1,721,140 research outputs found
Potential of remote sensing to predict species invasions: A modelling perspective
No full textUnderstanding the causes and effects of species invasions is a priority in ecology and conservation biology. One of the crucial steps in evaluating the impact of invasive species is to map changes in their actual and potential distribution and relative abundance across a wide region over an appropriate time span. While direct and indirect remote sensing approaches have long been used to assess the invasion of plant species, the distribution of invasive animals is mainly based on indirect methods that rely on environmental proxies of conditions suitable for colonization by a particular species. The aim of this article is to review recent efforts in the predictive modelling of the spread of both plant and animal invasive species using remote sensing, and to stimulate debate on the potential use of remote sensing in biological invasion monitoring and forecasting. Specifically, the challenges and drawbacks of remote sensing techniques are discussed in relation to: i) developing species distribution models, and ii) studying life cycle changes and phenological variations. Finally, the paper addresses the open challenges and pitfalls of remote sensing for biological invasion studies including sensor characteristics, upscaling and downscaling in species distribution models, and uncertainty of results. © The Author(s) 201
Deconstructing the control of the spotted alfalfa aphid Therioaphis maculata
No full textThe control of insect pests and other taxa may be a result of many factors that are difficult to separate and quantify. Introduced parasitoids, host plant resistance, pathogens and native predators led to the successful control of the spotted alfalfa aphid (SAA; Therioaphis maculata Monell) in California and elsewhere, although the relative contribution of each factor remained largely unknown. The relative contribution of each control factor was estimated using a weather-driven physiologically-based demographic system model consisting of alfalfa, SAA, its three exotic parasitoids [Aphelinus semiflavus Howard, Praon palitans Muesebeck and Trioxys complanatus (Quilis)], a native coccinellid beetle [Hippodamia convergens (Guérin-Menéville)], a fungal pathogen [Erynia neoaphidis Remaudière & Hennebert (Zygomycetes: Entomophthorales)] and host plant resistance (HPR). Daily weather data for the period 1995-2006 from 142 locations in Arizona and California were used to drive the model. The factors were introduced to the model singly or in combination to assess their effects in suppressing simulated SAA populations using SAA-daysm-2year-1 (i.e. density) as the metric of control. Data from selected runs were mapped using the geographic information system grass (http://grass.osgeo.org). The simulation data across all factor combinations, years and locations were summarized using linear multiple regression, with the dependent variable being log10SAA-daysm-2year-1 and the independent variables being the presence-absence (0, 1) of the various factors and their interactions. Marginal analysis of the regression model (∂y/∂xi) enabled separation of the average effects of the different factors (xi) given the average effects of the other factors. Alone, each factor failed to control SAA, as did combinations of the parasitoids and coccinellid predation. Control was predicted across all ecological zones only when all mortality factors were included. The marginal analysis suggests that the order of importance of the mortality factors is HPR > coccinellid beetles > T. complanatus>P. palitans>A. semiflavus > the fungal pathogen. The variability of control by coccinellid beetles and the fungal pathogen was high and hence unreliable. © 2013 The Royal Entomological Society
Analysis of invasive insects: Links to climate change
No full textClimate change is expected to alter the geographic distribution and abundance of many species, to increase the invasion of new areas by exotic species and, in some cases, to lead to species extinction. Th is chapter reviews some of the links between invasive insects and climate change. Th e effects of climate change on insect pest populations can be direct, through impacts on their physiology and behaviour, or indirect, through biotic interactions (i.e. bottom-up and top-down effects). Anthropogenic climate and global change is expected to be a major driver in the introduction, establishment, distribution, impact and changes in the efficacy of mitigation strategies for invasive species. To address these problems, we must be able to predict climate change impacts on species distribution and abundance. Commonly used ecological niche model ling approaches have implicit assumptions about the biology of the target species and attempt to characterize the ecological niche using aggregate weather and other factors in the area of recorded distribution. More holistic physiologically based demographic modelling approaches explicitly describe the biological and physio logical responses of species to weather and the species they interact with on fine temporal and spatial scales. Th e geographic distribution and relative abundance of four invasive insect pests are reviewed under observed and +2°C weather scenarios across the USA and Mexico: the tropical New World screwworm, the pink bollworm, the Mediterranean fruit fly (i.e. medfly) and the olive fly. Th e distribution of the olive fly is examined across the Mediterranean basin to illustrate the transferability of the model to analyses of new regions and climate change scenarios. © CAB International 2014
La timidezza nell'arco di vita
No full textShyness is a condition defined as discomfort and/or inhibition experienced in social and interpersonal situations and it is characterized on affective, behavioural, and cognitive levels. It involves feelings of anxiety, concern, and discomfort in the presence of others. Moreover, shy people display inhibited, reticent and awkward behaviours, and they tend to withdraw from social situations. Finally, on a cognitive level, shy individuals tend to have low self-esteem, negative self-concept, and negative thoughts about their social ability.
In the last thirty years, many researchers have developed a growing interest for the theme of shyness, as a result of possible negative outcomes that often characterize shy people. Indeed, it has been shown that shy- ness represents a risk factor for the development of psychological disorders and social problems. In particular, shy individuals tend to develop high levels of depression and anxiety and, in general, internalizing problems. Moreover, they have many interpersonal difficulties, such as establishing satisfying relationships, making new friendships, meeting people, and expressing their opinions. Shy people frequently experience others’ reject, and this experience tends to confirm their negative self- concept and increase their levels of anxiety in social situations.
The aim of this work is to analyse the literature about shyness. In particular, it analyses several factors that affect the development of shyness, such as biological, familiar, and social variables. In addiction, this review analyses individual correlates and developmental consequences of shyness from infancy to adulthood, as well as the influence of gender and cultural context on the socio-emotional adjustment of shy individuals. In fact, in cross-cultural studies, researchers have found that the significance of shyness and, consequently, its evolutive out- comes depend on the demands of a particular individual’s sociocultural context
Eradication of invasive species: Why the biology matters
No full textPublished bi- and tri-trophic physiologically based demographic system models having similar sub components are used to assess prospectively the geographic distributions and relative abundance (a measure of invasiveness) of six invasive herbivorous insect species across the United States and Mexico. The plant hosts and insect species included in the study are: 1) cotton/pink bollworm, 2) a fruit tree host/Mediterranean fruit fly, 3) olive/olive fly, 4) a perennial host/light brown apple moth, 5) grapevine/glassy-winged sharpshooter and its two egg parasitoids, and 6) grapevine/European grapevine moth. All of these species are currently or have been targets for eradication. The goal of the analyses is to predict and explain prospectively the disparate distributions of the six species as a basis for examining eradication or containment efforts against them. The eradication of the new world screwworm is also reviewed in the discussion section because of its pivotal role in the development of the eradication paradigm. The models used are mechanistic descriptions of the weather driven biology of the species. Observed daily weather data (i.e., max-min temperatures, solar radiation) from 1,221 locations across the United States and Mexico for the period 1983-2003 were used to drive the models. Soil moisture and nutrition were assumed nonlimiting. The simulation results were mapped using GRASS GIS. The mathematical underpinnings of the modeling approach are reviewed in the appendix and in the supplemental materials. © 2013 Entomological Society of America
Comments on the concept of ultra-low, cryptic tropical fruit fly populations
No full text[No abstract available
Invasion biology of spotted wing Drosophila (Drosophila suzukii): a global perspective and future priorities
No full textThe Asian vinegar fly Drosophila suzukii (spotted wing Drosophila [SWD]) has emerged as a major invasive insect pest of small and stone fruits in both the Americas and Europe since the late 2000s. While research efforts have rapidly progressed in Asia, North America, and Europe over the past 5 years, important new insights may be gained in comparing and contrasting findings across the regions affected by SWD. In this review, we explore common themes in the invasion biology of SWD by examining (1) its biology and current pest status in endemic and recently invaded regions; (2) current efforts and future research needs for the development of predictive models for its geographic expansion; and (3) prospects for both natural and classical (=importation) biological control of SWD in invaded habitats, with emphasis on the role of hymenopteran parasitoids. We conclude that particularly fruitful areas of research should include fundamental studies of its overwintering, host-use, and dispersal capabilities; as well as applied studies of alternative, cost-effective management techniques to complement insecticide use within the integrated pest management framework. Finally, we emphasize that outreach efforts are critical to effective SWD management by highlighting successful strategies and insights gained from various geographic regions. © 2015, Springer-Verlag Berlin Heidelberg
The new world screwworm: Prospective distribution and role of weather in eradication
No full textThe new world screwworm [Cochliomyia hominivorax (Coquerel)] was eradicated in North America, Libya and other locations using the sterile insect technique (SIT). To examine the role of weather in its eradication, a physiologically-based demographic model was developed and used to characterize its range of year-round persistence. Published data on developmental times, fecundity and mortality rates on temperature were used to parameterize the model. The lower and upper thermal thresholds for development are 14.5 and 43.5°C, and the optimal temperature for survival is 27.2°C. An index of favourability based on annual rainfall was used as an approximate estimate of the limiting effects of moisture in arid areas. The open source geographical information system software grass was used to map the simulation results, as well as county level myiasis incidence data for Texas for the 1962-1983 SIT eradication programme. Winter temperature and rainfall are shown to have a strong influence on screwworm outbreaks and in facilitating eradication in North America and Libya. Prospective analysis for the Mediterranean Basin suggests that eastern areas are most favourable for screwworm establishment (e.g. the Nile River area of Egypt). The SIT eradication programme and its possible extension into South America are discussed. Expected +2°C climate warming is predicted to increase the potential year-round range of screwworm in the southeast U.S.A. © 2014 The Royal Entomological Society
Prospective analysis of the geographic distribution and relative abundance of asian citrus psyllid (Hemiptera: Liviidae) and citrus greening disease in North America and the mediterranean basin
No full textThe invasive Asian citrus psyllid (Diaphorina citri Kuwayama) is the vector of the bacterial pathogen ('Candidatus Liberibacter asiaticus') that is the putative causal agent of citrus greening disease (Huanglongbing disease) in citrus in many areas of the world. The capacity to predict the potential geographic distribution, phenology and relative abundance of the pest and disease is pivotal to developing sound policy for their management. A weather-driven physiologically based demographic model (PBDM) system was developed to summarize the available data in the literature, and used to assess prospectively the geographic distribution and relative yield of citrus, the relative densities of the psyllid, its parasitoid (Tamarixia radiata Waterston), and the potential severity of citrus greening disease in North America and the Mediterranean Basin. The potential for natural and biological control of citrus psyllid was examined prospectively
Deconstructing Indian cotton: weather, yields, and suicides
No full textBackground: Cotton with coevolving pests has been grown in India more than 5000 years. Hybrid cotton was introduced in the 1970s with increases in fertilizer and in insecticide use against pink bollworm that caused outbreaks of bollworm. Hybrid Bt cotton, introduced in 2002 to control bollworm and other lepidopteran pests, is grown on more than 90 % of the cotton area. Despite initial declines, year 2013 insecticide use is at 2000 levels, yields plateaued nationally, and farmer suicides increased in some areas. Biological modeling of the pre-1970s cotton/pink bollworm system was used to examine the need for Bt cotton, conditions for its economic viability, and linkage to farmer suicides. Results: Yields in rainfed cotton depend on timing, distribution, and quantity of monsoon rains. Pink bollworm causes damage in irrigated cotton, but not in rainfed cotton unless infested from irrigated fields. Use of Bt cotton seed and insecticide in rainfed cotton is questionable. Conclusions: Bt cotton may be economic in irrigated cotton, whereas costs of Bt seed and insecticide increase the risk of farmer bankruptcy in low-yield rainfed cotton. Inability to use saved seed and inadequate agronomic information trap cotton farmers on biotechnology and insecticide treadmills. Annual suicide rates in rainfed areas are inversely related to farm size and yield, and directly related to increases in Bt cotton adoption (i.e., costs). High-density short-season cottons could increase yields and reduce input costs in irrigated and rainfed cotton. Policy makers need holistic analysis before new technologies are implemented in agricultural development. © 2015, Gutierrez et al
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