The Life History and Some Aspects of the Ecology of the Large Aspen Tortrix, Choristoneura conflictana (Wlkr.) (N. Comb.) (Lepidoptera: Tortricidae)

1955 ◽  
Vol 87 (11) ◽  
pp. 461-473 ◽  
Author(s):  
R. M. Prentice
Keyword(s):  
Life History ◽  
Populus Tremuloides ◽  
Field Studies ◽  
Trembling Aspen ◽  
Factors Affecting ◽  
Choristoneura Conflictana

Periodic outbreaks of the large aspen tortrix, Choristoneura conflictana (Wlkr.) severely defoliate trembling aspen, Populus tremuloides Michx., in parts of Manitoba and Saskatchewan. The inadequacy of information on the insect prompted further investigation of its life history and the factors affecting its abundance. Field studies were conducted in Northern Manitoba and Saskatchewan, where from 1950 to 1954 the insect was found at various population levels.

Potential for combining sex pheromones for the forest tent caterpillar (Lepidoptera: Lasiocampidae) and the large aspen tortrix (Lepidoptera: Tortricidae) within monitoring traps targeting both species

2005 ◽  
Vol 137 (5) ◽  
pp. 615-619 ◽  
Author(s):  
Maya L. Evenden
Keyword(s):  
Populus Tremuloides ◽  
Economic Value ◽  
Malacosoma Disstria ◽  
Forest Tent Caterpillar ◽  
Trembling Aspen ◽  
Commercially Important ◽  
Monitoring Traps ◽  
The Impact ◽  
Tent Caterpillar ◽  
Choristoneura Conflictana

Trembling aspen, Populus tremuloides Michx. (Salicaceae), is the most widely distributed tree species in North America (Perala 1990) and is considered to be an ecologically (Hogg et al. 2002) and economically important (Brandt et al. 2003) component of the boreal forest. Due to the recently increased economic value of trembling aspen (Brandt et al. 2003), the impact of native insect defoliators on tree growth and mortality has become commercially important. Two of the most significant defoliators of trembling aspen throughout its range in Canada are the forest tent caterpillar (FTC), Malacosoma disstria Hübner (Lepidoptera: Lasiocampidae), and the large aspen tortrix (LAT), Choristoneura conflictana Walker (Lepidoptera: Tortricidae).

Distribution and Seasonality of Macroalgae on Oyster Communities of Central Chesapeake Bay

1980 ◽  
Vol 23 (11) ◽  
Author(s):  
Judith L. Connor
Keyword(s):  
Life History ◽  
Sexual Reproduction ◽  
Chesapeake Bay ◽  
Physical Environment ◽  
Algal Species ◽  
Light Availability ◽  
Field Studies ◽  
Spatial And Temporal Distributions ◽  
Red Algal ◽  
Study Sites

AbstractField studies of the benthic macroalgae of fifteen selected Chesapeake Bay oyster communities were conducted over a period of a year (March 1977 to February 1978). Algal distribu tion and seasonal occurrence were studied in relation to changes in the physical environment. Salinity, temperature, and light availability were important factors in the spatial and temporal distributions of algae in these subtidal habitats.Seventeen species of Chlorophyta, Phaeophyta, and Rhodophyta were recorded from the fifteen study sites distributed over 130 kilometers within the Maryland portion of Chesapeake Bay. Species of Chlorophyta were associated with oyster communities throughout the year of study with maximum numbers of species and maximum biomass occurring in spring. Only once was a member of the Phaeophyta encountered; a single filamentous species, Ectocarpus, was collected during winter. Species of Rhodophyta were present throughout the year at the study sites.Most of the algae collected reproduced asexually by spores and/or vegetative fragments. Sexual reproduction occurred in some of the red algal species. The presence of tetrasporic and cystocarpic plants of Dasya baillouviana and Polysiphonia harveyi var. olneyi may indicate that the usual triphasic Florideophycean life history occurs in this estuary.

scholarly journals Factors Affecting Thanatosis in the Braconid Parasitoid Wasp Heterospilus prosopidis

Insects ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 48
Author(s):  
Mio Amemiya ◽  
Kôji Sasakawa
Keyword(s):  
Life History ◽  
Antipredator Behavior ◽  
Parasitoid Wasp ◽  
Ecological Perspective ◽  
Background Color ◽  
Factors Affecting ◽  
Death Feigning ◽  
Heterospilus Prosopidis ◽  
History Of

Thanatosis, also called death feigning, is often an antipredator behavior. In insects, it has been reported from species of various orders, but knowledge of this behavior in Hymenoptera is insufficient. This study examined the effects of sex, age (0 or 2 days old), temperature (18 or 25 °C), and background color (white, green, or brown) on thanatosis in the braconid parasitoid wasp Heterospilus prosopidis. Thanatosis was more frequent in 0-d-old individuals and in females at 18 °C. The duration of thanatosis was longer in females, but this effect of sex was weaker at 18 °C and in 0-d-old individuals. The background color affected neither the frequency nor duration. These results were compared with reports for other insects and predictions based on the life history of this species, and are discussed from an ecological perspective.

scholarly journals Ethylene enhances root water transport and aquaporin expression in trembling aspen (Populus tremuloides) exposed to root hypoxia

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Xiangfeng Tan ◽  
Mengmeng Liu ◽  
Ning Du ◽  
Janusz J. Zwiazek
Keyword(s):  
Gas Exchange ◽  
Water Transport ◽  
Populus Tremuloides ◽  
Leaf Gas Exchange ◽  
Hydraulic Conductance ◽  
Root Hydraulic Conductance ◽  
Trembling Aspen ◽  
Expression Levels ◽  
Root Hypoxia ◽  
Exogenous Ethylene

Abstract Background Root hypoxia has detrimental effects on physiological processes and growth in most plants. The effects of hypoxia can be partly alleviated by ethylene. However, the tolerance mechanisms contributing to the ethylene-mediated hypoxia tolerance in plants remain poorly understood. Results In this study, we examined the effects of root hypoxia and exogenous ethylene treatments on leaf gas exchange, root hydraulic conductance, and the expression levels of several aquaporins of the plasma membrane intrinsic protein group (PIP) in trembling aspen (Populus tremuloides) seedlings. Ethylene enhanced net photosynthetic rates, transpiration rates, and root hydraulic conductance in hypoxic plants. Of the two subgroups of PIPs (PIP1 and PIP2), the protein abundance of PIP2s and the transcript abundance of PIP2;4 and PIP2;5 were higher in ethylene-treated trembling aspen roots compared with non-treated roots under hypoxia. The increases in the expression levels of these aquaporins could potentially facilitate root water transport. The enhanced root water transport by ethylene was likely responsible for the increase in leaf gas exchange of the hypoxic plants. Conclusions Exogenous ethylene enhanced root water transport and the expression levels of PIP2;4 and PIP2;5 in hypoxic roots of trembling aspen. The results suggest that ethylene facilitates the aquaporin-mediated water transport in plants exposed to root hypoxia.

The bacteria in sapwood, wetwood, and heartwood of trembling aspen (Populus tremuloides)

1973 ◽  
Vol 51 (2) ◽  
pp. 498-500 ◽  
Author(s):  
Donald M. Knutson
Keyword(s):  
Populus Tremuloides ◽  
Trembling Aspen ◽  
Indigenous Bacteria ◽  
Large Populations ◽  
Xylem Tissue

Bacteria (Erwinia, Bacillus) were consistently isolated from all samples of aspen sapwood and heartwood. In wetwood zones (water-soaked xylem tissue) or discolored heartwood, large populations often occur. No organisms unique to wetwood were isolated. Wetwood probably is formed by nonmicrobial means and, once formed, merely supports large populations of indigenous bacteria.

Wounding of aspen roots promotes suckering

2004 ◽  
Vol 82 (3) ◽  
pp. 310-315 ◽  
Author(s):  
Erin C Fraser ◽  
Victor J Lieffers ◽  
Simon M Landhäusser
Keyword(s):  
Populus Tremuloides ◽  
Growth Rates ◽  
Growing Season ◽  
Organic Layer ◽  
Trembling Aspen ◽  
Layer Depth ◽  
Injury Type ◽  
Organic Layers ◽  
Root Injury ◽  
Root Sucker

In early May, 1-m sections of trembling aspen (Populus tremuloides Michx.) roots in a forest cutblock were carefully exposed and examined for damage. Undamaged roots were subjected to one of three wounding treatments (scrape, sever, or uninjured control) and were then reburied to either the full normal organic layer depth or to one third of the normal depth. Following one growing season, the roots were reexposed and assessed for aspen sucker numbers and growth rates. Results indicate that injured roots produced suckers nearly twice as often as uninjured roots. Further, injured roots produced more suckers per root, and these suckers were taller and had greater leaf area. Roots buried under shallow organic layers also generated more suckers, regardless of injury type. The side of injury (distal or proximal) did not affect any of the measured variables. The present study suggests that moderate wounding of aspen roots increases initial sucker numbers and growth rates.Key words: trembling aspen, root sucker, root injury, regeneration.

Factors Affecting Productivity of Refuse Compactor Vehicles in India

2021 ◽  
Vol 47 (3) ◽  
pp. 529-535
Author(s):  
Khant Shah ◽  
Devanshu Pandit
Keyword(s):  
Solid Waste Management ◽  
Field Studies ◽  
Operating Costs ◽  
Municipal Solid Waste Management ◽  
Critical Factors ◽  
Factors Affecting ◽  
Operation Optimization ◽  
Selection Parameters ◽  
Evaluation And Monitoring ◽  
Hierarchy Process

Shift towards mechanization in the municipal solid waste management (MSWM) is aimed at improving health wellbeing of the workers who are manually handling waste. With huge investment and operating costs, proper evaluation and monitoring of the performances of these equipment is essential. Identifying and rating the factors which impact the performance of equipment is the first step towards improving efficiency of a system. This research identifies the critical factors and issues in the operation optimization of refuse compactor vehicles. Interviews with experts and field studies helped in identification of 30 factors which were divided in five categories. The research uses analytical hierarchy process (AHP) for finding out the priority vectors of thus identified factors and categories. The study also highlights equipment selection parameters for the best suited model and make.

THE BEHAVIOUR OF FIVE WOOD SPECIES IN COMPRESSION

IAWA Journal ◽  
2002 ◽  
Vol 23 (2) ◽  
pp. 201-211 ◽  
Author(s):  
Simon Ellis ◽  
Paul Steiner
Keyword(s):  
Young’S Modulus ◽  
Populus Tremuloides ◽  
Wood Species ◽  
Young's Modulus ◽  
Douglas Fir ◽  
Thuja Plicata ◽  
Trembling Aspen ◽  
Moisture Contents ◽  
Red Cedar ◽  
Western Red Cedar

Five wood species, Oregon ash (Fraxinus latifolia Benth.), Balau (Shorea spp.), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), Western red cedar (Thuja plicata Donn ex D. Don), and Trembling aspen (Populus tremuloides Michx.) were loaded in compression longitudinally, radially and tangentially. The wood cubes were conditioned to one of four moisture contents prior to loading. Small cubes were loaded until no void space remained after which samples were released and soaked in water. Stress /strain curves were recorded over the whole range of strain and cube thicknesses were recorded at the end of the compression, after release from the testing apparatus, and after soaking in water. Denser woods resulted in a greater Young’s modulus, higher levels of stress and shorter time to densification than did less dense woods. Higher initial moisture contents apparently increased the plasticity of the wood leading to a lower Young’s modulus and lower levels of stress during compression, greater springback after release of stress and greater recovery after swelling in water. Differences observed in the radial and tangential behaviours were believed to be due to the supporting action of the rays when the wood was compressed in the radial direction in balau and trembling aspen and to the relative difference between the lower density earlywood and higher density latewood regions in ash, Douglas-fir and western red cedar.

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