A study of the host range and distribution of ticks and chiggers
(Acari) was undertaken in two contrasting forested areas of western
Oregon. Acarines were sampled from host mammals which were
trapped along line transects laid out in both areas, each consisting of
18 stations 50 feet apart. Hosts were...
The communicative behavior of five species and subspecies of
Tropisternus Solier (Coleoptera: Hydrophilidae) was studied. These
aquatic beetles have stress and calling chirps (both sexes), a second
male calling signal (one species), a single male courtship sound
(usually), a male copulatory sound, and a female aggressive rejection
buzz (three species)....
The western cherry fruit fly, Rhagoletis indifferens
Curran, was studied to determine the suitability of the
sterile insect technique for its control. To obtain
insect material, field collection of maggots is preferred
to sifting of soil or rearing on artificial diet.
The western cherry fruit fly is strictly univoltine;
only...
The purpose of this study was to examine various host and microclimatic influences affecting the survival and development of the flatheaded fir borer, Melanophila drummondi (Kirby) in Douglas fir, Pseudotsuga menziesii (Mirbel) Franco residues. It also expands current knowledge of the biology, bionomics, life history, ecology, and biotic potential for...
Prothoracicotropic hormone has been partially purified
from whole heads of tobacco hornworm larvae, Manduca sexta.
Activity was followed with a larval bioassay. Activity was
purified 4400 fold from crude extracts. The hormone was
found to be a heat-stable polypeptide with an approximate
molecular weight of 25,000 Daltons. The hormone has...
Aggregation and species association of 9 species of phytophagous and
predaceous mites were studied for 6 yr in an orchard with 100, 2 m tall 'Red
Delicious' apple trees. To quantify aggregation, a method was developed that is
powerful, and easily interpreted. It relates the proportion of habitat occupied to...
Behavioral responses exhibited by the Douglas-fir beetle,
Dendroctonus pseudotsugae Hopkins, to various attractant sources
were investigated under both laboratory and field conditions. Tests
were designed to observe olfactory responses. Results were correlated
and compared with collections from sampling nets and with
emergence patterns. Field data were collected during the flight...
The early stages of secondary succession of the
McDonald and Paul Dunn State Forests, Corvallis, Oregon,
were grouped into three stages; herb, herb-shrub, and
shrub, based on vegetation types. Flowers of herbaceous
species and residual shrubs dominated in the early years
after clear-cutting. Woody plants became increasing
abundant in the...
Meadowfoam (cultivar Mermaid) is an entomophilous
winter annual oilseed crop that has historically produced
an average of only two of five seeds per flower. Reference
to inadequate meadowfoam pollination exists in the literature,
but quantitative evidence is lacking. Studies were
undertaken to: 1) quantify meadowfoam pollination requirements
and 2) evaluate...
The probing behavior and feeding activity of green peach aphid, Myzus persicae
Sulzer, on Bacillus thuringiensis ssp. tenebrionis- transgenic potatoes, insecticide
treated potatoes, and host plants with different preference were electronically
monitored. I found that first, transgenic potatoes had no effect on green peach aphid
probing suggesting that transmission of...
The eruption of Mt. St. Helens provided the
opportunity to study secondary production of grazing insects in the context of disturbance. Two stream sites were chosen that significantly differed in how their
watersheds were impacted by the eruption. Clearwater Creek was catastrophically disturbed (physical alteration of habitat, loss of riparian...
Biology of Scaptomyza apicalis Hardy (Diptera: Drosophilidae) was studied in
relation to its host, meadowfoam, Limnanthes alba, a recent oil seed crop grown in the
Willamette Valley, Oregon. Populations of flies and larvae were monitored weekly over
three consecutive crop-years beginning in 1996. Yellow sticky traps gave relative
population estimates...
Understanding the mechanisms that regulate local species diversity and community structure is a perennial goal of ecology. Local community structure can be viewed as the result of numerous local and regional processes; these processes act as filters that reduce the regional species pool down to the observed local community. In...
Sprawled-posture insects exhibit a remarkable ability to rapidly run in a stable manner
over complex terrain, a feat that has yet to be equaled by man-made legged robots.
Recent experimental results suggest that these insects may employ a hierarchical
control structure, in which locomotion performance emerges from a combination of...
Role of temperature and photoperiod on development of the filbert leafroller, Archips rosanus L., (Lepidoptera: Tortricidae) from the Willamette Valley, Oregon was studied in the laboratory and in the field. Both temperature and photoperiod had a significant influence on the developmental rate of this species from neonate larva to adult...
My thesis explored the effects of environmental variability on population
dynamics and community composition of aquatic insects. Environmental variability in
the form of flow regime in streams can limit the distribution and life-history traits of
aquatic insects. I used tributaries to the McKenzie River in Oregon with dramatically
different flow...
Seven streams, one of them permanent, were studied in
western Oregon, USA. The research was designed to assess
the value of summer-dry headwaters for conservation
oriented landscape management. Streams were categorized
primarily according to exposure (forest versus meadow
sites) and secondarily according to flow duration
(ephemeral = short-flow versus temporary...
E8,E10-dodecadien-1-ol, the primary component of the female sex pheromone of codling moth, Cydia pomonella L., has no attraction to male Oriental fruit moth (OFM), C. molesta (Busck). However, this compound when added to the OFM pheromone blend of Z8-dodecenyl acetate (85.5%), E8-dodecenyl acetate (5.5%), and Z8- dodecen -1 -ol (9.0%),...
The biology and behavior of the codling moth, Cydia pomonella (L.), was studied to
determine factors responsible for differences in susceptibility to moth damage among apple
and pear cultivars.
In release experiments, codling moth adults were intercepted in significantly greater
numbers in host (apple, pear) than in non-host (maple) trees,...
Aquatic insects are used extensively to evaluate water quality. Despite their
widespread use as indicator organisms, relatively little is known about the
organismal characteristics that determine sensitivity differences to individual and
multiple stressors. Insects have evolved several respiratory strategies that range
from breathing atmospheric air to utilizing dissolved oxygen in...
The Colorado potato beetle (CPB), Leptinotarsa decemlineata (Say), is the most devastating foliage-feeding pest of potatoes in the United States. Potential biological control agents include the nematodes Heterorhabditis marelatus Liu & Berry and Steinernema riobrave Cabanillas, Poinar & Raulston, which provided nearly 100% CPB control in previous laboratory trials. In...
Three studies on Douglas-fir beetle (DFB), Dendroctonuspseudotsuae, were conducted to investigate its basic and applied biology. Studies included investigations into the spatial relationship of DFB infestations over multiple years and multiple landscapes, relationships between DFB brood adult lipid levels and position of development along the length of tree boles, and...
Aquatic insects are essential components of healthy stream ecosystems, contributing to nutrient cycling, trophic dynamics and other ecological functions. Aquatic insect species, particularly those in the orders Ephemeroptera, Plecoptera and Trichoptera (EPT taxa) are however, extremely sensitive to insecticide contamination. Given that urban and agricultural use of synthetic pyrethroid insecticides...
Drosophila suzukii Matsumura (Diptera: Drosophilidae) are small invasive flies that in the past five years (2009-2014) invaded berry and stone fruit production regions in Europe and the Americas. Evolutionary adaptations, biological traits, and anthropogenic factors have contributed to its current status as a global pest. Females oviposit eggs into ripe...
The cinnabar moth (Tyria jacobaeae (L.), Lepidoptera: Arctiidae) is an icon in
population ecology and biological control that has recently lost its shine based on evidence
that (1) it is less effective than alternatives (such as the ragwort flea beetle Longitarsus
jacobaeae (Waterhouse) (Coleoptera: Chrysomelidae) for controlling ragwort Senecio
jacobaea...
Conservation biological control involves manipulating farm landscapes or management systems to enhance populations of beneficial predators of agricultural pests. Farmscaping is one aspect of conservation biological control where predators of important pests are identified, the availability on the farm landscape of resources and habitat components needed by the beneficials to...
A study consisting of three parts was undertaken to investigate how variation in species interactions, population genetic structure, epidemiological parameters, and plant breeding system may influence the ecology and biological control of an apomictic invasive plant, Chondrilla juncea (Asteraceae). Interactions between natural enemy species may modify their net effect on...