62 research outputs found

    Effect of White Spruce Release on Subsequent Defoliation by the Yellowheaded Spruce Sawfly, Pikonema Alaskensis (Hymenoptera: Tenthredinidae)

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    Hand release of 22 5-year-old white spruce, Picea glauca (Moench) Voss, dramatically increased the amount of defoliation by the yellowheaded spruce sawfly, Pikonema alaskens is . The percent defoliation of the released trees was six times the defoliation in the control trees. A light overstory for young white spruce is suggested as a silvicultural method of reducing defoliation by this sawfly

    Estimating the Number of Eggs per Egg Mass of the Forest Tent Caterpillar, Malacosoma Disstria (Lepidoptera: Lasiocampidae)

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    Calculation of the number of eggs per egg mass of the forest tent caterpillar, Malacosoma disstria Hiibner, is required in survey and population studies. Eggs are usually laid in cylindrical masses around twigs of trees. Hodson (1941) determined the number of eggs in egg masses of the forest tent caterpillar by counting the number of eggs around the circumference and multiplying by the number of rows. This technique is apparently reliable for comparative counts, but because the eggs are frequently laid in oblique rather than straight rows on the twig, counts of both length and circumference are subject to error. In addition, adjacent rows are often offset to form a honeycomb pattern which leads to inaccuracies in length and circumference counts. Because of these shortcomings, we developed a quicker and more accurate method not subject to the effects of oblique or honeycomb egg patterns

    Eastern Pine Seedworm, \u3ci\u3eCydia Toreuta\u3c/i\u3e (Lepidoptera: Tortricidae) in Red Pine Cones in Wisconsin

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    Cydia toreuta population densities, prolonged diapause behavior, parasitism and adult emergence patterns were examined over four years at two red pine locations in Wisconsin. Last-instar densities ranged from 0.54 to 3.18 per cone. This was considered a wide range for this species in red pine. Population clumping was evident at last-instar densities below 2.90, however no consistent pattern was evident between years. Clumping disappeared at populations greater than 2.90 last-instars. Prolonged diapause varied from 7.8 to 38.9070. Parasitism rates var­ ied from 10.9 to 46.6 %. Phanerotoma toreuta (Hymenoptera: Braconidae) was the most abundant parasite at both sites and emerged in unison with male C. toreuta. Estimation of percent of last-instars undergoing prolonged diapause prior to spring emergence can be accomplished using forced emergence though cones should be collected after 31 January. Estimation of percent parasitism can be made as early as November. Resident moth populations could be estimated prior to spring flight utilizing this information. Emergence occurred over an approximately 2 week period between mid-May and early June. The majority of male moths emerged prior to females

    A Study in the Summer Phenology of Dionychious Spiders from Northern Minnesota Forests

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    Dionychious ground layer spiders from Larix and Populus stands were collected by pitfall traps. The typical pattern of dominant, influent and accessory species was well marked. Populus stands had greater diversity of species than Larix stands. Those species characterized by large male:female sex ratios had sharp peaks in the first month of collecting, and others had smaller early season peaks or early season and late season peaks. Traps with an apron leading to the trap caught twice as many specimens compared to traps without an apron

    Introduction of Parasites of the Larch Sawfly in Minnesota

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    Olesicampe benefactor Hinz and the Bavarian strain of Mesoleius tenthredinis Morley, European ichneunionid parasites of the larch sawfly, Pristiphora erichsonii (Hartig), were introduced into northern Minnesota from Manitoba in 1971 and 1972. Both species are now established. There was also natural spread of 0. benefactor into Minnesota from Manitoba releases in 1961 at a point ca. 200 miles northwest of the Minnesota plots

    Urochordate Histoincompatible Interactions Activate Vertebrate-Like Coagulation System Components

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    The colonial ascidian Botryllus schlosseri expresses a unique allorecognition system. When two histoincompatible Botryllus colonies come into direct contact, they develop an inflammatory-like rejection response. A surprising high number of vertebrates' coagulation genes and coagulation-related domains were disclosed in a cDNA library of differentially expressed sequence tags (ESTs), prepared for this allorejection process. Serine proteases, especially from the trypsin family, were highly represented among Botryllus library ortholgues and its “molecular function” gene ontology analysis. These, together with the built-up clot-like lesions in the interaction area, led us to further test whether a vertebrate-like clotting system participates in Botryllus innate immunity. Three morphologically distinct clot types (points of rejection; POR) were followed. We demonstrated the specific expression of nine coagulation orthologue transcripts in Botryllus rejection processes and effects of the anti-coagulant heparin on POR formation and heartbeats. In situ hybridization of fibrinogen and von Willebrand factor orthologues elucidated enhanced expression patterns specific to histoincompatible reactions as well as common expressions not augmented by innate immunity. Immunohistochemistry for fibrinogen revealed, in naïve and immune challenged colonies alike, specific antibody binding to a small population of Botryllus compartment cells. Altogether, molecular, physiological and morphological outcomes suggest the involvement of vertebrates-like coagulation elements in urochordate immunity, not assigned with vasculature injury
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