Animal Sciences Commons^™

Induction Of Winter Breeding In Small Mammals By 6-Mboa, Robert K. Rose, Roger K. Everton, Gregory E. Glass

Virginia Journal of Science

A plant-derived cyclic carbamate, 6-methoxybenzoxazolinone (6-MBOA), is

known to initiate reproductive activity in Microtus montanus. We studied

overwintering populations of four other rodent species, and observed increased

reproduction in experimental populations of two herbivorous species, Microtus

pennsylvanicus and Sigmodon hispidus, but not in two omnivorous species,

Oryzomys palustris and Mus musculus. These results suggest that low

concentrations of 6-MBOA may trigger seasonal breeding primarily in

herbivorous small mammals.

The Use Of Extractable Lipofuscin For Age Determination Of Crustaceans: Reply To Sheehy (2008), H. Rodger Harvey, David H. Secor, Se-Jong Ju

OES Faculty Publications

The heterogeneous mixture of metabolic by-products termed lipofuscin (LF) or age pigments has long been known to accumulate in post mitotic cells with increasing age. In crustaceans several approaches have been developed over the years to track LF accumulation and provide a proxy for chronological age. Histological approaches have been traditionally used for LF determination of crustaceans (e.g. Sheehy et al. 1994, Mar Biol 121:237-245), but over the last decade extraction approaches for neural tissues have been introduced (Ju et al. 1999, Mar Ecol Prog Ser 185:171-179) and tested (Ju et al. 2001, Mar Ecol Prog Ser 224:197-205; 2003, Fish …

Mycobacteriosis-Associated Mortality In Wild Striped Bass (Morone Saxatilis) From Chesapeake Bay, Usa, D. T. Gauthier, R. J. Latour, D. M. Heisey, C. F. Bonzek, J. Gartland, E. J. Burge, W. K. Vogelbein

Biological Sciences Faculty Publications

The striped bass (Morone saxatilis) is an economically and ecologically important finfish species along the Atlantic seaboard of the United States. Recent stock assessments in Chesapeake Bay (USA) indicate that non-fishing mortality in striped bass has increased since 1999, concomitant with very high (>50%) prevalence of visceral and dermal disease caused by Mycobacterium spp. Current fishery assessment models do not differentiate between disease and other components of non-fishing mortality (e. g., senescence, predation); therefore, disease impact on the striped bass population has not been established. Specific measurement of mortality associated with mycobacteriosis in wild striped bass is …

Advancing Epidemiological Science Through Computational Modeling: A Review With Novel Examples, Scott M. Duke-Sylvester, Eli N. Perencevich, Jon P. Furuno, Leslie A. Real, Holly Gaff

Biological Sciences Faculty Publications

Computational models have been successfully applied to a wide variety of research areas including infectious disease epidemiology. Especially for questions that are difficult to examine in other ways, computational models have been used to extend the range of epidemiological issues that can be addressed, advance theoretical understanding of disease processes and help identify specific intervention strategies. We explore each of these contributions to epidemiology research through discussion and examples. We also describe in detail models for raccoon rabies and methicillin-resis-tant Staphylococcus aureus, drawn from our own research, to further illustrate the role of computation in epidemiological modeling.

Population Ecology Of The Golden Mouse, Robert K. Rose

Biological Sciences Faculty Publications

An understanding of the population dynamics of a species requires knowledge of the major life-history parameters of a population, including age at maturity, distribution of age classes, and lifetime reproductive contribution of the sexes, sex ratio, length of the breeding season, mean litter size, rates of growth and survival, and life span. Because few long-term studies have been conducted with Ochrotomys nuttalli as the focal species of investigation, only fragmentary information is available for many population parameters. As importantly, densities of golden mice often are low, making them difficult to evaluate statistically. Little has been published on age at maturity …

Low-Density Rodent Communities In Eastern Virginia, Robert K. Rose, Jean F. Stankavich

Virginia Journal of Science

Two communities of small mammals were live trapped every other week for 15 months in linear oilfield habitat bordered by forested swampland in eastern Virginia. All nine species of the rodent community were present, mostly in low numbers and often intermittently. All species were characterized by high transiency, with a minority of marked animals becoming resident. Despite high trappability, all but two species in these communities had extremely low densities, suggesting that most species could not sustain populations via in situ reproduction.

The Effects Of Thawing Procedure And Supplementation On The Motility And Viability Of Frozen-Thawed Boar Semen, B. D. Whitaker, S. Clark, Z. Crouse, W. Martin, J. W. Knight

Virginia Journal of Science

The effect of two thawing procedures on frozen boar semen and supplementations to the fertilization media were studied. Frozen boar semen was thawed using either Percoll gradient or phosphate buffered saline (PBS)procedure. Supplementations were 1.0 mM L-glutamate, 1.0 mM N-acetylcysteine (NAC) , and 1.0 mM NAC-amide (NACA). Spermatozoa were analyzed for forward progressive motility (FPM) and viability every 0.5 h for 3 .0 h post-thawing. There were significantly (P < 0.05) higher numbers of viable (76.0 ± 5.1 %) and FPM (30 .0 ± 2.4%) spermatozoa at 3.0 h post thawing using the PBS procedure compared to the Percoll gradient thawed spermatozoa (65.0 ± 3.9%; 10.0 ± 4.5 %, respectively). Supplementation of 1.0 mM L-glutamate, 1.0 mM NAC, or 1.0 mM NACA had no significant effect on spermatozoa viability regardless of the time post-thaw.Supplementation of 1.0 mM L-glutamate, 1.0 mM NAC , or 1.0 mM NACA had no significant effect on FPM up to 1.0 h post-thaw. Spermatozoa with no supplementation or 1.0 mM L-glutamate had significantly higher (P < 0.05) FPM compared to the 1.0 mM NAC and 1.0 mM NACA supplemented groups at 1.5, 2.0, 2 .5, and 3.0 h post-thaw. There was no significant difference between no supplementation or 1.0 mM L-glutamate on FPM regardless of the time post-thaw. There was no significant difference between 1.0 mM NAC or 1.0 mM NACA on FPM regardless of the time post-thaw. These results indicate that thawing procedure has an effect on spermatozoa viability and FPM but supplementation does not have an effect on the overall viability of spermatozoa during thawing, but may reduce FPM.

Otolith Chemistry Indicates Population Structuring By The Antarctic Circumpolar Current, Julian R. Ashford, Cynthia M. Jones, Eileen E. Hofmann, Inigo Everson, Carlos A. Moreno, Guy Duhamel, Richard Williams

CCPO Publications

Large-scale transport of seawater in ocean currents may generate spatially complex population structure through the advection of life stages of marine fish species. To test this, we compared the chemistry of otolith nuclei from Patagonian toothfish (Dissostichus eleginoides), presently managed as spatially discrete Populations corresponding to fishing management areas along the Antarctic Circumpolar Current (ACC), which transports water eastward around the Southern Ocean. The chemistry of otolith nuclei, laid down during early life, differed significantly between fishing areas Off South America and the Antarctic and between some Antarctic areas. However, we found significant discrepancies from expectation for a …

Oviposition Behavior Partitions Aquatic Landscapes Along Predation And Nutrient Gradients, C. A. Binckley, W. J. Resetarits Jr.

Biological Sciences Faculty Publications

That individuals attempt to minimize the ratio of mortality risk/growth rate (μ/g) when foraging within individual habitat patches is well established. Do species partition among spatially discrete communities embedded in complex landscapes in a similar manner? We investigated how 3 ovipositing species (2 Hyla treefrogs and a hydrophilid beetle, Tropisternus lateralis) responded to simultaneous gradients of nutrients and predation risk. Species partitioned our experimental metacommunity primarily by reducing oviposition with fish. Tropisternus positively responded to increased nutrients, but the effect decreased with increasing risk, as predicted by μ/g theory. Use of fish habitats by Tropisternus was unrelated to breeding …

Swimming Dynamics And Propulsive Efficiency Of Squids Throughout Ontogeny, Ian K. Bartol, Paul S. Krueger, Joseph T. Thompson, William J. Stewart

Biological Sciences Faculty Publications

Synopsis Squids encounter vastly different flow regimes throughout ontogeny as they undergo critical morphological changes to their two locomotive systems: the fins and jet. Squid hatchlings (paralarvae) operate at low and intermediate Reynolds numbers (Re) and typically have rounded bodies, small fins, and relatively large funnel apertures whereas juveniles and adults operate at higher Re and generally have more streamlined bodies, larger fins, and relatively small funnel apertures. These morphological changes and varying flow conditions affect swimming performance in squids. To determine how swimming dynamics and propulsive efficiency change throughout ontogeny, digital particle image velocimetry (DPIV) and kinematic …