scholarly journals A Multi-Faceted Approach to Understand How Resource Diversity Can Mediate the Coexistence of Cryptic Marine Nematode Species

2021 ◽  
Vol 8 ◽  
Author(s):  
Rodgee Mae Guden ◽  
Sofie Derycke ◽  
Tom Moens
Keyword(s):  
Cryptic Species ◽  
Negative Impact ◽  
Interspecific Interactions ◽  
Food Resource ◽  
Nematode Species ◽  
Resource Concentration ◽  
Resource Concentration Hypothesis ◽  
Balanced Diet ◽  
Competitive Equilibria ◽  
Resource Diversity

Based on the principle of competitive exclusion, species occupying the same ecological niche cannot stably coexist due to strong interspecific competition for resources. Niche diversification, for instance through resource partitioning, may alleviate competition. Here, we investigate the effects of resource diversity on foraging behavior, fitness and interspecific interactions of four cryptic bacterivorous nematode species (Pm I–IV) of the Litoditis marina species complex with sympatric field distributions. Three resource (bacteria) diversity levels (low, medium, high) were used as food treatments and compared to a treatment with only Escherichia coli as food. Differences in taxis to food existed between the cryptic species and between bacterial mixtures of different diversity: all the cryptic species except Pm I showed higher attraction toward medium-diversity food. Furthermore, the cryptic species of L. marina generally exhibited higher fitness on a more diverse food resource. Resource diversity also impacted the interspecific interactions between the cryptic species. Our results show that resource diversity can alter the interspecific interactions among the cryptic species of L. marina, indicating that competitive equilibria between species are very context-dependent. Although a considerable body of evidence supports the hypotheses (e.g., “variance-in-edibility” hypothesis and the “dilution hypothesis” or “resource concentration hypothesis”) which predict a negative impact on consumers when resource diversity is increased, the benefits of a diverse resource can outweigh these disadvantages by offering a more complete and/or complementary range of nutritional resources as suggested by the “balanced diet” hypothesis.

scholarly journals The floriphilic katydid, Phaneroptera brevis, is a frequent flower visitor of non-native, flowering forbs

2019 ◽  
Vol 28 (2) ◽  
pp. 21-26
Author(s):  
Ming Kai Tan ◽  
Hui Lee ◽  
Hugh Tiang Wah Tan
Keyword(s):  
Model Organism ◽  
Environmental Parameters ◽  
Plant Species Richness ◽  
Limited Information ◽  
Pollination Services ◽  
Resource Concentration ◽  
Flower Visitors ◽  
Resource Concentration Hypothesis ◽  
Flower Visitation ◽  
Flower Visiting

Distribution of consumers in a patch of vegetation can be predicted by resource availability and explained by the resource-concentration and optimal-foraging hypotheses. These hypotheses have not been explored for flower-visiting Orthoptera because they are deemed less economically or ecologically important. Some flower-visiting orthopterans can provide pollination services, which warrants more attention. We studied a Singaporean, floriphilic katydid, Phaneropterabrevis, to investigate the following questions: 1) how frequently does P.brevis visit flowers compared to other flower visitors and 2) what factors predict the abundance of P.brevis? We collected abundance data for P.brevis and other flower-visiting arthropods and quantified seven environmental parameters, including flower abundance and host-plant species richness. We found that P.brevis frequents flowers significantly more often than some common and expected flower visitors such as hoverflies. In line with the prediction of the resource-concentration hypothesis, the abundance of P.brevis was positively correlated with a higher flower abundance. Owing to the limited information on unexpected wild flower visitors and pollinators, especially from the understudied tropics of Southeast Asia, we propose that P.brevis can be a model organism for future studies to answer fundamental questions on flower visitation.

scholarly journals Disentangling the environmental impact of different human disturbances: a case study on islands

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Sebastian Steibl ◽  
Christian Laforsch
Keyword(s):  
Anthropogenic Disturbance ◽  
Negative Impact ◽  
Local Population ◽  
Food Resource ◽  
Coastal Ecosystems ◽  
Hermit Crabs ◽  
Conservation Action ◽  
Human Disturbances ◽  
Study Approach ◽  
Urbanized Areas

Abstract Coastal ecosystems suffer substantially from the worldwide population growth and its increasing land demands. A common approach to investigate anthropogenic disturbance in coastal ecosystems is to compare urbanized areas with unaffected control sites. However, the question remains whether different types of anthropogenic disturbance that are elements of an urbanized area have the same impact on beach ecosystems. By investigating small islands that are utilized for tourism, inhabited by the local population, or remained completely uninhabited, we disentangled different anthropogenic disturbances and analysed their impacts on hermit crabs as indicator species. We observed a negative impact on abundance on tourist islands and a negative impact on body size on local islands. In comparison to the uninhabited reference, both disturbances had an overall negative impact. As both forms of disturbance also impacted the underlying food resource and habitat availability differently, we propose that the findings from our study approach are valid for most obligate beach species in the same system. This demonstrates that in urbanized areas, the coastal ecosystem is not always impacted identically, which emphasizes the importance of considering the particular type of anthropogenic disturbance when planning conservation action in urbanized areas.

scholarly journals Simulation of the effects of  movement patterns and  resource density on the egg  distributions of Pieris rapae  (Lepidoptera) at multiple  spatial scales.

2021 ◽  
Author(s):  
◽  
James Barritt
Keyword(s):  
Field Experiments ◽  
Pieris Rapae ◽  
Plant Density ◽  
Animal Movement ◽  
Multiple Scales ◽  
Spatial Scales ◽  
Large Body ◽  
Negative Relationship ◽  
Resource Concentration ◽  
Resource Concentration Hypothesis

<p>This thesis presents a spatially explicit, agent based simulation, used to explore the ovipositing behaviour of the Small Cabbage White butterfly, Pieris rapae (Lepidoptera). The study concerns the effects of host-plant (Cabbage, Brassica oleracae) density upon P. rapae egg distribution patterns, at multiple scales. A general review of the literature is provided which covers the ecology of animal movement, methods of quantifying movement, models of movement, ecological theory of herbivore responses to plant density (Resource Concentration Hypothesis) and the biology of P.rapae.  The construction of the simulation is described in detail and the source code plus an executable version of the software are available as a companion CD. A number of simulation experiments are reported which demonstrate the basic behaviour of the simulation over a simplified resource layout. The framework is then used to explore more complex layouts which are compared to field experiments conducted as part of a separate PhD thesis (Hasenbank, in prep). A Correlated Random Walk simulated a negative relationship between forager egg distributions and resource densities, observed at all scales. Including a diffuse attraction to resources (e.g. olfaction), simulated a negative relationship between egg distributions and resource densities at smaller scales, and a positive relationship at larger scales.  This work builds on a large body of previous simulation studies and attempts to produce a useful framework for subsequent researchers to explore the effects of animal movement through the use of random walks. It demonstrates the use of the framework with a specific example concerning the egg distributions of P. rapae and the effect of scale. It provides some useful insights into both the analysis of results from a complex spatial experimental layout, and potential responses which may be observed. It demonstrates that a simple model can, in the case of P rapae be used to obtain relatively realistic egg distributions.</p>

scholarly journals Habitat Management for Pest Management: Limitations and Prospects

2019 ◽  
Vol 112 (4) ◽  
pp. 302-317 ◽  
Author(s):  
Mauricio González-Chang ◽  
Sundar Tiwari ◽  
Sheela Sharma ◽  
Steve D Wratten
Keyword(s):  
Pest Management ◽  
Habitat Management ◽  
Food Sources ◽  
Floral Resources ◽  
Resource Concentration ◽  
Resource Concentration Hypothesis ◽  
Enemies Hypothesis ◽  
Host Selection Behavior ◽  
Insect Ecology ◽  
Alternative Food Sources

AbstractHabitat management is an important strategy for pest control in integrated pest management (IPM). Various categories of habitat management such as trap cropping, intercropping, natural enemy refuges such as ‘beetle banks’, and floral resources for parasitoids and predators, have been used in applied insect ecology for many years. In a broader sense, two mechanisms, the ‘enemies hypothesis’ and the ‘resource concentration hypothesis’ have been identified as acting independently or combined in pest population dynamics. The ‘enemies hypothesis’ directly supports the conservation and enhancement of natural enemies, floral resources such as shelter, nectar, alternative food sources, and pollen (SNAP) to improve conservation biological control. The ‘resource concentration hypothesis’ emphasizes how the host selection behavior of herbivores in a diverse habitat can reduce pest colonization in crops. This review emphasizes the potential of these approaches, as well as possible dis-services, and includes limitations and considerations needed to boost the efficacy of these strategies worldwide.

scholarly journals A Review on the Triggers of Pediatric Migraine with the Aim of Improving Headache Education

2020 ◽  
Vol 9 (11) ◽  
pp. 3717 ◽  
Author(s):  
Gaku Yamanaka ◽  
Shinichiro Morichi ◽  
Shinji Suzuki ◽  
Soken Go ◽  
Mika Takeshita ◽  
...  
Keyword(s):  
Children And Adolescents ◽  
Treatment Guidelines ◽  
Negative Impact ◽  
Current Treatment ◽  
Current Evidence ◽  
Lifestyle Interventions ◽  
Emotional States ◽  
Balanced Diet ◽  
Pediatric Migraine ◽  
As Stress

Although migraines are common in children and adolescents, they have a robustly negative impact on the quality of life of individuals and their families. The current treatment guidelines outline the behavioral and lifestyle interventions to correct common causative factors, such as negative emotional states, lack of exercise and sleep, and obesity; however, the evidence of their effectiveness is insufficient. To create a plan for disseminating optimal pediatric headache education, we reviewed the current evidence for factors correlated with migraine. We assessed three triggers or risk factors for migraines in children and adolescents: stress, sleep poverty, and alimentation (including diet and obesity). While there is a gradual uptick in research supporting the association between migraine, stress, and sleep, the evidence for diet-related migraines is very limited. Unless obvious dietary triggers are defined, clinicians should counsel patients to eat a balanced diet and avoid skipping meals rather than randomly limiting certain foods. We concluded that there is not enough evidence to establish a headache education plan regarding behavioral and lifestyle interventions. Clinicians should advise patients to avoid certain triggers, such as stress and sleep disorders, and make a few conservative dietary changes.

Resource Concentration Hypothesis

2008 ◽  
pp. 3173-3174
Author(s):  
Norman C. Leppla ◽  
Bastiaan M. Drees ◽  
Allan T. Showler ◽  
John L. Capinera ◽  
Jorge E. Peña ◽  
...  
Keyword(s):  
Resource Concentration ◽  
Resource Concentration Hypothesis

Variation in anti-predator behaviors of white-tailed deer (Odocoileus virginianus) in a multi-predator system

2019 ◽  
Vol 97 (11) ◽  
pp. 1030-1041
Author(s):  
E.R. Olson ◽  
T.R. Van Deelen ◽  
S.J. Ventura
Keyword(s):  
Odocoileus Virginianus ◽  
Interspecific Interactions ◽  
Food Resource ◽  
Risky Behaviors ◽  
Behavioral Observation ◽  
Relative Effect ◽  
Habitat Characteristics ◽  
Intraspecific Interactions ◽  
Intraspecific Interaction ◽  
A Site

Anti-predator responses to perceived predation risk can influence population demography. Understanding the relative effect of predator exposure and intraspecific interactions across a variety of anti-predator behaviors provides important insight into inter- and intra-specific drivers of species-specific behaviors. We merged classical behavioral observation methods with camera trapping techniques to examine anti-predator behaviors of white-tailed deer (Odocoileus virginianus (Zimmermann, 1780)) relative to variation in predator exposure and interspecific interactions. We coded 772 behavioral observations from >180 000 images spanning 605 trap-nights. Seasonal differences in behavioral responses to diminishing returns on foraging effort indicated that deer are risk-averse foragers and are more likely to exhibit risky behaviors in the presence of a concentrated food resource when the nutritional value of food resources are high. However, deer tended to spend less time at a site as resources diminished, supporting marginal value theories of habitat use. Intraspecific interaction predicted vigilance and the amount of time spent at a site. Similar to many other species, deer tended to be less vigilant and spend more time at a site as group size increased. Our research suggests that white-tailed deer in Wisconsin make foraging decisions based on factors associated with individual fitness, presence of conspecifics, and habitat characteristics.

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