Biology Commons^™

A Description Of Mixed-Species Insectivorous Bird Flocks In Western Mexico, Richard L. Hutto

Biological Sciences Faculty Publications

Insectivorous bird flocks were observed in all types of forested habitats during the nonbreeding season in western Mexico. The species composition of flocks changed markedly and predictably among five categories of habitat type. The average number of species per flock in lowland habitats was 4.7, while a mean of 18.6 species participated in highland flocks, ranking the latter among the most species-rich flocks in the world. The mean proportion of the local insectivorous species that participated in mixed-species flocks was significantly greater in the highlands (61.3%) than in the lowlands (24.6%). About half of the flock participants in both undisturbed …

Thermal Dependence Of Maximal Ca2+-Activated Force In Skinned Muscle Fibres Of The Toad Bufo Marinus Acclimated At Different Temperatures, Bernard Rees

Biological Sciences Faculty Publications

Mechanically skinned muscle fibres from the twitch region of the iliofibularis muscle of cool- (16 +/- 1 degree C) and warm- (32 +/- 1 degree C) acclimated cane toads (Bufo marinus) were activated maximally by Ca2+ in solutions of different pH and at different temperatures (approx. 1-35 degrees C). Acclimation of up to 12 weeks at 16 degrees C and up to 8 weeks at 32 degrees C did not modify the marked thermal dependence of isometric force in the skeletal muscle fibres of the cane toad. The prominent decline of maximum Ca2+-activated force at lower temperatures, a property which …

Heterozygosity And Oxygen-Consumption Rate As Predictors Of Growth And Developmental Rate In Rainbow-Trout, Roy G. Danzmann, Moira M. Ferguson, Fred W. Allendorf

Biological Sciences Faculty Publications

No abstract provided.

Characterization Of Protein-I From Serum-Sensitive And Serum-Resistance Transformants Of Neisseria-Gonorrhoeae, Ralph C. Judd, Milton Tam, Keith Joiner

Biological Sciences Faculty Publications

No abstract provided.

Distribution And Current Status Of The Threatened Dismal Swamp Southeastern Shrew, Sorex Longirostris Fisheri, Robert K. Rose, Roger K. Everton, Thomas M. Padgett

Biological Sciences Faculty Publications

The Dismal Swamp southeastern shrew, Sorex longirostris fisheri, was given "Threatened" status by the U.S. Fish and Wildlife Service in 1986 because of its limited distribution and the potential threat of interbreeding with the nearby upland subspecies, Sorex l. longirostris. Known from about 20 specimens collected before 1980 and a few dozen taken since then, "fisheri" seems to have morphologically diverged from the smaller upland "longirostris" in association with the development of the Dismal Swamp. The detection of southeastern shrews that are intermediate in size between the two subspecies, coupled with the location of these collection sites on …

The Identification Of The Threatened Southeastern Shrew Using Multivariate Statistical Techniques, Thomas M. Padgett, Roger K. Everton, Robert K. Rose

Biological Sciences Faculty Publications

The threatened subspecies of the southeastern shrew, Sorex longirostris fisheri, is endemic to the Great Dismal Swamp of southeastern Virginia. Previous studies based on discriminant analysis of external measurements determined that intergrades with the upland form, Sorex l. longirostris, exist along the periphery of the Swamp. To better discriminate among these populations, a study of cranial morphology was initiated. Fifteen cranial measurements were taken, using 59 specimens of Sorex collected previously form southeastern Virginia, including the Dismal Swamp. Both Principal Component and Cluster Analyses revealed no significant cranial variation or morphometric patterns within the specimens examined, but a …

Evidence For N-Terminal Exposure Of The Protein Ia Subclass Of Neisseria-Gonorrhoeae Protein-I, Ralph C. Judd

Biological Sciences Faculty Publications

The JS3 and FA638 strains of Neisseria gonorrhoeae bear a protein IA subclass of protein I (P.I). The purified P.Is of surface-labeled strains JS3 and FA638 were cleaved with the N-terminal degradation enzyme leucine amino peptidase (LAP), and the resultant fragments were separated in sodium dodecyl sulfate-polyacrylamide gels. Autoradiography demonstrated that the surface radiolabel was absent in a LAP-generated P.I peptide that was about 1,900 daltons lower in apparent molecular mass than the native P.I in both strains. Moreover, the 4G5 monoclonal epitope, known to be located on the surface of the organism, was also absent in the LAP-generated P.I …

A Fixed-Radius Point Count Method For Nonbreeding And Breeding-Season Use, Richard L. Hutto, Sandra M. Pletschet, Paul Hendricks

Biological Sciences Faculty Publications

We provide a detailed description of a fixed-radius point count method that carries fewer assumptions than most of the currently popular methods of estimating bird density and that can be used during both the nonbreeding and breeding seasons. The method results in three indices of bird abundance, any of which can be used to test for differences in community composition among sites, or for differences in the abundance of a given bird species among sites. These indices are (1) the mean number of detections within 25 m of the observer, (2) the frequency of detections within 25 m of the …

Reproductive Strategies Of Meadow Voles, Hispid Cotton Rats, And Eastern Harvest Mice In Virginia, Robert K. Rose

Biological Sciences Faculty Publications

Patterns of reproduction in small mammals in Virginia were examined by autopsying samples of meadow voles (Microtus pennsylvanicus) collected for 23 months near Charlottesville, of hispid cotton rats (Sigmodon hispidus) collected for 14 months in Portsmouth, and by evaluating live-caught eastern harvest mice (Reithrodontomys humulis) trapped for 15 months in Suffolk and for 12 months in Chesapeake. The meadow vole, a microtine rodent with a north temperate and sub-arctic distribution throughout North America, suspended breeding during the winter of peak density but not of declining density. High metabolic rates and other adaptations for winter …

Quantitation And Identification Of Organic N-Chloramines Formed In Stomach Fluid On Ingestion Of Aqueous Hypochlorite, Frank E. Scully Jr., Katherine Mazina, Daniel E. Sonenshine, Frederick Kopfler

Biological Sciences Faculty Publications

The chemical reactions that hypochlorite undergoes in the body when chlorinated water is ingested have received very little attention. Because amino nitrogen compounds are important components of the average diet, the reactions of hypochlorite with amino compounds in the stomach were investigated. Stomach fluid was recovered from Sprague-Dawley rats that had been fasted for 48 hr and administered 4 mL deionized water. The chlorine demand of the stomach fluid was determined. An average volume-independent demand of 2.7 mg chlorine was measured. At doses below 40 mg/L chlorine reducing reactions appeared to account for reduction of all oxidizing species within 15 …

Repellent Activity Of The Secretion Of Edessa Rufomarginata, A Neotropical Pentamid, Jerome J. Howard

Biological Sciences Faculty Publications

No abstract provided.

Going To Extremes: Why Do Sanderlings Migrate To The Neotropics?, J. P. Myers, John L. Maron, Michel Sallaberry A.

Biological Sciences Faculty Publications

Sanderlings (Calidris alba) breed within a small latitudinal range in the arctic while spreading in winter virtually throughout temperate and tropical marine beaches of the world. This paper examines spatial variation in Sanderlings nonbreeding density across the New World, documents annual cycle differences between populations wintering in California and those wintering in Peru and Chile, and then explores demographic and ecological factors underlying Sanderlings migration to different wintering grounds. Densities during the nonbreeding season are higher on the Pacific coast than on the Atlantic at all censused latitudes in the New World, and reach a peak in southwestern …

Seasonal Changes In Feeding Success, Activity Patterns, And Weights Of Nonbreeding Sanderlings (Calidris Alba), John L. Maron, J. P. Myers

Biological Sciences Faculty Publications

Seasonal changes in Sanderling (Calidris alba) feeding success, time budgets, and weights were followed throughout the nonbreeding season at Bodega Bay, California. Sanderlings spent more time roosting in fall than in winter, and in fall adults spent more time roosting than juveniles. Sanderling prey capture rates were high in fall and spring and declined through winter. Sanderling weights paralleled seasonal changes in feeding success and activity patterns: birds were heaviest in fall and spring and lightest in winter. These results reflect lowered food availability in winter and imply that birds may have difficulty balancing their energy budgets during …

Structure And Surface Exposure Of Protein-Iis Of Neisseria-Gonorrhoeae Js3, Ralph C. Judd

Biological Sciences Faculty Publications

Colonies of Neisseria gonorrhoeae JS3, each bearing a predominate protein II (PII) type, were derived from a progenitor transparent colony. Five distinct PIIs were identified and isolated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The PII bands were excised from gels of unlabeled whole cells and from gels containing lysates of surface-radioiodinated bacteria. These were subjected to alpha-chymotrypsin digestion and two-dimensional peptide mapping, which allowed for a comparison of both the primary structures of the PIIs and the identification of surface-exposed regions of the molecules. The results demonstrated that PIIs are unrelated to either Protein I or Protein III in structure …

Community Ecology, Robert K. Rose, Elmer C. Birney

Biological Sciences Faculty Publications

COMMUNITIES with Microtus tend to be structurally simple, usually grasslands or tundra, and to have no more than two species of Microtus and rarely more than six species of small mammals. Microtus often dominates both numerically and in total small mammal biomass, especially at higher latitudes. The small mammal community is most influenced by Microtus through its fluctuations in density, and thus also in biomass, by its relatively high level of diurnal activity, and by its year-round activity. Other species of small mammals may be adversely affected because Microtus usually is larger and behaviorally dominant and also because the mere …

Seasonal-Changes In The Habitat Distribution Of Transient Insectivorous Birds In Southeastern Arizona: Competition Mediated, Richard L. Hutto

Biological Sciences Faculty Publications

The distribution and abundance of 26 migratory insectivorous bird species were recorded over an elevational habitat gradient in the Chiricahua Mountains, Arizona for the spring and fall migratory seasons. Most of the species used this area only during migratory passage, and 54% exhibited significant shifts in the habitats occupied from spring to fall. The majority (69%) of species also exhibited significant changes in density within habitats between seasons. Using pairwise correlations of bird densities from 7 habitat types and 2 seasons, I identified 5 groups that contained species whose seasonal distributional patterns were similar to one another but independent and …

Chemical Leaf Repellency To An Attine Ant: Seasonal Distribution Among Potential Host Plant Species, Jerome J. Howard

Biological Sciences Faculty Publications

The chemical repellency of leaves to the leaf-cutting, fungus-growing ant Atta cephalotes was surveyed for 42 plant species randomly selected from the dry forest of Santa Rosa National Park, Guanacaste, Costa Rica. The sample represents about one-sixth of the potential host plant species available to the ants in the secondary, semideciduous forest at Santa Rosa. Repellencies of leaf extracts were measured by bioassay. A laboratory colony of A. cephalotes collected from Santa Rosa was used. Three-quarters of the species exhibited significantly repellent nonpolar (lipid-soluble) extractables (e.g., terpenoids, steroids, and waxes), and half of the species exhibited repellent polar extractables (e.g., …

Crystallization Of The Gene 45 Protein From The Dna Replication Fork Of Bacteriophage T4, C. Thaller, B. Alberts, E. Goldsmith, S. Sprang, R. Fletterick

Biological Sciences Faculty Publications

The gene 45 protein from bacteriophage T4 has been purified and is crystallized. This protein is part of the T4 DNA replication complex. The crystallized protein is active in complementation assays. X-ray diffraction analysis is in progress; data are measured for the native and several heavy atom derivatives. The crystals diffract to about 3.5-Å resolution.

Factors Affecting Nest Site Location In Gila Woodpeckers, Jerome J. Korol, Richard L. Hutto

Biological Sciences Faculty Publications

We investigated the locations of Gila Woodpecker (Melanerpes uropygialis) nest sites in Organ Pipe Cactus National Monument, Arizona. A significantly greater proportion of saguaro cacti in arroyos had woodpecker holes than did those on hillsides, ridgetops or desert flats. Saguaros used for nest-hole excavation were taller and more likely to have branches than randomly chosen saguaros. Both active and inactive nest holes were nonrandomly oriented, with the mean vectors of orientation being in northwesterly directions. Variation in nest-hole orientation probably is not due to seasonal differences in excavations because the orientation of spring active (late March) nest holes was not …

Superior Developmental Stability Of Heterozygotes At Enzyme Loci In Salmonid Fishes, Robb F. Leary, Fred W. Allendorf, Kathy L. Knudsen

Biological Sciences Faculty Publications

No abstract provided.

The Pan American Shorebird Program: A Progress Report, J. P. Myers, Gonzalo Castro, Brian Harrington, Marshall Howe, John L. Maron, Enrique Ortiz, Michel Sallaberry A., C. T. Schick, Elier Tablio

Biological Sciences Faculty Publications

No abstract provided.

An Evaluation Of Small Rodents In Four Dismal Swamp Plant Communities, F. Elizabeth Breidling, Frank P. Day Jr., Robert K. Rose

Biological Sciences Faculty Publications

Diversity and density of small rodents in the Dismal Swamp are believed to be low. Reasons for this may be excessive predation, heavy interspecific pressure from large rodents, lack of suitable habitat, low food availability or flooding.

Rodent populations were evaluated using live-traps and pitfall traps in four different Dismal Swamp plant communities. Habitat was compared on the basis of phytomass studies previously reported. Flood levels were recorded during live-trapping sessions. Mast from trees was collected in modified mast collectors, and fed to Peromyscus leucopus in the laboratory.

Only two small rodent species were captured: Ochrotomys nuttalli and Peromyscus leucopus …

Rationale And Suggestions For A Hemispheric Color-Marking Scheme For Shorebirds: A Way To Avoid Chaos, J. P. Myers, John L. Maron, Enrique Ortiz, Gonzalo Castro, Marshall Howe, R.I.G. Morrison, Brian A. Harrington

Biological Sciences Faculty Publications

No abstract provided.

Amount And Distribution Of Isozyme Variation In Ponderosa Pine From Eastern Montana, John Herbert Woods, G. M. Blake, Fred W. Allendorf

Biological Sciences Faculty Publications

Pinus ponderosa seeds from 50 trees in each of six small isolated stands located within a nine kilometer radius of Colstrip, Montana, were examined at 23 isozyme loci. Megagametophyte and embryo tissue from each seed were screened separately. Measures of genetic diversity showed no significant differences between male and female components within or between stands. The average proportion of heterozygous loci per embryo (H_e) was not significantly different between stands. For all stands combined, H_e was 0.012. Genotype proportions did not deviate from expected Hardy-Weinberg proportions.

Nearly 99 % of the genetic diversity resided within individual stands, …

Linkage Disequilibrium Generated By Selection Against Null Alleles At Duplicate Loci, Fred W. Allendorf

Biological Sciences Faculty Publications

No abstract provided.

Shell-Dropping Behavior Of Western Gulls (Larus Occidentalis), John L. Maron

Biological Sciences Faculty Publications

Westem Gulls (Larus occidentalis) at Bodega Bay, California drop shelled prey items to break them. I presented Washington clams (Saxidomus nuttalli) of known weight to free-flying gulls to investigate factors affecting shell-dropping behavior. All adult gulls dropped clams, whereas only 55% of immature gulls did so. The other 45% of immature gulls that were given clams pecked at them on the ground instead. Gulls dropped clams on both hard and soft substrates. Flight distance and kleptoparasitism seemed important in influencing drop location. Adult Western Gulls dropped heavy clams from lower heights than they dropped light clams. …

Structure Of Maltoheptaose By Difference Fourier Methods And A Model For Glycogen, E. Goldsmith, S. Sprang, R. Fletterick

Biological Sciences Faculty Publications

The structure of the glucose heptamer, maltoheptaose, has been determined by difference Fourier analysis at 0.25 nm resolution through its binding to phosphorylase a. It is a left-handed helical structure, with 6.5 glucose residues per turn and a rise per residue of 2.4 Å. The molecule shows short-range order when no protein is present to stabilize its conformation in solution. With one exception, the individual torsion angles between sugar residues vary over a narrow range and preserve a good O₍₂₎O_(3′) hydrogen bond. The length of an individual chain for glycogen can be extrapolated from the maltoheptaose data …

Electrophoretic Variation In Large Mammals. Iii. The Ringed Seal, Pusa-Hispida, The Harp Seal, Pagophilus-Groenlandicus, And The Hooded Seal, Cystophora-Cristata, V. Simonsen, Fred W. Allendorf, W. F. Eanes, F. O. Kapel

Biological Sciences Faculty Publications

No abstract provided.

Small Mammals In Openings In Virginia's Dismal Swamp, Robert K. Rose

Biological Sciences Faculty Publications

In a study of small mammals of openings in the Dismal Swamp of Virginia, seven species were obtained using pitfall traps. Samples included several species rarely caught in the Swamp - seven specimens of the Dismal Swamp subspecies of the southern bog lemming, Synaptomys cooperi helaletes, the first collected in this century; two least shrews, Cryptotis parva; and 15 southeastern shrews, Sorex longirostris fisheri . Results are compared to previous studies, conducted primarily in forested habitats, in which the white-footed mouse, Peromyscus leucopus, and the golden mouse, Ochrotomys nuttalli, were numerically dominant.

Seasonal Variation In The Foraging Behavior Of Some Migratory Western Wood Warblers, Richard L. Hutto

Biological Sciences Faculty Publications

I observed the foraging behavior of four warbler species (Dendroica petechia, Oporornis tolmiei, Geothlypis trichas, and Wilsonia pusilla) in the summer in Wyoming and in the winter in Nayarit, Mexico. Of six variables (absolute foraging height, relative foraging height, vegetation density, horizontal foraging position, feeding method, and foraging substrate) believed to be potentially important in distinguishing the warbler species ecologically, the two foragingheight variables provided the greatest separation of the four species in both summer and winter. An analysis of the behavioral similarity of each species from summer to winter revealed that feeding method was the least …