Seasonal changes in glycerol content and supercooling points of Megachile rotundata (F.) and M. relativa Cress.

1971 ◽  
Vol 49 (5) ◽  
pp. 663-666 ◽  
Author(s):  
M. D. Krunic ◽  
R. W. Salt
Keyword(s):  
Exotic Species ◽  
Seasonal Changes ◽  
Indigenous Species ◽  
Megachile Rotundata ◽  
Glycerol Content ◽  
Cold Night ◽  
Southern Alberta

Supercooling points of prepupae of the exotic species Megachile rotundata during storage at 5 °C are not closely related to glycerol content and are not sufficiently low to avoid freezing outdoors in southern Alberta. In contrast, supercooling points of prepupae of the indigenous species M. relativa are inversely related to glycerol concentrations, which are double those of M. rotundata and are low enough for successful overwintering. Neither species is frost-tolerant.Older feeding larvae of M. rotundata also synthesize glycerol in the fall, probably in response to cold night temperatures.

scholarly journals Basic and Grade Stress for Some Timber in Sarawak

2011 ◽  
Vol 2 (2) ◽  
pp. 35-38
Author(s):  
Gaddafi Ismaili ◽  
Badorul Hisham Abu Bakar ◽  
Khairul Khuzaimah Abdul Rahim
Keyword(s):  
Exotic Species ◽  
Modulus Of Elasticity ◽  
Acacia Mangium ◽  
Wood Properties ◽  
Strength Properties ◽  
Indigenous Species ◽  
Medium Density ◽  
Compression Stress ◽  
Strength Group ◽  
Fast Growing Species

Strength properties’ tests are conducted in the small clear sample. This paper aim to acquire the basic and grade stresses of some fast growing species thus identifies its strength group. Thus, the information of wood properties from different species and condition are acquired from strength property's test. The required information namely, bending parallel to the grain, compression stress parallel to grain, shear parallel to grain and modulus of elasticity. The condition of the trees which is referred to green and air-dry condition. Three different species which are referred to exotic species of Acacia mangium and indigenous species of Aras. The results from the study indicated that, Acacia mangium classified under the strength group SG5, whilst Aras was classified under the strength group SG7. The timber is of medium density Light Hardwood ranging from 0.37-0.52g/cm3 air-dry condition.

Barrier plants in South Africa

Bothalia ◽  
1983 ◽  
Vol 14 (3/4) ◽  
pp. 635-639 ◽  
Author(s):  
L. Henderson
Keyword(s):  
South Africa ◽  
Exotic Species ◽  
Potential Barrier ◽  
Literature Survey ◽  
Indigenous Species ◽  
Different Types

It is stated that there is a need both to extend the range of barrier plants available in South Africa, and to replace some much-used exotic species that have become invasive. A literature survey and computerized herbarium search revealed that of the 428 plants recorded as having been used as barriers 62% are exotics. Of these. 26% are naturalized or invasive in one or other part of South Africa. Ideal characteristics for different types of barrier plants have been defined and used as a guide in selecting a range of potential barrier plants from the indigenous species available. Lists of recognized barrier plants are given including some species revealed as a result of the present investigation.

EFFECT OF ENVIRONMENT AND EQUIPMENT ON PRODUCTIVITY OF ALFALFA LEAFCUTTER BEES (HYMENOPTERA: MEGACHILIDAE) IN SOUTHERN ALBERTA, CANADA

1996 ◽  
Vol 128 (1) ◽  
pp. 47-56 ◽  
Author(s):  
K.W. Richards
Keyword(s):  
Environmental Variables ◽  
Total Cell ◽  
Significant Positive Effect ◽  
Megachile Rotundata ◽  
Southern Alberta ◽  
Temperature Heat ◽  
Leafcutter Bee ◽  
Nesting Material ◽  
Higher Temperature ◽  
Positive Effect

AbstractFour indicators of productivity and quality for the alfalfa leafcutter bee, Megachile rotundata (Fab.), were examined over a 3-year period and the influence of different shelter designs, nesting materials, and 34 environmental variables evaluated. A higher percentage of cocoons per total cells was produced in polystyrene nesting material than in pinewood nesting material. Both nesting materials had similar percentages of tunnels capped or containing cells and total numbers of cells per hive. Shelters with conspicuous orientation patterns or silhouettes had more tunnels capped per hive, tunnels with cells, and greater total cell production per hive than did other shelter designs. The time of maximum bee production varied greatly among the 3 years. Many environmental variables, especially those associated with higher temperature, heat units, and mean actual temperature, had a significant positive effect on bee productivity and cell quality. The information contained in this study may help delineate those climatic areas where this valuable alfalfa pollinator can be most effective, and may assist beekeepers in making management decisions that will improve their operations.

CHALCIDOID (HYMENOPTERA) PARASITES OF THE ALFALFA LEAF-CUTTER BEE, MEGACHILE ROTUNDATA, IN CANADA

1969 ◽  
Vol 101 (4) ◽  
pp. 418-422 ◽  
Author(s):  
Oswald Peck
Keyword(s):  
Megachile Rotundata ◽  
Parasitic Species ◽  
Water Traps ◽  
Southern Alberta ◽  
Alfalfa Leaf ◽  
Fourth Species

AbstractMegachile rotundata (F.) is a domesticated bee used to pollinate alfalfa in southern Alberta. There it may have four species of parasites, all chalcidoids. These parasites are removable by water traps before the hives are set in the field. Three of these parasites, Monodontomerus obscurus Westw., Dibrachys maculipennis Sz., and Pteromalus venustus Wlkr,, are European in origin. The first seems not to be established in Canada; the latter two have been reared from Canadian species of Megachile and thereby may prove a source of parasitism. The fourth species, Melittobia chalybii Ashm., is a widespread, nearctic, multivoltine species and is known as a laboratory pest of hymenopterous nests; it is likely to be the major parasite in rotundata nests. A key is given for the parasitic species.

Household fuelwood use in small electrified towns of the Makana District, Eastern Cape, South Africa

2007 ◽  
Vol 18 (4) ◽  
pp. 4-10 ◽  
Author(s):  
C.M. Shackleton ◽  
J. Gambiza ◽  
R. Jones
Keyword(s):  
Exotic Species ◽  
Energy Use ◽  
Energy Planning ◽  
Indigenous Species ◽  
Eastern Cape Province ◽  
Eastern Cape ◽  
Local Planning ◽  
Use Patterns ◽  
The Poor ◽  
Urban Settlements

Access to secure energy supplies is a key foundation for sustainable development. Consequently local planning and development initiatives must be based on a sound knowledge of the energy use patterns and preferences of local users. This paper reports on such for three small urban settlements in the Eastern Cape Province, with a particular focus on fuelwood use. Despite widespread electrification over a decade ago, and perceptions that the ease of fuelwood collection was declining, most households continued to use fuelwood for cooking and space heating, whereas electricity was favoured for light-ing. The most common reason for this was because fuelwood was cheap (or free) compared to electric-ity. Annual demand was approximately 1 450 kg per household per year. Households that collected their own supplies of fuelwood were significantly poorer than those that either bought their stocks, or those that did not use fuelwood at all. Indigenous species were favoured over exotic species, although fuelwood vendors traded mostly in exotic species, particularly Eucalyptus and wattle. The greater reliance of poorer and unelectrified households on fuelwood requires that local authorities consider this in energy planning, otherwise the poor will be neg-lected in policies such as the Free Basic Electricity.

scholarly journals Brazilian landscape styles and tree biodiversity in public garden squares

FLORESTA ◽  
2020 ◽  
Vol 50 (3) ◽  
pp. 1510
Author(s):  
Jennifer Viezzer ◽  
Daniela Biondi ◽  
Antonio Carlos Batista ◽  
Angeline Martini ◽  
Emidio Neves De Moraes
Keyword(s):  
Exotic Species ◽  
Biodiversity Conservation ◽  
Tree Species ◽  
Species Number ◽  
Indigenous Species ◽  
Statistical Calculation ◽  
Public Garden ◽  
Number Of Individuals

The main features of the Brazilian contemporary landscape style are the recovery of degraded areas and the use of indigenous species. This study aimed at analyzing the vegetation of the Curitiba-PR public garden squares to verify if the areas created during the contemporary period (from 1990 on) have a greater diversity of tree species than other squares and, therefore, are more significant for biodiversity conservation. For this, 32 of the city's 454 squares were sampled as determined by statistical calculation, then classified by creation year and landscape style. Trees species, families, and individuals were identified and classified as to their origin; and the variables richness; average species; number of individuals; density of individuals; and the Shannon, Pielou, and Odum indexes were analyzed. The 15 contemporary style squares presented 399 individuals of 54 species and 27 families, with 43.61% of the individuals and 50.00% of the species of exotic origin; individuals average of 26.60 ±9.72 per square and 43.09 ±35.13 per hectare; species average of 6.93 ±4.98 per square and 13.95 ±10.63 per hectare; and diversity indexes of Shannon 3.39, Pielou 0.85, and Odum 9.02. The squares in the contemporary style presented higher diversity indexes, but they have, on average, fewer species, families, and individuals, in addition to a greater proportion of exotic species and individuals. These results indicate that these squares did not follow the typical characteristics of the contemporary style and are of no greater significance for biodiversity conservation when compared to other squares.

EFFECTS OF GLYCEROL ON COLD-HARDINESS IN INSECTS

1964 ◽  
Vol 42 (1) ◽  
pp. 87-101 ◽  
Author(s):  
Lauritz Sømme
Keyword(s):  
Seasonal Changes ◽  
Cold Hardiness ◽  
Polyhydric Alcohol ◽  
Melting Points ◽  
Glycerol Content

The effects of glycerol on cold-hardiness in insects and seasonal changes in glycerol concentrations were investigated. The presence of this polyhydric alcohol was demonstrated in overwintering stages of 10 species. Larvae of one species also contained sorbitol, and eggs of two species another polyhydric alcohol, probably mannitol.Evidence gathered from various diapausing species showed that glycerol accumulated during the fall. This increase in concentration was observed in eggs of one species at temperatures ranging from −5° to 20 °C. No decrease in glycerol content was observed in any species as long as it was in diapause. After diapause was broken glycerol was lost in all species, in some even at temperatures down to −5 °C. Increase in concentration was never found in postdiapause insects. In two species, which do not have a diapause, the glycerol content increased below a certain temperature and decreased at higher temperatures.Three species were freezing-tolerant, although one contained less than 3% and another no glycerol, whereas eight species, most of which contained more than 15%, were killed by freezing. Thus glycerol alone cannot protect against freezing injuries.In several species the cold-hardiness was increased by the presence of glycerol because supercooling points were depressed. These depressions were more than those of the corresponding melting points. The regression of amount of supercooling on concentration of glycerol was linear in five species.

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