UnexpectedListronotus bonariensis(Coleoptera: Curculionidae) mortality in the presence of parasitoids

2004 ◽  
Vol 94 (5) ◽  
pp. 411-417 ◽  
Author(s):  
S.L. Goldson ◽  
J.R. Proffitt ◽  
M.R. McNeill ◽  
C.B. Phillips ◽  
N.D. Barlow ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Mortality Rates ◽  
Ecological Significance ◽  
Time Intervals ◽  
Larval Parasitoid ◽  
Mortality Effect ◽  
Listronotus Bonariensis ◽  
Field And Laboratory Conditions ◽  
The Impact ◽  
Microctonus Hyperodae

AbstractField enclosure and laboratory cage experiments designed to measure the impact of the parasitoidMicroctonus hyperodaeLoan on the Argentine stem weevil,Listronotus bonariensis(Kuschel) have shown that under high parasitoid pressure, there is significant weevil mortality without obvious parasitism. Parasitoid-exposed, but unparasitized portions of caged populations died at rates significantly higher than both the parasitized weevils from the same population and the unexposed controls. Unexpectedly, parasitized weevils had the lowest mortality rates (prior to larval parasitoid emergence). It was of ecological significance that this mortality effect was detected under field conditions using several years of empirically-collected population dynamics data. Under both field and laboratory conditions this mortality was found to occur within shorter time intervals than that required for full parasitoid larval development; thus it could not be attributed to the mortality that occurs after the emergence of prepupal parasitoids. The mechanism for this mortality remains undetermined, although it could possibly be linked to pseudoparasitism.

scholarly journals The current status of Argentine stem weevil (Listronotus bonariensis) as a pest in the North Island of New Zealand

2011 ◽  
Vol 64 ◽  
pp. 55-62 ◽  
Author(s):  
A.J. Popay ◽  
M.R. McNeill ◽  
S.L. Goldson ◽  
C.M. Ferguson
Keyword(s):  
New Zealand ◽  
Perennial Ryegrass ◽  
Italian Ryegrass ◽  
Current Status ◽  
The North ◽  
Listronotus Bonariensis ◽  
Low Levels ◽  
The Impact ◽  
Microctonus Hyperodae ◽  
Behavioural Adaptations

Recent sampling in Waikato and Taranaki shows that Argentine stem weevil (Listronotus bonariensis) can still cause major damage to susceptible ryegrass pastures despite the introduction of the parasitoid Microctonus hyperodae in 1991 Percentage of tillers with L bonariensis larval damage in diploid and tetraploid perennial ryegrass and Italian ryegrass in January and February were between 11 and 68 High egg numbers were noted on occasion Although there is evidence that M hyperodae reduces host populations parasitism levels vary considerably between years in Canterbury and are low in Otago and Southland where high populations of L bonariensis have recently been recorded Factors that may be lessening the impact of M hyperodae are considered These include asynchronous generations of the parasitoid and its host host behavioural adaptations compensatory oviposition and inhibition of flight in parasitised individuals leading to low levels of parasitism in new pastures

SIMULATION MODEL FOR THE POPULATION DYNAMICS OF THE CARROT WEEVIL, LISTRONOTUS OREGONENSIS (LECONTE) (COLEOPTERA: CURCULIONIDAE)

1991 ◽  
Vol 123 (1) ◽  
pp. 63-76 ◽  
Author(s):  
D.X. Zhao ◽  
G. Boivin ◽  
R.K. Stewart
Keyword(s):  
Population Dynamics ◽  
Simulation Model ◽  
Mortality Rates ◽  
Egg Parasitoid ◽  
Adult Density ◽  
Larval Population ◽  
Listronotus Oregonensis ◽  
The Mean ◽  
Carrot Weevil ◽  
The Impact

AbstractA simulation model was developed for the population dynamics of a carrot weevil, Listronotus oregonensis (LeConte), population on muck-grown carrots. The model includes mortality rates of eggs, larvae, and pupae for different sowing dates of carrots. It also incorporates the overwintered adult density, the temperature-dependent growth rates of the above-mentioned life stages, the age-, temperature-, and phenology-dependent oviposition rates, and the impact of an egg parasitoid, Anaphes sordidatus (Girault), on egg mortality rates. Model output was evaluated by comparing simulated results with observed results on the seasonal totals and time of population peaks of the egg and larval populations. The mean percentage differences between the simulated and observed seasonal egg totals were 3.1 ± 0.66 (SE) in 1987 and 1988, and 4.2 ± 0.05 in 1989. They were not statistically different. The mean percentage differences between the simulated and observed seasonal larval totals were 10 ± 3.33 in 1987 and 1988 and 29.8 ± 0.66 in 1989. Independent data sets (i.e. field data in 1989) showed a significant increase in the simulation error of the larval population. Sensitivity analysis indicated that A. sordidatus had a large influence on the population dynamics of L. oregonensis.

Damage potential of Argentine stem weevil in Lincoln dairy pasture: has biological control by Microctonus hyperodae altered the balance?

2001 ◽  
pp. 247-254
Author(s):  
M.R. Mcneill ◽  
T.L. Knight ◽  
D.B. Baird
Keyword(s):  
Biological Control ◽  
Dairy Farm ◽  
Egg Laying ◽  
Damage Potential ◽  
Pasture Production ◽  
Listronotus Bonariensis ◽  
Main Plot ◽  
Tiller Density ◽  
The Impact ◽  
Microctonus Hyperodae

To measure the impact of biological control of Argentine stem weevil, Listronotus bonariensis (ASW) by Microctonus hyperodae in dairy pasture, a research site was established in the autumn of 1997 on a dairy farm near Lincoln, where the parasitoid had been present since 1994. Existing pasture was killed with glyphosate and four ryegrass cultivar treatments consisting of three perennial (Nui, Embassy, Vedette) and one hybrid mixture (Marsden/Greenstone), each containing either low or high levels of Neotyphodium lolii endophyte, were sown by direct drilling. A third main plot treatment was low endophyte plus insecticide. Between 1997 and 1999, seasonal pasture production was measured in all plots. Herbage composition was also measured in all plots for the first 2 years but only in the Nui treatments in 1999. ASW adult and larval densities, larval damage to ryegrass, parasitism by M. hyperodae and ryegrass tiller density were measured on Nui plots in spring and again in summer, coinciding with periods of peak ASW egg laying and larval development. Between 1997 and 2000, ASW adult densities in Nui were highest in the first summer (26 January 1998) following establishment. Thereafter, densities did not rise above c. 60 ASW/m2. Densities of adults, larvae, levels of larval damage to ryegrass, and parasitism by M. hyperodae were significantly higher in summer than spring (P

Argentine stem weevil (Listronotus bonariensis, Coleoptera: Curculionidae) population dynamics in Canterbury, New Zealand dryland pasture

2010 ◽  
Vol 101 (3) ◽  
pp. 295-303 ◽  
Author(s):  
S.L. Goldson ◽  
M.C. Barron ◽  
J.M. Kean ◽  
C. van Koten
Keyword(s):  
Population Dynamics ◽  
New Zealand ◽  
Population Analysis ◽  
Larval Survival ◽  
Compensatory Response ◽  
The North ◽  
Key Factor ◽  
Listronotus Bonariensis ◽  
Pupal Mortality ◽  
Microctonus Hyperodae

AbstractThe Argentine stem weevil (Listronotus bonariensis) was an economically important pest in New Zealand pastures until the release of the parasitoidMicroctonus hyperodae. This contribution uses historical data to investigate the regulation of the pest populations prior to, and somewhat during, the establishment of this parasitoid in dryland Canterbury, New Zealand. Thus, a significant goal of this study is to provide anL. bonariensispopulation dynamics baseline for any future work that aims to analyse the full effects ofM. hyperodaeon the weevil, now that equilibrium with the weevil host has been reached.The population dynamics ofL. bonariensis, based on a life-table approach, were investigated using data collected regularly for eight years from populations in Canterbury, New Zealand. The key factor affecting end-of-seasonL. bonariensisdensity was found to be variation in second generation fourth instar prepupal and pupal mortality. This may have been caused by arrested development and ongoing mortality resulting from the onset of cooler autumnal conditions.A compensatory response was found in recruitment to the second summer weevil generation, whereby the realised fecundity of the emergent first summer generation of weevils was found to be negatively related to the density of adult weevils per ryegrass tiller. This is the first time that this has been found via long-term population analysis ofL. bonariensis, although indications of this have been found elsewhere in caging, pot and small plot experiments.In this study, the effect of the parasitoid biocontrol agentMicroctonus hyperodaeonL. bonariensispopulation dynamics was unclear, as the analysis covered a period when the parasitoidMicroctonus hyperodaewas introduced and still establishing. It does, however, raise important questions for future analysis in terms of the interaction between parasitism and unrealised fecundity.The results in this contribution also highlighted regional differences. Overwintering mortality of adult weevils in Canterbury was constant between years, whilst earlier studies in the North Island Waikato region indicated this mortality was density dependent. In addition, the availability of tillers in endophyte-free ryegrass pastures in Canterbury had no influence on egg and early-instar larval survival, which contrasts with the finding from endophytic Waikato pastures.

Long-term population dynamics of the red deer and European roe deer at the protected and not-protected areas in Mountain Crimea

2017 ◽  
Vol 7 (4) ◽  
pp. 65-72
Author(s):  
V. N. Shmagol' ◽  
V. L. Yarysh ◽  
S. P. Ivanov ◽  
V. I. Maltsev
Keyword(s):  
Population Dynamics ◽  
Protected Areas ◽  
Red Deer ◽  
Nature Reserve ◽  
Roe Deer ◽  
Precipitation Amount ◽  
Annual Precipitation ◽  
Population Number ◽  
The Impact

<p>The long-term population dynamics of the red deer (<em>Cervus elaphus</em> L.) and European roe deer (<em>Capreolus</em> <em>capreolus</em> L.) at the mountain and forest zone of Crimea during 1980-2017 is presented. Fluctuations in numbers of both species are cyclical and partly synchronous. Period of oscillations in the population of red deer is about 25 years, the average duration of the oscillation period of number of roe deer is 12.3 years. During the fluctuations in the number the increasing and fall in population number of the red deer had been as 26-47 %, and roe deer – as 22-34 %. Basing on the dada obtained we have assumed that together with large-scale cycles of fluctuations in population number of both red deer and roe deer the short cycles of fluctuations in the number of these species with period from 3.5 to 7.5 years take place. Significant differences of the parameters of cyclical fluctuations in the number of roe deer at some sites of the Mountainous Crimea: breaches of synchronicity, as well as significant differences in the duration of cycles are revealed. The greatest deviations from the average values of parameters of long-term dynamics of the number of roe deer in Crimea are noted for groups of this species at two protected areas. At the Crimean Nature Reserve the cycle time of fluctuations of the numbers of roe deer was 18 years. At the Karadag Nature Reserve since 1976 we can see an exponential growth in number of roe deer that is continued up to the present time. By 2016 the number of roe deer reached 750 individuals at a density of 437 animals per 1 thousand ha. Peculiarity of dynamics of number of roe deer at some sites proves the existence in the mountain forest of Crimea several relatively isolated groups of deer. We assumed that "island" location of the Crimean populations of red deer and European roe deer, their relatively little number and influence of permanent extreme factors of both natural and anthropogenic origination have contributed to a mechanism of survival of these populations. The elements of such a mechanism include the following features of long-term dynamics of the population: the reduction in the period of cyclic population fluctuations, while maintaining their amplitude and the appearance of additional small cycles, providing more flexible response of the population to the impact of both negative and positive environmental factors. From the totality of the weather conditions for the Crimean population of roe deer the recurring periods of increases and downs in the annual precipitation amount may have relevance. There was a trend of increase in the roe deer population during periods of increasing annual precipitation.</p>

scholarly journals Simultaneous Casualty Admissions—Do they Affect Treatment in the Receiving Trauma Center?

2021 ◽  
Author(s):  
Michel Paul Johan Teuben ◽  
Carsten Mand ◽  
Laura Moosdorf ◽  
Kai Sprengel ◽  
Alba Shehu ◽  
...  
Keyword(s):  
Injury Severity ◽  
Damage Control ◽  
Ct Scanning ◽  
Mortality Rates ◽  
Trauma Centers ◽  
Simultaneous Treatment ◽  
Diagnostic Pathway ◽  
Injured Patients ◽  
The Impact ◽  
Mean Time

Abstract Background Simultaneous trauma admissions expose medical professionals to increased workload. The impact of simultaneous trauma admissions on hospital allocation, therapy, and outcome is currently unclear. We hypothesized that multiple admission-scenarios impact the diagnostic pathway and outcome. Methods The TraumaRegister DGU® was utilized. Patients admitted between 2002–2015 with an ISS ≥ 9, treated with ATLS®- algorithms were included. Group ´IND´ included individual admissions, two individuals that were admitted within 60 min of each other were selected for group ´MULT´. Patients admitted within 10 min were considered as simultaneous (´SIM´) admissions. We compared patient and trauma characteristics, treatment, and outcomes between both groups. Results 132,382 admissions were included, and 4,462/3.4% MULTiple admissions were found. The SIM-group contained 1,686/1.3% patients. The overall median injury severity score was 17 and a mean age of 48 years was found. MULT patients were more frequently admitted to level-one trauma centers (68%) than individual trauma admissions were (58%, p < 0.001). Mean time to CT-scanning (24 vs. 26/28 min) was longer in MULT / SIM patients compared to individual admissions. No differences in utilization of damage control principles were seen. Moreover, mortality rates did not differ between the groups (13.1% in regular admissions and 11.4%/10,6% in MULT/SIM patients). Conclusion This study demonstrates that simultaneous treatment of injured patients is rare. Individuals treated in parallel with other patients were more often admitted to level-one trauma centers compared with individual patients. Although diagnostics take longer, treatment principles and mortality are equal in individual admissions and simultaneously admitted patients. More studies are required to optimize health care under these conditions.

scholarly journals The Impact of Bushfire Smoke on Cattle—A Review

Animals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 848
Author(s):  
Benjamin Eid ◽  
David Beggs ◽  
Peter Mansell
Keyword(s):  
Particulate Matter ◽  
Prolonged Exposure ◽  
Negative Impact ◽  
Airborne Particulate Matter ◽  
Mortality Rates ◽  
Airborne Particulate ◽  
Primary Mechanism ◽  
Background Mortality ◽  
Fire Front ◽  
The Impact

In 2019–2020, a particularly bad bushfire season in Australia resulted in cattle being exposed to prolonged periods of smoke haze and reduced air quality. Bushfire smoke contains many harmful pollutants, and impacts on regions far from the fire front, with smoke haze persisting for weeks. Particulate matter (PM) is one of the major components of bushfire smoke known to have a negative impact on human health. However, little has been reported about the potential effects that bushfire smoke has on cattle exposed to smoke haze for extended periods. We explored the current literature to investigate evidence for likely effects on cattle from prolonged exposure to smoke generated from bushfires in Australia. We conducted a search for papers related to the impacts of smoke on cattle. Initial searching returned no relevant articles through either CAB Direct or PubMed databases, whilst Google Scholar provided a small number of results. The search was then expanded to look at two sub-questions: the type of pollution that is found in bushfire smoke, and the reported effects of both humans and cattle being exposed to these types of pollutants. The primary mechanism for damage due to bushfire smoke is due to small airborne particulate matter (PM). Although evidence demonstrates that PM from bushfire smoke has a measurable impact on both human mortality and cardiorespiratory morbidities, there is little evidence regarding the impact of chronic bushfire smoke exposure in cattle. We hypothesize that cattle are not severely affected by chronic exposure to smoke haze, as evidenced by the lack of reports. This may be because cattle do not tend to suffer from the co-morbidities that, in the human population, seem to be made worse by smoke and pollution. Further, small changes to background mortality rates or transient morbidity may also go unreported.

scholarly journals Mortality Associated with Idiopathic Pulmonary Fibrosis in Northeastern Italy, 2008–2020: A Multiple Cause of Death Analysis

2021 ◽  
Vol 18 (14) ◽  
pp. 7249
Author(s):  
Alessandro Marcon ◽  
Elena Schievano ◽  
Ugo Fedeli
Keyword(s):  
Idiopathic Pulmonary Fibrosis ◽  
Pulmonary Fibrosis ◽  
Cause Of Death ◽  
Age Groups ◽  
Mortality Rates ◽  
Annual Percent Change ◽  
Northeastern Italy ◽  
Mortality Ratio ◽  
The Impact ◽  
Related Mortality

Mortality from idiopathic pulmonary fibrosis (IPF) is increasing in most European countries, but there are no data for Italy. We analysed the registry data from a region in northeastern Italy to assess the trends in IPF-related mortality during 2008–2019, to compare results of underlying vs. multiple cause of death analyses, and to describe the impact of the COVID-19 epidemic in 2020. We identified IPF (ICD-10 code J84.1) among the causes of death registered in 557,932 certificates in the Veneto region. We assessed time trends in annual age-standardized mortality rates by gender and age (40–74, 75–84, and ≥85 years). IPF was the underlying cause of 1310 deaths in the 2251 certificates mentioning IPF. For all age groups combined, the age-standardized mortality rate from IPF identified as the underlying cause of death was close to the European median (males and females: 3.1 and 1.3 per 100,000/year, respectively). During 2008–2019, mortality rates increased in men aged ≥85 years (annual percent change of 6.5%, 95% CI: 2.0, 11.2%), but not among women or for the younger age groups. A 72% excess of IPF-related deaths was registered in March–April 2020 (mortality ratio 1.72, 95% CI: 1.29, 2.24). IPF mortality was increasing among older men in northeastern Italy. The burden of IPF was heavier than assessed by routine statistics, since less than two out of three IPF-related deaths were directly attributed to this condition. COVID-19 was accompanied by a remarkable increase in IPF-related mortality.

Population dynamics driven by truncated stable processes with Markovian switching

2021 ◽  
Vol 58 (2) ◽  
pp. 505-522
Author(s):  
Zhenzhong Zhang ◽  
Jinying Tong ◽  
Qingting Meng ◽  
You Liang
Keyword(s):  
Population Dynamics ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Markovian Switching ◽  
Stable Processes ◽  
Necessary And Sufficient ◽  
The Impact

AbstractWe focus on the population dynamics driven by two classes of truncated $\alpha$-stable processes with Markovian switching. Almost necessary and sufficient conditions for the ergodicity of the proposed models are provided. Also, these results illustrate the impact on ergodicity and extinct conditions as the parameter $\alpha$ tends to 2.

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