167 research outputs found
Understanding insect foraging in complex habitats by comparing trophic levels : insights from specialist host-parasitoid-hyperparasitoid systems
Full text linkInsects typically forage in complex habitats in which their resources are surrounded by non-resources. For herbivores, pollinators, parasitoids, and higher level predators research has focused on how specific trophic levels filter and integrate information from cues in their habitat to locate resources. However, these insights frequently build specific theory per trophic level and seldom across trophic levels. Here, we synthesize advances in understanding of insect foraging behavior in complex habitats by comparing trophic levels in specialist host-parasitoid-hyperparasitoid systems. We argue that resources may become less apparent to foraging insects when they are member of higher trophic levels and hypothesize that higher trophic level organisms require a larger number of steps in their foraging decisions. We identify important knowledge gaps of information integration strategies by insects that belong to higher trophic levels.</p
En route to resources: Foraging strategies of plant-associated insects to identify resources in complex dynamic environments
Full text linkIn plant-associated communities, foraging insects aim to find different resources of interest. Herbivores look for the most nutritious plant tissues, pollinators for sweet nectar and protein-rich pollen, and carnivores for their preferred prey. Although these foragers look for different resources, they face similar problems: resource cues are often highly variable and need to be detected in complex environments among non-resources. Search templates—a subset of stimuli that is likely correlated with the occurrence of a particular resource—help foragers across trophic levels to find their resources. However, search-template-based foraging can also cause perception errors. Here, we synthesize knowledge on foraging by insects from functional groups belonging to different trophic levels to reveal common problems experienced by foragers and strategies to solve such problems. We focus mostly on volatile-based foraging because this searching strategy is best studied across functional groups. We argue that search templates are both multimodal (including multiple trait types, e.g. odour and visual) and hierarchical (including multiple foraging steps). Search templates are plastic and updated by experience to match the dynamic foraging environment over time. By comparing insects from different functional groups spanning multiple trophic levels, we have identified important missing gaps on cue use and foraging strategies which should be addressed in the future in order to reduce knowledge asymmetries among functional groups about search-template-based foraging. We propose a way to achieve this goal arguing that studies on less well investigated functional groups can advance rapidly by borrowing, testing and adjusting already available hypotheses and theories formulated for other insect groups. Knowledge of search-template-based foraging across functional groups will give new insights into the evolution of foraging behaviour in complex ecological communities, help predict ecological consequences of large-scale human-made disturbances and help optimize insect-delivered ecosystem services (pollination and biological control) in cropping systems. Read the free Plain Language Summary for this article on the Journal blog
Nine New Poets: An Anthology by Arlo Quint
No full textNine New Poets: An Anthology by Arlo Quint is an experimental poetry/poetics project that explores issues of style, form, sincerity, persona, canonmaking, and meaning in modern poetry. Its title gets at the basic form of the project; it is a poetry anthology written by one person. The fictional premise of the anthology is that there are a group of poets hand-making poetry booklets whose only distribution is at the Boston Public Library and whose only readership is each other and whoever else might discover the books in the stacks. A librarian discovers this coterie and edits an anthology of their work intended to introduce them to the outside world. This fictional anthology is the main text of this thesis. The fiction is broken at the end of the anthology, with an afterword by the author. The anthology has been a major tool used in the world of modem poetry in attempts to define what kind of poetry people read. The two most important wouldbe canon makers in modem poetry are Donald Allen and Donald Hall who began what has been called the battle of the anthologies in the early 1960\u27s. The terms of this battle are not exact but, in general, Hall\u27s anthology promotes a style of poetry grounded in the New Critical understanding of poetry whereas the Allen could be said to promote poetry grounded in styles or theories identified with a few particular locales and poetry movements, namely Black Mountain College, the Beat movement, the New York School, and the San Francisco Renaissance. There is a strong division in contemporary poetry that can be traced back to these competing anthologies. Those that see themselves in the tradition promoted by Allen might accuse the other tradition of using a rhetoric of sincerity or being overly reliant on the lyric I. Those poets that are more in line with Hall\u27s tradition might accuse the other tradition of being cliquish, having no substance, or writing nonsense. This thesis attempts to explore this division in contemporary poetry in its own terms. What might be considered the mark of a poetry clique, their very own anthology, is adopted as a formal device. Within the poetry of this anthology the lyric I is used while openly adopting the styles of other poets and the styles of other poets are used as the substance of poetry. The personae of the poets are established in prose pieces and interviews as well as the poetry in an attempt to see how a grouping of not just poets butpmonaktie~m ight really function as a formal device. My hope is that this experiment reveals something of the way in which meaning is made in contemporary poetry
Caught between friends and foes : plant-mediated interactions between herbivores and flower visitors
No full textUnderstanding the interplay between ecology and evolution in complex multispecies communities is a major challenge for ecologists. Most plant species are flowering plants, and to maximize their contribution to the next generation they need to deal with antagonistic herbivores while also engaging in interactions with mutualistic pollinators. Plants respond to attack by herbivores with phenotypic changes to repel or kill the attackers, and when plants are flowering, these changes extent to flower-trait expression. As a result, herbivore attack can alter interactions with pollinators and flower feeders. Knowledge on the specificity of herbivore-induced changes in flower traits, importance for the assembly of flower-visitor networks, and associated consequences for plant fitness is limited to date. The aim of this thesis project was to investigate how attack by a range of herbivore species affects plant interactions with mutualistic and antagonistic flower visitors and whether these interactions have consequences for plant fitness. I was especially interested in specificity of plant-mediated herbivore - flower-visitor interactions. The study used the Black mustard (Brassica nigra) plant and ten different herbivore species with different feeding behaviours: some choose to feed among their favourite tissues, others are highly specialized and engage in intimate and manipulative feeding relations with the plant, whereas a few take bites or sips from different plant parts. Black mustard is an annual plant species which relies on insect pollinators for reproduction. The large fragrant inflorescences contain hundreds of small yellow flowers which attract various generalist pollinators, but also specialist florivores such as pollen beetles, Meligethes spp. Chapter 2 addresses the current knowledge on flower plasticity in response to herbivory and places flower plasticity in a community context. The chapter reviews the extent to which herbivore-induced plant responses affect multiple flower traits, and the molecular mechanisms underlying floral plasticity. To understand the adaptive value of flower plasticity with contrasting differences on pairwise interactions, it is important to adopt a community perspective. Chapter 3 evaluates specificity of plant responses to different herbivore species and how these plant responses affect flower visitors and plant fitness. The results show that attack of B. nigra by a range of different herbivores influenced plant interactions with mutualistic pollinators and an antagonistic florivore, the pollen beetle Meligethes aeneus, with consequences for plant reproduction. In Chapter 4, my aim was to investigate whether herbivore - flower-visitor interactions and associated plant fitness consequences are different when timing of herbivore attack varies over plant ontogeny. My data shows that the indirect interaction web between herbivores and flower visitors is dynamic and variable over plant ontogeny, and that consequences of herbivory for plant reproductive output are strongest when plants are attacked by herbivores early in life. Chapter 5 explored the underlying mechanisms of specificity in herbivore – flower-visitor interactions. I found that flowers show extensive plasticity in response to herbivores, that herbivore-induced changes in flower traits are mostly herbivore-species specific, and have contrasting effects on pollinators. In Chapter 6, I use manipulative experiments to explore whether herbivore choice for a given feeding site determines the outcome of plant-mediated herbivore-pollinator interactions. The results show that variation in herbivore feeding site has profound impact on the outcome of herbivore-pollinator interactions. The data presented in this thesis contribute to our understanding of the complex ecological and evolutionary dynamics in multispecies communities with antagonists and mutualists, and this is discussed in Chapter 7.</p
O encontro como categoria teol?gica a partir da obra de Alfonso L?pez Quint?s
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Previous issue date: 2018-06-26The definition of encounter, according to the Spanish philosopher Alfonso L?pez Quint?s, is the starting point for to draw around the encounter as a theological category. The purpose was to clearly identify the essential characteristics and the fruits of the interpersonal encounter, as well as the discovery of the values and the longing for transcendence. When contrasting the theory of the encounter of L?pez Quint?s with the work of different philosophers, theologians and thinkers who focused on the idea of "encounter with God", it is possible to glimpse and make explicit, in the work of this author, the main features of a legitimate theology of the encounter.A partir do pensamento do fil?sofo espanhol Alfonso L?pez Quint?s, tenciona-se delinear nesta disserta??o o encontro como categoria teol?gica, identificando com clareza as caracter?sticas essenciais, as exig?ncias e os frutos do encontro interpessoal, da descoberta dos valores que decorrem do encontro e do desejo de transcend?ncia. Contrastando a teoria do encontro de L?pez Quint?s com o trabalho de diferentes fil?sofos, te?logos e pensadores que se debru?aram sobre a ideia de um ?encontro com Deus?, ? poss?vel vislumbrar e explicitar na obra deste autor os principais tra?os de uma leg?tima teologia do encontro
Barbara Ehrenreich, author of Blood Rites: Origins and History of the Passions
No full textBarbara Ehrenreich, author of Blood Rites: Origins and History of the Passions of War and a prolific writer, spoke at the Maine People\u27s Alliance awards dinner in Portland last week. Others receiving awards from the organization included Maine Rural Workers Coalition Director Juan Soto, state representative Michael Quint, and health-care reform advocate Peg Tebbets
De la mémoire médiatique des temps de guerre. Le travail de mémoire, les cadres paratextuels et les stratégies narratives dans Effroyables jardins de Michel Quint et son adaptation cinématographique par Jean Becker
No full textDans cet article, l’auteur analyse les approches médiatiques du roman Effroyables Jardins de l’écrivain français Michel Quint (2000) et de son adaptation cinématographique (2002) par Jean Becker. L’accent est mis sur les stratégies narratives et paratextuelles utilisées pour véhiculer les ambiguïtés psychologiques de l’Histoire, présentes tant dans le roman que dans le film. L’analyse révèle une contextualisation cohérente des moyens littéraires et audiovisuels employés pour déconstruire l’idée d’une vision simpliste de la Deuxième Guerre mondiale et du temps de l’occupation allemande en France. L’auteur démontre que dans le cas du roman et du film, il s’agit de véritables lieux de mémoire franco-allemands construits à l’aide d’une imbrication unique d’événements narratifs et d’éléments intermédiaux, ainsi qu’une constellation sophistiquée de personnages et de ruptures temporelles.This article analyzes the medial approach of the novel Effroyables Jardins written by Michel Quint (2000) and his adaption on screen of the same title (2002) by Jean Becker. The author focuses on the narrative and paratextual strategies and techniques used in the novel as well as in the movie to convey the psychological ambiguities of History. The analysis reveals a coherent contextualization of literary and audiovisual means to deconstruct the idea of a simplistic vision of World War II and the German occupation in France. The author shows how the novel’s and the movie’s unique conception of interlacing several narrative events and intermedial elements as well as its sophisticated constellation of characters, temporal ruptures and staging makes them veritable Franco-German memory spaces
Dealing with mutualists and antagonists : Specificity of plant-mediated interactions between herbivores and flower visitors, and consequences for plant fitness
No full textPlants need to deal with antagonists, such as herbivores, while maintaining interactions with mutualists, such as pollinators that help plants to maximize their reproductive output. Although many plant species have inducible defences to save metabolic costs of defence in the absence of herbivores, plant responses induced by herbivore attack can have ecological costs. For example, herbivore-induced responses can affect flower traits and alter interactions with flower visitors. Such plant-mediated interactions between herbivores and flower visitors can affect plant reproductive output. Current knowledge on the generality and specificity of plant-mediated herbivore-flower-visitor interactions and its consequences for plant fitness is limited. In this study, we investigated whether a broad range of herbivores feeding on the annual plant Brassica nigra affect interactions with flower visitors, whether the direction of interactions is predicted by the feeding modes (chewing and sap-feeding) and sites (above- and belowground) of the herbivores, and whether it results in fitness consequences for the plant. Our results show that attack of B. nigra by a range of different herbivores influenced plant interactions with mutualist pollinators and an antagonist florivore, the pollen beetle Meligethes aeneus. Pollinator community composition was affected by herbivory, whereas overall pollinator attraction was maintained. Pollinator community composition of uninfested plants differed from that of chewing and root herbivore-infested plants. Main responders in the pollinator communities to changes induced by herbivory were syrphid flies, bumblebees, and solitary bees. Although the preference of pollen beetle adults was not affected by herbivory, beetle larvae performed best on plants infested with the nematode Heterodera schachtii. The changes in pollinator community composition and syrphid fly visitation can explain the observed increase in seed set of root herbivore-infested plants. Interactions of flowering B. nigra plants with mutualist and antagonist insects are well integrated and conflicting interactions do not reduce reproductive output. Our results suggest some degree of specificity in herbivore-flower-visitor interactions with consequences for plant fitness. Specificity of plant responses were determined at the species level as well as the herbivore functional group level, and differed depending on the flower visitor. Because plant reproduction was affected by indirect plant-mediated interactions, these can potentially result in selection on plant strategies to optimize growth, defence and reproduction. A plain language summary is available for this article
Improving the creation process of catoptric anamorphosis using a reference pattern
No full textCatoptric anamorphosis is an image which seems to be distorted, but looks normal when observed from a specific point of view and indirectly via a reflective object. While some methods already exist that can create such images, they are limited in the amount of differently shaped reflective objects they support or they require you to obtain a 3D model of your object. We propose a new method, that can work with a reflective object of any shape and that requires minimal work from the user. After a suitable reference pattern is generated, the user can give a picture of both the reflective object and the pattern along with a picture of the reflection of the anamorphosis as input and the output is the corresponding anamorphosis. The results show that the method creates accurate catoptric anamorphoses for most differently shaped reflective objects. It is concluded that this method can help existing and new artists to create catoptric anamorphoses more easily while still offering the same features as older methods.Individual Research ProjectComputer Science and Engineerin
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