scholarly journals Intraspecific Competition and the Promotion of Ecological Specialization

2021 ◽  
Author(s):  
Abdel H. Halloway ◽  
Joel S. Brown
Keyword(s):  
Resource Use ◽  
Intraspecific Competition ◽  
Niche Breadth ◽  
Evolutionary Model ◽  
Ecological Specialization ◽  
Secondary Resources ◽  
Cast Doubt ◽  
The Face ◽  
Game Theoretic ◽  
Diversification Hypothesis

AbstractThe evolution of ecological specialization can be summed up in a single question: why would a species evolve a more-restricted niche space? Various hypotheses have been developed to explain the promotion or suppression of ecological specialization. One hypothesis, competitive diversification, states that increased intraspecific competition will cause a population to broaden its niche breadth. With individuals alike in resource use preference, more individuals reduce the availability of preferred resources and should grant higher fitness to those that use secondary resources. However, recent studies cast doubt on this hypothesis with increased intraspecific competition reducing niche breadth in some systems. We present a game-theoretic evolutionary model showing greater ecological specialization with intraspecific competition under specific conditions. This is in contrast to the competitive diversification hypothesis. Our analysis reveals that specialization can offer a competitive advantage. Largely, when facing weak competition, more specialized individuals are able to acquire more of the preferred resources without greatly sacrificing secondary resources and therefore gain higher fitness. Only when competition is too great for an individual to significantly affect resource use will intraspecific competition lead to an increased niche breadth. Other conditions, such as a low diversity of resources and a low penalty to specialization, help promote ecological specialization in the face of intraspecific competition. Through this work, we have been able to discover a previously unseen role that intraspecific competition plays in the evolution of ecological specialization.

The Evolution of Household Bargaining

2019 ◽  
pp. 181-193
Author(s):  
Cailin O'Connor
Keyword(s):  
Evolutionary Model ◽  
Social Conditions ◽  
The Other ◽  
Household Bargaining ◽  
Evolutionary Models ◽  
Total Work ◽  
Starting Point ◽  
The Face ◽  
Game Theoretic ◽  
Traditional Game

This chapter first presents an explicitly evolutionary model of the emergence of coordination in modern households. The chapter shows why certain conditions might favor market labor for one gender and home labor for the other. The goal is to provide a proof of concept for the usefulness of evolutionary models in this domain, as opposed to traditional game theoretic models. The chapter also argues that once these patterns have emerged, they should be relatively stable in the face of changing social conditions. Using these patterns of coordination as a starting point, the chapter then shows why emerging patterns of household bargaining, i.e., over who does more total work, and has more total leisure time, should favor whichever gender tends to be employed in market work.

Why do people believe in a zero-sum economy?

2018 ◽  
Vol 41 ◽  
Author(s):  
Samuel G. B. Johnson
Keyword(s):  
Perspective Taking ◽  
Evolutionary Model ◽  
Everyday Experience ◽  
Coalitional Psychology ◽  
The Face ◽  
Zero Sum

AbstractZero-sum thinking and aversion to trade pervade our society, yet fly in the face of everyday experience and the consensus of economists. Boyer & Petersen's (B&P's) evolutionary model invokes coalitional psychology to explain these puzzling intuitions. I raise several empirical challenges to this explanation, proposing two alternative mechanisms – intuitive mercantilism (assigning value to money rather than goods) and errors in perspective-taking.

scholarly journals Resource use by two electric fishes (Gymnotiformes) of the National Forest Saracá-Taquera, Oriximiná, Pará

2017 ◽  
Vol 15 (2) ◽  
Author(s):  
Bruno E. Soares ◽  
Daniela C. O. Rosa ◽  
Nathália C. S. Silva ◽  
Miriam P. Albrecht ◽  
Érica P. Caramaschi
Keyword(s):  
Resource Use ◽  
Niche Breadth ◽  
Feeding Strategy ◽  
Stomach Contents ◽  
Niche Overlap ◽  
Feeding Strategies ◽  
National Forest ◽  
Microhabitat Use ◽  
Use Patterns ◽  
Head Morphology

ABSTRACT Fishes of the order Gymnotiformes have high diversity of oral and head morphology, which suggests trophic specializations within each clade. The aim of this study was to describe resource use patterns by two fish species (Gymnorhamphichthys rondoni and Gymnotus coropinae) in the National Forest Saracá-Taquera, Oriximiná - Pará, analyzing microhabitat use, diet composition, feeding strategies, niche breadth and niche overlap. Stomach contents of 101 individuals (41 G. rondoni and 60 G. coropinae), sampled in 23 headwater streams were analyzed and volume of food items was quantified to characterize their feeding ecology. Gymnorhamphichthys rondoni was captured mainly on sandy bottoms, whereas G. coropinae in crevices. Both species had a zoobenthivorous diet and consumed predominantly Sediment/Detritus and Diptera larvae, but also included allochthonous prey in their diet. These species had high niche overlap, with small variations related to the higher consumption of Ceratopogonidae larvae by G. rondoni and of Chironomidae larvae by G. coropinae. Both species had a generalist feeding strategy, but G. coropinae had a broader niche breadth. Our results demonstrate that G. rondoni and G. coropinae occupy different microhabitats but rely on similar food resources.

scholarly journals Competition and the origins of novelty: experimental evolution of niche-width expansion in a virus

2013 ◽  
Vol 9 (1) ◽  
pp. 20120616 ◽  
Author(s):  
Lisa M. Bono ◽  
Catharine L. Gensel ◽  
David W. Pfennig ◽  
Christina L. Burch
Keyword(s):  
Host Range ◽  
Resource Use ◽  
Intraspecific Competition ◽  
Experimental Evolution ◽  
Resource Competition ◽  
Experimental Tests ◽  
Model System ◽  
Standard Laboratory ◽  
Narrow Host Range ◽  
Competition For Resources

Competition for resources has long been viewed as a key agent of divergent selection. Theory holds that populations facing severe intraspecific competition will tend to use a wider range of resources, possibly even using entirely novel resources that are less in demand. Yet, there have been few experimental tests of these ideas. Using the bacterial virus (bacteriophage) ϕ 6 as a model system, we examined whether competition for host resources promotes the evolution of novel resource use. In the laboratory, ϕ 6 exhibits a narrow host range but readily produces mutants capable of infecting novel bacterial hosts. Here, we show that when ϕ 6 populations were subjected to intense intraspecific competition for their standard laboratory host, they rapidly evolved new generalist morphs that infect novel hosts . Our results therefore suggest that competition for host resources may drive the evolution of host range expansion in viruses. More generally, our findings demonstrate that intraspecific resource competition can indeed promote the evolution of novel resource-use phenotypes.

scholarly journals Clearing of Blast Waves on Finite-Sized Targets – an Overlooked Approach

2011 ◽  
Vol 82 ◽  
pp. 669-674 ◽  
Author(s):  
Andrew Tyas ◽  
Terry Bennett ◽  
James A. Warren ◽  
Stephen D. Fay ◽  
Sam E. Rigby
Keyword(s):  
Blast Wave ◽  
Experimental Testing ◽  
Experimental Studies ◽  
Blast Loading ◽  
Blast Waves ◽  
Total Impulse ◽  
Cast Doubt ◽  
The Face ◽  
Loading Parameter ◽  
Semi Empirical

The total impulse imparted to a target by an impinging blast wave is a key loading parameter for the design of blast-resistant structures and façades. Simple, semi-empirical approaches for the prediction of blast impulse on a structure are well established and are accurate in cases where the lateral dimensions of the structure are sufficiently large. However, if the lateral dimensions of the target are relatively small in comparison to the length of the incoming blast wave, air flow around the edges of the structure will lead to the propagation of rarefaction or clearing waves across the face of the target, resulting in a premature reduction of load and hence, a reduction in the total impulse imparted to the structure. This effect is well-known; semi-empirical models for the prediction of clearing exist, but several recent numerical and experimental studies have cast doubt on their accuracy and physical basis. In fact, this issue was addressed over half a century ago in a little known technical report at the Sandia Laboratory, USA. This paper presents the basis of this overlooked method along with predictions of the clearing effect. These predictions, which are very simple to incorporate in predictions of blast loading, have been carefully validated by the current authors, by experimental testing and numerical modelling. The paper presents a discussion of the limits of the method, concluding that it is accurate for relatively long stand-off blast loading events, and giving some indication of improvements that are necessary if the method is to be applicable to shorter stand-off cases.

scholarly journals Resource use and coexistence of two syntopic hylid frogs (Anura, Hylidae)

2005 ◽  
Vol 22 (1) ◽  
pp. 61-72 ◽  
Author(s):  
Marcelo Menin ◽  
Denise de C. Rossa-Feres ◽  
Ariovaldo A. Giaretta
Keyword(s):  
Resource Use ◽  
Resource Partitioning ◽  
Niche Breadth ◽  
Reproductive Season ◽  
Seasonal Occurrence ◽  
Temporary Pond ◽  
Site Characteristics ◽  
Structural Differences ◽  
Time Periods

The objectives of this study were to measure and compare niche breadth and overlap of males of Hyla nana Boulenger, 1889 and Hyla sanborni Schmidt, 1944 in three neighboring ponds. The measured niche dimensions were seasonal occurrence, call site, and diet. The reproductive season of H. sanborni was longer in permanent ponds, whereas H. nana had a longer reproductive season in the temporary pond. Call site characteristics were similar for both species, however H. sanborni called from higher perches than H. nana. Diptera (Nematocera) were the most consumed item by both species in the three ponds but, in general, H. nana ingested larger prey than H. sanborni. For both species, the consumption of prey types was correlated with the availability in the environment. The multidimensional overlap between H. nana and H. sanborni was higher in the permanent ponds than the temporary pond, in which H. sanborni was rare. These species differed in abundance among ponds, consumed prey of different sizes, and probably fed in different time periods. Moreover, the data obtained suggest that structural differences in the ponds may modify the dynamics of resource partitioning between the two species. Beside the great overlap found in the major niche dimensions analyzed the detected differences may be great enough to allow their coexistence.

The challenges for environment and development economics

2014 ◽  
Vol 19 (3) ◽  
pp. 287-290 ◽  
Author(s):  
Edward B. Barbier
Keyword(s):  
Environmental Impact ◽  
Resource Use ◽  
Development Economics ◽  
Pollution Control ◽  
Common Property ◽  
Environmental Problems ◽  
The Face ◽  
Property B ◽  
Environment And Development ◽  
Stock Depletion

I consider that the field of environment and development economics (EDE) began with the publication of The Control of Resources by Partha Dasgupta (1982). Although he did not confine his focus to developing countries, Dasgupta (1982: 10) suggested that managing environmental resources was much broader than conventional resource stock depletion or pollution control: To sum up: environmental discussions need to be conducted in the face of a clear recognition that, (a) these resource are often common property, (b) resolutions of environmental problems usually involve changes in the allocation of property rights, (c) resource use may well be irreversible (e.g. it may lead to their exhaustion when in fact this could have been avoided), (d) resource stocks often affect welfare directly, (e) the environmental impact of certain types of activity are cumulative and only become noticeable at some time in the future, and (f) the environmental impact of certain types of activity are uncertain. It is no wonder that environmental problems are formidable to analyse, let alone solve.

scholarly journals Bidding Strategies for Simultaneous Ascending Auctions

2008 ◽  
Vol 8 (1) ◽  
Author(s):  
Michael P Wellman ◽  
Anna Osepayshvili ◽  
Jeffrey K MacKie-Mason ◽  
Daniel Reeves
Keyword(s):  
Analytic Solutions ◽  
Bidding Strategies ◽  
New Family ◽  
Ascending Auctions ◽  
Demand Reduction ◽  
Reduction Strategies ◽  
The Face ◽  
Game Theoretic ◽  
Exposure Problem ◽  
Homogeneous Good

Simultaneous ascending auctions present agents with various strategic problems, depending on preference structure. As long as bids represent non-repudiable offers, submitting non-contingent bids to separate auctions entails an exposure problem: bidding to acquire a bundle risks the possibility of obtaining an undesired subset of the goods. With multiple goods (or units of a homogeneous good) bidders also need to account for their own effects on prices. Auction theory does not provide analytic solutions for optimal bidding strategies in the face of these problems. We present a new family of decision-theoretic bidding strategies that use probabilistic predictions of final prices: self-confirming distribution-prediction strategies. Bidding based on these is provably not optimal in general. But evidence using empirical game-theoretic methods we developed indicates the strategy is quite effective compared to other known methods when preferences exhibit complementarities. When preferences exhibit substitutability, simpler demand-reduction strategies address the own price effect problem more directly and perform better.

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