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Articles 871 - 900 of 932

Full-Text Articles in Biology

Purification, Characterization, And Submitochondrial Localization Of The 32-Kilodalton Nadh Dehydrogenase From Maize, Andrew F. Knudten, Jay J. Thelen, Michael Hans Luethy, Thomas Elthon Jan 1994

Purification, Characterization, And Submitochondrial Localization Of The 32-Kilodalton Nadh Dehydrogenase From Maize, Andrew F. Knudten, Jay J. Thelen, Michael Hans Luethy, Thomas Elthon

School of Biological Sciences: Faculty Publications

Plant mitochondria have the unique ability to directly oxidize exogenous NAD(P)H. We recently separated two NAD(P)H dehydrogenase activities from maize (Zea mays 1.) mitochondria using anion-exchange (Mono Q) chromatography. The first peak of activity oxidized only NADH, whereas the second oxidized both NADH and NADPH. In this paper we describe the purification of the first peak of activity to a 32-kD protein. Polyclonal antibodies to the 32-kD protein were used to show that it was present in mitochondria from several plant species. Two-dimensional gel analysis of the 32-kD NADH dehydrogenase indicated that it consisted of two major and one minor …

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Characterization Of The Unique Intron - Exon Junctions Of Euglena Gene(S) Encoding The Polyprotein Precursor To The Light-Harvesting Chlorophyll A/B Binding Protein Of Photosystem Ii, Umesh Shyamsunder Muchhal, Steven D. Schwartzbach Jan 1994

Characterization Of The Unique Intron - Exon Junctions Of Euglena Gene(S) Encoding The Polyprotein Precursor To The Light-Harvesting Chlorophyll A/B Binding Protein Of Photosystem Ii, Umesh Shyamsunder Muchhal, Steven D. Schwartzbach

School of Biological Sciences: Faculty Publications

The precursor to the Euglena light harvesting chlorophyll a/b binding protein of photosystem 11 (LHCPII) Is a polyprotein containing multiple copies of LHCPII covalently joined by a decapeptide linker. cDNA and genomic clones encoding the 5 and 3' end of a 6.6 kb LHCPII mRNA were sequenced. A 3.1 kb genomic region encoding 1.05 kb of the 5' end of LHCPII mRNA contains 4 introns. A 7.6 kb genomic region encoding 3.3 kb of the 3' end of LHCPII mRNA contains 10 introns. The 5' and 3' ends of the 14 Identified Euglena introns lacked the conserved dinucleotides (5'-GT and …

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Enhanced Competitiveness Of Tomato Bushy Stunt Virus Defective Interfering Rnas By Segment Duplication Or Nucleotide Insertion, K. Andrew White, T. Jack Morris Jan 1994

Enhanced Competitiveness Of Tomato Bushy Stunt Virus Defective Interfering Rnas By Segment Duplication Or Nucleotide Insertion, K. Andrew White, T. Jack Morris

School of Biological Sciences: Faculty Publications

We have analyzed atypical tomato bushy stunt virus defective interfering (DI) RNA species which accumulated during a passage series in protoplasts. We present a rationale for the order of appearance of these molecules and show, using competition assays, that either segment duplication or single nucleotide insertion can enhance DI RNA competitiveness. Possible mechanisms for the introduction of the modifications observed in these DI RNAs are discussed.

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Geological Field Guide To The Cedar Point Biological Station, Keith County, Nebraska, Robert F. Diffendal Jr., Roger K. Pabian Feb 1993

Geological Field Guide To The Cedar Point Biological Station, Keith County, Nebraska, Robert F. Diffendal Jr., Roger K. Pabian

School of Natural Resources: Faculty Publications

This field guide was produced by staff members of the Conservation and Survey Division of the University of Nebraska originally in 1979 at the request of Dr. Brent Nickol, former Director of the Cedar Point Biological Station. It is an introduction to the geologic history and paleoecology of the Cedar Point area intended for students, staff, and other persons using the camp. This revision has been made some 15 years after the first version to reflect changes in ideas resulting from new data collected during that time.

Users of this guide should take care when studying the rock exposures described …

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The Functional Analysis Of Nonsense Suppressors Derived From In Vitro Engineered Saccharomyces Cerevisiae TrnaTrp Genes, Audrey L. Atkin, M. A. Riazia, C. L. Greer, K. L. Roye, J. B. Bell Jan 1993

The Functional Analysis Of Nonsense Suppressors Derived From In Vitro Engineered Saccharomyces Cerevisiae TrnaTrp Genes, Audrey L. Atkin, M. A. Riazia, C. L. Greer, K. L. Roye, J. B. Bell

School of Biological Sciences: Faculty Publications

Nonsense suppressors derived from Saccharomyces cerevisiae tRNATrp genes have not been identified by classical genetic screens, although one can construct efficient amber (am) suppressors from them by making the appropriate anticodon mutation in vitro. Herein, a series of in vitro constructed putative suppressor genes was produced to test if pre-tRNATrp processing difficulties could help to explain the lack of classical tRNATrp-based suppressors. It is clear that inefficient processing of in-trons from precursor tRNATrp, or inaccurate overall processing, may explain why some of these constructs fail to promote nonsense suppression in vivo. However, deficient processing …

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Arabidopsis Glabrous1 Gene Requires Downstream Sequences For Function, John C. Larkin, David G. Oppenheimer, Susan Pollock, M. David Marks Jan 1993

Arabidopsis Glabrous1 Gene Requires Downstream Sequences For Function, John C. Larkin, David G. Oppenheimer, Susan Pollock, M. David Marks

School of Biological Sciences: Faculty Publications

The Arabidopsis GLABROUSl (GL1) gene is a myb gene homolog required for the initiation of trichome development. In situ hybridiration revealed that the highest levels of GL1 transcripts were present in developing trichomes. In contrast, previous work had shown that putative promoter sequences from the 5‘ noncoding region of the GL1 gene directed the expression of a β-glucuronidase (GUS) reporter gene only in stipules. Deletion analysis of the 3’ noncoding region of GL1 has identified an enhancer that is essential for GL1 function. Sequences fmm the region containing the enhancer, in conjunction with GL1 upstream sequences, direct the expression of …

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Meristic And Organogenetic Variation In Ruppia Occidentalis And R. Maritima, Robert B. Kaul Jan 1993

Meristic And Organogenetic Variation In Ruppia Occidentalis And R. Maritima, Robert B. Kaul

School of Biological Sciences: Faculty Publications

Floral meristic and organogenetic variation was sampled in Ruppia occidentalis from an alkaline lake of the Nebraska Sandhills and in Ruppia maritima var. rostrata from a saline, non-Sandhills lake nearby. The androecium is meristically stable, always having two stamens, but the gynoecium is not. Seventy-two percent of the flowers of R. maritima had four carpels and the others had three, and in 80% of inflorescences the two flowers had the same number. In about one-third of inflorescences having dissimilar carpel numbers, the four-carpellate flower was uppermost. The number of carpels in each flower of R. occidentalis ranged from four to …

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Molecular Approaches For Control Of Tomato Bushy Stunt Virus, H. B. Scholthof, M. Borja, Thomas Jack Morris, A. O. Jackson Jan 1993

Molecular Approaches For Control Of Tomato Bushy Stunt Virus, H. B. Scholthof, M. Borja, Thomas Jack Morris, A. O. Jackson

School of Biological Sciences: Faculty Publications

I N this overview strategies are discussed that are currently being tested in our laboratory in an effort to engineer resistance against tomato bushy stunt virus (TBSV) in plants. TBSV is chosen as a model-system since this is an economically important RNA virus that is well characterized at the molecular level and the virus has some interesting and potentially useful features that can be exploited to produce resistant plants. Moreover, we anticipate that the information derived from our studies with TBSV will be applicable in developing resistance to other plant viruses. Some approaches that we are attempting to apply to …

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Lek Formation In Sage Grouse: The Effect Of Female Choice On Male Territory Settlement, Robert M. Gibson Mar 1992

Lek Formation In Sage Grouse: The Effect Of Female Choice On Male Territory Settlement, Robert M. Gibson

School of Biological Sciences: Faculty Publications

Previous studies of female choice in sage grouse, Centrocercus urophasianus, have identified two processes that could drive the local clustering of male territories at leks: (1) fidelity of females to previous mating sites (“temporal spillover” hypothesis), and (2) “spatial spillover” of matings from an attractive male to his immediate neighbors (“hotshot” hypothesis). The effects of each process on male territory settlement were investigated using observations of the resettlement of vacant territories and of individual site fidelity during a 7-year field study. The frequency with which vacant territories were resettled both within and between seasons increased with mating success of …

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Characterization Of The TrnaTrp Genes Of Saccharomyces Cerevisiae, Audrey L. Atkin, R. W. Henry, K. L. Roy, J. B. Bell Jan 1992

Characterization Of The TrnaTrp Genes Of Saccharomyces Cerevisiae, Audrey L. Atkin, R. W. Henry, K. L. Roy, J. B. Bell

School of Biological Sciences: Faculty Publications

The purpose of this work was to examine the tRNATrp-encoding genes (tRNATrp) of Saccharomyces cerevisiae to gain insight as to why tRNATrp amber suppressors, isolated by conventional genetic techniques, have not been reported. The results herein indicate that the haploid yeast genome contains six tRNATrp genes which map to five or six chromosomes. Not only do the six genes have identical coding sequences but their introns are also identical. Gene replacement experiments indicate that five copies of tRNATrp are sufficient for cell viability. Thus, mutation of one tRNATrp gene to a suppressor in …

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The Costs Of Female Choice In A Lekking Bird, Robert M. Gibson, Gwendolyn C. Bachman Jan 1992

The Costs Of Female Choice In A Lekking Bird, Robert M. Gibson, Gwendolyn C. Bachman

School of Biological Sciences: Faculty Publications

We investigated the costs of active female choice in sage grouse, Centrocercus urophasianus, a lekking species in which females make repeated, lengthy visits to leks to assess males before mating. Several potential costs were measured by monitoring changes in hens' ranging behavior, time budgets, and encounter rates with predators when they visited leks. Two costs were identified: hens moved further per day and encountered golden eagles, Aquila chrysaetos, more frequently when visiting leks. However, extra travel due to visiting leks increased predicted daily energetic expenditure by only about 1%, and the risk of predation by golden eagles over …

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Mate Choice In Lekking Sage Grouse Revisited: The Roles Of Vocal Display, Female Site Fidelity, And Copying, Robert M. Gibson, Jack W. Bradbury, Sandra L. Vehrencamp Jul 1991

Mate Choice In Lekking Sage Grouse Revisited: The Roles Of Vocal Display, Female Site Fidelity, And Copying, Robert M. Gibson, Jack W. Bradbury, Sandra L. Vehrencamp

School of Biological Sciences: Faculty Publications

In lekking sage grouse (Centrocercus urophasianus), females exhibit relatively unanimous mate choice for particular males, but a satisfactory explanation for this unanimity has been elusive. We present analyses of mating distributions from two leks over 4 years that provide evidence for female choice based on differences in vocal display performance of males, the locations at which hens mated in the previous year, and the choices of other females (copying). The unanimity of female choice varied markedly among leks and years in correlation with changes in the mean numbers of hens that mated at the same time and hence …

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Survivorship And Recruitment In A Long-Lived Prairie Perennial, Ipomoea Leptophylla (Convolvulaceae), Kathleen H. Keeler Jul 1991

Survivorship And Recruitment In A Long-Lived Prairie Perennial, Ipomoea Leptophylla (Convolvulaceae), Kathleen H. Keeler

School of Biological Sciences: Faculty Publications

Little is known of the lifespans of herbaceous plants, especially in grasslands, although this information is basic to understanding the dynamics of species and ecosystems. Permanently marked plants of the bush morning glory, Ipomoea leptophylla (Convolvulaceae), in Nebraska sandhills prairie were censused annually from 1979-1989. While the average annual death rate was 2.6 per 100, virtually all the mortality was among smaller and probably younger plants. Recruitment varied greatly among years. Of plants of known age, the median age at first flowering was 6 yr. After 9 yr 30% had never flowered. Larger size classes flowered more frequently than smaller …

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Potential Impacts Of Biomass Production In The United States On Biological Diversity, James H. Cook, Jan Beyea, Kathleen H. Keeler Jan 1991

Potential Impacts Of Biomass Production In The United States On Biological Diversity, James H. Cook, Jan Beyea, Kathleen H. Keeler

School of Biological Sciences: Faculty Publications

Biomass could be a renewable source of energy and chemicals that would not add CO2 to the atmosphere. It will become economically competitive as its cost decreases relative to energy costs, and biotechnology is expected to accelerate this trend by increasing biomass productivity. Pressure to slow global warming may also make biomass more attractive. Substantial dependence on biomass would entail massive changes in land use, risking serious reductions in biodiversity through destruction of habitat for native species. Forests could be managed and harvested more intensively, and virtually all arable land unsuitable for high-value agriculture or silviculture might be used …

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Mitochondrial Malate Dehydrogenase From Corn, Marianne K. Hayes, Michael Hans Luethy, Thomas Elthon Jan 1991

Mitochondrial Malate Dehydrogenase From Corn, Marianne K. Hayes, Michael Hans Luethy, Thomas Elthon

School of Biological Sciences: Faculty Publications

A method to fractionate com (Zea mays L. B73) mitochondria into soluble proteins, high molecular weight soluble proteins, and membrane proteins was developed. These fractions were analyzed by both sodium dodecyl sulfate-polyacrylamide gel electrophoresis and assays of mitochondrial enzyme activities. The Krebs cycle enzymes were enriched in the soluble fraction. Malate dehydrogenase has been purified from the soluble fraction by a two-step fast protein liquid chromatography method. Six different malate dehydrogenase peaks were obtained from the Mono 0 column. These peaks were individually purified using a Phenyl Superose column. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the purified peaks showed that …

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Construction Of An Opal Suppressor By Oligonucleotide-Directed Mutagenesis Of A Saccharomyces Cerevisiae Trna Gene, Audrey L. Atkin, K. L. Roy, J. B. Bell Jan 1990

Construction Of An Opal Suppressor By Oligonucleotide-Directed Mutagenesis Of A Saccharomyces Cerevisiae Trna Gene, Audrey L. Atkin, K. L. Roy, J. B. Bell

School of Biological Sciences: Faculty Publications

In vitro mutagenesis was used to create putative opal suppressor alleles of a tRNATrp gene of Saccharomyces cerevisiae. The construct with the requisite anticodon change did not result in an active suppressor, whereas when a second change was introduced into the portion of the gene encoding the intron, an active and specific opal suppressor was produced. We propose that the secondary structure of transcripts from the first mutant may prevent efficient pre-tRNA processing, whereas normal processing occurs with the double mutant.

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The Functional Organization Of The Vestigial Locus In Drosophila Melanogaster, Jim A. Williams, Audrey L. Atkin, John B. Bell Jan 1990

The Functional Organization Of The Vestigial Locus In Drosophila Melanogaster, Jim A. Williams, Audrey L. Atkin, John B. Bell

School of Biological Sciences: Faculty Publications

Vestigial mutants are associated with imaginal disc cell death which results in the deletion of adult wing and haltere structures. The vestigial locus has previously been cloned, and mutational lesions associated with a number of vg alleles were mapped within a 19 kb DNA region defined as essential for vg function. Herein we report the identification and characterization of a developmentally regu-lated 3.8 kb vg transcript which is spliced from exons distributed throughout the essential interval defined above. All the characterized classical alleles have predictable effects on this transcription unit, and the severity of this effect is directly proportional to …

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Relationships Between Blood Parasites, Mating Success And Phenotypic Cues In Male Sage Grouse Centrocercus Urophasianus, Robert M. Gibson Jan 1990

Relationships Between Blood Parasites, Mating Success And Phenotypic Cues In Male Sage Grouse Centrocercus Urophasianus, Robert M. Gibson

School of Biological Sciences: Faculty Publications

In lek breeding Sage Grouse Centrocercus urophasianus in eastern California, male mating success is strongly correlated with individual differences in lek attendance, and in the rate and acoustic quality of courtship display, suggesting that these provide cues by which females choose mates. Increased lek attendance and high display rates also associated with elevated metabolic expenditure. This paper examines the hypothesis that the ability to commit energy to display is related to the incidence of blood parasites. A single hematozoan genus, Haemoproteus, was found in 37.5% of 184 Sage Grouse sampled over a five year period. Parasitism varied across years and …

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The Water Vapor Conductance Of Squamate Reptilian Eggs: The Influence Of Scaling On Nesting Ecology., Louis A. Somma Sep 1989

The Water Vapor Conductance Of Squamate Reptilian Eggs: The Influence Of Scaling On Nesting Ecology., Louis A. Somma

Papers in Herpetology

Flexible-shelled eggs of squamate reptiles are strongly influenced by their surrounding microclimate, particularly the hydric conditions of the nest. The eggshell water vapor conductance of an egg can be an indication of its requirement for water from the nest. Ackerman et al. (1985. Physiol. Zool. 58:129-137) have described the scaling relationship for eggshell water vapor conductance (GH2O) of flexible-shelled reptilian eggs (GH2O = 981.8M0.52). This scaling relationship was investigated with water vapor conductance data obtained from 8 species of lizards representing the families Iguanidae (Anolis carolinensis, A. sagrai, Sceloporus woodi, S. virgatus) …

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Field Playback Of Male Display Attracts Females In Lek Breeding Sage Grouse, Robert M. Gibson Jun 1989

Field Playback Of Male Display Attracts Females In Lek Breeding Sage Grouse, Robert M. Gibson

School of Biological Sciences: Faculty Publications

Recent correlational studies of lekking sage grouse suggest that male vocal display attracts females. To test this hypothesis further, the natural displays of a territorial male were supplemented with the tape-recorded display of another reproductively successful individual. Significantly, more females approached the speaker's location on days when the recording was played, and also on nonplayback days immediately following a playback, than on other nonplayback days. Analysis of male displays indicated that females were responding to the playback itself rather than to changes in male behavior. The "after-response" following a playback suggests that some females present during a playback remembered its …

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Trichome Development In Arabidopsis Thaliana. 1. T-Dna Tagging Of The Glabrous1 Gene, M. David Marks, Kenneth A. Feldmann Jan 1989

Trichome Development In Arabidopsis Thaliana. 1. T-Dna Tagging Of The Glabrous1 Gene, M. David Marks, Kenneth A. Feldmann

School of Biological Sciences: Faculty Publications

Progeny from a transformed Arabidopsis plant (produced by the Agrobacterium-mediated seed transformation procedure) were found to be segregating for an altered trichome phenotype. The mutant plants have normal leaf trichomes but completely lack trichomes usually found on the stem. The mutation is tightly linked to a T-DNA insert. Complementation analysis with genetically characterized trichome mutants revealed that the new mutation is an allele of the GL1 locus. The new trichome mutant has been designated gl1-43. DNA gel blot analysis indicated that the insert site contains a complex array of at least four tandemly linked T-DNA units oriented as both …

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Trichome Development In Arabidopsis Thaliana. Ii. Lsolation And Complementation Of The Glabrous1 Gene, Patricia L. Herman, M. David Marks Jan 1989

Trichome Development In Arabidopsis Thaliana. Ii. Lsolation And Complementation Of The Glabrous1 Gene, Patricia L. Herman, M. David Marks

School of Biological Sciences: Faculty Publications

We are using the formation of trichomes in Arabidopsis thaliana as a model system to study gene expression during cellular differentiation. To initiate the molecular characterization of this system, we tagged and isolated a gene that is specifically required for the development of the specialized trichome cell. We confirmed the identity of this gene, GLABROUS1 (GL1), by complementation. These results demonstrate that a crucial gene in a plant developmental pathway can be successfully identified by complementation.

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Elaphe Bairdi (Baird’S Rat Snake): Drinking Behavior., Louis A. Somma Jan 1989

Elaphe Bairdi (Baird’S Rat Snake): Drinking Behavior., Louis A. Somma

Papers in Herpetology

On 13 February 1988. at 1600 h. a captive-bred (hatched July 1985) male Elaphe bairdi (TL.136.9 cm, SVL .. 89.54 cm). maintained in a 50.5 x 25 x 30 cm terrerium was accidently splashed with water. As beads of water on the snake's head rolled down to the upper labial sceles. swallowing was observed. The water on the labial scales was drawn Into the mouth while It was closed. This behavior lasted 42 sec. This behavior was repeated 23 out of 24 trials conducted during the next 24 days. The duration of swallowing wes 9-62 sec (avg 35.8, N = …

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Effect Of Biotin Limitation On The Conversion Of Xylose To Ethanol And Xylitol By Pachysolen Tannophilus And Candida Guilliermondii, Hung Lee, Audrey L. Atkin, Maria F.S. Barbosa, Delbert R. Dorscheid, Henry Schneider Jan 1988

Effect Of Biotin Limitation On The Conversion Of Xylose To Ethanol And Xylitol By Pachysolen Tannophilus And Candida Guilliermondii, Hung Lee, Audrey L. Atkin, Maria F.S. Barbosa, Delbert R. Dorscheid, Henry Schneider

School of Biological Sciences: Faculty Publications

The relative amount of ethanol and xylitol accumulated in aerobic batch cultures of Pachysolen tannophilus and Candida guilliermondii on D-xylose depended on the extent of limitation by biotin. In high biotin media P. tannophilus favored ethanol production over that of xylitol while C. guilliermondii favored xylitol formation. However, as the extent of biotin limitation increased, the ratio of ethanol to xylitol produced by both organisms increased. The results are of interest in efforts to control such ratios.

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Cupular Structure In Paleotropical Castanopsis (Fagaceae), Robert B. Kaul Jan 1988

Cupular Structure In Paleotropical Castanopsis (Fagaceae), Robert B. Kaul

School of Biological Sciences: Faculty Publications

The structure and some developmental aspects of the cupules of 22 species of paleotropical Castanopsis are discussed and illustrated. Some species have cupules massively invested with strong, sharp spines, but others are less spiny, and some are nearly smooth. Most cupular armament results from spines produced axillary to the valvular scales and basally adnate to them. Columns of scales straddling the sutures between the cupular valves do not become spines, but the numerous scales elsewhere on the valves become somewhat spiny with age. Dehiscence in the spiny-valved species is mostly along the sutures. The smooth cupules of some species have …

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Dna Sequencing, Lyle R. Middendorf, John A. Brumbaugh Jan 1988

Dna Sequencing, Lyle R. Middendorf, John A. Brumbaugh

School of Biological Sciences: Faculty Publications

To sequence long strands of DNA, cloned strands having lengths longer than 100 bases are, in one embodiment, marked on one end with biotin. These strands are divided into 4 aliquots and each aliquot: (1) is uniquely chemically treated to randomly terminate the strands at the non-biotinylated end at a selected type of base; and (2) is moved continuously by electrophoresis through a different one of four identical channels. In the one embodiment, the strands are randomly terminated at a selected base type and they are moved into avidin, which due to high affinity, combines with the biotin marked ends …

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Reproductive Structure Of Lithocarpus Sensu Lato (Fagaceae): Cymules And Fruits, Robert B. Kaul Jan 1987

Reproductive Structure Of Lithocarpus Sensu Lato (Fagaceae): Cymules And Fruits, Robert B. Kaul

School of Biological Sciences: Faculty Publications

Seventy-three species were examined for structural and developmental details of the cymules and fruits. The cymules bear one to seven or more flowers and are subtended by one to nine or more bracteoles. Generally, the number of flowers and bracteoles in the pistillate cymules is the same or less than in the staminate ones. Some of the latter have an inner set of bracteoles that could be homologous to the pistillate cupule. Scales are present at anthesis on the cupules of all species examined, but in some species they fail to enlarge, are torn or disintegrate, or fall away as …

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Evolution And Reproductive Biology Of Inflorescences In Lithocarpus, Castanopsis, Castanea, And Quercus (Fagaceae), Robert B. Kaul Jan 1986

Evolution And Reproductive Biology Of Inflorescences In Lithocarpus, Castanopsis, Castanea, And Quercus (Fagaceae), Robert B. Kaul

School of Biological Sciences: Faculty Publications

Of Lithocarpus, Castanopsis, Castanea, and Quercus, only Lithocarpus frequently bears branched spikes suggestive of the primitive condition in the Fagaceae; the other genera sometimes have them in some individuals. Simple and branched spikes can occur on the same tree. Evolution of the simple spike is interpreted as the loss of branching capacity in the branched spikes. The Fagaceae show various transitional stages from perfect, entomophilous to imperfect, anemophilous flowers and from mixed-sex to unisexual spikes. Complete separation of staminate from pistillate function into separate spikes and catkins occurs only in Quercus, which is also the only …

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Sexual Selection In Lekking Sage Grouse: Phenotypic Correlates Of Male Mating Success, Robert M. Gibson, Jack W. Bradbury Dec 1985

Sexual Selection In Lekking Sage Grouse: Phenotypic Correlates Of Male Mating Success, Robert M. Gibson, Jack W. Bradbury

School of Biological Sciences: Faculty Publications

Mate choice cues in sage grouse were reinvestigated by analyzing relationships between male mating success and a range of suggested cues. Display cues were implicated by significant relationships between mating status (whether or not a male mated) and lek attendance, display rate (corrected for effects of female proximity and time of day) and an acoustic component related to temporal and frequency measures of a whistle emitted during the strut display. Although display rate and the acoustic component were intercorrelated, both exerted significant partial effects on mating success in multivariate analyses. These display measures also differed significantly between males. In contrast, …

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Extrafloral Nectaries On Plants In Communities Without Ants: Hawaii, Kathleen H. Keeler Jan 1985

Extrafloral Nectaries On Plants In Communities Without Ants: Hawaii, Kathleen H. Keeler

School of Biological Sciences: Faculty Publications

Since the Hawaiian Islands lack native ants, it was hypothesized that extrafloral nectaries, an ant-related mutualistic trait, should be lacking on native species. Presence of extrafloral nectaries (EFNs) on plants was determined by direct observation and related to vegetation structure and floral composition. Frequency of plants with EFNs was low by all possible comparisons. However, several endemic species had functional EFNs. The hypotheses to explain these anomalies are (1) phylogenetic inertia or (2) mutualism with some other organism than ants.

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