Kenneth F Raffa

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I between plants and insects encompass half of all ecological relationships (Strong et al. 1984), yet natural constraints keep most species from undergoing widescale population eruptions. Understanding the dynamics of eruptive species can provide valuable insights into fundamental ecological processes such as ecosystem disturbance, multitrophic(More)
Scolytid bark beetles that colonize living conifers are frequently associated with specific fungi that are carried in specialized structures or on the body surface. These fungi are introduced into the tree during the attack process. The continuing association suggests that there is mutual benefit to the fitness of both beetles and fungi. The fungal species(More)
Little is known about bacteria associated with Lepidoptera, the large group of mostly phytophagous insects comprising the moths and butterflies. We inventoried the larval midgut bacteria of a polyphagous foliivore, the gypsy moth (Lymantria dispar L.), whose gut is highly alkaline, by using traditional culturing and culture-independent methods. We also(More)
Climate-driven vegetation mortality is occurring globally and is predicted to increase in the near future. The expected climate feedbacks of regional-scale mortality events have intensified the need to improve the simple mortality algorithms used for future predictions, but uncertainty regarding mortality processes precludes mechanistic modeling. By(More)
By defining the somatic embryo developmental stage which expressed β-glucuronidase (GUS) at a high level yet was also competent to form embryogenic callus at a high frequency under selection, we obtained transformed Picea glauca (white spruce) embryogenic callus, embryos and seedlings expressing GUS in all cells. Plasmid DNA, containing three chimeric(More)
Bacillus thuringiensis is the most widely applied biological insecticide and is used to manage insects that affect forestry and agriculture and transmit human and animal pathogens. This ubiquitous spore-forming bacterium kills insect larvae largely through the action of insecticidal crystal proteins and is commonly deployed as a direct bacterial spray.(More)
1. Colonisation of host trees by an endophytic herbivore, the spruce beetle, Dendroctonus rufipennis , is accompanied by invasion of its galleries by a number of fungal species. Four of these associated species were identified as Leptographium abietinum , Aspergillus fumigatus , Aspergillus nomius , and Trichoderma harzianum . 2. Trichoderma and Aspergillus(More)
Chemical, physiological and behavioral components of pheromone communication have been described for a number of bark beetle species, yet our understanding of how these signals function under natural conditions remains relatively limited. Development of ecologically based models is complicated by the multiple functions and sources of variability inherent in(More)
Microbial communities comprise an interwoven matrix of biological diversity modified by physical and chemical variation over space and time. Although these communities are the major drivers of biosphere processes, relatively little is known about their structure and function, and predictive modeling is limited by a dearth of comprehensive ecological(More)
Commensalmicroorganismshave signiÞcant impacts on thehealthofmany insecthosts. Little is known, however, about the structure of commensal bacterial communities associatedwith the Cerambycidae, despite the important roles this large family of herbivorous endophytic insects plays in ecosystem processes, economic losses to ornamental and forest trees, and(More)