scholarly journals Influence of delayed density and ultraviolet radiation on caterpillar granulovirus infection and mortality

2021 ◽  
Author(s):  
Adam Pepi ◽  
Vincent Pan ◽  
Richard Karban
Keyword(s):  
Ultraviolet Radiation ◽  
Viral Infection ◽  
Density Dependence ◽  
Infection Rate ◽  
Population Cycles ◽  
Viral Disease ◽  
Environmental Persistence ◽  
Density Dependent ◽  
Delayed Density Dependence ◽  
Occlusion Bodies

AbstractInfectious disease is an important potential driver of population cycles, but this must occur through delayed density-dependent infection and resulting fitness effects. Delayed density-dependent infection by baculoviruses can be caused by environmental persistence of viral occlusion bodies, which can be influenced by environmental factors. In particular, ultraviolet radiation is potentially important in reducing the environmental persistence of viruses by inactivating viral occlusion bodies.Delayed density-dependent viral infection has rarely been observed empirically at the population level although theory predicts that it is necessary for these pathogens to drive population cycles. Similarly, field studies have not examined the potential effects of ultraviolet radiation on viral infection rates in natural animal populations. We tested if viral infection is delayed density-dependent with the potential to drive cyclic dynamics and if ultraviolet radiation influences viral infection.We censused 18 moth populations across nearly 9° of latitude over two years and quantified the effects of direct and delayed density and ultraviolet radiation on granulovirus infection rate, infection severity, and survival to adulthood. Caterpillars were collected from each population in the field and reared in the laboratory.We found that infection rate, infection severity, and survival to adulthood exhibited delayed density-dependence. Ultraviolet radiation in the previous summer decreased infection severity, and increased survival probability of the virus. Structural equation modelling found that the effect of lagged density on moth survival was mediated through infection rate and infection severity, and was 2.5 fold stronger than the effect of ultraviolet radiation on survival through infection severity.Our findings provide clear evidence that delayed density dependence can arise through viral infection rate and severity in insects, which supports the role of viral disease as a potential mechanism, among others, that may drive insect population cycles. Furthermore, our findings support predictions that ultraviolet radiation can modify viral disease dynamics in insect populations, most likely through attenuating viral persistence in the environment.

Geographic variation in population cycles of Canadian muskrats (Ondatra zibethicus)

2000 ◽  
Vol 78 (6) ◽  
pp. 1009-1016 ◽  
Author(s):  
John Erb ◽  
Nils Chr. Stenseth ◽  
Mark S Boyce
Keyword(s):  
Density Dependence ◽  
Trophic Interactions ◽  
Dynamic Properties ◽  
Population Cycles ◽  
Period Length ◽  
Ondatra Zibethicus ◽  
Delayed Density Dependence ◽  
Relative Contribution ◽  
Arctic Regions ◽  
Harvest Data

We investigated the dynamic properties of population cycles in Canadian muskrats (Ondatra zibethicus). Ninety-one historic time series of muskrat-harvest data obtained from the Hudson's Bay Company Archives were analyzed. Most series were 25 years in length (1925–1949) and were distributed primarily throughout five ecozones. For each series, we estimated period length and coefficients for a second-order autoregressive model. Estimated period length varied between 3 and 13 years, with 3- to 5-year periods located in Subarctic-Arctic ecozones. We hypothesize that the 4-year cycles are largely a result of predation by red fox (Vulpes vulpes), which exhibit 4-year cycles in Arctic regions. The remaining ecozones generally averaged 8–9 years in period length. However, the relative contributions of direct and delayed density dependence varied along a latitudinal gradient. We hypothesize that both social and trophic interactions are necessary to produce the observed dynamics, but that shifts in the nature of mink predation were responsible for the changes in the relative contribution of direct and delayed density dependence. Essentially, there is a tension between population-intrinsic and trophic interactions that may bound the length of the cycle.

scholarly journals Population Cycles Produced by Delayed Density Dependence in an Annual Plant

2006 ◽  
Vol 168 (3) ◽  
pp. 318
Author(s):  
Gonzalez-Andujar ◽  
Fernandez-Quintanilla ◽  
Navarrete
Keyword(s):  
Density Dependence ◽  
Population Cycles ◽  
Annual Plant ◽  
Delayed Density Dependence

scholarly journals Population Cycles Produced by Delayed Density Dependence in an Annual Plant

2006 ◽  
Vol 168 (3) ◽  
pp. 318-322 ◽  
Author(s):  
J. L. Gonzalez‐Andujar ◽  
C. Fernandez‐Quintanilla ◽  
L. Navarrete
Keyword(s):  
Density Dependence ◽  
Population Cycles ◽  
Annual Plant ◽  
Delayed Density Dependence

ANALYSIS OF LIFE TABLES FOR THE LARCH CASEBEARER (LEPIDOPTERA: COLEOPHORIDAE) IN OREGON

1986 ◽  
Vol 118 (12) ◽  
pp. 1255-1263 ◽  
Author(s):  
R.B. Ryan
Keyword(s):  
Density Dependence ◽  
Introduced Species ◽  
Adult Mortality ◽  
Life Tables ◽  
Density Dependent ◽  
Delayed Density Dependence ◽  
Coleophora Laricella ◽  
Key Factor ◽  
Expanding Population ◽  
High Range

AbstractLife tables for Coleophora laricella (Hübner) at three locations in Oregon were completed for six generations from overwintering larvae in 1978–1979 through overwintering larvae in 1984–1985. Egg densities (per 100 buds) were high (range 279–1038) at Catherine Creek, moderate (49–705) at Tollgate, and low (14–200) at Emigrant Springs. Mortality of early stages was in the order CC>T>ES and tended to equalize overwintering densities. Ten within-generation mortalities (k-values) were calculated. Adult mortality (or reduced fecundity) was always highest. The key factor at Tollgate was mortality of needleminers along with winter-to-spring disappearance. At Catherine Creek, the key factor was mortality of fall casebearers. At Emigrant Springs, the expanding population of an introduced parasite, Agathis pumila (Ratz.), indicated a change in the key factor from mortality of needleminers to parasitism. Mortality of fall casebearers at Emigrant Springs was density dependent. Parasitism caused by A. pumila and another introduced species, Chrysocharis laricinellae (Ratz.), showed characteristics of delayed density dependence.

Modern aspects of tactics in the genital herpes viral infection (literature review)

GYNECOLOGY ◽  
2018 ◽  
Vol 20 (2) ◽  
pp. 67-73
Author(s):  
T Yu Pestrikova ◽  
E A Yurasova ◽  
I V Yurasov ◽  
A V Kotelnikova
Keyword(s):  
Literature Review ◽  
Viral Infection ◽  
Genital Herpes ◽  
Fetal Death ◽  
Malignant Tumors ◽  
Adult Population ◽  
Viral Disease ◽  
Intrauterine Fetal Death ◽  
Complicated Course ◽  
Simplex Virus

Genital herpes affects all population groups. 98% of the adult population worldwide have antibodies to the herpes simplex virus (HSV-1 or 2). This viral infection is a significant medical and social problem. HSV can lead to a complicated course of pregnancy, causing miscarriages, premature birth, intrauterine fetal death, systemic viral disease in newborns. There is evidence that HSV has a connection with malignant tumors of the prostate and cervix, contributing to their development. This literature review contains modern aspects of epidemiology, etiology, pathogenesis, clinic, diagnosis, treatment of genital herpes, including its recurring forms with valacyclovir (Valvir). Indications for hospitalization of patients with genital herpes were noted and the prognosis of this pathology was determined. The tactics of managing pregnant women with this pathology is presented.

In silico approach to predict the SARS-CoV2 derived candidate miRNAs as potential antiviral therapy

2021 ◽  
Vol 16 ◽  
Author(s):  
Soudabeh Kavousi Pour ◽  
Shiva Mohammadi ◽  
Ebrahim Eftekhar ◽  
Sajad Jalili ◽  
Elham Arabizadeh ◽  
...  
Keyword(s):  
Viral Infection ◽  
Immune Escape ◽  
Genome Structure ◽  
Antiviral Agents ◽  
Experimental Studies ◽  
Viral Disease ◽  
Potential Candidate ◽  
Viral Mirnas ◽  
Host Interaction ◽  
Viral Virulence

Background: The coronavirus disease 2019 (COVID-19) pandemic is a contagious disease originating from severe acute respiratory syndrome coronavirus 2 (SARS-CoV2). Previous experimental studies indicate that viral miRNAs (vMirs) have essential functions in pathogen-host interaction, immune escape, host cell death, and tumorigenesis during viral infection. MiRNAs are small, single-stranded RNAs that exist in viruses as well as in animals. Thus, these molecules can play a pivotal role in viral disease pathogenesis. Objective: Since no approved drugs or vaccines currently exist for SARS-CoV2 and its pathogenic mechanism is unknown, we explored and proposed viral microRNAs (vmiRNAs) platforms as potential antiviral therapeutic agents against its SARS-CoV2. Therefore, the development of antiviral drugs to target vmiRNAs may result in down-regulation of viral virulence genes expression and suppression of viral proliferation. Methods: In this study, to attain insight into the potential role of SARS-CoV2 derived miRNAs in the viral infection background, we used a set of computational methods to scan the SARS-CoV2 genome that finally led to computationally predicted 13 potential candidate viral microRNAs. Furthermore, we expected the potential genes in a human host that were the target of these candidate vmiRNAs by applying mirPath software. Results: Our study proposed a theory indicating that these predicted viral miRNAs might have a plausible role in altering human target gene expression, mainly contributing to the viral infectious state, inflammation, and immune system escape. This vmiRNAs maight have therapeutic trends as antiviral agents against Covid-19 infection. Conclusion: These findings offer a reference idea for a supplementary study on miRNA identification as a drug target and the necessity to increase understanding of SARS-CoV2 genome structure for better combat against the virus.

Population cycles caused by overcompensating density-dependence in an annual plant

Oecologia ◽  
1986 ◽  
Vol 71 (1) ◽  
pp. 156-158 ◽  
Author(s):  
E. Symonides ◽  
J. Silvertown ◽  
V. Andreasen
Keyword(s):  
Density Dependence ◽  
Population Cycles ◽  
Annual Plant

scholarly journals Conspecific negative density dependence and why its study should not be abandoned

2020 ◽  
Author(s):  
Joseph A. LaManna ◽  
Scott A. Mangan ◽  
Jonathan A. Myers
Keyword(s):  
Density Dependence ◽  
Latitudinal Gradient ◽  
Null Model ◽  
Statistical Bias ◽  
Fitness Components ◽  
Density Dependent ◽  
Statistical Errors ◽  
Negative Density Dependence ◽  
Model Approach

AbstractRecent studies showing bias in the measurement of density dependence have the potential to sow confusion in the field of ecology. We provide clarity by elucidating key conceptual and statistical errors with the null-model approach used in Detto et al. (2019). We show that neither their null model nor a more biologically-appropriate null model reproduces differences in density-dependent recruitment between forests, indicating that the latitudinal gradient in negative density dependence is not an artefact of statistical bias. Finally, we suggest a path forward that combines observational comparisons of density dependence in multiple fitness components across localities with mechanistic and geographically-replicated experiments.

Sign in / Sign up

Export Citation Format

Share Document