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

Digital Commons Network™

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

Entomology

Selected Works

2002

Articles 1 - 4 of 4

Full-Text Articles in Entire DC Network

An Inexpensive, Accurate Method For Measuring Leaf Area And Defoliation Through Digital Image Analysis, Matthew E. O'Neal, Douglas A. Landis, Rufus Isaacs Dec 2002

An Inexpensive, Accurate Method For Measuring Leaf Area And Defoliation Through Digital Image Analysis, Matthew E. O'Neal, Douglas A. Landis, Rufus Isaacs

Matthew E. O'Neal

We report a protocol using a common desk-top scanner and public domain software for measuring existing leaf area and leaf area removed as a result of herbivory. We compared the accuracy and precision of this method to that of a standard leaf area meter. Both methods were used to measure metal disks of a known area, the area of soybean (Glycine max L.) leaves, and the area removed by simulating leaf feeding with a hole-punch. We varied the amount of injury across a low, medium, and high degree of simulated feeding. The mean area of 10 cm2 and 50 cm2 …

Go to article

Costs Of Reproduction In The Terrestrial Isopod Porcellio Laevis Latreille (Isopoda: Oniscidea): Brood-Bearing And Locomotion, Scott Kight Jan 2002

Costs Of Reproduction In The Terrestrial Isopod Porcellio Laevis Latreille (Isopoda: Oniscidea): Brood-Bearing And Locomotion, Scott Kight

Scott Kight

Female terrestrial isopods carry eggs and young throughout early development, a habit that places constraints on reproductive success. One such constraint is impaired locomotion during the brooding period. Brooding and non-brooding females were subjected to a negative-phototaxis experiment in which females moved away from a light source along a graduated surface. In both groups, velocity was positively and significantly correlated with distance traveled. Velocity and distance were also significantly associated with the physical dimensions of the exoskelton: larger females moved greater distances at faster speeds. Non-brooding females, however, moved significantly farther at significantly greater velocities than brooding females, suggesting that …

Go to article

Individual Variation In The Duration Of Territory Occupation By Males Of The Dragonfly Perithemis Tenera (Odonata: Libellulidae), Paul V. Switzer Jan 2002

Individual Variation In The Duration Of Territory Occupation By Males Of The Dragonfly Perithemis Tenera (Odonata: Libellulidae), Paul V. Switzer

Paul V. Switzer

In the dragonfly Perithemis tenera Say, males defend territories around oviposition sites and defense of a site is critical for reproductive success. This study first demonstrated that individual males varied consistently in how long they defended a particular territory within a day (their “tenure”) and in the quality of the sites they defended. I then investigated a number of factors that may have affected territory tenure and may have led to the observed variation among males. Territory occupations that ended “voluntarily” were significantly longer than those that ended because the male was evicted from his territory. For voluntary desertions, tenure …

Go to article

Host Effects On Herbivory And Pollination In A Hemiparasitic Plant, Lynn Adler Jan 2002

Host Effects On Herbivory And Pollination In A Hemiparasitic Plant, Lynn Adler

Lynn Adler

The indirect effects of hosts on interactions between parasites and other species are not well understood, and it may be difficult to predict the outcome of host species effects on parasite performance due to the complexity of potential direct and indirect effects. For example, parasitic plants obtain defensive compounds as well as nutrients from their hosts, and thus many attributes of parasitic plants are dependent on the quality of their host species. Here I measure the effect of a lupine host species (Lupinus argenteus) compared to other host species on herbivory, pollination, and female plant fitness in the hemiparasite Indian …

Go to article