data

Snowshoe hares (Lepus americanus Erxleben, 1777) fluctuate in 9–10 year cycles throughout much of their North American range. These cycles show large variations in cyclic amplitude and we ask what factors could cause amplitude variation. We gathered data from 1976 to 2012 on hare numbers in the boreal forest of Alaska, Yukon, Northwest Territories, and northern British Columbia to describe the amplitude of hare fluctuations and to evaluate four possible causes. First, weather could cause variation in amplitude via hare reproduction or survival, but this mechanism does not fit our data. Second, bottom-up processes involving forest succession could explain amplitude variation through changes in winter forage availability, but succession is too slow a variable in our study areas. Third, plant defenses entrained by hare over-browsing in one cycle can produce variation in plant quality and quantity in subsequent cycles. A mathematical model suggests this is a possible explanation. Fourth, predator recovery following the cyclic low is inversely related to hare cyclic amplitude, and the existing data are consistent with this mechanism. A standardized regional monitoring program is needed to improve our understanding of cyclic amplitude variation in hares and the possible role of predators and winter foods in affecting amplitude.

Prediction of the body composition of lambs from the composition of their non-carcass components

1995 ◽  
Vol 61 (2) ◽  
pp. 265-268 ◽  
Author(s):  
R. G. Wilkinson ◽  
J. F. D. Greenhalgh
Keyword(s):  
Body Composition ◽  
Body Weight ◽  
Chemical Composition ◽  
Chemical Analysis ◽  
Specific Gravity ◽  
Crude Protein ◽  
Energy Content ◽  
The Body ◽  
Viable Alternative ◽  
Whole Body

AbstractInformation on the chemical composition of Suffolk × Blackface lambs was collected and used to predict empty body (EB) component weights from empty body weight (EBW) and non-carcass (NC) component weights. EBW accounted proportionately for 0·94, 0·89 and 0·95 of the variation in EB crude protein, fat and energy content. A combination of NC component weights accounted proportionately for 0·94, 0·95 and 0·96 of the variation in EB crude protein, fat and energy content. EBW and a combination of NC component weights together accounted proportionately for 0·97, 0·97 and 0·98 of the variation in EB crude protein, fat and energy content. Chemical analysis of NC components is cheaper and easier than whole body analysis and provides a viable alternative to sample joint or specific gravity analysis.

scholarly journals Serologic Survey of Snowshoe Hares (Lepus americanus) in the Greater Yellowstone Area for Brucellosis, Tularemia, and Snowshoe Hare Virus

2015 ◽  
Vol 51 (3) ◽  
pp. 769-773 ◽  
Author(s):  
Jack Rhyan ◽  
Dan Tyers ◽  
Jeremy Zimmer ◽  
Kristen Lewandowski ◽  
Steve Hennager ◽  
...  
Keyword(s):  
Lepus Americanus ◽  
Snowshoe Hare ◽  
Greater Yellowstone Area ◽  
Snowshoe Hares ◽  
Greater Yellowstone ◽  
Serologic Survey

Antibodies to Francisella tularensis in the snowshoe hare (Lepus americanus struthopus) populations of Nova Scotia and Prince Edward Island and in the moose (Alces alces americana Clinton) population of Nova Scotia

1982 ◽  
Vol 28 (4) ◽  
pp. 403-405 ◽  
Author(s):  
M. B. Akerman ◽  
J. A. Embil
Keyword(s):  
Nova Scotia ◽  
Francisella Tularensis ◽  
Prince Edward Island ◽  
Alces Alces ◽  
Lepus Americanus ◽  
Snowshoe Hare ◽  
Serological Survey ◽  
First Report ◽  
Snowshoe Hares

A serological survey showed antibodies to Francisella tularensis present in 1.55% of snowshoe hares (Lepus americanus struthopus) and 1.06% of moose (Alces alces americana Clinton) sampled in Nova Scotia. No antibody-positive hares were found in Prince Edward Island, however. We believe this to be the first report of antibodies to F. tularensis in the moose.

scholarly journals California encephalitis virus endemicity in the Yukon Territory, 1972

1973 ◽  
Vol 71 (2) ◽  
pp. 391-402 ◽  
Author(s):  
D. M. McLean ◽  
Alison M. Clarke ◽  
E. J. Goddard ◽  
A. S. Manes ◽  
C. A. Montalbetti ◽  
...  
Keyword(s):  
Yukon Territory ◽  
Ground Squirrels ◽  
Lepus Americanus ◽  
Encephalitis Virus ◽  
Tamiasciurus Hudsonicus ◽  
Snowshoe Hare ◽  
Snowshoe Hares ◽  
Tree Squirrels ◽  
Culiseta Inornata ◽  
Aedes Communis

SUMMARYSera from 218 of 1574 (14%) small mammals collected in the Yukon Territory between 14 May and 13 August 1972 neutralized a Yukon strain of California encephalitis virus (snowshoe-hare subtype). These included 133 of 319 (42%) snowshoe hares (Lepus americanus), 84 of 1243 (7%) ground squirrels (Citellus undulatus) and 1 of 12 (8%) tree squirrels (Tamiasciurus hudsonicus). California encephalitis virus (snow-shoe hare subtype) was isolated from four pools of unengorged Aedes communis mosquitoes collected near Whitehorse (61° N., 135° W.) and on one occasion each from pools of the same species collected at Hunker Creek (64° N., 138° W.) and at mile 125, Dempster Highway (66° N., 138° W.) during July 1972. Replication of a Yukon strain of California encephalitis virus was observed in wild-caught Culiseta inornata and Aedes canadensis mosquitoes after intrathoracic injection and holding at temperatures of 80°, 50° and 40° F.

Description of nine species of Eimeria (Protozoa, Eimeriidae) in the snowshoe hare, Lepus americanus, of central Alberta

1977 ◽  
Vol 55 (10) ◽  
pp. 1671-1683 ◽  
Author(s):  
H. P. Samoil ◽  
W. M. Samuel
Keyword(s):  
New Species ◽  
Statistical Analysis ◽  
Lepus Americanus ◽  
Snowshoe Hare ◽  
Similar Species ◽  
Snowshoe Hares ◽  
Genus Eimeria

Nine species of the genus Eimeria were found during the examination of 629 snowshoe hares from central Alberta. Four, E. robertsoni, E. leporis, E. ruficaudati, and E. townsendi, described previously from other leporids, are redescribed; while five, E. athabascensis, E. keithi, E. holmesi, E. rochesterensis, and E. rowani are described as new species. The nine species belong to four groups of morphologically similar species. Species were distinguished on the basis of morphology, primarily the presence or absence of oocyst and sporocyst residua and a micropyle, and statistical analysis of oocyst and sporocyst measurements. The eimerians of all lagomorphs are reviewed and a key to the 19 species from Lepus spp. is presented.

Ectoparasites of rabbits and hares in Manitoba, Canada, with observations on age-specific dispersal in Haemodipsus setoni (Phthiraptera: Anoplura: Polyplacidae)

2012 ◽  
Vol 144 (3) ◽  
pp. 439-446 ◽  
Author(s):  
Terry D. Galloway
Keyword(s):  
Lepus Americanus ◽  
Snowshoe Hare ◽  
Sylvilagus Floridanus ◽  
Mean Intensity ◽  
Pulex Irritans ◽  
Snowshoe Hares ◽  
Eastern Cottontail ◽  
First Time

AbstractDuring 1994–2008, 58 adult and 195 juvenile eastern cottontail rabbits (Sylvilagus floridanus (Allen)), one adult and 23 juvenile snowshoe hares (Lepus americanus Erxleben), and eight adult white-tailed jackrabbits (Lepus townsendii Bachman) (Mammalia: Leporidae) were examined for ectoparasites. The most abundant ectoparasite on cottontails was the sucking louse, Haemodipsus setoni Ewing (Phthiraptera; Polyplacidae), recorded from this host for the first time. Infestations in adult and juvenile cottontails were highly aggregated, k = 0.136 and 0.153, respectively. Prevalence of infestation in adult cottontails was 70.6%, with a mean intensity of 5614.1 (range: 1–166 249); 10 adults had more than 1000 lice. In juvenile cottontails, prevalence was 34.8% and mean intensity was 6.2 (range: 1–87). On adult cottontails, 73.4% of the total lice were nymphs, while on juvenile cottontails only 11.6% were nymphs. It appears that dispersal from parents to offspring is overwhelmingly achieved by adult lice. Seventeen adult cottontails were infested with the tick, Haemaphysalis leporispalustris (Packard) (Acari: Ixodidae). No fleas specific to rabbits were collected but small numbers of the rodent fleas Monopsyllus vison (Baker), Orchopeas caedens (Jordan), and Aetheca wagneri (Baker) (Siphonaptera: Ceratophyllidae) were recorded. Only one snowshoe hare was infested with H. setoni and three were infested with H. leporispalustris; no fleas were found on snowshoe hares. Two white-tailed jackrabbits were infested with H. leporispalustris; one carried Pulex irritans Linnaeus (Siphonaptera: Pulicidae), and none carried lice.

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