BACKGROUND Many behavioral responses to odors are synergistic, particularly in insects. In beetles, synergy often involves a pheromone and a plant odor, and pest management relies on them for the use of combined lures. To investigate olfactory synergy mechanisms, we need to distinguish synergistic effects from additive ones, when all components of the mixture are active. RESULTS As versatile ...

This review points out the problem of processing multiple sensory inputs and provides evidence that generalists suffer a disadvantage compared with specialists with respect to efficiency of host plant choice and discrimination. The specialists' mechanisms for improved efficiency are discussed as well as some of the processes that may be selected to increase processing efficiency in generalists....

The hypothesis of isolation by distance (IBD) predicts that genetic differentiation between populations increases with geographic distance. However, gene flow is governed by numerous factors and the correlation between genetic differentiation and geographic distance is never simply linear. In this study, we analyze the interaction between the effects of geographic distance and of wild or domest...

iii ACKNOWLEDGEMENTS I am deeply indebted to my advisor, Andrew Forbes, whose encouragement and support over the years has been invaluable. I wish to thank my committee, for their guidance, support and feedback. A special thanks goes to my lab-mates Amanda Nelson, Alaine Hippee, Kristina Ottens and Eric Tvedte for driving me crazy while keeping me sane over the past five years. Thank you to Eil...

Pihlgren, A. 2007. Small-scale structures and grazing intensity in semi-natural pastures effects on plants and insects. Doctor’s dissertation. ISSN 1652-6880, ISBN 91-576-7312-1. Semi-natural grasslands characterized by nutrient poor soils are among the most species-rich habitats in Europe and they harbour many red-listed species. The area of semi-natural grasslands has decreased drastically du...

Experiments were conducted to test whether the facultatively phytophagous predator Orius insidiosus (Say) (Heteroptera: Anthocoridae) ingested phloem, xylem or mesophyll contents from soybean plants (Glycine max L.). Potential uptake of phloem sap was examined by radiolabeling photosynthate with CO2 and then measuring the accumulation of radiolabeled metabolites in feeding animals. Most O. insi...

Glucose-averse (Glu/Glu) male German cockroaches, Blattella germanica, rejected brief exposures to glucose solutions despite food deprivation so extreme as to cause high mortality. In the 24-h period following 5 days of food deprivation, both Glu/Glu and wild-type (+/+) were given a continuous source of 1 M glucose solution. Although Glu/Glu visited the solution as frequently as +/ + , feeding ...

The armored scale Aulacaspis yasumatsui invaded the northern range of the cycad Cycas micronesica in 2003, and epidemic tree mortality ensued due to a lack of natural enemies of the insect. We quantified cycad demographic responses to the invasion, but the ecological responses to the selective removal of this foundation species have not been addressed. We use this case to highlight information ...