Model Of Resource Partitioning Research Articles

Siderophore-mediated iron partition promotes dynamical coexistence between cooperators and cheaters

Microbes shape their habitats by consuming resources and producing a diverse array of chemicals that can serve as public goods. Despite the risk of exploitation by cheaters, genes encoding sharable molecules like siderophores are widely found in nature, prompting investigations into the mechanisms that allow producers to resist invasion by cheaters. In this work, we presented the chemostat-typed "resource partition model" to demonstrate that dividing the iron resource between private and public siderophores can promote stable or dynamic coexistence between producers and cheaters in a well-mixed environment. Moreover, our analysis shows that when microbes not only consume but also produce resources, chemical innovation leads to stability criteria that differ from those of classical consumer resource models, resulting in more complex dynamics. Our work sheds light on the role of chemical innovations in microbial communities and the potential for resource partition to facilitate dynamical coexistence between cooperative and cheating organisms.

A model of resource partitioning between foraging bees based on learning.

Central place foraging pollinators tend to develop multi-destination routes (traplines) to exploit patchily distributed plant resources. While the formation of traplines by individual pollinators has been studied in detail, how populations of foragers use resources in a common area is an open question, difficult to address experimentally. We explored conditions for the emergence of resource partitioning among traplining bees using agent-based models built from experimental data of bumblebees foraging on artificial flowers. In the models, bees learn to develop routes as a consequence of feedback loops that change their probabilities of moving between flowers. While a positive reinforcement of movements leading to rewarding flowers is sufficient for the emergence of resource partitioning when flowers are evenly distributed, the addition of a negative reinforcement of movements leading to unrewarding flowers is necessary when flowers are patchily distributed. In environments with more complex spatial structures, the negative experiences of individual bees on flowers favour spatial segregation and efficient collective foraging. Our study fills a major gap in modelling pollinator behaviour and constitutes a unique tool to guide future experimental programs.

Resource Partitioning and the Organizational Dynamics of “Fringe Banking”

We examine the emergence and proliferation of payday lenders, fringe businesses that provide small short-term, but high-cost loans. We link the organizational dynamics of these businesses to two trends in consumer lending in the United States: the continuing consolidation of mainstream financial institutions; and the expansion of such institutions in the provision of financial services regarded as similar to payday loans. We explain the coexistence in mature industries of large-scale organizations in the market center and smaller specialists in the periphery by testing and extending the organizational model of resource partitioning. Our focus is on two under-examined aspects of the model: the dynamic underlying the partitioning process, and the conditions under which the market remains partitioned. The empirical analysis covers payday lenders, banks, and credit unions operating in Wisconsin between 1994 and 2008.

Resource partitioning for soil phosphorus: a hypothesis

Summary Organic phosphorus is abundant in soil and its turnover can supply a considerable fraction of the phosphorus taken up by natural vegetation. Despite this, the ecological significance of organic phosphorus remains poorly understood, which is remarkable given the biological importance of phosphorus in terrestrial environments. Of particular interest is the possibility that coexisting plant species partition soil organic phosphorus to reduce competition. This seems likely given the large number of biologically available phosphorus compounds that occur in soil and the variety of mechanisms by which plants can utilize them. Here I propose a conceptual model of resource partitioning for soil phosphorus. The model describes a hypothetical example of four coexisting plant species that differ in their ability to access soil organic phosphorus compounds, which are grouped to form a gradient of biological availability based on the processes involved in their utilization by plants. Synthesis: Resource partitioning for soil phosphorus could provide an additional mechanism to explain the coexistence and distribution of plant species. It is likely to occur widely in terrestrial environments, but should have greatest ecological significance wherever productivity is limited by the availability of soil phosphorus. This includes freshwater wetlands, super‐humid temperate regions and ecosystems developed on strongly‐weathered soils that cover vast areas of ancient landscapes in Africa, Australia and South America.

Flexible niche partitioning via a foraging mode shift: a proposed mechanism for coexistence in stream‐dwelling charrs

Summary1. Foraging behaviour, diet and interference competition were examined for two morphologically similar charrs,Salvelinus malma(Dolly Varden) andS. leucomaenis(white‐spotted charr), under varying food resource conditions over four summers in a Japanese mountain stream. Data were used to test predictions from a mechanistic model of resource partitioning developed from an earlier field experiment.2. The charrs adopted one of two distinct foraging modes, ambushing drifting invertebrates from relatively fixed foraging positions or actively searching for benthic prey over large areas. The proportion of benthos foragers increased markedly when drifting prey declined, and was much greater inS. malmathanS. leucomaeniswhen drift was lean, upholding predictions made from our earlier experiment.3. For drift foragers of both species, frequency of foraging attempts decreased as drift rate declined, and aggressive encounters increased. In contrast, for benthos foragers of both species the frequency of foraging attempts was essentially constant across the range of benthos biomass measured, and aggressive encounters remained low.4. Salvelinus leucomaenisate larger drifting prey thanS. malma, even though the former charr were smaller. In contrast,S. malmaforaged on benthic prey at a higher rate thanS. leucomaenis, although there was no difference in prey mass. Thus, the optimal point to shift to benthic foraging is at a higher drift threshold forS. malmathanS. leucomaenis, most probably due to differences in jaw morphology. Moreover, because dominance for favourable drift foraging positions was based on size alone,S. malmashifted to benthos foraging at a larger size thanS. leucomaenis, as predicted by a simple model.5. Charr consumed distinct prey types according to their foraging mode. Drift foragers primarily ate terrestrial invertebrates, whereas benthos foragers ate mainly chironomid larvae. Consequently, diet overlap was high when drift was abundant and both species were drift foragers, but declined as drift declined andS. malmashifted to benthos foraging. Therefore, species‐specific differences in foraging mode shifts across the resource gradient explained the flexible resource partitioning we observed, and probably account for the coexistence of these congeneric charrs in zones of sympatry in northern Japan.

Low Preferred Foraging Temperatures and Nocturnal Foraging in a Desert Harvester Ant

Previous articleNext article No AccessLetters to the EditorsLow Preferred Foraging Temperatures and Nocturnal Foraging in a Desert Harvester AntGeorge L. Hunt, Jr.George L. Hunt, Jr. Search for more articles by this author PDFPDF PLUS Add to favoritesDownload CitationTrack CitationsPermissionsReprints Share onFacebookTwitterLinkedInRedditEmail SectionsMoreDetailsFiguresReferencesCited by The American Naturalist Volume 111, Number 979May - Jun., 1977 Published for The American Society of Naturalists Article DOIhttps://doi.org/10.1086/283187 Views: 4Total views on this site Citations: 3Citations are reported from Crossref Copyright 1977 The University of ChicagoPDF download Crossref reports the following articles citing this article:Christina L. Kwapich and Bert Hölldobler Destruction of Spiderwebs and Rescue of Ensnared Nestmates by a Granivorous Desert Ant (Veromessor pergandei), The American Naturalist 194, no.33 (Jul 2019): 395–404.https://doi.org/10.1086/704338Avalon C. S. Owens, Sara M. Lewis The impact of artificial light at night on nocturnal insects: A review and synthesis, Ecology and Evolution 8, no.2222 (Oct 2018): 11337–11358.https://doi.org/10.1002/ece3.4557D. Gillon, F. Adam, B. Hubert Production et consommation de graines en milieu sahélo-soudanien au Sénégal les fourmis,Messor galla, Insectes Sociaux 31, no.11 (Mar 1984): 51–73.https://doi.org/10.1007/BF02223692