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Full-Text Articles in Life Sciences

Community Structure And Ecological Specialization In Plant-Ant Interactions, Paola Barriga Dec 2012

Community Structure And Ecological Specialization In Plant-Ant Interactions, Paola Barriga

Graduate Theses and Dissertations

Positive associations among species have contributed to the maintenance of biodiversity. These interactions are typically studied in pairwise fashion where two interacting organisms are the focus. This dissertation uses network theory to analyze positive plant-ant associations in three Neotropical forests. Obligate plant-ant mutualisms were used, where plants host the ants in domatia and provide food bodies while the ants protect the plants and can feed them. A network approach was used to depict all obligate plant-ant interactions within a community. The main questions asked at the community level were: 1) Do network structure and levels of specialization change geographically and, …


Effects Of Associated Subcortical Beetles On Oviposition Behavior And Early-Stage Survival Of Sirex Nigricornis F. (Hymenoptera: Siricidae), Ace J. Lynn-Miller Dec 2012

Effects Of Associated Subcortical Beetles On Oviposition Behavior And Early-Stage Survival Of Sirex Nigricornis F. (Hymenoptera: Siricidae), Ace J. Lynn-Miller

Graduate Theses and Dissertations

Sirex (Hymenoptera: Siricidae) woodwasps develop within xylem of host conifers. Sirex females drill through the bark, phloem and into xylem tissues where they deposit eggs along with a symbiotic Amylostereum fungus. The presence of Amylostereum is necessary for successful development of Sirex immatures as the larvae are unable to derive adequate nutrition from xylem in the absence of the fungus. The Eurasian woodwasp, Sirex noctilio F., was discovered in northeastern North America in 2004. Sirex noctilio has caused significant economic damage in Pinus radiata D. Don plantations of the southern hemisphere, but is of little economic significance in its native …


The Biological Control Of Spotted Knapweed In The Southeastern United States, Carey R. Minteer Dec 2012

The Biological Control Of Spotted Knapweed In The Southeastern United States, Carey R. Minteer

Graduate Theses and Dissertations

Spotted knapweed is an invasive, short-term-perennial plant that is native to Eurasia. It was accidentally introduced into North America in the early 1890's and has since spread across The United States and Canada. Spotted knapweed degrades rangelands and pastures by negatively impacting native plants, increasing soil surface runoff and stream sediment yields, and reducing soil infiltration. A biological control program for spotted knapweed using Larinus minutus (Coleoptera: Curculionidae), was initiated in Arkansas in 2008. In this dissertation I described the releases of L. minutus and investigated the adult activity in the southeastern United States (Chapter 1), investigated the effects of …


Effects Of Felled Shortleaf Pine (Pinus Echinata Mill.) Moisture Loss On Oviposition Preferences And Survival Of Sirex Nigricornis F. (Hymenoptera: Siricidae), Jessica Hartshorn Dec 2012

Effects Of Felled Shortleaf Pine (Pinus Echinata Mill.) Moisture Loss On Oviposition Preferences And Survival Of Sirex Nigricornis F. (Hymenoptera: Siricidae), Jessica Hartshorn

Graduate Theses and Dissertations

The European woodwasp, Sirex noctilio F. (Hymenoptera: Siricidae) utilizes pine as its host during larval development. Females drill through pine bark to deposit eggs, a symbiotic fungus, Amylostereum, and phytotoxic mucus into the tree. In their native range, these insects are not viewed as primary pests because they attack dead or dying trees. Over the last century, this woodwasp has been accidentally introduced into several countries in the southern hemisphere. Some regions have incurred millions of dollars in damage to large plantations of the widely planted pine species, radiata pine (Pinus radiata D. Don). Sirex noctilio was discovered …


Flight Period And Species Composition Of Sirex (Hymenoptera: Siricidae) And Associated Deladenus (Nematoda: Neotylenchidae) Within Arkansas Pine Forests, Danielle Keeler Aug 2012

Flight Period And Species Composition Of Sirex (Hymenoptera: Siricidae) And Associated Deladenus (Nematoda: Neotylenchidae) Within Arkansas Pine Forests, Danielle Keeler

Graduate Theses and Dissertations

The European woodwasp, Sirex noctilio F. (Hymenoptera: Siricidae), which is a known destructive pest of pine in the southern hemisphere was recently discovered in the eastern United States. Before we can understand how S. noctilio may affect pine forests throughout the United States, we need a better understanding of native Sirex and the role they play in the ecosystem. The objectives of this research were to 1) determine species composition and flight period for native Sirex; 2) confirm presence of parasitic nematodes, Deladenus (Nematoda: Neotylenchidae), within adult Sirex; 3) investigate Deladenus parasitism rates; 4) verify the number of Deladenus species …


The Role Of Ascorbic Acid In The Plant-Herbivore Interaction, Kelly Ann Carruthers May 2012

The Role Of Ascorbic Acid In The Plant-Herbivore Interaction, Kelly Ann Carruthers

Graduate Theses and Dissertations

Ascorbic acid (AsA), vitamin C, is an important molecule that is vital for both human and plant health, because it aids in the detoxification of reactive oxygen species (ROS) caused by various abiotic and biotic stresses including UV, salinity, ozone, and attack from pathogens In order to understand the role of AsA in the plant-herbivore interaction, we looked at the effects of the wound-responsive hormones, jasmonate, wounding, and herbivory on AsA content. Our study is the first to directly compare the effects of wounding and jasmonates on AsA levels in plants. We looked at the effects of wounding and methyl …


Early Season Population Dynamics And Residual Insecticide Effects On Bird Cherry-Oat Aphid, Rhopalosiphum Padi In Arkansas Winter Wheat, Beven Mcwilliams May 2012

Early Season Population Dynamics And Residual Insecticide Effects On Bird Cherry-Oat Aphid, Rhopalosiphum Padi In Arkansas Winter Wheat, Beven Mcwilliams

Graduate Theses and Dissertations

Bird cherry-oat aphid is a common pest of Arkansas winter wheat. This aphid vectors barley yellow dwarf virus which may cause extensive crop damage and yield loss when wheat is infested by virulent aphids in the fall. Some suggest this damage may be avoided using insecticide seed treatments if growers are unable to delay planting, as is recommended. Field population dynamics of bird cherry-oat aphid during fall 2009 and 2010 was assessed through random sampling of whole plants and pan trapping methods to evaluate aphid immigration. The field plots were divided into four subplots treated with a systemic insecticide seed …


Invertebrate Abundances And Diversity Of A Six Year Old Organic Apple Orchard In Northwest Arkansas, Cory Johnson, Brina Smith, Mary C. Savin Jan 2012

Invertebrate Abundances And Diversity Of A Six Year Old Organic Apple Orchard In Northwest Arkansas, Cory Johnson, Brina Smith, Mary C. Savin

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

Ground cover mulch applications in perennial systems can have multiple benefits, one of which may be to enhance the size and diversity of the ground surface faunal community. To determine if ground cover and organic fertilizer applications altered invertebrate communities, litters in an experimental 0.4-ha organic apple orchard in Fayetteville, Ark. were sampled during a four week period beginning in February 2012. The orchard was planted in 2006 in a replicated 4 × 3 factorial design with organic ground cover and fertilizer treatments applied annually each April. Invertebrates were extracted using Berlese funnels and hand sorting techniques. Ground covers (wood …


Instructions For Authors, Discovery Editors Jan 2012

Instructions For Authors, Discovery Editors

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.


Contents, Discovery Editors Jan 2012

Contents, Discovery Editors

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.


Discovery: The Student Journal Of Dale Bumpers College Of Agricultural, Food And Life Sciences - Volume 13 2012, Several Authors Jan 2012

Discovery: The Student Journal Of Dale Bumpers College Of Agricultural, Food And Life Sciences - Volume 13 2012, Several Authors

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.


Letter From The Dean, Michael Vayda Jan 2012

Letter From The Dean, Michael Vayda

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.


Population Structuring And Transmission Dynamics Of A Laboratory Colony Of Gromphadorholaelaps Schaeferi: A Symbiotic Mite Of The Madagascar Hissing Cockroach Gromphadorhina Portentosa, D. J. Richardson Jan 2012

Population Structuring And Transmission Dynamics Of A Laboratory Colony Of Gromphadorholaelaps Schaeferi: A Symbiotic Mite Of The Madagascar Hissing Cockroach Gromphadorhina Portentosa, D. J. Richardson

Journal of the Arkansas Academy of Science

Gromphadorholaelaps schaeferi is a symbiotic mite associated with the Madagascar hissing cockroach Gromphdorhina portentosa. The population structuring of G. schaeferi is described based on examination of 19,421 mites collected from 1,915 individuals of G. portentosa taken from a large laboratory colony. The mites exhibited an overall prevalence of 50.7% and mean intensity (+SE) of 20.0 (+0.6) with an infestation intensity range of 1-116, and relative abundance (+SE) of 10.1 (+0.4). Both prevalence and mean intensity of infestation exhibited a dramatic increase with increasing cockroach size/age. By the time cockroaches reach 40 mm the prevalence is nearly 100%. Mean intensity increases …


New Geographic Distribution Records For Centipedes (Chilopoda: Scolopendromorpha) In Arkansas, Including The First From Crowley's Ridge And The Grand Prairie, C. T. Mcallister, H. W. Robison, L. C. Thompson, M. B. Connior Jan 2012

New Geographic Distribution Records For Centipedes (Chilopoda: Scolopendromorpha) In Arkansas, Including The First From Crowley's Ridge And The Grand Prairie, C. T. Mcallister, H. W. Robison, L. C. Thompson, M. B. Connior

Journal of the Arkansas Academy of Science

No abstract provided.


New Geographic Distribution Records For Horsehair Worms (Nematomorpha: Gordiida) In Arkansas, Including New State Records For Chordodes Morgani And Paragordius Varius, H. W. Robison, C. T. Mcallister, B. Hanelt Jan 2012

New Geographic Distribution Records For Horsehair Worms (Nematomorpha: Gordiida) In Arkansas, Including New State Records For Chordodes Morgani And Paragordius Varius, H. W. Robison, C. T. Mcallister, B. Hanelt

Journal of the Arkansas Academy of Science

No abstract provided.