The Relationship between certain Ant Species with particular Reference to Biological Control of the Coreid, Theraptus sp.

1953 ◽  
Vol 44 (4) ◽  
pp. 669-691 ◽  
Author(s):  
M. J. Way
Keyword(s):  
Biological Control ◽  
Low Temperature ◽  
East Africa ◽  
Coastal Region ◽  
Sandy Soils ◽  
Ground Vegetation ◽  
Oecophylla Longinoda ◽  
Nesting Habits ◽  
Anoplolepis Custodiens ◽  
The Relationship

In the coastal region of British East Africa three ant species, Anoplolepis custodiens, A. longipes and Pheidole punctulata may destroy the ant Oecophylla longinoda which is a valuable predator on the coconut pest Theraptus sp. (Coreidae). The three first-named species do not prey on Theraptus, which may severely damage palms occupied by them.Nesting habits of the three ant species and their behaviour towards O. longinoda and certain other insects are described.O. longinoda has been exterminated in the limited areas occupied by the two Anoplolepis species. P. punctulata is widespread and is usually common in areas occupied by O. longinoda and is also present, though relatively less common, in A. longipes areas.The distribution of the Anoplolepis species, particularly A. custodiens, is correlated with sandy soils bearing a sparse ground vegetation. Where there are heavy soils or a thick ground vegetation of grasses and creepers the Anoplolepis species are absent and O. longinoda is usually present. It is suggested that the Anoplolepis species are limited by the relatively low temperature of soils shaded from sunlight by thick vegetation.

Gebirgswaldpflege – es kommt auf den Standort an | Mountain silviculture – it all depends on the site

2001 ◽  
Vol 152 (5) ◽  
pp. 169-176 ◽  
Author(s):  
Monika Frehner
Keyword(s):  
Nature Conservation ◽  
Low Temperature ◽  
Tree Species ◽  
Forest Stand ◽  
Ground Vegetation ◽  
Mountain Forests ◽  
Research Projects ◽  
Snow Mould ◽  
The Relationship ◽  
Protection Forests

The article shows that knowledge of the site of a particular forest stand, together with research results and experience, can provide information that is important for the cultivation of mountain forests, including knowledge of the composition of the tree species and the structure and growth capacity of natural forest. Furthermore, certain sites can, thus, be characterized by factors that influence restocking, such as snow mould,lush ground vegetation or low temperature. The guidelines«minimale Pflegemassnahmen» – «Minimal tending of protection forests» (WASSER und FREHNER, 1996) are based on this principle. For individual sites, warnings about natural dangers such as rock fall or statements concerning nature conservation can be made (e.g., the occurrence of tree species, suitability as a biotope for Capercaille). In conclusion, two research projects on the relationship between site and natural dangers will be presented.

Studies of the Life History and Ecology of the Ant Oecophylla longinoda Latreille

1954 ◽  
Vol 45 (1) ◽  
pp. 93-112 ◽  
Author(s):  
M. J. Way
Keyword(s):  
Life History ◽  
Apis Mellifera ◽  
East Africa ◽  
Honey Bee ◽  
Insect Species ◽  
Oecophylla Longinoda ◽  
Large Numbers ◽  
Wide Range ◽  
Nesting Habits ◽  
Food Reserves

In British East Africa Oecophylla longinoda (Latr.) var. textor Santschi is locally common in the costal region. Inland it is absent from higher altitudes and from areas where there is a pronounced dry season.In Zanzibar Island, O. longinoda at least 89 species of trees and shurbs; the largest populations occur on the clove (Jambosa caryophyllus), Citrus spp., Bridelia micrantha and Canthium zanzibaricum.The nesting habits and colony composition of O. longinoda are such that one colony may spread over a number of adjacent trees; it contains only one gravid queen.Winged virgin sexual forms are released at the beginning of the wet seasons and new colonies are initiated by a single queen, who uses her food reserves to bring the first batch of brood to maturity.In Zanzibzr, O. longinoda tends a wide range of Homoptera that produce honey-dew, but apparently “ prefers ” certain Coccids, notably Saissetia spp.The degree of attention afforded by an ant species determines the species of Homoptera which it is able to attend.The insect species preyed upon by O. longinoda include the honey bee, Apis mellifera, and the driver ant, Dorylus nigricans, of which large numbers may be destroyed.O. longinoda is of undoubted value for controlling certain coconut pests, notably Theraptus sp. (Coreidae), and its efficiency in coconut plantations could probably be much enhanced.

scholarly journals Influence of Preaging Temperature on the Indentation Strength of 3Y-TZP Aged in Ambient Atmosphere

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2767
Author(s):  
Ki-Won Jeong ◽  
Jung-Suk Han ◽  
Gi-Uk Yang ◽  
Dae-Joon Kim
Keyword(s):  
Residual Stress ◽  
Phase Transformation ◽  
Low Temperature ◽  
Compressive Residual Stress ◽  
Yttria Stabilized Zirconia ◽  
Ambient Atmosphere ◽  
Aged Specimen ◽  
Stabilized Zirconia ◽  
M Phase ◽  
The Relationship

Yttria-stabilized zirconia (3Y-TZP) containing 0.25% Al2O3, which is resistant to low temperature degradation (LTD), was aged for 10 h at 130–220 °C in air. The aged specimens were subsequently indented at loads ranging from 9.8 to 490 N using a Vickers indenter. The influence of preaging temperature on the biaxial strength of the specimens was investigated to elucidate the relationship between the extent of LTD and the strength of zirconia restorations that underwent LTD. The indented strength of the specimens increased as the preaging temperature was increased higher than 160 °C, which was accompanied by extensive t-ZrO2 (t) to m-ZrO2 (m) and c-ZrO2 (c) to r-ZrO2 (r) phase transformations. The influence of preaging temperature on the indented strength was rationalized by the residual stresses raised by the t→m transformation and the reversal of tensile residual stress on the aged specimen surface due to the indentation. The results suggested that the longevity of restorations would not be deteriorated if the aged restorations retain compressive residual stress on the surface, which corresponds to the extent of t→m phase transformation less than 52% in ambient environment.

Drift-dissipative instability of the electromagnetic convection mode in a low-temperature plasma

1992 ◽  
Vol 47 (3) ◽  
pp. 439-443 ◽  
Author(s):  
Hamid Saleem ◽  
M. Y. Yu
Keyword(s):  
Low Temperature ◽  
Collisional Plasma ◽  
Low Temperature Plasma ◽  
Temperature Plasma ◽  
Electromagnetic Effects ◽  
Dissipative Instability ◽  
Low Temperature Plasmas ◽  
The Relationship

The convection mode in a collisional plasma is investigated, with the inclusion of electromagnetic effects. It is shown that a dissipative instability can occur. The relationship to several well-known modes as well as applications to typical low-temperature plasmas are discussed.

Studies on Theraptus sp. (Coreidae); the Cause of the Gumming Disease of Coconuts in East Africa

1953 ◽  
Vol 44 (4) ◽  
pp. 657-667 ◽  
Author(s):  
M. J. Way
Keyword(s):  
East Africa ◽  
Solomon Islands ◽  
Coastal Region

Theraptus sp. is widespread in the coastal region of British East Africa where it severely damages developing coconut fruits.The female may lay over 100 eggs. There are five nymphal instars and, in the field, it is probable that about nine generations are produced each year.Damage to coconuts is similar to that caused by Amblypelta cocophaga China in the Solomon Islands. Female coconut flowers and young nuts may be destroyed by a single feeding puncture. Damaged 10–16-week-old nuts may reach maturity but are undersized and often distorted by lesions from which gummy material exudes.

scholarly journals Biological control of tick populations: review and reflections

1994 ◽  
Vol 10 (1) ◽  
pp. 47-52 ◽  
Author(s):  
Norma V. Labarthe
Keyword(s):  
Biological Control ◽  
Genetic Selection ◽  
Effective Vaccine ◽  
Control Methods ◽  
The Relationship ◽  
Selection Of

This study is concerned with aspects of the relationship between ticks and their hosts that have a bearing on biological control of tick populations. It proposes control methods based on a program that would combine development of an effective vaccine with genetic selection of hosts.

scholarly journals Leaf Carbohydrates and Flower Formation in Citrus

1995 ◽  
Vol 120 (2) ◽  
pp. 222-227 ◽  
Author(s):  
A. Garcia-Luis ◽  
F. Fornes ◽  
J.L. Guardiola
Keyword(s):  
Low Temperature ◽  
Induction Period ◽  
Flower Induction ◽  
Flower Formation ◽  
Citrus Unshiu ◽  
Satsuma Mandarin ◽  
Leaf Carbohydrates ◽  
Carbohydrate Levels ◽  
The Relationship ◽  
Carbohydrate Contents

The carbohydrate contents of the leaves of satsuma mandarin (Citrus unshiu Marc.) trees were altered before or during the low temperature flower induction period to determine the relationship between gross levels of carbohydrates and flower formation. Early removal of the fruit and girdling of the branches on either fruiting or defruited trees caused an accumulation of carbohydrates in the leaves and increased flower formation. Shading the trees resulted in a transient reduction in leaf carbohydrate levels and in a decrease in flower formation. Although a relationship between carbohydrate levels and flowering was consistently found, our results show that the gross levels of carbohydrates do not appear to limit flower formation in citrus.

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