CONSUMPTION OF VARIOUS DOUGLAS-FIR CONE STRUCTURES BY BARBARA COLFAXIANA (LEPIDOPTERA: OLETHREUTIDAE)

1977 ◽  
Vol 109 (9) ◽  
pp. 1293-1294
Author(s):  
T. Evan Nebeker
Keyword(s):  
Energy Transfer ◽  
Seed Production ◽  
Energy Budget ◽  
Forest Ecosystem ◽  
Larval Stage ◽  
Douglas Fir ◽  
National Forest ◽  
Larval Instars ◽  
Production Area

During 1971 a study was conducted to determine the amount of the various Douglasfir cone structures (bracts, scales, and seeds) consumed by the Douglas-fir cone moth, Barbara colfaxiana (Kft.), in the Buckhead Seed Production Area, Willamette National Forest, Oregon. It was not the intent of this study to develop a complete energy budget for B. colfaxiana, but rather to determine the number of calories consumed, on the average, by an individual during the larval stage. The behavior of the various larval instars has been discussed by Radcliffe (1952), Keen (1958), Hedlin (1960), and Nebeker (1977). The calorie was selected as the unit of measure due to its usefulness in modeling energy transfer from one component to another in the forest ecosystem.

A PARTIAL LIFE TABLE FOR THE DOUGLAS-FIR CONE MOTH, BARBARA COLFAXIANA (LEPIDOPTERA: OLETHREUTIDAE)

1977 ◽  
Vol 109 (7) ◽  
pp. 943-951 ◽  
Author(s):  
T. Evan Nebeker
Keyword(s):  
Life Table ◽  
Seed Production ◽  
Critical Factor ◽  
Douglas Fir ◽  
National Forest ◽  
Production Area ◽  
Critical Age

AbstractA population of the Douglas-fir cone moth, Barbara colfaxiana (Kft.), was studied on the Buckhead Seed Production Area, Lowell Ranger District, Willamette National Forest, Oregon, during 1971. Factors contributing to the mortality of B. colfaxiana are presented in a partial life table and discussed. The egg – instar I was identified as the critical age interval and resinosis the critical factor.

LIFE CYCLE OF THE NYMPH FLY PALAEODIPTERON WALKERI IDE 1965 (DIPTERA: NYMPHOMYIIDAE) IN THE WHITE MOUNTAINS OF SOUTHERN QUÉBEC

1989 ◽  
Vol 121 (7) ◽  
pp. 603-607 ◽  
Author(s):  
P.P. Harper ◽  
Michel Lauzon
Keyword(s):  
Life Cycle ◽  
Larval Stage ◽  
White Mountains ◽  
Larval Instars ◽  
The Third ◽  
Summer Generation

AbstractCollections of larvae over 1 year in the River Clinton in the White Mountains of southern Québec indicated that Palaeodipteron walkeri Ide is bivoltine and that there are five larval instars. In April, larvae were in their fourth and fifth instars. Adults emerging in May and June gave rise to a summer generation in which most individuals emerged in August and September. The offspring of these adults, together with stragglers from the summer generation, formed an overwintering generation. Overwintering was completed in the larval stage, mainly the third and fourth instars. There was some growth in winter and development increased in the spring. Our data were compared with previously published observations; although no discrepancy occurred, our interpretation was different. Previous schemes proposed for the life cycle in this species were based on few specimens and lacked winter observations.

Black Bears Prefer Urea-Fertilized Trees

1989 ◽  
Vol 4 (1) ◽  
pp. 13-15 ◽  
Author(s):  
E. E. Nelson
Keyword(s):  
Pseudotsuga Menziesii ◽  
Dominant Species ◽  
Tree Mortality ◽  
Ursus Americanus ◽  
Douglas Fir ◽  
Black Bears ◽  
National Forest ◽  
Feeding Damage ◽  
Mount Hood ◽  
The Difference

Abstract Feeding damage by black bears (Ursus americanus) to urea-fertilized 25-yr-old Douglas-firs (Pseudotsuga menziesii) in the Mount Hood National Forest, Oregon, resulted in tree mortality four times as severe as among unfertilized trees. Damage was most apparent following application of urea at 448 kg N/ha in 1972, and 224 kg N/ha in 1977. Only Douglas-fir, the dominant species in the stand, was attacked. Attacked trees were somewhat larger than the stand average, but the difference was not significant. Bears appeared to be attracted to the more vigorous trees, which were on fertilized plots. West. J. Appl. For. 4(1):13-15, January 1989.

scholarly journals Larval predation on different instars in blowfly populations

2004 ◽  
Vol 47 (6) ◽  
pp. 887-894 ◽  
Author(s):  
Lucas Del Bianco Faria ◽  
Wesley Augusto Conde Godoy ◽  
Sérgio Furtado dos Reis
Keyword(s):  
Larval Stage ◽  
Choice Experiments ◽  
Predation Rate ◽  
Predatory Behavior ◽  
Larval Instars ◽  
Chrysomya Megacephala ◽  
Chrysomya Albiceps ◽  
Cochliomyia Macellaria ◽  
Third Instar Larvae

During its larval stage, Chrysomya albiceps (Diptera: Calliphoridae) is a facultative predator on other blowflies. In this study, we evaluated the predation by third instar larvae of C. albiceps on first, second and third instar larvae of Chrysomya megacephala and Cochliomyia macellaria in no-choice experiments in order to compare the vulnerability of larval instars to predation. With first and second instar prey the highest predation rate by C. albiceps was on C. megacephala. For third instar prey, the highest predation rate was on C. macellaria. With second instar prey, there was complete predation on C. megacephala within 90 min, whereas in C. macellaria only 55% of the larvae were eaten by 90 min. For third instar prey most predation on C. macellaria (80%) occurred within 90 min, whereas in C. megacephala only 35% of the larvae were eaten by 90 min. Chrysomya albiceps changes the predatory behavior on its preys depending on which instar and species it will consume.

Further observations on the pollination mechanism and seed production of Douglas-fir

1982 ◽  
Vol 12 (2) ◽  
pp. 431-434 ◽  
Author(s):  
John N. Owens ◽  
Sheila J. Simpson
Keyword(s):  
Seed Production ◽  
Pollen Grains ◽  
Germination Percentage ◽  
Douglas Fir ◽  
Pollination Mechanism ◽  
Supplemental Pollination

The pollination mechanism of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) was studied. Pollen stained five different colors and applied to the same conelets at five different times showed that the pollen applied on the 1st and 3rd days after conelets became receptive was taken into the micropyle in significantly greater quantities than pollen applied at later dates. A second supplemental pollination did not increase the seed efficiency for individual cones. Seeds produced when an average of less than 1.2 pollen grains were taken into the micropyle had essentially the same germination percentage and proportion of abnormal germinants as seeds resulting when an average of 3.4 or more pollen grains were taken into the micropyle.

Genetic structure and mating system of white spruce (Piceaglauca) in a seed production area

1984 ◽  
Vol 14 (5) ◽  
pp. 639-643 ◽  
Author(s):  
John N. King ◽  
Bruce P. Dancik ◽  
Narinder K. Dhir
Keyword(s):  
Genetic Structure ◽  
Mating System ◽  
Seed Production ◽  
Gel Electrophoresis ◽  
Random Mating ◽  
White Spruce ◽  
Starch Gel Electrophoresis ◽  
Starch Gel ◽  
Production Area ◽  
Mating Model

Embryos and megagametophytes of open-pollinated seed of 37 white spruce (Piceaglauca (Moench) Voss) trees from a seed production area were analyzed by starch gel electrophoresis to determine the genetic structure and mating system over 2 seed crop years. Analysis of four polymorphic enzyme loci (Gdh, Idh, Pgm, and Pgi-2) for spatial and temporal genetic structure and mating system indicated substantial deviations from the random mating model that is assumed when open-pollinated families are designated as half-sibs.

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