scholarly journals Inquiline predator increases nutrient-cycling efficiency of Nepenthes rafflesiana pitchers

2019 ◽  
Vol 15 (12) ◽  
pp. 20190691
Author(s):  
Weng Ngai Lam ◽  
Ying Yi Chou ◽  
Felicia Wei Shan Leong ◽  
Hugh Tiang Wah Tan
Keyword(s):  
Experimental Data ◽  
Nutrient Cycling ◽  
Ecosystem Functioning ◽  
Trophic Levels ◽  
Resource Model ◽  
Pitcher Plants ◽  
Predator Prey ◽  
Invertebrate Prey ◽  
Cycling Efficiency ◽  
Consumer Resource

The modified-leaf pitchers of Nepenthes rafflesiana pitcher plants are aquatic, allochthonous ecosystems that are inhabited by specialist inquilines and sustained by the input of invertebrate prey. Detritivorous inquilines are known to increase the nutrient-cycling efficiency (NCE) of pitchers but it is unclear whether predatory inquilines that prey on these detritivores decrease the NCE of pitchers by reducing detritivore populations or increase the NCE of pitchers by processing nutrients that may otherwise be locked up in detritivore biomass. Nepenthosyrphus is a small and poorly studied genus of hoverflies and the larvae of one such species is a facultatively detritivorous predator that inhabits the pitchers of N. rafflesiana . We fitted a consumer–resource model to experimental data collected from this system. Simulations showed that systems containing the predator at equilibrium almost always had higher NCEs than those containing only prey (detritivore) species. We showed using a combination of simulated predator/prey exclusions that the processing of the resource through multiple pathways and trophic levels in this system is more efficient than that accomplished through fewer pathways and trophic levels. Our results thus support the vertical diversity hypothesis, which predicts that greater diversity across trophic levels results in greater ecosystem functioning.

Use of Time in the Phenology of Vertical Species Interactions

2019 ◽  
pp. 133-166
Author(s):  
Eric Post
Keyword(s):  
Species Interactions ◽  
Trophic Levels ◽  
Plant Interactions ◽  
Predator Prey ◽  
Host Interactions ◽  
Use Of Time ◽  
Resource Interactions ◽  
Survival And Reproduction ◽  
Consumer Resource

This chapter examines the role of time in vertical species interactions. Vertically structured communities are those shaped primarily by interactions among organisms at different trophic levels. Hence, these comprise exploitation interactions typified by predator—prey interactions, pathogen—host interactions, herbivore—plant interactions, and consumer—resource interactions in general. In such interactions, consumer success—in terms of growth, survival, and reproduction—depends upon synchronization of consumer phenology with resource phenology. In contrast, the success of resource species may depend upon minimizing synchronization of their phenology with that of species by which they are consumed. In mutualistic interactions, however, in which both species function as a resource for one another, the success of both species depends upon phenological overlap. The chapter then explores some examples of the role of time in the phenology of all three types of players in vertical species interactions—resource species, consumer species, and mutualistic species.

scholarly journals Quantitative Analysis of Lysobacter Predation

2015 ◽  
Vol 81 (20) ◽  
pp. 7098-7105 ◽  
Author(s):  
Ivana Seccareccia ◽  
Christian Kost ◽  
Markus Nett
Keyword(s):  
Experimental Data ◽  
Feeding Strategy ◽  
Predatory Behavior ◽  
Bacterial Group ◽  
Potential Prey ◽  
Bacterial Populations ◽  
Content Type ◽  
Predator Prey ◽  
Prey Killing ◽  
Predatory Potential

ABSTRACTBacteria of the genusLysobacterare considered to be facultative predators that use a feeding strategy similar to that of myxobacteria. Experimental data supporting this assumption, however, are scarce. Therefore, the predatory activities of threeLysobacterspecies were tested in the prey spot plate assay and in the lawn predation assay, which are commonly used to analyze myxobacterial predation. Surprisingly, only one of the testedLysobacterspecies showed predatory behavior in the two assays. This result suggested that not allLysobacterstrains are predatory or, alternatively, that the assays were not appropriate for determining the predatory potential of this bacterial group. To differentiate between the two scenarios, predation was tested in a CFU-based bioassay. For this purpose, defined numbers ofLysobactercells were mixed together with potential prey bacteria featuring phenotypic markers, such as distinctive pigmentation or antibiotic resistance. After 24 h, cocultivated cells were streaked out on agar plates and sizes of bacterial populations were individually determined by counting the respective colonies. Using the CFU-based predation assay, we observed thatLysobacterspp. strongly antagonized other bacteria under nutrient-deficient conditions. Simultaneously, theLysobacterpopulation was increasing, which together with the killing of the cocultured bacteria indicated predation. Variation of the predator/prey ratio revealed that all threeLysobacterspecies tested needed to outnumber their prey for efficient predation, suggesting that they exclusively practiced group predation. In summary, the CFU-based predation assay not only enabled the quantification of prey killing and consumption byLysobacterspp. but also provided insights into their mode of predation.

Predator–prey interactions and climate change

2019 ◽  
pp. 199-220 ◽  
Author(s):  
Vincent Bretagnolle ◽  
Julien Terraube
Keyword(s):  
Climate Change ◽  
Species Interactions ◽  
Experimental Studies ◽  
Trophic Levels ◽  
Generalist Predators ◽  
Top Down ◽  
Predator Prey ◽  
Key Topics ◽  
Available Information

Climate change is likely to impact all trophic levels, although the response of communities and ecosystems to it has only recently received considerable attention. Further, it is expected to affect the magnitude of species interactions themselves. In this chapter, we summarize why and how climate change could affect predator–prey interactions, then review the literature about its impact on predator–prey relationships in birds, and provide prospects for future studies. Expected effects on prey or predators may include changes in the following: distribution, phenology, population density, behaviour, morphology, or physiology. We review the currently available information concerning particular key topics: top-down versus bottom-up control, specialist versus generalist predators, functional versus numerical responses, trophic cascades and regime shifts, and lastly adaptation and selection. Finally, we focus our review on two well-studied bird examples: seabirds and raptors. Key future topics include long-term studies, modelling and experimental studies, evolutionary questions, and conservation issues.

scholarly journals Examining predator–prey body size, trophic level and body mass across marine and terrestrial mammals

2014 ◽  
Vol 281 (1797) ◽  
pp. 20142103 ◽  
Author(s):  
Marlee A. Tucker ◽  
Tracey L. Rogers
Keyword(s):  
Community Structure ◽  
Body Size ◽  
Body Mass ◽  
Marine Environment ◽  
Trophic Level ◽  
Marine Mammals ◽  
Trophic Position ◽  
Trophic Levels ◽  
Predator Prey ◽  
Terrestrial Mammals

Predator–prey relationships and trophic levels are indicators of community structure, and are important for monitoring ecosystem changes. Mammals colonized the marine environment on seven separate occasions, which resulted in differences in species' physiology, morphology and behaviour. It is likely that these changes have had a major effect upon predator–prey relationships and trophic position; however, the effect of environment is yet to be clarified. We compiled a dataset, based on the literature, to explore the relationship between body mass, trophic level and predator–prey ratio across terrestrial ( n = 51) and marine ( n = 56) mammals. We did not find the expected positive relationship between trophic level and body mass, but we did find that marine carnivores sit 1.3 trophic levels higher than terrestrial carnivores. Also, marine mammals are largely carnivorous and have significantly larger predator–prey ratios compared with their terrestrial counterparts. We propose that primary productivity, and its availability, is important for mammalian trophic structure and body size. Also, energy flow and community structure in the marine environment are influenced by differences in energy efficiency and increased food web stability. Enhancing our knowledge of feeding ecology in mammals has the potential to provide insights into the structure and functioning of marine and terrestrial communities.

scholarly journals An Invasive Mussel (Arcuatula senhousia, Benson 1842) Interacts with Resident Biota in Controlling Benthic Ecosystem Functioning

2020 ◽  
Vol 8 (12) ◽  
pp. 963
Author(s):  
Guillaume Bernard ◽  
Laura Kauppi ◽  
Nicolas Lavesque ◽  
Aurélie Ciutat ◽  
Antoine Grémare ◽  
...  
Keyword(s):  
Nutrient Cycling ◽  
Ecosystem Functioning ◽  
Atlantic Coast ◽  
Sediment Cores ◽  
Environmental Drivers ◽  
Zostera Noltei ◽  
Invasion Stage ◽  
Solute Fluxes ◽  
Excretion Rates ◽  
Invasive Mussel

The invasive mussel Arcuatula senhousia has successfully colonized shallow soft sediments worldwide. This filter feeding mussel modifies sedimentary habitats while forming dense populations and efficiently contributes to nutrient cycling. In the present study, the density of A. senhousia was manipulated in intact sediment cores taken within an intertidal Zostera noltei seagrass meadow in Arcachon Bay (French Atlantic coast), where the species currently occurs at levels corresponding to an early invasion stage. It aimed at testing the effects of a future invasion on (1) bioturbation (bioirrigation and sediment mixing) as well as on (2) total benthic solute fluxes across the sediment–water interface. Results showed that increasing densities of A. senhousia clearly enhanced phosphate and ammonium effluxes, but conversely did not significantly affect community bioturbation rates, highlighting the ability of A. senhousia to control nutrient cycling through strong excretion rates with potential important consequences for nutrient cycling and benthic–pelagic coupling at a broader scale. However, it appears that the variability in the different measured solute fluxes were underpinned by different interactions between the manipulated density of A. senhousia and several faunal and/or environmental drivers, therefore underlining the complexity of anticipating the effects of an invasion process on ecosystem functioning within a realistic context.

scholarly journals Trophic cascades alter eco-evolutionary dynamics and body size evolution

2020 ◽  
Vol 287 (1938) ◽  
pp. 20200526
Author(s):  
Thomas M. Luhring ◽  
John P. DeLong
Keyword(s):  
Body Mass ◽  
Trophic Level ◽  
Evolutionary Dynamics ◽  
Trophic Cascades ◽  
Trophic Levels ◽  
Chain Model ◽  
Top Predator ◽  
Predator Prey ◽  
Top Predators ◽  
Time Changes

Trait evolution in predator–prey systems can feed back to the dynamics of interacting species as well as cascade to impact the dynamics of indirectly linked species (eco-evolutionary trophic cascades; EETCs). A key mediator of trophic cascades is body mass, as it both strongly influences and evolves in response to predator–prey interactions. Here, we use Gillespie eco-evolutionary models to explore EETCs resulting from top predator loss and mediated by body mass evolution. Our four-trophic-level food chain model uses allometric scaling to link body mass to different functions (ecological pleiotropy) and is realistically parameterized from the FORAGE database to mimic the parameter space of a typical freshwater system. To track real-time changes in selective pressures, we also calculated fitness gradients for each trophic level. As predicted, top predator loss generated alternating shifts in abundance across trophic levels, and, depending on the nature and strength in changes to fitness gradients, also altered trajectories of body mass evolution. Although more distantly linked, changes in the abundance of top predators still affected the eco-evolutionary dynamics of the basal producers, in part because of their relatively short generation times. Overall, our results suggest that impacts on top predators can set off transient EETCs with the potential for widespread indirect impacts on food webs.

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