scholarly journals Parasitism effects on coexistence and stability within simple trophic modules

2018 ◽  
Author(s):  
Loïc Prosnier ◽  
Vincent Médoc ◽  
Nicolas Loeuille
Keyword(s):  
Food Webs ◽  
Species Coexistence ◽  
Prey Species ◽  
Foraging Strategies ◽  
Intrinsic Growth Rate ◽  
Direct Effects ◽  
Trophic Networks ◽  
Stabilizing Effect ◽  
Indirect Impacts ◽  
Infected Prey

AbstractParasites are important components of food webs. Although their direct effects on hosts are well-studied, indirect impacts on trophic networks, thus on non-host species, remain unclear.In this study, we investigate the consequences of parasitism on coexistence and stability within a simple trophic module: one predator consuming two prey species in competition. We test how such effects depend on the infected species (prey or predator). We account for two effects of parasitism: the virulence effect (parasites affect the infected species intrinsic growth rate through direct effects on fecundity or mortality) and the interaction effect (increased vulnerability of infected prey or increased food intake of infected predators).Results show that coexistence is favored when effects have intermediate intensity. We link this result to modifications of direct and apparent competitions among prey species. Given a prey infection, accounting for susceptible-infected population structure highlights that coexistence may also be reduced due to predator-parasite competition.Parasites affect stability by modulating energy transfer from prey to predator. Predator infection therefore has a stabilizing effect due to increased energy fluxes and/or predator mortality.Our results suggest that parasites potentially increase species coexistence. Precise predictions however require an assessment of various parasite effects. We discuss the implications of our results for the functioning of trophic networks and the evolution of foraging strategies within food webs.

scholarly journals Evolution of predator foraging in response to prey infection favors species coexistence

2020 ◽  
Author(s):  
Loïc Prosnier ◽  
Vincent Médoc ◽  
Nicolas Loeuille
Keyword(s):  
Species Coexistence ◽  
Prey Species ◽  
Niche Overlap ◽  
Foraging Strategies ◽  
Generalist Predators ◽  
Facilitation Effect ◽  
Predator Diet ◽  
Predator Foraging ◽  
Evolutionary Consequences ◽  
Infected Prey

AbstractAs acknowledged by Optimal Foraging theories, predator diets depend on prey profitability. Parasites, ubiquitous in food webs, are known to affect simultaneously host vulnerability to predation and host energy contents, thereby affecting profitability. In this work, we study the eco-evolutionary consequences of prey infection by a non trophically-transmitted parasite, with a simple lifecycle, on predator diet. We also analyze the consequences for coexistence between prey, predators and parasites. We model a trophic module with one predator and two prey species, one of these prey being infected by a parasite, and distinguish between two effects of infection: a decrease in host fecundity (virulence effect) and an increase in vulnerability to predation (facilitation effect). Predator foraging may evolve toward specialist or generalist strategies, the latter being less efficient on a given resource. We show that the virulence effect leads to specialisation on the non-infected prey while the facilitation effect, by increasing prey profitability, favors specialisation on the infected prey. Combining the two effects at intermediate intensities promotes either generalist predators or the diversification of foraging strategies (coexistence of specialists), depending of trade-off shape. We then investigate how the evolution of predator diet affects the niche overlap between predator and parasite. We show that facilitation effects systematically lead to a high niche overlap, ultimately resulting in the loss of the parasite. Virulence effects conversely favor coexistence by allowing a separation of the predator and parasite niches.

Trophic Cascades in Grasslands

2018 ◽  
Author(s):  
Brian J. Wilsey
Keyword(s):  
Indirect Effects ◽  
Prey Species ◽  
Trophic Levels ◽  
Herbaceous Plant ◽  
Direct Effects ◽  
Temperate Grasslands ◽  
Cascading Effect ◽  
Top Predators ◽  
Invertebrate Predators ◽  
Ecology Of Fear

Top predators have effects that can ‘cascade down’ on lower trophic levels. Because of this cascading effect, it matters how many trophic levels are present. Predators are either ‘sit and wait’ or ‘active’. Wolves are top predators in temperate grasslands and can alter species composition of smaller-sized predators, prey, and woody and herbaceous plant species, either through direct effects or indirect effects (‘Ecology of Fear’). In human derived grasslands, invertebrate predators fill a similar ecological role as wolves. Migrating populations of herbivores tend to be more limited by food than non-migratory populations. The phenology and synchrony of births vary among prey species in a way that is consistent with an adaptation to predation. Precocious species have highly synchronous birth dates to satiate predators. Non-precocious species (‘hiders’) have asynchronous births. Results from studies that manipulate both predators and food support the hypothesis that bottom-up and top-down effects interact.

Predator-dependent transmissible disease spreading in prey under Holling type-II functional response

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Dipankar Ghosh ◽  
Prasun K. Santra ◽  
Abdelalim A. Elsadany ◽  
Ghanshaym S. Mahapatra
Keyword(s):  
Functional Response ◽  
Prey Species ◽  
Linearization Method ◽  
Logistic Growth ◽  
Type Ii ◽  
Disease Spreading ◽  
Predator Interactions ◽  
The Stability ◽  
Infected Prey ◽  
Type Ii Functional Response

Abstract This paper focusses on developing two species, where only prey species suffers by a contagious disease. We consider the logistic growth rate of the prey population. The interaction between susceptible prey and infected prey with predator is presumed to be ruled by Holling type II and I functional response, respectively. A healthy prey is infected when it comes in direct contact with infected prey, and we also assume that predator-dependent disease spreads within the system. This research reveals that the transmission of this predator-dependent disease can have critical repercussions for the shaping of prey–predator interactions. The solution of the model is examined in relation to survival, uniqueness and boundedness. The positivity, feasibility and the stability conditions of the fixed points of the system are analysed by applying the linearization method and the Jacobian matrix method.

scholarly journals Prey-Related Asphyxiation in Harbor Porpoises (Phocoena phocoena) along the U.S. West Coast: Importance of American Shad (Alosa sapidissima) on Adult Female Harbor Porpoise Mortality

Oceans ◽  
2020 ◽  
Vol 1 (3) ◽  
pp. 94-108
Author(s):  
Cindy R. Elliser ◽  
John Calambokidis ◽  
Dalin N. D’Alessandro ◽  
Deborah A. Duffield ◽  
Jessica L. Huggins ◽  
...  
Keyword(s):  
Native American ◽  
West Coast ◽  
Prey Species ◽  
Reproductive Status ◽  
American Shad ◽  
Foraging Strategies ◽  
Phocoena Phocoena ◽  
Harbor Porpoise ◽  
Harbor Porpoises ◽  
The U.S

Harbor porpoise (Phocoena phocoena) diets are predominantly comprised of small fish species (<30 cm) and squid. However, predation on larger species (up to 63 cm) occurs, raising the question of increased risk of asphyxiation associated with this behavior. Literature was reviewed and stranding data from 1983 to 2020 from the U.S. West Coast (including California, Oregon and Washington) were searched for cases of prey-related asphyxiation of harbor porpoises and analyzed in relation to age, sex, reproductive status and prey species. Twenty-nine cases were documented. Twenty-seven cases involved large prey; non-native American shad caused the asphyxiation in 87% of the cases where the prey species was identified. The majority (92%) of harbor porpoises were females, and at least 83.3% were pregnant or recently post-partum. Reproductively active females may be more likely to attempt potentially risky behavior in order to compensate for their increased energetic needs. Increasing numbers of non-native American shad may pose a unique danger in this region for harbor porpoises not adapted to deal with the challenges of that prey. This may be a cause for concern, as there is likely an interaction between location, age and reproductive status on the diet composition and foraging strategies of harbor porpoises.

Adaptive omnivory and species coexistence in tri-trophic food webs

2005 ◽  
Vol 67 (2) ◽  
pp. 85-99 ◽  
Author(s):  
Vlastimil Křivan ◽  
Sebastian Diehl
Keyword(s):  
Food Webs ◽  
Species Coexistence

Predator-dependent functional responses and interaction strengths in a natural food web

2004 ◽  
Vol 61 (11) ◽  
pp. 2215-2226 ◽  
Author(s):  
Timothy E Essington ◽  
Sture Hansson
Keyword(s):  
Food Webs ◽  
Functional Response ◽  
Gadus Morhua ◽  
Prey Species ◽  
Clupea Harengus ◽  
Natural Food ◽  
Functional Responses ◽  
Predation Mortality ◽  
Highly Sensitive ◽  
Predator Abundance

Predator-dependent functional responses decouple predation mortality from fluctuations in predator abundance and therefore can prevent strong "top-down" interaction strengths in food webs. We evaluated whether contrasts in the functional response of Baltic Sea cod (Gadus morhua) were consistent with the contrasting population dynamics of two prey species, herring (Clupea harengus) and sprat (Sprattus sprattus): sprat abundance increased nearly threefold following a sharp decline in the cod population (a strong interaction), whereas herring abundance failed to increase (a weak interaction). We found striking differences in the functional response of cod on alternative prey, and these were consistent with the observed patterns in interaction strengths. Cod predation was the dominant source of mortality for age-1 and age-2 sprat but was only important for age-1 herring. Moreover, the magnitude of predation mortality on age-1 and age-2 sprat was highly sensitive to cod biomass, whereas predation mortality on herring was only moderately sensitive to cod biomass. These analyses suggest the possibility that food webs are comprised of linkages that vary with respect to the magnitude and importance of predation mortality and how this mortality varies with changes in predator abundance.

scholarly journals Linking killer whale survival and prey abundance: food limitation in the oceans' apex predator?

2009 ◽  
Vol 6 (1) ◽  
pp. 139-142 ◽  
Author(s):  
John K. B. Ford ◽  
Graeme M. Ellis ◽  
Peter F. Olesiuk ◽  
Kenneth C. Balcomb
Keyword(s):  
Prey Species ◽  
Killer Whale ◽  
Prey Availability ◽  
Trophic Position ◽  
Marine Ecosystem ◽  
Food Limitation ◽  
Ecosystem Dynamics ◽  
Foraging Strategies ◽  
Limiting Factor ◽  
Killer Whales

Killer whales ( Orcinus orca ) are large predators that occupy the top trophic position in the world's oceans and as such may have important roles in marine ecosystem dynamics. Although the possible top-down effects of killer whale predation on populations of their prey have received much recent attention, little is known of how the abundance of these predators may be limited by bottom-up processes. Here we show, using 25 years of demographic data from two populations of fish-eating killer whales in the northeastern Pacific Ocean, that population trends are driven largely by changes in survival, and that survival rates are strongly correlated with the availability of their principal prey species, Chinook salmon ( Oncorhynchus tshawytscha ). Our results suggest that, although these killer whales may consume a variety of fish species, they are highly specialized and dependent on this single salmonid species to an extent that it is a limiting factor in their population dynamics. Other ecologically specialized killer whale populations may be similarly constrained to a narrow range of prey species by culturally inherited foraging strategies, and thus are limited in their ability to adapt rapidly to changing prey availability.

Complex Interactions of Multiple Aquatic Consumers: An Experimental Mesocosm Manipulation

1993 ◽  
Vol 50 (1) ◽  
pp. 29-42 ◽  
Author(s):  
William B. Richardson ◽  
Stephen T. Threlkeld
Keyword(s):  
Food Webs ◽  
Fish Species ◽  
Micropterus Salmoides ◽  
Interactive Effects ◽  
Direct Effects ◽  
Treatment Results ◽  
Complex Interactions ◽  
Menidia Beryllina ◽  
Young Of The Year ◽  
Keratella Quadrata

In 7-m3 outdoor tanks filled with lake water, the presence/absence of omnivorous young-of-the-year Micropterus salmoides, zooplanktivorous Menidia beryllina, and herbivorous larval Hyla chrysocelis was experimentally manipulated. A cross-classified design was used to assess the interactive effects of these vertebrate consumers on the experimental food webs. Large zooplankters and large, actively swimming macroinvertebrates (Ceriodaphnia, Simocephalus, Corixidae, Notonectidae, and Dytiscidae) were particularly susceptible to depletion by both fish species. Micropterus tanks contained greater numbers of Keratella quadrata and Hebridae but fewer benthic cyclopoid copepods. Menidia tanks contained more Synedra and algal filaments. Hyla exerted only minor direct effects on the tank communities. When both fish species were in the same tank, both had elevated mortality. Micropterus, in tanks with Menidia and Hyla, were larger and in better condition than in tanks without Hyla. The primary effects of the experimental manipulations on food web components were two- and three-way interactions in which the effect of a given treatment was dependent on the presence of another treatment. Results suggest that the addition or removal of consumers may not cause linear, additive changes in food webs.

scholarly journals Stability analysis of an ecoepidemiological model consisting of a prey and tow competing predators with Si-disease in prey and toxicant

2020 ◽  
Vol 99 (3) ◽  
pp. 55-61
Author(s):  
Evren Hincal ◽  
◽  
Shorsh Mohammed ◽  
Bilgen Kaymakamzade ◽  
◽  
...  
Keyword(s):  
Stability Analysis ◽  
Functional Response ◽  
Linear Functional ◽  
Prey Species ◽  
Equilibrium Points ◽  
Dynamical Behavior ◽  
Epidemiological Models ◽  
Proposed Model ◽  
Infected Prey ◽  
Disease In Prey

In the present paper, we study two eco-epidemiological models. The first one consists of a prey and two competing predators with SI-disease in prey species spreading by contacts between susceptible prey and infected prey. This model assumes linear functional response. The second model is the modification of the first one when the effect of toxicant is taken into account. In this paper, we examine the dynamical behavior of non-survival and free equilibrium points of our proposed model.

scholarly journals Ocean warming increases availability of crustacean prey via riskier behavior

2019 ◽  
Vol 31 (2) ◽  
pp. 287-291 ◽  
Author(s):  
Emma Marangon ◽  
Silvan U Goldenberg ◽  
Ivan Nagelkerken
Keyword(s):  
Natural Resources ◽  
Foraging Behavior ◽  
Risk Taking ◽  
Prey Species ◽  
Ocean Warming ◽  
Direct Effects ◽  
Metabolic Demand ◽  
Predator Prey ◽  
Increased Risk ◽  
Time Periods

Abstract Marine prey and predators will respond to future climate through physiological and behavioral adjustments. However, our understanding of how such direct effects may shift the outcome of predator–prey interactions is still limited. Here, we investigate the effects of ocean warming and acidification on foraging behavior and biomass of a common prey (shrimps, Palaemon spp.) tested in large mesocosms harboring natural resources and habitats. Acidification did not alter foraging behavior in prey. Under warming, however, prey showed riskier behavior by foraging more actively and for longer time periods, even in the presence of a live predator. No effects of longer-term exposure to climate stressors were detected on prey biomass. Our findings suggest that ocean warming may increase the availability of some prey to predators via a behavioral pathway (i.e., increased risk-taking by prey), likely by elevating metabolic demand of prey species.

Sign in / Sign up

Export Citation Format

Share Document