Fertility control of rodent pests

2008 ◽  
Vol 35 (6) ◽  
pp. 487 ◽  
Author(s):  
Jens Jacob ◽  
Grant R. Singleton ◽  
Lyn A. Hinds
Keyword(s):  
Reproductive Output ◽  
Simulation Models ◽  
Population Level ◽  
Fertility Control ◽  
Reproductive Period ◽  
Future Research ◽  
House Mice ◽  
Breeding Period ◽  
Pest Species ◽  
Small Rodents

Ricefield rats (Rattus argentiventer) in south-east Asian rice fields and house mice (Mus domesticus) in Australian grain fields are major pest species. They cause damage before and after harvest and carry zoonotic diseases. For both species, management techniques have been pursued using the approach of immunocontraceptive vaccination. We review results from a series of enclosure and field studies conducted with these species to assess the effects of fertility control in small rodents. In the experiments, fertility control was simulated by tubal ligation, ovariectomy or progesterone treatment. A once-off sterilisation of 50–75% of enclosed founder females considerably reduced reproductive output of ricefield rat populations until the end of the reproductive period. In house mice, similar success was achieved when a sterility level of 67% of female founders and offspring was maintained. Repeated antifertility treatments are required because of the much longer breeding period of house mice versus ricefield rats. Comparing the results of enclosure trials with the outcome of simulation models suggests that partial compensation of treatment effects can occur through enhanced reproduction of the remaining fertile females and improved survival of juveniles. However, such compensatory effects as well as behavioural consequences of sterility in field populations are not likely to prevent the management effect at the population level. The challenge for effective fertility control of small rodents in the field is the wide-scale delivery of an antifertility treatment to founders at the beginning of the breeding season and to fertile immigrants that are recruited into the population, which otherwise contribute to the reproductive output at the population level. Future research efforts should focus on species-specific techniques and on agents that can be effectively delivered via bait.

scholarly journals From individual to population level: Temperature and snow cover modulate fledging success through breeding phenology in greylag geese (Anser anser)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Didone Frigerio ◽  
Petra Sumasgutner ◽  
Kurt Kotrschal ◽  
Sonia Kleindorfer ◽  
Josef Hemetsberger
Keyword(s):  
Ambient Temperature ◽  
Reproductive Output ◽  
Population Level ◽  
Egg Laying ◽  
Future Research ◽  
Breeding Phenology ◽  
Anser Anser ◽  
Fledging Success ◽  
Average Annual Temperature ◽  
Greylag Geese

AbstractLocal weather conditions may be used as environmental cues by animals to optimize their breeding behaviour, and could be affected by climate change. We measured associations between climate, breeding phenology, and reproductive output in greylag geese (Anser anser) across 29 years (1990–2018). The birds are individually marked, which allows accurate long-term monitoring of life-history parameters for all pairs within the flock. We had three aims: (1) identify climate patterns at a local scale in Upper Austria, (2) measure the association between climate and greylag goose breeding phenology, and (3) measure the relationship between climate and both clutch size and fledging success. Ambient temperature increased 2 °C across the 29-years study period, and higher winter temperature was associated with earlier onset of egg-laying. Using the hatch-fledge ratio, average annual temperature was the strongest predictor for the proportion of fledged goslings per season. There is evidence for an optimum time window for egg-laying (the earliest and latest eggs laid had the lowest fledging success). These findings broaden our understanding of environmental effects and population-level shifts which could be associated with increased ambient temperature and can thus inform future research about the ecological consequences of climate changes and reproductive output in avian systems.

scholarly journals Outbreaks of Tomostethus nigritus (Fabricius, 1804) (Hymenoptera, Tenthredinidae) on Fraxinus angustifolia ‘Raywood’ in Belgium

2019 ◽  
Vol 72 ◽  
pp. 67-81
Author(s):  
Fons Verheyde ◽  
Geert Sioen
Keyword(s):  
Population Dynamics ◽  
Crucial Role ◽  
Western Europe ◽  
Population Level ◽  
Climatic Conditions ◽  
Future Research ◽  
Pest Species ◽  
Satisfactory Explanation ◽  
Fraxinus Angustifolia ◽  
The City

In Western Europe the ash sawfly Tomostethus nigritus is known to occur at low densities on Fraxinus excelsior and is uncommonly reported as a pest species. However, we show here that outbreaks can occur on non-endemic trees such as F. angustifolia, and that the species is able to spread quickly using city infrastructure. At the visited localities near the city of Ghent, foliage of Fraxinus angustifolia ‘Raywood’ emerged approximately one month earlier than on F. excelsior. At the same time, changed climatic conditions in the last decade, i.e. higher temperatures in March, caused adults to emerge earlier. Synchronicity of the potential hosts and T. nigritus may therefore have altered, playing a crucial role in population dynamics. Future research should aim to confirm if the species dramatically declines in numbers after reaching its peak population level, an effect which was observed in previous studies, but for which there is still no satisfactory explanation.

The Energy Politics of India

2020 ◽  
pp. 532-561
Author(s):  
Lydia Powell
Keyword(s):  
Simulation Models ◽  
Future Research ◽  
Economic Power ◽  
Political Will ◽  
Political Factors ◽  
Academic Literature ◽  
Social Perspectives ◽  
Energy Politics ◽  
Social Structural ◽  
Poor Outcomes

While it is not surprising that political factors shape the Indian energy landscape, few systematic attempts have been made to address exactly what interests most heavily influence energy choices and the precise nature of their impacts. Available research suggests that scholars need to move beyond simplistic explanations, such as lack of political will or capacity constraints, and recognize a broader set of interacting social, structural, institutional, and political agency variables. The technocratic analyses and projections based on simulation models that dominate the academic literature neglect political and social perspectives as unscientific, esoteric, or theoretical. Thus this chapter argues that future research should focus on political and economic power relations at the national, regional, and domestic levels when tracking poor outcomes of energy choices and policies. In the future, an emphasis on theoretically informed analysis will deepen understanding of hard choices related to the equitable distribution of energy in India and also facilitate implementation of more progressive energy policies.

scholarly journals A Linkage Map and QTL Analysis for Pyrethroid Resistance in the Bed Bug Cimex lectularius

2016 ◽  
Vol 6 (12) ◽  
pp. 4059-4066 ◽  
Author(s):  
Toby Fountain ◽  
Mark Ravinet ◽  
Richard Naylor ◽  
Klaus Reinhardt ◽  
Roger K Butlin
Keyword(s):  
Insecticide Resistance ◽  
Candidate Gene ◽  
Linkage Map ◽  
Pyrethroid Resistance ◽  
Cimex Lectularius ◽  
Future Research ◽  
Potential Candidate ◽  
Pest Species ◽  
Diverse Range ◽  
Bed Bug

Abstract The rapid evolution of insecticide resistance remains one of the biggest challenges in the control of medically and economically important pests. Insects have evolved a diverse range of mechanisms to reduce the efficacy of the commonly used classes of insecticides, and finding the genetic basis of resistance is a major aid to management. In a previously unstudied population, we performed an F2 resistance mapping cross for the common bed bug, Cimex lectularius, for which insecticide resistance is increasingly widespread. Using 334 SNP markers obtained through RAD-sequencing, we constructed the first linkage map for the species, consisting of 14 putative linkage groups (LG), with a length of 407 cM and an average marker spacing of 1.3 cM. The linkage map was used to reassemble the recently published reference genome, facilitating refinement and validation of the current genome assembly. We detected a major QTL on LG12 associated with insecticide resistance, occurring in close proximity (1.2 Mb) to a carboxylesterase encoding candidate gene for pyrethroid resistance. This provides another example of this candidate gene playing a major role in determining survival in a bed bug population following pesticide resistance evolution. The recent availability of the bed bug genome, complete with a full list of potential candidate genes related to insecticide resistance, in addition to the linkage map generated here, provides an excellent resource for future research on the development and spread of insecticide resistance in this resurging pest species.

scholarly journals The Influence of a Seedling Recruitment Strategy and a Clonal Architecture on a Spatial Genetic Structure of a Salvia brachyodon (Lamiaceae) Population

Plants ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 828
Author(s):  
Ivan Radosavljević ◽  
Oleg Antonić ◽  
Dario Hruševar ◽  
Josip Križan ◽  
Zlatko Satovic ◽  
...  
Keyword(s):  
Genetic Structure ◽  
Seedling Recruitment ◽  
Spatial Genetic Structure ◽  
Population Level ◽  
Significant Negative Correlation ◽  
Recruitment Strategy ◽  
Future Research ◽  
Clonal Architecture ◽  
Surrounding Areas ◽  
Spatial Genetic Analysis

By performing a high-resolution spatial-genetic analysis of a partially clonal Salvia brachyodon population, we elucidated its clonal architecture and seedling recruitment strategy. The sampling of the entire population was based on a 1 × 1 m grid and each sampled individual was genotyped. Population-genetic statistics were combined with geospatial analyses. On the population level, the presence of both sexual and clonal reproduction and repeated seedling recruitment as the prevailing strategy of new genets establishment were confirmed. On the patch level, a phalanx clonal architecture was detected. A significant negative correlation between patches’ sizes and genotypic richness was observed as young plants were not identified within existing patches of large genets but almost exclusively in surrounding areas. The erosion of the genetic variability of older patches is likely caused by the inter-genet competition and resulting selection or by a random die-off of individual genets accompanied by the absence of new seedlings establishment. This study contributes to our understanding of how clonal architecture and seedling recruitment strategies can shape the spatial-genetic structure of a partially clonal population and lays the foundation for the future research of the influence of the population’s clonal organization on its sexual reproduction.

scholarly journals Perspectives from animal demography on incorporating evolutionary mechanism into plant population dynamics

2018 ◽  
Author(s):  
Maria Paniw
Keyword(s):  
Environmental Change ◽  
Evolutionary Dynamics ◽  
Natural Populations ◽  
Population Level ◽  
Plant Population ◽  
Future Research ◽  
Phenotypic Traits ◽  
Plant Population Dynamics ◽  
Future Research Agenda ◽  
Powerful Approach

AbstractWith a growing number of long-term, individual-based data on natural populations available, it has become increasingly evident that environmental change affects populations through complex, simultaneously occurring demographic and evolutionary processes. Analyses of population-level responses to environmental change must therefore integrate demography and evolution into one coherent framework. Integral projection models (IPMs), which can relate genetic and phenotypic traits to demographic and population-level processes, offer a powerful approach for such integration. However, a rather artificial divide exists in how plant and animal population ecologists use IPMs. Here, I argue for the integration of the two sub-disciplines, particularly focusing on how plant ecologists can diversify their toolset to investigate selection pressures and eco-evolutionary dynamics in plant population models. I provide an overview of approaches that have applied IPMs for eco-evolutionary studies and discuss a potential future research agenda for plant population ecologists. Given an impending extinction crisis, a holistic look at the interacting processes mediating population persistence under environmental change is urgently needed.

scholarly journals Incorporating biomarkers in ecological risk assessment of chemical contaminants of soils

2007 ◽  
Vol 26 (2) ◽  
pp. 120-137
Author(s):  
A. J. Reinecke ◽  
S. A. Reinecke ◽  
M. S. Maboeta ◽  
J. P. Odendaal ◽  
R. Snyman
Keyword(s):  
Risk Assessment ◽  
South African ◽  
Field Experiments ◽  
Early Stage ◽  
Population Level ◽  
Diagnostic Tools ◽  
Future Research ◽  
Chemical Contaminants ◽  
Toxic Response ◽  
Future Research Directions

Soil is an important but complex natural resource which is increasingly used as sink for chemicals. The monitoring of soil quality and the assessment of risks posed by contaminants have become crucial. This study deals with the potential use of biomarkers in the monitoring of soils and the assessment of risk resulting from contamination. Apart from an overview of the existing literature on biomarkers, the results of various of our field experiments in South African soils are discussed. Biomarkers may have potential in the assessment of risk because they can indicate at an early stage that exposure has taken place and that a toxic response has been initiated. It is therefore expected that early biomarkers will play an increasing role as diagnostic tools for determining exposure to chemicals and the resulting effects. They may have predictive value that can assist in the prevention or minimising of risks. The aim of this study was to investigate the possibilities of using our results on biomarker responses of soil dwelling organisms to predict changes at higher organisational levels (which may have ecological implications). Our recent experimental results on the evaluation of various biomarkers in both the laboratory and the field are interpreted and placed in perspective within the broader framework of response biology. The aim was further to contribute to the development and application of biomarkers in regulatory risk assessment schemes of soils. This critical review of our own and recent literature on biomarkers in ecotoxicology leads to the conclusion that biomarkers can, under certain conditions, be useful tools in risk assessment. Clear relationships between contamination loads in soil organisms and certain biomarker responses were determined in woodlice, earthworms and terrestrial snails. Clear correlations were also established in field experiments between biomarker responses and changes at the population level. This indicated that, in spite of the fact that direct mechanistic links are still not clarified, biomarkers may have the potential to provide early indications of forthcoming changes at higher organisational levels. Ways are proposed in which biomarkers could be used in the future in risk assessment schemes of soils and future research directions are suggested. 

Role of computer simulation in the application of knowledge to animal industries

1993 ◽  
Vol 44 (3) ◽  
pp. 541 ◽  
Author(s):  
JL Black ◽  
GT Davies ◽  
JF Fleming
Keyword(s):  
Management Strategies ◽  
Research Priorities ◽  
Simulation Models ◽  
Relative Price ◽  
Biological Efficiency ◽  
Future Research ◽  
Mechanistic Models ◽  
Animal Performance ◽  
Financial Return ◽  
Widespread Application

The net financial return of an enterprise depends on the interaction among a great many factors. Some of these factors relate to the animal, some to its diet, some to its environment, some to the prevalence of disease and some to circumstances outside the production enterprise such as the premiums paid for products of different quality, the relative price structure of feeds and products, and the availability and cost of capital, labour, breeding stock and other resources. Although there has been a great deal of research into many of these factors, the complexity of the interactions between them makes it virtually impossible for the human mind to assess accurately the consequences of alternative management strategies on either the efficiency of production or the long-term profitability of a livestock enterprise. By transforming the concepts and knowledge into mathematical equations and integrating them in computer programs using simulation modelling techniques, this vast store of information can be applied directly to improving the management of commercial animal enterprises. Models are also valuable for defining research priorities. These simulation models should, as far as possible, be based on descriptions of the mechanisms perceived to determine animal function, not on empirical relationships of correlation and association. This need for mechanistic models has major implications for the direction and nature of future research into animal function. Mechanistic models of animal performance alone are unlikely to result in the widespread application of knowledge to the animal industries. Models must be integrated with other modules that cover the major areas of an enterprise determining its profitability, as well as with programming features that make the whole Decision Support Software System easy to use and interpret by industry personnel. The animal model is likely to represent less than 20% of a commercially useful package. A major factor limiting the application of animal growth models is lack of an adequate description of the conditions within commercial enterprises. Collection of such data is difficult and frequently regarded as unattractive by scientists and funding organisations, but it is essential for effective application of existing knowledge through simulation models. Furthermore, industry must make frequent measurements of factors determining animal performance and enterprise profitability if the significance of predictions from animal models is to be evaluated fully. An example is presented illustrating how simulation models can improve the biological efficiency and profitability of a commercial animal enterprise when this information is available.

Parenting Support in the Workplace

2017 ◽  
pp. 262-271
Author(s):  
Divna M. Haslam ◽  
Nicole Penman
Keyword(s):  
Family Conflict ◽  
Organizational Context ◽  
Population Level ◽  
Work And Family ◽  
Future Research ◽  
Demographic Changes ◽  
Parenting Support ◽  
Successful Program ◽  
Family Demands ◽  
The Impact

Demographic changes over the last 40 years means the majority of parents are now employed in some capacity. This chapter outlines some of the challenges parents face in balancing competing work and family demands. The concept of work and family conflict is defined, and the impact of work and family conflict on individuals and families is discussed. A rationale is provided for the provision of parenting support via the workplaces as a means of improving the lives of employees and as a way of increasing population-level access to parenting support. A brief review of the efficacy of workplace parenting support is provided alongside practical examples of how to ensure successful program delivery in an organizational context. The chapter concludes with a discussion about the implications and provides some directions for future research.

Annotated checklist and illustrated key to parasitoids (Hymenoptera: Diapriidae, Eulophidae and Pteromalidae) of fruit flies (Diptera, Tephritidae) in Brazil

Zootaxa ◽  
2020 ◽  
Vol 4858 (1) ◽  
pp. 53-70
Author(s):  
EDUARDO MITIO SHIMBORI ◽  
VALMIR ANTONIO COSTA ◽  
ROBERTO ANTONIO ZUCCHI
Keyword(s):  
Ceratitis Capitata ◽  
Taxonomic Status ◽  
Fruit Flies ◽  
Future Research ◽  
Pest Species ◽  
Key To Species ◽  
Spalangia Endius ◽  
Pupal Parasitoids ◽  
Hymenopteran Parasitoids ◽  
Annotated Checklist

The hymenopteran parasitoids of pest species of Tephritidae in Brazil are best known by their most prominent species, members of Braconidae and Figitidae. Species in the less-studied families Diapriidae, Eulophidae and Pteromalidae, which are mostly pupal parasitoids, have been largely neglected and the literature on these groups is sparse and scattered. Therefore, their importance as natural enemies of fruit flies is likely underestimated. Here, we present a parasitoid-host-plant checklist of all diapriids, eulophids and pteromalids that parasitize fruit flies of economic importance in Brazil, namely Anastrepha species and Ceratitis capitata. A compilation of information of the seven species of these parasitoids occurring in Brazil—Coptera haywardi Loiácono and Trichopria anastrephae Lima (Diapriidae), Tetrastichus giffardianus Silvestri (Eulophidae), Pachycrepoideus vindemmiae (Rondani), Spalangia endius Walker, S. gemina Bouček and S. simplex Perkins (Pteromalidae)—including their taxonomic status, general biology, and potential as biocontrol agents, is presented. Additionally, we provide an illustrated key to species, aiming to highlight key morphological features and facilitate identification at species level, stimulating future research on these groups. 

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