THE RELATIONSHIP BETWEEN A PARASITE, TETRASTICHUS INCERTUS (HYMENOPTERA: EULOPHIDAE), AND ITS HOST, THE ALFALFA WEEVIL, HYPERA POSTICA (COLEOPTERA: CURCULIONIDAE), IN NEW YORK

1971 ◽  
Vol 103 (1) ◽  
pp. 83-94 ◽  
Author(s):  
David J. Horn
Keyword(s):  
New York ◽  
Laboratory Data ◽  
Field Studies ◽  
Host Population ◽  
Winter Mortality ◽  
Northeastern United States ◽  
Alfalfa Weevil ◽  
Hypera Postica ◽  
Almost All ◽  
The Relationship

AbstractTetrastichus incertus, a parasite of the alfalfa weevil (Hypera postica) larva, occurs throughout the northeastern United States, including almost all of New York. Field studies in 1967 and 1968 indicated that the parasite and its host were not closely synchronized in New York; the parasite was uncommon in June when hosts were abundant while the opposite was true in July. In 1966 and 1967, the proportion of parasites entering diapause increased throughout the summer, from 1–31% in June to 67–100% in September. Therefore, most parasites produced in June, when hosts were abundant, emerged in July when hosts were scarce. Winter mortality among parasites in diapause was high (51–64%) in field cages. The survivors of the overwintering generation of T. incertus constituted a small fraction of the annual production of parasites.In the laboratory the offspring of older T. incertus tended more to enter diapause than did the offspring of younger parasites. This indicated the incidence of diapause may be correlated with host availability; when hosts are uncommon, diapausing parasites are produced.Field and laboratory data indicated a ratio of one T. incertus to eight alfalfa weevil larvae would be necessary to achieve 50% parasitism of the host population. Such a host:parasite ratio never occurs when the hosts are common.

Red spruce decline on Whiteface Mountain, New York. II. Relationships between apical and radial growth decline

1990 ◽  
Vol 20 (9) ◽  
pp. 1415-1421 ◽  
Author(s):  
David C. LeBlanc ◽  
Dudley J. Raynal
Keyword(s):  
New York ◽  
Radial Growth ◽  
Red Spruce ◽  
Northeastern United States ◽  
Spruce Decline ◽  
Growth Decline ◽  
Whiteface Mountain ◽  
The 1960S ◽  
Crown Dieback ◽  
The Relationship

Understanding the relationship between apical and radial growth decline can contribute toward the evaluation of hypotheses regarding causal mechanisms of red spruce decline. The etiology of red spruce decline in montane spruce-fir forests of the northeastern United States includes loss of foliage at branch apices, crown dieback, and unreversed radial growth decline since the 1960s. Demographic analyses of crown damage and radial growth decline for red spruce on Whiteface Mountain, New York, indicate that large, canopy-emergent trees with exposed crowns exhibit greater decline than codominant trees within an intact canopy. In this paper, radial growth decline is shown to have been coincident with decreased apical growth and increased incidence of injury to terminal leaders. Incidence of leader mortality is greatest for canopy-emergent red spruce or trees with exposed crowns, similar to patterns described for radial growth. This relationship suggests that the post-1960 decline of red spruce on Whiteface Mountain is caused, at least in part, by stresses that act directly on the crown.

BIOLOGICAL CONTROL OF THE ALFALFA WEEVIL HYPERA POSTICA (COLEOPTERA: CURCULIONIDAE) IN NEW YORK

1971 ◽  
Vol 103 (12) ◽  
pp. 1653-1658 ◽  
Author(s):  
R. Larry Richardson ◽  
Dean E. Nelson ◽  
Alan C. York ◽  
George G. Gyrisco
Keyword(s):  
New York ◽  
Biological Control ◽  
Life Cycle ◽  
Control Agent ◽  
Effective Control ◽  
Critical Levels ◽  
Alfalfa Weevil ◽  
Hypera Postica ◽  
Late Fall ◽  
Natural Dispersal

AbstractTwo hymenopterous parasites Bathyplectes curculionis (Thomson) and Tetrastichus incertus (Ratzeburg) parasitized 16.5% of their principal host the alfalfa weevil Hypera postica (Gyllenhal) in 1970. A total of 2703 parasites was reared and released in localities where their activity was reported low or non-existent prior to this study. Maximum parasitism by T. incertus and B. curculionis occurred later than periods of peak weevil larvae activity; however, T. incertus emerged earlier in several areas possibly as a natural adjustment of its life cycle, and B. curculionis persisted in multiple non-diapausing generations until late fall. The braconid parasite Microtonus aethiops (Nees) shows promise in becoming a very effective control agent through its ability to prevent weevil oviposition now that it is rapidly dispersing throughout New York. Having parasites established statewide through both releases and natural dispersal has lowered weevil populations below critical levels, and will increase parasite effectiveness in dealing with future alfalfa weevil generations.

Control of the Alfalfa Weevil, Hypera postica, in New York

1965 ◽  
Vol 58 (5) ◽  
pp. 940-942 ◽  
Author(s):  
Edward J. Armbrust ◽  
George G. Gyrisco
Keyword(s):  
New York ◽  
Alfalfa Weevil ◽  
Hypera Postica

Contemporary Qur'anic Studies in Iran and its Relationship with Qur'anic Studies in the West

2012 ◽  
Vol 14 (1) ◽  
pp. 45-72
Author(s):  
Morteza Karimi-Nia
Keyword(s):  
Islamic Law ◽  
Human Sciences ◽  
The West ◽  
Communications Technologies ◽  
Religious Learning ◽  
The Status ◽  
Islamic Republic Of Iran ◽  
Almost All ◽  
The Impact ◽  
The Relationship

The status of tafsīr and Qur'anic studies in the Islamic Republic of Iran has changed significantly during recent decades. The essay provides an overview of the state of Qur'anic studies in Iran today, aiming to examine the extent of the impact of studies by Western scholars on Iranian academic circles during the last three decades and the relationship between them. As in most Islamic countries, the major bulk of academic activity in Iran in this field used to be undertaken by the traditional ʿulamāʾ; however, since the beginning of the twentieth century and the establishment of universities and other academic institutions in the Islamic world, there has been increasing diversity and development. After the Islamic Revolution, many gradual changes in the structure and approach of centres of religious learning and universities have occurred. Contemporary advancements in modern sciences and communications technologies have gradually brought the institutions engaged in the study of human sciences to confront the new context. As a result, the traditional Shīʿī centres of learning, which until 50 years ago devoted themselves exclusively to the study of Islamic law and jurisprudence, today pay attention to the teaching of foreign languages, Qur'anic sciences and exegesis, including Western studies about the Qur'an, to a certain extent, and recognise the importance of almost all of the human sciences of the West.

Die Konstruktion von Natur – Central Park neu besichtigt | The Construction of Nature – Central Park Revisited

2005 ◽  
Vol 156 (8) ◽  
pp. 288-296
Author(s):  
Vittorio Magnago Lampugnani
Keyword(s):  
New York ◽  
Hudson River ◽  
The United States ◽  
Central Park ◽  
Housing Developments ◽  
Hudson River School ◽  
The North ◽  
Man And Nature ◽  
The 19Th Century ◽  
The Relationship

In the first half of the 19th century scientific philosophers in the United States, such as Emerson and Thoreau, began to pursue the relationship between man and nature. Painters from the Hudson River School discovered the rural spaces to the north of New York and began to celebrate the American landscape in their paintings. In many places at this time garden societies were founded, which generated widespread support for the creation of park enclosures While the first such were cemeteries with the character of parks, housing developments on the peripheries of towns were later set in generous park landscapes. However, the centres of the growing American cities also need green spaces and the so-called «park movement»reached a first high point with New York's Central Park. It was not only an experimental field for modern urban elements, but even today is a force of social cohesion.

Mathematical Model Investigation of Far-Field Transport of Ocean-Dumped Sewage Sludge Related to Remote Sensing

1982 ◽  
Vol 14 (3) ◽  
pp. 33-39
Author(s):  
C Y Kuo
Keyword(s):  
New York ◽  
Sewage Sludge ◽  
Laboratory Data ◽  
Three Dimensional ◽  
Approximate Model ◽  
Transport Processes ◽  
Far Field ◽  
New York Bight ◽  
Mean Current

An existing, three-dimensional, Eulerian-Lagrangian finite-difference model was modified and used to examine the far-field transport processes of dumped sewage sludge in the New York Bight. Both in situ and laboratory data were utilized in an attempt to approximate model inputs such as mean current speed, vertical and horizontal diffusion coefficients, particle size distributions, and specific gravities. Concentrations of the sludge near the sea surface predicted from the computer model were compared qualitatively with those remotely sensed.

scholarly journals Effects of heterogeneity in infection-exposure history and immunity on the dynamics of a protozoan parasite

2007 ◽  
Vol 4 (16) ◽  
pp. 841-849 ◽  
Author(s):  
Maite Severins ◽  
Don Klinkenberg ◽  
Hans Heesterbeek
Keyword(s):  
Dynamic Behaviour ◽  
Protozoan Parasite ◽  
Host Population ◽  
Infection Process ◽  
Control Measures ◽  
Complex Dynamic ◽  
Systems Models ◽  
Exposure History ◽  
The Relationship ◽  
Initial Contamination

Infection systems where traits of the host, such as acquired immunity, interact with the infection process can show complex dynamic behaviour with counter-intuitive results. In this study, we consider the traits ‘immune status’ and ‘exposure history’, and our aim is to assess the influence of acquired individual heterogeneity in these traits. We have built an individual-based model of Eimeria acervulina infections, a protozoan parasite with an environmental stage that causes coccidiosis in chickens. With the model, we simulate outbreaks of the disease under varying initial contaminations. Heterogeneity in the traits arises stochastically through differences in the dose and frequency of parasites that individuals pick up from the environment. We find that the relationship between the initial contamination and the severity of an outbreak has a non-monotonous ‘wave-like’ pattern. This pattern can be explained by an increased heterogeneity in the host population caused by the infection process at the most severe outbreaks. We conclude that when dealing with these types of infection systems, models that are used to develop or evaluate control measures cannot neglect acquired heterogeneity in the host population traits that interact with the infection process.

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