Females restrict the position of domatia and suffer more herbivory than hermaphrodites in Myriocarpa longipes, a neotropical facultative myrmecophyte

2021 ◽  
pp. 1-7
Author(s):  
Mario A. Sandoval-Molina ◽  
Bernardo Rafael Lugo-García ◽  
Alan Daniel Mendoza-Mendoza ◽  
Mariusz Krzysztof Janczur
Keyword(s):  
Resource Allocation ◽  
Resource Competition ◽  
Plant Interactions ◽  
Herbivore Damage ◽  
Ant Colonies ◽  
Hollow Structures ◽  
Size Number ◽  
Competition Hypothesis ◽  
Investment In Reproduction ◽  
Competition For Resources

Abstract Domatia are hollow structures in plants occupied by ant colonies, in turn ants provide protection against herbivores. In plants, competition for resources has driven sex-related changes in the patterns of resource allocation to life-history traits and defence traits. The resource-competition hypothesis (RCH) proposes that female plants due to their higher investment in reproduction will allocate fewer resources to defence production, showing greater herbivore damage than other sexual forms. We hypothesise the existence of sex-related differences in defensive traits of domatia-bearing plants, being female plants less defended due to differences in domatia traits, such as size, number of domatia and their position, exhibiting more herbivore damage than hermaphrodite plants of Myriocarpa longipes, a facultative neotropical myrmecophyte. We found eight species of ants inhabiting domatia; some species co-inhabited the same plant, even the same branch. Our results are consistent with the predictions of RCH, as female plants had ant-inhabited domatia restricted to the middle position of their branches and exhibited greater herbivore damage in leaves than hermaphrodites. However, we did not find differences in domatia size and leaf area between sexual forms. Our study provides evidence for intersexual differences in domatia position and herbivory in a facultative ant–plant mutualism in M. longipes. We highlight the importance of considering the plant sex in ant–plant interactions. Differences in resource allocation related to sexual reproduction could influence the outcome of ant–plant interactions.

scholarly journals Wolf, Canis lupus, Pup Mortality: Interspecific Predation or Non-Parental Infanticide?

2011 ◽  
Vol 125 (2) ◽  
pp. 158 ◽  
Author(s):  
A. David M. Latham ◽  
Stan Boutin
Keyword(s):  
Canis Lupus ◽  
Resource Competition ◽  
The Other ◽  
Gray Wolf ◽  
Gps Collar ◽  
Competition Hypothesis ◽  
Interspecific Predation ◽  
Pup Mortality ◽  
First Time

A breeding male Gray Wolf, Canis lupus, equipped with a GPS collar was documented going to the den site of another Gray Wolf pack. This trip was coincident with an attack on the den of the other pack and the occurrence of a dead and partially consumed Gray Wolf pup at the same location. We present two possible explanations - interspecific predation and non-parental infanticide - to account for this observation. Because the Gray Wolf with the GPS collar and his mate were first-time breeders and were attempting to establish a territory space of their own, we speculate that, based on the available evidence, this observation most likely represents a case of non-parental infanticide that fits the predictions of the resource competition hypothesis.

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.

Response Modalities and Time-Sharing Performance

1986 ◽  
Vol 30 (4) ◽  
pp. 337-341 ◽  
Author(s):  
Michael A. Vidulich
Keyword(s):  
Experimental Design ◽  
Resource Competition ◽  
Control Device ◽  
Significant Finding ◽  
Time Sharing ◽  
Transfer Effects ◽  
Speech Technology ◽  
Modality Effects ◽  
Response Modality ◽  
Competition Hypothesis

The recent development of speech technology has provided an opportunity for new approaches in display/control design. Some researchers have proposed that the use of speech can reduce resource competition with manual controls and improve multi-task performance. However, it has also been suggested that due to the heavy reliance on within-subject experimental designs, the research supporting the resource competition hypothesis was potentially contaminated by asymmetric transfer. The present study examined the value of speech responses as a control device in a dual-task experiment. The experimental design permitted the evaluation of asymmetric transfer effects. Despite numerous significant effects supporting the advantage of mixing manual and speech responses there was no statistically significant finding that suggested the occurrence of asymmetric transfer. Also, the value of speech output was demonstrated in between-subject analyses that were logically immune to asymmetric transfer effects. Therefore, although the possibility of asymmetric transfer remains a legitimate experimental design concern, it is not a sufficient explanation for the observed response modality effects. The present results supported the resource competition hypothesis of response modality effects, and suggested that in operational environments the judicious use of speech technology can enhance performance.

scholarly journals Dynamic allocation of orthogonal ribosomes facilitates uncoupling of co-expressed genes

2017 ◽  
Author(s):  
Alexander P.S. Darlington ◽  
Juhyun Kim ◽  
José I. Jiménez ◽  
Declan G. Bates
Keyword(s):  
Resource Allocation ◽  
Circuit Design ◽  
Resource Competition ◽  
Dynamic Resource Allocation ◽  
Dynamic Allocation ◽  
16S Rna ◽  
Synthetic Circuit ◽  
Dynamic Resource ◽  
The Impact ◽  
Host Genes

AbstractIntroduction of synthetic circuits into host microbes creates competition between circuit and host genes for shared cellular resources, such as RNA polymerases and ribosomes. This can lead to the emergence of unwanted coupling between the expression of different genes, complicating circuit design and potentially leading to circuit failure. Here we demonstrate the ability of orthogonal ribosomes to alleviate the effects of this resource competition. We partition the ribosome pool by expressing an engineered 16S RNA with altered specificity, and use this division of specificity to build simple resource allocators which reduce the level of ribosome-mediated gene coupling. We then design and implement a dynamic resource allocation controller, which acts to increase orthogonal ribosome production as the demand for translational resources by a synthetic circuit increases. Our results highlight the potential of dynamic translational resource allocation as a means of minimising the impact of cellular limitations on the function of synthetic circuitry.

Politics and Pain in Managing Information Technology: A Case Study from Insurance

1992 ◽  
Vol 13 (2) ◽  
pp. 211-228 ◽  
Author(s):  
David Knights ◽  
Fergus Murray
Keyword(s):  
Information Technology ◽  
Resource Allocation ◽  
Career Advancement ◽  
Resource Competition ◽  
System Development ◽  
Political Activity ◽  
Investment Strategies ◽  
Study Material ◽  
It Systems

Drawing on case study material, this paper explores the politics of career and resource competition that is a medium and outcome of IT investment strategies and system development priorities. This is achieved by examining the manner in which different managers and operating divisions in the case study organization perceive and pursue distinct IT priorities. This they do by involving particular constructions of 'markets', 'technology', and 'organization'. The paper argues that the difficulties encountered around the development of IT systems in the case study company are symptomatic of tensions which are a condition and conse quence of struggles over resource allocation and career advancement within management. These activities necessarily generate considerable political activity which has potentially painful consequences for actors tied into power/identity relations in the modem organization.

Competitive Motherhood from a Comparative Perspective

2016 ◽  
Author(s):  
Katherine A. Valentine ◽  
Norman P. Li ◽  
Jose C. Yong
Keyword(s):  
Reproductive Success ◽  
Sex Ratio ◽  
Nonhuman Primates ◽  
Resource Competition ◽  
Sex Ratios ◽  
Comparative Perspective ◽  
Future Directions ◽  
Competition Hypothesis ◽  
Resource Enhancement

Mothers play an important role in helping their children achieve maximal reproductive success. We explore how mothers across species manipulate birth sex ratios favoring the sex that will be best suited to their environments and how maternal competition affects offspring reproductive success in nonhuman mammals as well as humans. The Trivers-Willard hypothesis, resource competition hypothesis, resource enhancement hypothesis, and maternal dominance hypothesis are considered with respect to maternal birth sex ratio manipulation. Next, the primate literature is reviewed as inspiration for hypotheses on maternal competition for positive offspring outcomes. Nonhuman primates as well as humans are argued to compete for status, breeding opportunities, and allomothers (i.e., caregivers apart from the mother), and these factors have an impact on their reproductive success. Status is passed on from mother to offspring, amplifying the effects of competition for status. Future directions are delineated to fill in gaps in the existing literature.

scholarly journals Biomass explains the intensity of facilitative – not competitive – interactions: three intraspecific tests with annuals

Web Ecology ◽  
2012 ◽  
Vol 12 (1) ◽  
pp. 49-55 ◽  
Author(s):  
C. Ariza ◽  
K. Tielbörger
Keyword(s):  
Size Dependence ◽  
Resource Competition ◽  
Theoretical Models ◽  
Plant Size ◽  
Competitive Interactions ◽  
Positive Interactions ◽  
Plant Interactions ◽  
Belowground Competition ◽  
Size Dependent ◽  
Negative Effect

Abstract. Despite efforts to discern the role of plant size in resource competition, the circumstances under which size-dependent plant-plant interactions occur are still unclear. The traditional assumption is that competition intensifies with increasing neighbour size. However, recent studies suggest that the size (biomass) dependence of competitive interactions is strongest at very low biomass levels and becomes negligible after a certain threshold neighbour biomass has been reached. We searched for the generality of such patterns for three common annual plant species in Israel. We monitored target and neighbour biomass along their entire lifecycle using an even-aged, intraspecific and intrapopulation competition screenhouse experiment under water-limited conditions. For all focal species, neighbour presence had a net negative effect on vegetative biomass at harvest. However, this was not explained by increasing neighbour biomass over time, as a consistent pattern of size-dependent facilitative, rather than competitive, interactions was observed at all life stages. We explain these observations in terms of co-occurring aboveground facilitation and dominant belowground competition for water. Since our findings are the first of their kind and contradict theoretical predictions of biomass dependence of net negative interactions, we advocate further experiments addressing size dependence in interactions among plants. In particular, theoretical models addressing size dependence of positive interactions must be developed.

scholarly journals Spatial ecology of territorial populations

2019 ◽  
Vol 116 (36) ◽  
pp. 17874-17879 ◽  
Author(s):  
Benjamin G. Weiner ◽  
Anna Posfai ◽  
Ned S. Wingreen
Keyword(s):  
Mixed Models ◽  
Spatial Ecology ◽  
Allee Effect ◽  
Spatial Organization ◽  
Resource Competition ◽  
Physical Space ◽  
Small Perturbations ◽  
Trade Offs ◽  
Nutrient Diffusion ◽  
Competition For Resources

Many ecosystems, from vegetation to biofilms, are composed of territorial populations that compete for both nutrients and physical space. What are the implications of such spatial organization for biodiversity? To address this question, we developed and analyzed a model of territorial resource competition. In the model, all species obey trade-offs inspired by biophysical constraints on metabolism; the species occupy nonoverlapping territories, while nutrients diffuse in space. We find that the nutrient diffusion time is an important control parameter for both biodiversity and the timescale of population dynamics. Interestingly, fast nutrient diffusion allows the populations of some species to fluctuate to zero, leading to extinctions. Moreover, territorial competition spontaneously gives rise to both multistability and the Allee effect (in which a minimum population is required for survival), so that small perturbations can have major ecological effects. While the assumption of trade-offs allows for the coexistence of more species than the number of nutrients—thus violating the principle of competitive exclusion—overall biodiversity is curbed by the domination of “oligotroph” species. Importantly, in contrast to well-mixed models, spatial structure renders diversity robust to inequalities in metabolic trade-offs. Our results suggest that territorial ecosystems can display high biodiversity and rich dynamics simply due to competition for resources in a spatial community.

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