Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 9 of 9

Full-Text Articles in Life Sciences

The Male-Male Tandem: A Novel Form Of Mate Guarding In Perithemis Tenera, Paul V. Switzer, Jaime K. Schultz Jan 2000

The Male-Male Tandem: A Novel Form Of Mate Guarding In Perithemis Tenera, Paul V. Switzer, Jaime K. Schultz

Paul V. Switzer

No abstract provided.


Proximate Constraints On Intruder Detection In The Dragonfly Perithemis Tenera (Odonata: Libellulidae): Effects Of Angle Of Approach And Background, Paul V. Switzer, Perri K. Eason Jan 2000

Proximate Constraints On Intruder Detection In The Dragonfly Perithemis Tenera (Odonata: Libellulidae): Effects Of Angle Of Approach And Background, Paul V. Switzer, Perri K. Eason

Paul V. Switzer

The implications of insects’ vision for territorial defense have been relatively little studied in the field. In the dragonfly Perithemis tenera Say we investigated whether either the angle at which an intruder was viewed by a territorial resident or the background against which it was viewed affected the detection of that intruder. Residents detected intruders at a greater distance if the intruders were directly in front of them; they also detected more intruders in front of them than from other angles. Intruders viewed against distant vegetation were detected more readily than were intruders against near vegetation. Residents detected more intruders …


Proximate Constraints On Intruder Detection In The Dragonfly Perithemis Tenera (Odonata: Libellulidae): Effects Of Angle Of Approach And Background, Paul Switzer, Perri Eason Jan 2000

Proximate Constraints On Intruder Detection In The Dragonfly Perithemis Tenera (Odonata: Libellulidae): Effects Of Angle Of Approach And Background, Paul Switzer, Perri Eason

Faculty Research & Creative Activity

The implications of insects’ vision for territorial defense have been relatively little studied in the field. In the dragonfly Perithemis tenera Say we investigated whether either the angle at which an intruder was viewed by a territorial resident or the background against which it was viewed affected the detection of that intruder. Residents detected intruders at a greater distance if the intruders were directly in front of them; they also detected more intruders in front of them than from other angles. Intruders viewed against distant vegetation were detected more readily than were intruders against near vegetation. Residents detected more intruders …


Effects Of Leafy Spurge (Euphorbia Esula) Infestation On Breeding Birds Of The Sheyenne National Grassland, Nd, Daniel M. Scheiman Jan 2000

Effects Of Leafy Spurge (Euphorbia Esula) Infestation On Breeding Birds Of The Sheyenne National Grassland, Nd, Daniel M. Scheiman

Masters Theses

Leafy spurge (Euphorbia esula) is an exotic invasive weed in the northern Great Plains. We examined the effects of leafy spurge infestation on densities and nest success of breeding birds in grasslands on the Sheyenne National Grassland (SNG), ND. We categorized spurge-infested grasslands into three levels of infestation, based on the area covered by spurge patches: (a) low (0-20%), (b) medium (20-60%) and, (c) high (> 60%). We surveyed 60 100-m radius circular plots (20 in each category), and searched for nests in three 16-ha plots (one in each category). There were no statistically significant differences in mean species richness …


Impacts Of White-Tailed Deer Grazing On Spring Wildflower Communities, Faye Frankland Jan 2000

Impacts Of White-Tailed Deer Grazing On Spring Wildflower Communities, Faye Frankland

Masters Theses

High deer densities on state forests and nature preserves throughout Illinois have prompted concerns that deer are impacting the growth, survival, and reproduction of spring-flowering herbaceous plants. I investigated the impacts of white-tailed deer (Odocoileus virginianus) on the herbaceous vegetation, particularly spring wildflowers, at Beall Woods Nature Preserve (BWNP). BWNP was selected as the site for this study because it supports a diverse community of spring wildflowers and a large deer population. The objectives for this study were to: (1) quantify the extent of deer foraging on representative spring-flowering plant species at Beall Woods Nature Preserve, (2) investigate the effects …


Prairie Analysis At Prairie Ridge State Natural Area, Jasper County, Il, Annette Kessler Jan 2000

Prairie Analysis At Prairie Ridge State Natural Area, Jasper County, Il, Annette Kessler

Masters Theses

Five restored prairie sites at Prairie Ridge State Natural Area in Jasper County were studied during the growing season of 1998. These sites varied in age from two years to thirty years and in size from 4 acres to 10 acres. Key areas of data recorded were an overall and site specific vascular species lists, phenology of various species, and cover analysis of each site. Frequency cover and importance values of the taxa were determined using randomly located quadrats along line transects. Prairie quality of each site was determined, as well as a similarity index that compared the sites to …


The Male-Male Tandem: A Novel Form Of Mate Guarding In Perithemis Tenera, Paul Switzer, Jaime Schultz Jan 2000

The Male-Male Tandem: A Novel Form Of Mate Guarding In Perithemis Tenera, Paul Switzer, Jaime Schultz

Faculty Research & Creative Activity

No abstract provided.


The Male-Male Tandem: A Novel Form Of Mate Guarding In Perithemis Tenera, Paul V. Switzer, Jaime K. Schultz Jan 2000

The Male-Male Tandem: A Novel Form Of Mate Guarding In Perithemis Tenera, Paul V. Switzer, Jaime K. Schultz

Faculty Research & Creative Activity

No abstract provided.


Proximate Constraints On Intruder Detection In The Dragonfly Perithemis Tenera (Odonata: Libellulidae): Effects Of Angle Of Approach And Background, Paul V. Switzer, Perri K. Eason Jan 2000

Proximate Constraints On Intruder Detection In The Dragonfly Perithemis Tenera (Odonata: Libellulidae): Effects Of Angle Of Approach And Background, Paul V. Switzer, Perri K. Eason

Faculty Research & Creative Activity

The implications of insects’ vision for territorial defense have been relatively little studied in the field. In the dragonfly Perithemis tenera Say we investigated whether either the angle at which an intruder was viewed by a territorial resident or the background against which it was viewed affected the detection of that intruder. Residents detected intruders at a greater distance if the intruders were directly in front of them; they also detected more intruders in front of them than from other angles. Intruders viewed against distant vegetation were detected more readily than were intruders against near vegetation. Residents detected more intruders …