Efficient sampling of ground-dwelling arthropods using pitfall traps in arid steppes

Pitfall trapping is probably the most frequently used method for sampling grounddwelling arthropods. While the capture of specimens in pitfall traps largely depends on the number of individuals in the sampled area, trap design and trapping effort for a given environment, can also affect sampling success. The aim of this study was to determine the best pitfall trapping design for collecting ground-dwelling arthropods in the wind-blown and cold arid steppe areas of Patagonia. We tested four designs of traps, six types of preservative and different times of activation as well as the quantity of traps. Both preservation attributes and sampling efficiency differed between different trap designs and fluids compared. We conclude that in order to obtain reliable data on the structure of a community of ground-dwelling arthropods in Patagonia, at least three pitfall traps per experimental unit are required. In addition, traps should be opened for a minimum of 10 days filled with 300 ml of 30% ethylene glycol. We also suggested the use of a simple trap design (i. e. without funnel or roof). We believe these findings will contribute to more appropriate sampling of the ground dwelling fauna of Patagonia as well as other arid areas, leading to more reliable diversity studies.EEA BarilocheFil: Cheli, German Horacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico; ArgentinaFil: Corley, Juan Carlos. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Grupo de Ecología de Poblaciones de Insectos; Argentin

Life history traits of Sirex noctilio F. (Hymenoptera: Siricidae) can explain outbreaks independently of environmental factors

The woodwasp Sirex noctilio is a major pest of pine plantations worldwide. Economically significant damage is however limited to outbreak populations. To understand what determines outbreaks dynamics in this species, we developed an individual based model for a wasp population developing within a pine plantation. We show that outbreaks may be the result of the insect's life history. Specifically we show that limited dispersal may not only increase population persistence but also create the conditions for eruptive dynamics. When the probability of long distance dispersal is greater than zero, but relatively small (PLDD= 0.1) large outbreaks are the norm, with all of the suitable trees dead at the end of the simulation. For PLDD= 0 (only local dispersal allowed) outbreaks are smaller in size, and in some cases not well defined and spread over longer periods. For PLDD= 1 (only long distance dispersal allowed), the frequency of local population extinction (without outbreaks) increases significantly. Aggregated attacks may induce physiological changes in the trees which could allow other wasps to detect them. These changes may in turn trigger an outbreak. In contrast, healthy, vigorous trees are not suitable for wasp oviposition. In our model the density of suitable trees (healthy trees but yet suitable for oviposition) are a key factor determining population persistence before outbreaks. From an applied perspective, our results emphasize the importance of adequate plantation management in preventing woodwasp infestation.Centro de Estudios Parasitológicos y de Vectore

Life history traits of Sirex noctilio F. (Hymenoptera: Siricidae) can explain outbreaks independently of environmental factors

The woodwasp Sirex noctilio is a major pest of pine plantations worldwide. Economically significant damage is however limited to outbreak populations. To understand what determines outbreaks dynamics in this species, we developed an individual based model for a wasp population developing within a pine plantation. We show that outbreaks may be the result of the insect's life history. Specifically we show that limited dispersal may not only increase population persistence but also create the conditions for eruptive dynamics. When the probability of long distance dispersal is greater than zero, but relatively small (PLDD= 0.1) large outbreaks are the norm, with all of the suitable trees dead at the end of the simulation. For PLDD= 0 (only local dispersal allowed) outbreaks are smaller in size, and in some cases not well defined and spread over longer periods. For PLDD= 1 (only long distance dispersal allowed), the frequency of local population extinction (without outbreaks) increases significantly. Aggregated attacks may induce physiological changes in the trees which could allow other wasps to detect them. These changes may in turn trigger an outbreak. In contrast, healthy, vigorous trees are not suitable for wasp oviposition. In our model the density of suitable trees (healthy trees but yet suitable for oviposition) are a key factor determining population persistence before outbreaks. From an applied perspective, our results emphasize the importance of adequate plantation management in preventing woodwasp infestation.Centro de Estudios Parasitológicos y de Vectore

Factores que afectan el éxito de las agallas de Aditrochus coihuensis (Hymenoptera: Pteromalidae)

Galls of Aditrochus coihuensis (Hymenoptera: Pteromalidae) were collected from their host tree, the southern beech Nothofagus dombeyi, near San Carlos de Bariloche, Argentina, during the spring of 2007. Galls were carefully examined and classifi ed as successful or unsuccessful based on insect remains and emergence-hole diameter. Gall properties (diameter, wall thickness, chamber diameter, wall toughness) were measured and compared between successful galls and unsuccessful (parasitized) galls. Gall diameter and wall thickness were strongly correlated and thick walls seem to function as a protection against parasitoids. Parasitoids (Torymidae) that were found within some galls had an ovipositor length shorter than wall thickness of fully developed galls. Most likely, parasitoids attack galls only during a limited time when the wall is thin enough. Wall toughness did not seem to infl uence gall success. In total 67% of the galls suffered from parasitoids. Inquilines (Curculionidae) were found within some gall walls, with preference for larger galls and for those with thicker walls. Traces of potential bird or wasp predation were also found in a few specimens. Our present fi ndings contribute original descriptive information on these galls. Overall, our results lend further support on the potential importance of natural enemies on gall evolution.Agallas provocadas por Aditrochus coihuensis (Hymenoptera: Pteromalidae) sobre su hospedero, Nothofagus dombeyi, fueron colectadas en la vecindad de San Carlos de Bariloche, Argentina, durante la primavera de 2007. Las mismas fueron examinadas y clasificadas como exitosas o no, sobre la base de restos de insectos dentro de ellas y el diámetro del agujero de emergencia. Distintas propiedades de las agallas (diámetro, grosor y dureza de la pared y diámetro de la cámara) fueron medidas y comparadas como exitosas y no exitosas (parasitadas). El diámetro de las agallas tuvo una fuerte correlación con el grosor de la pared, variable que se asocia con la protección contra los parasitoides. Los parasitoides (Torymidae), que fueron hallados dentro de las agallas, poseen un ovipositor más corto que el grosor de las paredes en aquellas plenamente desarrolladas. Sin embargo, es posible que los parasitoides ataquen las agallas por una ventana temporal, cuando las paredes son aún delgadas. La dureza de las mismas, por su parte, no influyó sobre el éxito de las agallas. También, se hallaron inquilinos (Curculionidae) dentro de ellas, en mayor frecuencia en las de mayor tamaño y con paredes más gruesas. Finalmente, se observaron evidencias de depredación, posiblemente por aves o avispas.Fil: Nilsson, Michael . Lund University; SueciaFil: Corley, Juan Carlos. Instituto Nacional de Tecnologia Agropecuaria. Centro Reg.patagonia Norte. Estacion Exptal.agrop.s.c.de Bariloche. Laboratorio de Ecologia de Insectos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Anderbrant, Olle . Lund University; Sueci

Non-native wasps in Patagonia: the importance of Invasion Ecology in pest management

El manejo integrado de plagas (MIP) se basa en el conocimiento de la ecología de las especies problema. Se ha sugerido que cuando las plagas son especies invasoras, la comprensión del proceso de invasión puede mejorar aun más nuestra capacidad de control de las plagas. Nuestro objetivo es revisar algunos atributos claves de la ecología y el comportamiento en el proceso de invasión de la avispa de los pinos Sirex noctilio y de la avispa chaqueta amarilla Vespula germanica, y discutir sus implicancias sobre las acciones de manejo implementadas en el N.O. de la Patagonia Argentina. Investigaciones previas identificaron los factores determinantes del éxito de invasión, como la demografía, los atributos de la comunidad receptora y el papel de los disturbios, tanto para estas especies invasoras como para otras. Aquí ampliamos ese conocimiento y nos enfocamos en aquellos aspectos ecológicos y de conducta característicos de las distintas etapas del proceso de invasión. Mientras las acciones de control para la avispa de los pinos tuvieron carácter regional y forman parte de un plan de manejo establecido, para la chaqueta amarilla las medidas fueron de carácter local y sin coordinación espacio-temporal. En ambos casos, y pese a las acciones ejecutadas, las especies avanzaron geográficamente, se establecieron con éxito y generaron impactos importantes en nuevas áreas. Sugerimos que los limitados alcances en términos de eficiencia de control de las poblaciones son, en parte, consecuencia de acciones diseñadas e implementadas con una escasa contemplación de los atributos ecológicos y comportamentales clave de estas especies.Integrated pest management (IPM) relies on thorough ecological knowledge of the targeted pests. It has been suggested that when these are non-native species, information on their invasion ecology could improve our abilities to successfully manage pest populations. Our aim is to revise the invasion history of two exotic wasps that have invaded NW Patagonia, and critically review control actions that have been and are implemented to manage their populations. Some critical factor affecting invasion success of the wood-wasp Sirex noctilio and the German wasp Vespula germanica have been previously investigated. Here, we extend such work, and focus on those ecological and behavioural aspects, relevant to each of the different stages of the invasion process. While most activities carried out to manage woodwasp populations are held at a regional level (covering the invaded habitats) and as part of specific management plan for the German wasp, actions are local and lack any spatial or temporal coordination. In both cases, despite the control activities implemented, regional spreads of the species have increased and populations established in new areas. We suggest that the limited success in control of these wasps could have been circumvented by considering both species not only as pests but as successful invaders.Fil: Villacide, José María. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche; ArgentinaFil: Masciocchi, Maité. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Corley, Juan Carlos. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Foraging behavior interactions between two non-native social wasps, Vespula germanica and V. vulgaris (Hymenoptera: Vespidae) : implications for invasion success?

Vespula vulgaris is an invasive scavenging social wasp that has very recently arrived in Patagonia (Argentina), a territory previously invaded – 35 yrs earlier – by another wasp, Vespula germanica. Although V. vulgaris wasps possess features that could be instrumental in overcoming obstacles through several invasion stages, the presence of preestablished populations of V. germanica could affect their success. We studied the potential role played by V. germanica on the subsequent invasion process of V. vulgaris wasps in Patagonia by focusing on the foraging interaction between both species. This is because food searching and exploitation are likely to overlap strongly among Vespula wasps. We carried out choice tests where two types of baits were presented in a pairwise manner. We found experimental evidence supporting the hypothesis that V. germanica and V. vulgaris have an asymmetrical response to baits with stimuli simulating the presence of each other. V. germanica avoided baits with either visual or olfactory cues indicating the V. vulgaris presence. However, V. vulgaris showed no preference between baits with or lacking V. germanica stimuli. These results suggest that the presence of an established population of V. germanica may not contribute to added biotic resistance to V. vulgaris invasionFil: Pereira, Ana Julia. Consejo Nacional de Investigaciones Científicas y Técnicas-Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Grupo de Ecología de Poblaciones de Insectos; ArgentinaFil: Pirk, Gabriela I. Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad del Comahue. INIBIOMA. Laboratorio de Ecotono; ArgentinaFil: Corley, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas-Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Grupo de Ecología de Poblaciones de Insectos; Argentin

Fivebranes from gauge theory

We study theories with sixteen supercharges and a discrete energy spectrum. One class of theories has symmetry group $SU(2|4)$. They arise as truncations of ${\cal N}=4$ super Yang Mills. They include the plane wave matrix model, 2+1 super Yang Mills on $R \times S^2$ and ${\cal N}=4$ super Yang Mills on $R \times S^3/Z_k$. We explain how to obtain their gravity duals in a unified way. We explore the regions of the geometry that are relevant for the study of some 1/2 BPS and near BPS states. This leads to a class of two dimensional (4,4) supersymmetric sigma models with non-zero $H$ flux, including a massive deformed WZW model. We show how to match some features of the string spectrum with the Yang Mills theory. The other class of theories are also connected to ${\cal N}=4$ super Yang Mills and arise by making some of the transverse scalars compact. Their vacua are characterized by a 2d Yang Mills theory or 3d Chern Simons theory. These theories realize peculiar superpoincare symmetry algebras in 2+1 or 1+1 dimensions with "non-central" charges. We finally discuss gravity duals of ${\cal N}=4$ super Yang Mills on $AdS_3 \times S^1$.Comment: 50+24 pages, 9 figures, latex. v2: typos corrected, references adde

First record of Vespula vulgaris (Hymenoptera: Vespidae) in Argentina

Vespula vulgaris (Linnaeus) es un véspido social nativo de la región Holártica. En este trabajo reportamos la primera detección de esta especie en Argentina. Obreras de esta avispa fueron capturadas cerca de la ciudad de San Carlos de Bariloche (Argentina) en Febrero de 2010, mientras se tomaban muestras de otra avispa invasora, Vespula germanica (Fabricius) o chaqueta amarilla, de morfología externa y hábitos similares a la anteriormente mencionada. Además, detallamos algunos caracteres de identificación y características biológicas.Vespula vulgaris (Linnaeus) is a social vespid native to the Holarctic region. The first detection of this species in Argentina is here reported. Workers were captured close to San Carlos de Bariloche (Argentina) during February 2010, while sampling for another successful invader, the German wasp or Yellowjacket, Vespula germanica (Fabricius). Both these wasp species are very similar morphologically and share a number of common habits. Also, some identification features and biological characters are here explained .Fil: Masciocchi, Maité. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnologia Agropecuaria. Centro Reg.patagonia Norte. Estacion Exptal.agrop.s.c.de Bariloche. Laboratorio de Ecologia de Insectos; ArgentinaFil: Beggs, Jacqueline R.. The University Of Auckland; Nueva ZelandaFil: Carpenter, James M.. American Museum Of Natural History; Estados UnidosFil: Corley, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnologia Agropecuaria. Centro Reg.patagonia Norte. Estacion Exptal.agrop.s.c.de Bariloche. Laboratorio de Ecologia de Insectos; Argentin

Revisiting pre-trained remote sensing model benchmarks: resizing and normalization matters

Research in self-supervised learning (SSL) with natural images has progressed rapidly in recent years and is now increasingly being applied to and benchmarked with datasets containing remotely sensed imagery. A common benchmark case is to evaluate SSL pre-trained model embeddings on datasets of remotely sensed imagery with small patch sizes, e.g., 32x32 pixels, whereas standard SSL pre-training takes place with larger patch sizes, e.g., 224x224. Furthermore, pre-training methods tend to use different image normalization preprocessing steps depending on the dataset. In this paper, we show, across seven satellite and aerial imagery datasets of varying resolution, that by simply following the preprocessing steps used in pre-training (precisely, image sizing and normalization methods), one can achieve significant performance improvements when evaluating the extracted features on downstream tasks -- an important detail overlooked in previous work in this space. We show that by following these steps, ImageNet pre-training remains a competitive baseline for satellite imagery based transfer learning tasks -- for example we find that these steps give +32.28 to overall accuracy on the So2Sat random split dataset and +11.16 on the EuroSAT dataset. Finally, we report comprehensive benchmark results with a variety of simple baseline methods for each of the seven datasets, forming an initial benchmark suite for remote sensing imagery

El Mes de la Entomología: acercando el laboratorio de investigación científica a las escuelas de nivel inicial de la Patagonia

Como investigadores en ciencias, entendemos que enseñar las ciencias naturales en la escuela primaria es un desafío para los docentes y una excelente oportunidad para sentar las bases del pensamiento científico. “El Mes de la Entomología” fue un proyecto llevado a cabo por investigadores y becarios del CONICET y del INTA Bariloche, cuyo objetivo principal fue mejorar el conocimiento existente sobre la biología de los insectos, de docentes y estudiantes de nivel primario de escuelas de Bariloche y escuelas rurales del NO de la Patagonia. Se resaltaron los aspectos positivos de los insectos, destacando tanto su importancia biológica y aplicada así como su diversidad y abundancia. Participaron un total de 12 escuelas de las 55 invitadas (entre privadas y públicas) y 600 estudiantes. “El Mes de la Entomología” fue una actividad que además sirvió tanto para explorar problemáticas científicas locales, como para acercar la figura del científico a los docentes y estudiantes.As science researchers we believe that teaching Natural Sciences at elementary school level is both a challenge for teachers and an excellent opportunity to establish the foundations of scientific thinking. “The Entomology Month” was a project, carried out by researchers and scholars from CONICET and INTA Bariloche, whose main objective was to improve the existing knowledge about insect biology. Activities were addressed to teachers and elementary school students from Bariloche and rural areas in NW Patagonia. The positive aspects of insects were especially highlighted, by enhancing their biological and applied importance, as well as their diversity and abundance. Twelve out of the 55 invited schools (both private and public) and 600 students were counted among the participants. The “Entomology Month” served both to address local scientist difficulties and to bring closer the figure of the scientist to teachers and students.Fil: Fischbein, Deborah. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche. Laboratorio de Ecología de Insectos; ArgentinaFil: Pereira, Ana Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche. Laboratorio de Ecología de Insectos; ArgentinaFil: Fernandez Ajó, Alejandro Apolo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche. Laboratorio de Ecología de Insectos; ArgentinaFil: Corley, Juan Carlos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche. Laboratorio de Ecología de Insectos; Argentin