The Effects of Clearcutting and Glyphosate Herbicide Use on Parasitic Wasps in Maine Forests

Parasitic wasps (parasitoids) play an important role as natural enemies of insects and contribute substantially to world biodiversity (May, 1988), yet they have received relatively little attention outside of agricultural settings. Clearcut harvesting and herbicide (glyphosate) application are frequent and widespread disturbances in Maine forests that drastically alter the local environment. Parasitoids are particularly susceptible to disturbance for several reasons: 1) they are vulnerable to small changes in environmental conditions, 2) they occupy a high trophic level, and 3) many are host specific. However, there may be potential benefits of disturbance such as increased food resources (floral nectaries) and increased abundance and diversity of hosts. This thesis discusses a study of several wasp taxonomic families within managed forest in western Maine. To investigate the effects of clearcut timber harvesting and glyphosate application on parasitoids this study compared five forest treatment types to mature forest in western Maine (Somerset county). The forest types consisted of young (35 years since harvest) glyphosate treated clearcuts, young untreated clearcuts, old (1421 years since harvest) glyphosate treated clearcuts, old untreated clearcuts, plantations (1417 years since harvest, glyphosate treated, and planted with black spruce seedlings), and mature forest (more than 50 years old). Wasp communities were sampled using two malaise traps in each replicated forest treatment type throughout the summers of 2000 and 2001. To investigate the relationship between floral resources and parasitoid abundance in forest ecosystems, floral communities were sampled in each site along four 40m linear transects. Although not always significant, parasitoid abundance at the family level tended to be greater in plantations and lower in young clearcuts compared to mature forest. Braconidae abundance tended to be greater in old clearcuts compared to mature forest, but equivalent for other families. At the family level, parasitoid abundance was not affected by glyphosate. The effect of forest type on parasitoid morphospecies was inconsistent in 2000 and 2001. The effect of floral communities on wasp family abundance was inconsistent between years, but overall appeared to have no effect. However, the abundance of the native perennial plant, bunchberry (Cornus canadensis), was correlated with the abundance of Ichneumonidae, Braconidae, and Pompilidae, as well as several morphospecies. Chalcidoidea abundance was correlated with the abundance of wild strawberry (Fragaria spp.). Taken together, the results of this study suggest that clearcutting has an overall negative shortterm effect on parasitoid abundance, but a positive (particularly when replanted with spruce) or neutral longterm effect. These effects appear to be unrelated to floral community, but specific floral species may provide direct benefit or be indicators. Host availability, microclimate and habitat complexity are likely to be important factors to consider for future studies of this nature

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

Population dynamics and biological control of elongate hemlock scale, Fiorinia externa

Elongate hemlock scale (Fiorinia externa) is an invasive species from Japan that was first detected in the United States in 1908 and has established in most states where eastern hemlock (Tsuga canadensis ) occurs. Scale density is much higher in the US (21 to \u3e400 scales per 100 needles) compared to Japan (\u3c1 scale per 100 needles) despite the presence in both regions of the parasitoid Encarsia citrina that has been assumed to be responsible for low densities in Japan. I have found that phenology of the vulnerable scale stage was asynchronous with E. citrina flight throughout the eastern United States. This asynchrony was the result of overlapping life stages and generations of elongate hemlock scale throughout the growing season. This overlap appears to result from delayed senescence of first generation adult females. To investigate the impact of E. citrina on elongate hemlock scale, natural enemy exclusion experiments were conducted. I found that E. citrina exerts some control on elongate hemlock scale, but insufficient to maintain density at levels seen in its native Japan. Existing records of parasitoids of elongate hemlock scale in Japan are limited to the Kyoto area. I sampled the parasitoid community of elongate hemlock scale and other scales on hemlock throughout Japan. Sequence data from two gene loci, 28SD2 and COI, were used to identify the number of unique parasitoid species attacking scales on Japanese hemlocks. This sequence data was also used to identify possible cryptic species within E. citrina in Japan. Twenty-two genetically distinct parasitoids were identified (seven singletons). Eleven (three singletons) of these were from elongate hemlock scale. With the exception of E. citrina, parasitoids tended to be host species specific. No evidence of cryptic species within E. citrina was found. The parasitoids identified dramatically increase the number of elongate hemlock scale parasitoids previously reported and this study may lead to the identification of several potential biological control agents of elongate hemlock scale for introduction to the United States

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least 4 m. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the 6.5 m James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 yr, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit