scholarly journals As temperature increases, predator attack rate is more important to survival than a smaller window of prey vulnerability

Ecology ◽  
2018 ◽  
Vol 99 (7) ◽  
pp. 1584-1590 ◽  
Author(s):  
Adam Pepi ◽  
Patrick Grof-Tisza ◽  
Marcel Holyoak ◽  
Richard Karban
Keyword(s):  
Attack Rate ◽  
Predator Attack ◽  
Prey Vulnerability

scholarly journals Stochastic dynamics of consumer-resource interactions

2021 ◽  
Author(s):  
Abhyudai Singh
Keyword(s):  
Attack Rate ◽  
Stochastic Dynamics ◽  
Reproduction Rate ◽  
Population Densities ◽  
Predator Prey ◽  
Density Dependent ◽  
Predator Prey Model ◽  
Predator Attack ◽  
Resource Interactions ◽  
Consumer Resource

AbstractThe interaction between a consumer (such as, a predator or a parasitoid) and a resource (such as, a prey or a host) forms an integral motif in ecological food webs, and has been modeled since the early 20th century starting from the seminal work of Lotka and Volterra. While the Lotka-Volterra predator-prey model predicts a neutrally stable equilibrium with oscillating population densities, a density-dependent predator attack rate is known to stabilize the equilibrium. Here, we consider a stochastic formulation of the Lotka-Volterra model where the prey’s reproduction rate is a random process, and the predator’s attack rate depends on both the prey and predator population densities. Analysis shows that increasing the sensitivity of the attack rate to the prey density attenuates the magnitude of stochastic fluctuations in the population densities. In contrast, these fluctuations vary non-monotonically with the sensitivity of the attack rate to the predator density with an optimal level of sensitivity minimizing the magnitude of fluctuations. Interestingly, our systematic study of the predator-prey correlations reveals distinct signatures depending on the form of the density-dependent attack rate. In summary, stochastic dynamics of nonlinear Lotka-Volterra models can be harnessed to infer density-dependent mechanisms regulating consumer-resource interactions. Moreover, these mechanisms can have contrasting consequences on population fluctuations, with predator-dependent attack rates amplifying stochasticity, while prey-dependent attack rates countering to buffer fluctuations.

Differential Bird Predator Attack Rate on Seasonal Forms of the Map Butterfly (Araschnia levana L.): Does the Substrate Matter?

Ethology ◽  
2010 ◽  
Vol 116 (11) ◽  
pp. 1020-1026 ◽  
Author(s):  
Augustin Joiris ◽  
Safia Korati ◽  
Hans Van Dyck
Keyword(s):  
Attack Rate ◽  
Predator Attack

scholarly journals Temporally auto-correlated predator attacks structure ecological communities

2021 ◽  
Author(s):  
Sebastian Schreiber
Keyword(s):  
Prey Species ◽  
Species Interaction ◽  
The Other ◽  
Ecological Communities ◽  
Vital Rates ◽  
Predator Density ◽  
Priority Effect ◽  
Predator Attack ◽  
Prey Vulnerability ◽  
Common Resource

For species regulated by a common predator, the P* rule predicts that the prey species that supports the highest mean predator density (P*) excludes the other prey species. This prediction is re-examined in the presence of temporal fluctuations in the vital rates of the interacting species including predator attack rates. When the fluctuations in predator attack rates are temporally uncorrelated, the P* rule still holds even when the other vital rates are temporally auto-correlated. However, when temporal auto-correlations in attack rates are positive but not too strongly, the prey species can coexist due to the emergence of a positive covariance between predator density and prey vulnerability. This coexistence mechanism is similar to the storage effect for species regulated by a common resource. Strongly positive or negative auto-correlations in attack rates generate a negative covariance between predator density and prey vulnerability and a stochastic priority effect can emerge: with non-zero probability either prey species is excluded. These results highlight how temporally auto-correlated species' interaction rates impact the structure and dynamics of ecological communities.

scholarly journals Stochastic dynamics of predator-prey interactions

PLoS ONE ◽  
2021 ◽  
Vol 16 (8) ◽  
pp. e0255880
Author(s):  
Abhyudai Singh
Keyword(s):  
Attack Rate ◽  
Stochastic Dynamics ◽  
Volterra Model ◽  
Reproduction Rate ◽  
Predator Population ◽  
Population Densities ◽  
Predator Prey ◽  
Density Dependent ◽  
Predator Prey Model ◽  
Predator Attack

The interaction between a consumer (such as, a predator or a parasitoid) and a resource (such as, a prey or a host) forms an integral motif in ecological food webs, and has been modeled since the early 20th century starting from the seminal work of Lotka and Volterra. While the Lotka-Volterra predator-prey model predicts a neutrally stable equilibrium with oscillating population densities, a density-dependent predator attack rate is known to stabilize the equilibrium. Here, we consider a stochastic formulation of the Lotka-Volterra model where the prey’s reproduction rate is a random process, and the predator’s attack rate depends on both the prey and predator population densities. Analysis shows that increasing the sensitivity of the attack rate to the prey density attenuates the magnitude of stochastic fluctuations in the population densities. In contrast, these fluctuations vary non-monotonically with the sensitivity of the attack rate to the predator density with an optimal level of sensitivity minimizing the magnitude of fluctuations. Interestingly, our systematic study of the predator-prey correlations reveals distinct signatures depending on the form of the density-dependent attack rate. In summary, stochastic dynamics of nonlinear Lotka-Volterra models can be harnessed to infer density-dependent mechanisms regulating predator-prey interactions. Moreover, these mechanisms can have contrasting consequences on population density fluctuations, with predator-dependent attack rates amplifying stochasticity, while prey-dependent attack rates countering to buffer fluctuations.

KEJADIAN LUAR BIASA KERACUNAN “CUMI-CUMIAN” DI SEKOLAH DASAR NEGERI 1 TRASAN BANDONGAN KABUPATEN MAGELANG

2018 ◽  
Vol 7 (2) ◽  
pp. 131-136
Author(s):  
Nasir Ahmad
Keyword(s):  
Abdominal Pain ◽  
Bacillus Cereus ◽  
Rhodamine B ◽  
Attack Rate ◽  
Food Poisoning ◽  
Health Department ◽  
Analysis Data ◽  
Food Samples ◽  
Bivariate Analysis ◽  
School Committee

Background: On May 4th, 2016, at 12:30 district surveillance officer of Magelang Health Department received reports from Public Health Center of Bandongan about 21 students of SDN 1 Trasan who suffered from the same food-poisoning symptoms. Objective: Investigation was carried out to identify the source, how it spread and how to control it. Methods: This study used descriptive analytic and mapping the cases distribution location. The case was people experiencing symptoms of dizziness or abdominal pain or nausea or vomiting. Data analysis was done by using bivariate analysis. Data collection were done through interviews, observations and laboratory tests on the food samples. Results: The case was 50 students (from 1-6 grade students). The perceived symptoms were dizziness (77%), nausea (42%), abdominal pain (40%) and vomiting (8%). Attack rate found ranged from 14.3% to 60% with the highest Attack rate found on class three (60%). The incubation period of 15-240 minutes (mean 72.3 minutes). Calamari like positive Bacillus cereus and Rhodamine-B 10 mg/kg. Conclusion: The outbreak of food poisoning because calamari like contaminated Bacillus cereus. We suggested the school committee to provide the socialization of harmful food for the students. The teachers should restrict the permission for the food vendor to sell at school.   Keywords: Bacillus cereus, , Food Poisoning, Outbreak, Rhodamine B, School Food

scholarly journals Modeling the interplay between demography, social contact patterns, and SARS-CoV-2 transmission in the South West Shewa Zone of Oromia Region, Ethiopia

BMC Medicine ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Filippo Trentini ◽  
Giorgio Guzzetta ◽  
Margherita Galli ◽  
Agnese Zardini ◽  
Fabio Manenti ◽  
...  
Keyword(s):  
Attack Rate ◽  
Reproduction Number ◽  
Demographic Factors ◽  
School Closure ◽  
Sub Saharan Africa ◽  
The South ◽  
South West ◽  
Mixing Patterns ◽  
Sub Saharan ◽  
Socio Demographic Factors

Abstract Background COVID-19 spread may have a dramatic impact in countries with vulnerable economies and limited availability of, and access to, healthcare resources and infrastructures. However, in sub-Saharan Africa, a low prevalence and mortality have been observed so far. Methods We collected data on individuals’ social contacts in the South West Shewa Zone (SWSZ) of Ethiopia across geographical contexts characterized by heterogeneous population density, work and travel opportunities, and access to primary care. We assessed how socio-demographic factors and observed mixing patterns can influence the COVID-19 disease burden, by simulating SARS-CoV-2 transmission in remote settlements, rural villages, and urban neighborhoods, under school closure mandate. Results From national surveillance data, we estimated a net reproduction number of 1.62 (95% CI 1.55–1.70). We found that, at the end of an epidemic mitigated by school closure alone, 10–15% of the population residing in the SWSZ would have been symptomatic and 0.3–0.4% of the population would require mechanical ventilation and/or possibly result in a fatal outcome. Higher infection attack rates are expected in more urbanized areas, but the highest incidence of critical disease is expected in remote subsistence farming settlements. School closure contributed to reduce the reproduction number by 49% and the attack rate of infections by 28–34%. Conclusions Our results suggest that the relatively low burden of COVID-19 in Ethiopia observed so far may depend on social mixing patterns, underlying demography, and the enacted school closures. Our findings highlight that socio-demographic factors can also determine marked heterogeneities across different geographical contexts within the same region, and they contribute to understand why sub-Saharan Africa is experiencing a relatively lower attack rate of severe cases compared to high-income countries.

scholarly journals Investigation of Four Clusters of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in Rwanda, 2020

2021 ◽  
Vol 18 (13) ◽  
pp. 7018
Author(s):  
Olivier Nsekuye ◽  
Edson Rwagasore ◽  
Marie Aime Muhimpundu ◽  
Ziad El-Khatib ◽  
Daniel Ntabanganyimana ◽  
...  
Keyword(s):  
High Risk ◽  
Severe Acute Respiratory Syndrome ◽  
Symptom Onset ◽  
Attack Rate ◽  
Positive Sample ◽  
Contact Tracing ◽  
Face To Face ◽  
Laboratory Confirmation ◽  
Closed Environment ◽  
Index Cases

We reported the findings of the first Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) four clusters identified in Rwanda. Case-investigations included contact elicitation, testing, and isolation/quarantine of confirmed cases. Socio-demographic and clinical data on cases and contacts were collected. A confirmed case was a person with laboratory confirmation of SARS-CoV-2 infection (PCR) while a contact was any person who had contact with a SARS-CoV-2 confirmed case within 72 h prior, to 14 days after symptom onset; or 14 days before collection of the laboratory-positive sample for asymptomatic cases. High risk contacts were those who had come into unprotected face-to-face contact or had been in a closed environment with a SARS-CoV-2 case for >15 min. Forty cases were reported from four clusters by 22 April 2020, accounting for 61% of locally transmitted cases within six weeks. Clusters A, B, C and D were associated with two nightclubs, one house party, and different families or households living in the same compound (multi-family dwelling). Thirty-six of the 1035 contacts tested were positive (secondary attack rate: 3.5%). Positivity rates were highest among the high-risk contacts compared to low-risk contacts (10% vs. 2.2%). Index cases in three of the clusters were imported through international travelling. Fifteen of the 40 cases (38%) were asymptomatic while 13/25 (52%) and 8/25 (32%) of symptomatic cases had a cough and fever respectively. Gatherings in closed spaces were the main early drivers of transmission. Systematic case-investigations contact tracing and testing likely contributed to the early containment of SARS-CoV-2 in Rwanda.

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