scholarly journals Adaptation to larval crowding in Drosophila ananassae and Drosophila nasuta nasuta: increased larval competitive ability without increased larval feeding rate

2014 ◽  
Author(s):  
Archana Nagarajan ◽  
Sharmila Bharathi Natarajan ◽  
Mohan Jayaram ◽  
Ananda Thammanna ◽  
Sudarshan Chari ◽  
...  
Keyword(s):  
Competitive Ability ◽  
High Density ◽  
Drosophila Ananassae ◽  
Larval Feeding ◽  
Food Conversion ◽  
Standard View ◽  
Larval Crowding ◽  
The Cost ◽  
Drosophila Nasuta

The standard view of adaptation to larval crowding in fruitflies, built on results from 25 years of multiple experimental evolution studies on D. melanogaster, is that enhanced competitive ability evolves primarily through increased larval feeding and foraging rate, at the cost of efficiency of food conversion to biomass, and increased larval tolerance to nitrogenous wastes. These results, moreover, were at odds from the predictions of classical K-selection theory, notably the expectation that selection at high density should result in the increase of efficiency of conversion of food to biomass, and were better interpreted through the lens of alpha-selection. We show here that populations of D. ananassae and D. n. nasuta subjected to extreme larval crowding evolve greater competitive ability and pre-adult survivorship at high density primarily through a combination of reduced larval duration, faster attainment of minimum critical size for pupation, greater time efficiency of food conversion to biomass, increased pupation height with a relatively small role of increased urea/ammonia tolerance, if at all. This is a very different suite of traits than that seen to evolve under similar selection in D. melanogaster and seems to be closer to the expectations from the canonical theory of K-selection. We discuss possible reasons for these differences in results across the three species. Overall, the results reinforce the view that our understanding of the evolution of competitive ability in fruitflies needs to be more nuanced than before, with an appreciation that there may be multiple evolutionary routes through which higher competitive ability can be attained.

scholarly journals Evolution of increased larval competitive ability in Drosophila melanogaster without increased larval feeding rate

2015 ◽  
Author(s):  
Manaswini Sarangi ◽  
Archana Nagarajan ◽  
Snigdhadip Dey ◽  
Joy Bose ◽  
Amitabh Joshi
Keyword(s):  
Competitive Ability ◽  
Unit Volume ◽  
Larval Density ◽  
Larval Feeding ◽  
Food Conversion ◽  
Feeding Rates ◽  
Laboratory Populations ◽  
Larval Crowding ◽  
The Cost

Multiple experimental evolution studies on D. melanogaster in the 1980s and 1990s indicated that enhanced competitive ability evolved primarily through increased larval tolerance to nitrogenous wastes and increased larval feeding and foraging rate, at the cost of efficiency of food conversion to biomass, and this became the widely accepted view of how adaptation to larval crowding evolves in fruitflies. We recently showed that populations of D. ananassae and D. n. nasuta subjected to extreme larval crowding evolved greater competitive ability without evolving higher feeding rates, primarily through a combination of reduced larval duration, faster attainment of minimum critical size for pupation, greater efficiency of food conversion to biomass, increased pupation height and, perhaps, greater urea/ammonia tolerance. This was a very different suite of traits than that seen to evolve under similar selection in D. melanogaster and was closer to the expectations from the theory of K-selection. At that time, we suggested two possible reasons for the differences in the phenotypic correlates of greater competitive ability seen in the studies with D. melanogaster and the other two species. First, that D. ananassae and D. n. nasuta had a very different genetic architecture of traits affecting competitive ability compared to the long-term, laboratory populations of D. melanogaster used in the earlier studies, either because the populations of the former two species were relatively recently wild-caught, or by virtue of being different species. Second, that the different evolutionary trajectories in D. ananassae and D. n. nasuta versus D. melanogaster were a reflection of differences in the manner in which larval crowding was imposed in the two sets of selection experiments. The D. melanogaster studies used a higher absolute density of eggs per unit volume of food, and a substantially larger total volume of food, than the studies on D. ananassae and D. n. nasuta. Here, we show that long-term laboratory populations of D. melanogaster, descended from some of the populations used in the earlier studies, evolve essentially the same set of traits as the D. ananassae and D. n. nasuta crowding-adapted populations when subjected to a similar larval density at low absolute volumes of food. As in the case of D. ananassae and D. n. nasuta, and in stark contrast to earlier studies with D. melanogaster, these crowding-adapted populations of D. melanogaster did not evolve greater larval feeding rates as a correlate of increased competitive ability. The present results clearly suggest that the suite of phenotypes through which the evolution of greater competitive ability is achieved in fruitflies depends critically not just on larval density per unit volume of food, but also on the total amount of food available in the culture vials. We discuss these results in the context of an hypothesis about how larval density and the height of the food column in culture vials might interact to alter the fitness costs and benefits of increased larval feeding rates, thus resulting in different routes to the evolution of greater competitive ability, depending on the details of exactly how the larval crowding was implemented.

scholarly journals Adaptation to larval crowding in Drosophila ananassae and Drosophila nasuta nasuta: increased larval competitive ability without increased larval feeding rate

2016 ◽  
Vol 95 (2) ◽  
pp. 411-425 ◽  
Author(s):  
ARCHANA NAGARAJAN ◽  
SHARMILA BHARATHI NATARAJAN ◽  
MOHAN JAYARAM ◽  
ANANDA THAMMANNA ◽  
SUDARSHAN CHARI ◽  
...  
Keyword(s):  
Competitive Ability ◽  
Feeding Rate ◽  
Drosophila Ananassae ◽  
Larval Feeding ◽  
Larval Crowding ◽  
Drosophila Nasuta ◽  
Drosophila Nasuta Nasuta

Hostile Takeovers and Anti-takeover Defenses in the Russian Corporate Market

2007 ◽  
pp. 70-84 ◽  
Author(s):  
E. Demidova
Keyword(s):  
Cost Benefit Analysis ◽  
Cost Benefit ◽  
Benefit Analysis ◽  
Costs And Benefits ◽  
Hostile Takeovers ◽  
Russian Market ◽  
Takeover Defenses ◽  
The Cost ◽  
European Markets

This article analyzes definitions and the role of hostile takeovers at the Russian and European markets for corporate control. It develops the methodology of assessing the efficiency of anti-takeover defenses adapted to the conditions of the Russian market. The paper uses the cost-benefit analysis, where the costs and benefits of the pre-bid and post-bid defenses are compared.

Changing Role of Agriculture in Income and Employment, and Trends of Agricultural Worker Productivity in Indian States

2020 ◽  
pp. 183-189
Keyword(s):  
Green Revolution ◽  
Positive Trend ◽  
Worker Productivity ◽  
Indian States ◽  
Agricultural Worker ◽  
The Sixties ◽  
High Level ◽  
The Cost ◽  
Changing Role

The productivity of land has been often discussed and deliberated by the academia and policymakers to understand agriculture, however, very few studies have focused on the agriculture worker productivity to analyze this sector. This study concentrates on the productivity of agricultural workers from across the states taking two-time points into consideration. The agriculture worker productivity needs to be dealt with seriously and on a time series basis so that the marginal productivity of worker can be ascertained but also the dependency of worker on agriculture gets revealed. There is still disguised unemployment in all the states and high level of labour migration, yet most of the states showed the dependency has gone down. Although a state like Madhya Pradesh is doing very well in terms of income earned but that is at the cost of increased worker power in agriculture as a result of which, the productivity of worker has gone down. States like Mizoram, Meghalaya, Nagaland and Tripura, though small in size showed remarkable growth in productivity and all these states showed a positive trend in terms of worker shifting away from agriculture. The traditional states which gained the most from Green Revolution of the sixties are performing decently well, but they need to have the next major policy push so that they move to the next orbit of growth.

Music publications in Galicia in the 19th — beginning of the 20th centuries: production, advertising, pricing

2019 ◽  
pp. 481-499
Author(s):  
Olga Osadtsia
Keyword(s):  
Book Publishing ◽  
Initial Form ◽  
Music Production ◽  
Bibliographic Information ◽  
Financial Factor ◽  
Determining Factors ◽  
Book Selling ◽  
The Cost ◽  
Import Trade

The main forms and methods of distribution of music publications in Galicia in the XIX — early XX centuries are scrutinized. The demand for the relevant music production is one of the determining factors in the formation of the musical publishing repertoire, its structure and special features in the process of the existence of music publications in society. It is noted that export-import trade in books has become especially widespread in Galicia; there are facts about the links between publishers and booksellers in Lviv and Warsaw. The basic types of presentation of book advertising of music products, its regional peculiarities, and ways of its placement are considered. Special emphasis is placed on the role of specialized press in the advertising of music products, typical examples of press advertising. The registration bibliographic information as the initial form of music bibliography and the forms of its compilation are distinguished. The emphasis is placed on the importance of thorough critical articles as a separate typological group of bibliographic publications under the conditions of formation of the Ukrainian bibliography, in which the main importance is given to the disclosure of the content and evaluation of the reviewed work. The combination of article genres and reviews on examples of separate publications by Stanislav Lyudkevych and Ivan Franko is traced. Special book-selling and book-publishing catalogs are characterized. While executing the marketing and advertising function, these directories were addressed primarily to foreign consumers and distributors (the so-called commissioners).One way to distribute music is to subscribe through libraries. A significant financial factor in the distribution of any printed matter was the price that depended primarily on the cost of each process associated with its publication. Keywords: music publications, bookstore, book-trading enterprise, advertising of publications, pricing.

scholarly journals Importance of Apolipoprotein A-I and A-II Composition in HDL and Its Potential for Studying COVID-19 and SARS-CoV-2

Medicines ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 38
Author(s):  
Kyung-Hyun Cho
Keyword(s):  
Antiviral Activity ◽  
High Density ◽  
High Density Lipoproteins ◽  
Potent Antiviral Activity ◽  
Apolipoprotein A ◽  
Putative Role

The composition and properties of apolipoprotein (apo) A-I and apoA-II in high-density lipoproteins (HDL) might be critical to SARS-CoV-2 infection via SR-BI and antiviral activity against COVID-19. HDL containing native apoA-I showed potent antiviral activity, while HDL containing glycated apoA-I or other apolipoproteins did not. However, there has been no report to elucidate the putative role of apoA-II in the antiviral activity of HDL.

Sign in / Sign up

Export Citation Format

Share Document