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Nancy E. Mathews - One of the best experts on this subject based on the ideXlab platform.
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costs of multiple Parasitism for an avian brood parasite the brown headed cowbird molothrus ater
Canadian Journal of Zoology, 2011Co-Authors: Christopher B. Goguen, David R. Curson, Nancy E. MathewsAbstract:The Brown-headed Cowbird (Molothrus ater (Boddaert, 1783)) is a generalist brood parasite that often lays into nests that contain conspecific eggs. Although it has often been assumed that this multiple Parasitism reduces Cowbird sur- vival, this has rarely been evaluated. We measured Cowbird survival in nests of the Blue-gray Gnatcatcher (Polioptila caeru- lea (L., 1766)), Plumbeous Vireo (Vireo plumbeus Coues, 1866), and Western Tanager (Piranga ludoviciana (A. Wilson, 1811)) in New Mexico, USA. Our objectives were to measure the costs of intraspecific competition on Cowbird survival in multiply-parasitized nests, evaluate if these costs were related to host size, and to compare the costs of multiple Parasitism relative to other mortality sources that occur over the entire nesting cycle. Intraspecific competition reduced Cowbird sur- vival during the nestling period in nests of all three hosts, and was of particular importance in nests of the two smaller hosts. When all sources of egg mortality were considered, however, the costs of multiple Parasitism were small compared with the large effects of predation and nest desertion. Given that multiple Parasitism reduces Cowbird egg survival, it is un- clear why Cowbirds multiply-parasitize. Possible explanations depend on an improved understanding of fecundity and level of host nest selectivity by female Cowbirds. Resume : Le vacher a tete brune (Molothrus ater (Boddaert, 1783)) est un parasite generaliste des couvees qui pond sou- vent dans des nids qui contiennent des œufs de sa propre espece. Bien qu'on ait souvent presume que ce Parasitisme multi- ple reduit la survie des vachers, on a rarement evalue la situation. Nous avons mesure la survie des vachers dans des nids du gobemoucheron gris-bleu (Polioptila caerulea (L., 1766)), du vireo plombe (Vireo plumbeus Coues, 1866) et du tangara a tete rouge (Piranga ludoviciana (A. Wilson, 1811)) au Nouveau-Mexique, E.-U. Notre objectif est de mesurer le cout de la competition intraspecifique sur la survie des vachers dans des nids a Parasitisme multiple, d'evaluer si ces couts sont re- lies a la taille de l'hote et de comparer les couts du Parasitisme multiple aux autres sources de mortalite qui se produisent au cours de l'ensemble du cycle de nidification. La competition intraspecifique reduit la survie des vachers durant la periode de nidification dans les nids des trois hotes et est d'importance particuliere surtout dans les nids des deux hotes plus petits. Lorsqu'on tient compte de toutes les sources de mortalite des œufs, les couts du Parasitisme multiple sont faibles par rapport aux grands effets de la predation et de l'abandon des nids. Puisque le Parasitisme multiple reduit la survie des œufs des va- chers, il n'est pas clair pourquoi les vachers pratiquent le Parasitisme multiple. Les explications possibles requierent une meilleure comprehension de la fecondite et du niveau de selection des nids des hotes chez les vachers femelles. (Traduit par la Redaction)
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local gradients of cowbird abundance and Parasitism relative to livestock grazing in a western landscape
Conservation Biology, 2000Co-Authors: Christopher B. Goguen, Nancy E. MathewsAbstract:: We studied local patterns of Brown-headed Cowbird (Molothrus ater) abundance, Parasitism rates, and nest success of a common host, the Plumbeous Vireo (Vireo plumbeus), in relation to the distribution of livestock grazing in an undeveloped region of northeastern New Mexico, 1992–1997. We predicted that both cowbird abundance and Parasitism rates of vireo nests would decrease with increasing distance from active livestock grazing, and that the nesting success of vireos would increase. We measured cowbird abundance and host density and located and monitored vireo nests in pinyon-juniper and mixed-conifer habitats that ranged from actively grazed to isolated from livestock grazing by up to 12 km. Cowbird abundance declined with distance from active livestock grazing and was not related to host density or habitat type. Brood Parasitism levels of vireo nests (n = 182) decreased from> 80% in actively grazed habitats to 33% in habitats that were 8–12 km from active grazing but did not vary by habitat type or distance to forest edge. Vireo nesting success was higher in mixed-conifer habitat than in pinyon-juniper but was unrelated to distance from active livestock grazing. Nest losses due to Parasitism declined with distance from active livestock grazing. Our results suggest that cowbird abundance and Parasitism rates of hosts may be distributed as a declining gradient based on distance from cowbird feeding sites and that isolation from feeding sites can reduce the effects of Parasitism on host populations. These findings provide support for management techniques that propose to reduce local cowbird numbers and Parasitism levels by manipulating the distribution of cowbird feeding sites. The presence of parasitized nests> 8 km from active livestock grazing suggests that, in some regions, management efforts may need to occur at larger scales than previously realized. Resumen: Estudiamos patrones locales de abundancia del tordo cabeza cafe (Molothrus ater), las tasas de Parasitismo y el exito de nidada de un hospedero comun, el vireo (Vireo plumbeus), en relacion con la distribucion del pastoreo en una region poco desarrollada del noreste de Nuevo Mexico, entre 1992 y 1997. Pronosticamos que tanto la abundancia del tordo, como las tasas de Parasitismo de nidos de vireo disminuirian con un incremento en la distancia a las zonas de pastoreo activo de ganado y el exito de nidada de vireos incrementaria. Medimos la abundancia de tordos y la densidad de hospederos y localizamos y monitoreamos los nidos de vireos en habitats de pino-cedro y de coniferas mixtas que variaron desde activamente pastoreadas hasta sitios distanciados del pastoreo hasta por 12 km. La abundancia de los tordos disminuyo con la distancia de las zonas de pastoreo activo de ganado y no estuvo relacionada con la densidad de hospederos o el tipo de habitat. Los niveles de Parasitismo de las nidadas del vireo (n = 182) disminuyeron de> 80% en habitats activamente pastoreados a 33% en habitats que estuvieron de 8 a 12 km de distancia de los sitios de pastoreo activo, pero no variaron con el tipo de habitat ni la distancia al borde del bosque. El exito de nidada de vireos fue mayor en el habitat mixto de coniferas que en el habitat de pino-cedro, pero no estuvo relacionado con la distancia al sitio de pastoreo. Las perdidas debidas al Parasitismo disminuyeron con la distancia al sitio activo de pastoreo. Nuestros resultados sugieren que la abundancia de tordos y las tasas de Parasitismo de hospederos podria estar distribuida en forma de un gradiente en descenso basado en la distancia a los sitios de alimentacion de los tordos y a que el aislamiento de los sitios de alimentacion puede reducir los efectos del Parasitismo de las poblaciones de hospederos. Estos resultados apoyan las tecnicas de manejo que proponen la reduccion local de numeros de tordos y los niveles de Parasitismo al manipular la distribucion de sitios de alimentacion de tordos. La presencia de nidos parasitados> 8 km de sitios con pastoreo activo sugiere que, en algunas regiones, los esfuerzos de manejo deben ocurrir a escalas mayores a lo que anteriormente se pensaba.
David A Cimprich - One of the best experts on this subject based on the ideXlab platform.
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dependence of the endangered black capped vireo on sustained cowbird management
Conservation Biology, 2014Co-Authors: Chad B Wilsey, Joshua J Lawler, David A Cimprich, Nathan H SchumakerAbstract:Conservation-reliant species depend on active management, even after surpassing recovery goals, for protection from persistent threats. Required management may include control of another species, habitat maintenance, or artificial recruitment. Sometimes, it can be difficult to determine whether sustained management is required. We used nonspatial stochastic population projection matrix simulation and a spatially explicit population model to estimate the effects of Parasitism by a brood parasite, the Brown-headed Cowbird (Moluthrus ater), on a population of endangered Black-capped Vireos (Vireo atricapilla). We simulated Parasitism as a percentage of breeding vireo pairs experiencing decreased fecundity due to cowbirds. We estimated maximum sustainable Parasitism (i.e., highest percentage of parasitized vireo breeding pairs for which population growth is ≥1) with the nonspatial model under multiple scenarios designed to assess sensitivity to assumptions about population growth rate, demographic effects of Parasitism, and spatial distribution of Parasitism. We then used the spatially explicit model to estimate cumulative probabilities of the population falling below the population recovery target of 1000 breeding pairs for a range of Parasitism rates under multiple scenarios. We constructed our models from data on vireos collected on the Fort Hood Military Reservation, Texas (U.S.A.). Estimates of maximum sustainable Parasitism rates ranged from 9–12% in scenarios with a low (6%) vireo population growth rate to 49–60% in scenarios with a high (24%) growth rate. Sustained Parasitism above 45–85%, depending on the scenario, would likely result in the Fort Hood Vireo population dropping below its recovery goal within the next 25 years. These estimates suggest that vireos, although tolerant of low Parasitism rates, are a conservation-reliant species dependent on cowbird management. Dependencia de Vireo atricapilla, Especie en Peligro, hacia el Manejo Sostenido de Moluthurs ater Resumen Las especies dependientes de la conservacion dependen del manejo activo, incluso despues de obtener las metas de recuperacion, para la proteccion de amenazas persistentes. El manejo requerido puede incluir el control de otra especie, el mantenimiento del habitat o el reclutamiento artificial. Algunas veces puede ser dificil determinar si un manejo sostenido es requerido. Usamos una simulacion de matriz de proyeccion de poblacion estocastica y no espacial y un modelo de poblacion espacialmente explicito para estimar los efectos del Parasitismo por una especie parasita de reproduccion, Moluthrus ater, sobre una poblacion de la especie en peligro Vireo atricapilla. Simulamos el Parasitismo como un porcentaje de parejas de vireos que experimentan fertilidad baja debido a los M. ater. Estimamos el maximo Parasitismo sostenible (p. ej.: el porcentaje mas alto de parejas reproductivas parasitadas para las cuales el crecimiento poblacional es ≥1) con el modelo no espacial bajo escenarios multiples asignados para estudiar la sensibilidad a los supuestos sobre la tasa de crecimiento poblacional, los efectos demograficos del Parasitismo y la distribucion espacial del Parasitismo. Despues utilizamos el modelo espacialmente explicito para estimar las probabilidades acumulativas de que la poblacion cayera por debajo del objetivo de recuperacion de 1000 parejas reproductivas para un rango de tasas de Parasitismo bajo escenarios multiples. Construimos nuestros modelos a partir de datos de vireos colectados en la Reservacion Militar Fort Hood, Texas (E.U.A.). Los estimados de la tasa de Parasitismo maximo sostenible abarcaron desde 9–12% en escenarios con una tasa baja de crecimiento poblacional (6%) de vireos hasta 49–60% en escenarios con una tasa alta de crecimiento (24%). El Parasitismo sostenido por encima del 45–85%, dependiendo del escenario, probablemente resultaria en la poblacion de vireos de Fort Hood disminuyendo por debajo de su objetivo de recuperacion dentro de los siguientes 25 anos. Estos estimados sugieren que los vireos, aunque tolerantes a las tasas bajas de Parasitismo, son una especie cuya conservacion depende del manejo de M. ater.
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effects of brown headed cowbird molothrus ater removal on black capped vireo vireo atricapilla nest success and population growth at fort hood texas
Ornithological Monographs, 2005Co-Authors: Richard M Kostecke, Scott G Summers, Gilbert H Eckrich, David A CimprichAbstract:In 1988 at Fort Hood, Texas, after high Parasitism (up to 91%) of the endangered Black-capped Vireo (Vireo atricapilla) by Brown-headed Cowbirds (Molothrus ater) and associated low nest success (<5%), a cowbird control program was implemented. We review and re-assess data related to that program and provide an update on control efforts. Initial control efforts were beneficial but limited. With onset of more intensive control efforts in 1991, Parasitism fell below 20%, and Black-capped Vireo nest success rose above 20%. Number of Blackcapped Vireo pairs within three study areas at Fort Hood also increased over time. Parasitism and Black-capped Vireo nest success varied with management (i.e. different combinations of trapping, shooting, and cattle grazing) across regions of Fort Hood, but generally decreased and increased, respectively, over time. Because removal techniques were applied simultaneously, it is difficult to determine the magnitude of effect that individual techniques had on Parasitism and Black-capped Vireo nest success. A reduction in cattle stocking rate on the East Range of Fort Hood appeared to reduce Parasitism during 1997-1998. However, an earlier cattle removal on West Fort Hood had no apparent effect on Parasitism. We attribute reductions in Parasitism on West Fort Hood primarily to shooting, because trapping efforts there have been minimal. Fort Hood currently meets both local and regional recovery goals for the Blackcapped Vireo. We attribute success in meeting those goals primarily to cowbird control. Resumen. En 1988 en Fort Hood, Texas luego de detectar un alto Parasitismo (mas del 91%) de Vireo atricapilla por parte de Molothrus ater asociado a un bajo exito de nidificacion (<5%), se aplico un programa de control de Molothus ater. Aqui revisamos y reevaluamos los datos relativos a aquel programa y proveemos una actualization sobre la eficacia del control. La eficacia de control inicial fue benefica pero limitada. Con el inicio de esfuerzos de control mas intensos en 1991, el Parasitismo cayo por debajo del 20%, y el exito de nidificacion de Vireo atricapilla se elevo a mas del 20 %. El numero de parejas de Vireo atricapilla en tres sitios de estudio dentro de Fort Hood tambien se incremento a lo largo del tiempo. Tanto el Parasitismo como el exito de nidificacion de Vireo atricapilla variaron con el tipo de manejo (e.j. diferentes combinaciones de trampeo, caza con armas de fuego, y pastoreo de ganado) entre regiones de Fort Hood. En general, el Parasitismo disminuyo y el exito de nidificacion se incremento a lo largo del tiempo. Debido a que las tecnicas de remocion de Molothrus ater fueron aplicadas simultaneamente, es dificil determinar la magnitud del efecto individual de cada una sobre las tasas de Parasitismo y el exito de nidificacion de Vireo. atricapilla. Una reduction en la carga ganadera en el rango este de Fort Hood aparentemente redujo el Parasitismo durante 1997-1998. Sin embargo, una remocion de ganado mas temprana en el oeste de Fort Wood no tuvo efecto aparente sobre el Parasitismo. Nosotros atribuimos las reducciones en Parasitismo en el este de Fort Wood primariamente a la caza con armas de fuego, ya que el esfuerzo de trampeo en dicha area fue minimo. Fort Hood actualmente cumple tanto con las metas locales y regionales de recuperation de Vireo atricapilla. Nosostros consideramos que el exito logrado en el cumplimento de dichas metas es debido principalmente al control de Molothrus ater. 3E-mail: rkostecke@tnc.org
José Nilton Costa - One of the best experts on this subject based on the ideXlab platform.
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Parasitismo na população da broca-do-café Hypothenemus hampei (Ferrari) (Coleoptera: Scolytidae), pelo parasitoide Cephalonomia stephanoderis Betrem (Hymenoptera: Bethylidae)
Entomologistas do Brasil, 2014Co-Authors: Moisés De Souza, C. A. D. Teixeira, Alexandre Silva, José Nilton CostaAbstract:A broca-do-café, Hypothenemus hampei (Ferrari) é responsável por grandes prejuízos em plantios de café, causando perdas de produtividade aos cafeicultores e danos quantitativos e qualitativos aos grãos. O controle biológico da praga tem sido principalmente à base de fungos entomopatogênicos. Em Rondônia, Brasil, as informações acerca dos parasitoides de H. hampei são escassas. O parasitoide Cephalonomia stephanoderis Betrem é um inimigo natural da broca do café e já é utilizado como agente de controle biológico em países da África e da América Latina. Constatou-se a presença desse parasitoide em cafezais de Rondônia. O objetivo do presente estudo foi investigar os níveis de ocorrência e Parasitismo do parasitóide em uma plantação de café no município de Ouro Preto D’Oeste, Estado de Rondônia. Foram analisados semanalmente frutos de café coletados diretamente das plantas e caídos sobre o solo, de janeiro a dezembro de 2004. Observou-se a ocorrência do parasitoide durante os meses de maior infestação da praga. Durante o período estudado, a taxa de Parasitismo nos diferentes microambientes variou de 2 a 24%. Parasitism in the Population of the Coffee Berry Borer Hypothenemus hampei (Ferrari) (Coleoptera: Scolytidae) by the Parasitoid Cephalonomia stephanoderis Betrem (Hymenoptera: Bethylidae) Abstract. The coffee berry borer, Hypothenemus hampei (Ferrari) attacks coffee plantations, greatly decreasing the production of coffee plants, causing quantitative and qualitative damage to the grains. Biological control of this pest has focused mostly on entomopathogenic fungi. In the state of Rondonia, studies on Parasitism levels of the parasitoids of H. hampei are scarce. The parasitoid Cephalonomia stephanoderis Betrem is a natural enemy of the coffee berry borer and is already used as an agent of biological control in countries of Africa and Latin America. The objective of the present study was to investigate the occurrence and Parasitism levels of the parasitoid in a coffee plantation in the municipality of Ouro Preto D’Oeste, State of Rondonia. Coffee beans collected directly from the plants and on the ground were analyzed weekly from January to December 2004. Parasitoid occurred in months of the highest pest infestation. During the studied period, Parasitism rate in different microenvironments ranged from 2 to 24%
Iede, Edson Tadeu - One of the best experts on this subject based on the ideXlab platform.
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Use of sequential sampling to evaluate the efficiency of Deladenus (Beddingia) siricidicola (Nematoda: Neotylenchidae) Parasitism on Sirex noctilio adults (Hymenoptera: Siricidae)
Centro de Pesquisas Florestais - CEPEF Departamento de Ciências Florestais - DCFL Programa de Pós Graduação em Engenharia Florestal - PPGEF, 2009Co-Authors: Penteado, Susete Do Rocio Chiarello, De Oliveira, Edílson Batista, Iede, Edson TadeuAbstract:O nematóide Deladenus (Beddingia) siricidicola (Nematoda: Neotylenchidae) é o principal agente de controle de Sirex noctilio (Hymenoptera: Siricidae), vespa-da-madeira. ao esterilizar as fêmeas do inseto, atinge níveis de Parasitismo próximos a 100%, com média de 70%. o monitoramento da eficiência do nematóide tem sido realizado pela avaliação da sua presença no aparelho reprodutor de machos e fêmeas do inseto. porém, esse processo é exaustivo e antieconômico quando aplicado a amostras muito grandes. o objetivo desta pesquisa foi testar a técnica da amostragem seqüencial para avaliação da eficiência do Parasitismo de Deladenus (Beddingia) siricidicola em adultos de Sirex noctilio, a qual se mostrou como uma alternativa viável, pois se baseia em um tamanho variável de amostra, definido em função dos resultados obtidos durante os levantamentos amostrais, resultando em redução do tamanho da amostra, dos custos da atividade e precisão nos resultados. foram também abordados aspectos do Parasitismo por Deladenus (Beddingia) siricidicola.The nematode Deladenus (Beddingia) siricidicola (Nematoda: Neotylenchidae) is the main control agent of the woodwasp Sirex noctilio (Hymenoptera: Siricidae). It acts by female sterilization and reaches Parasitism levels close to 100%, averaging 70%. The monitoring of the efficiency of this nematode Parasitism has been done by evaluating the presence of the worm in the reproductive apparatus of male and female wasps, but this process is time consuming and expensive when applied to large samples. The objective of this research was to apply the sequential sampling which has proved to be a viable alternative to evaluate the efficiency of the Parasitism of Deladenus (Beddingia) siricidicola on Sirex noctilio. It is based on a variable sample size that is defined in function of the results obtained from the survey, reducing the costs of sampling and obtaining a satisfactory precision level. Some aspects of Parasitism by Deladenus (Beddingia) siricidicola are addressed
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Utilização da amostragem seqüencial para avaliar a eficiência do Parasitismo de Deladenus (Beddingia) siricidicola (Nematoda: Neotylenchidae) em adultos de Sirex noctilio (Hymenoptera: Siricidae).
'Universidad Federal de Santa Maria', 2008Co-Authors: Penteado, Susete Do Rocio Chiarello, Edilson Batista De Oliveira, Iede, Edson TadeuAbstract:The nematode Deladenus (Beddingia) siricidicola (Nematoda: Neotylenchidae) is the main control agent of the woodwasp Sirex noctilio (Hymenoptera: Siricidae). It acts by female sterilization and reaches Parasitism levels close to 100%, averaging 70%. The monitoring of the efficiency of this nematode Parasitism has been done by evaluating the presence of the worm in the reproductive apparatus of male and female wasps, but this process is time consuming and expensive when applied to large samples. The objective of this research was to apply the sequential sampling which has proved to be a viable alternative to evaluate the efficiency of the Parasitism of Deladenus (Beddingia) siricidicola on Sirex noctilio. It is based on a variable sample size that is defined in function of the results obtained from the survey, reducing the costs of sampling and obtaining a satisfactory precision level. Some aspects of Parasitism by Deladenus (Beddingia) siricidicola are addressed.O nematóide Deladenus (Beddingia) siricidicola (Nematoda: Neotylenchidae) é o principal agente de controle de Sirex noctilio (Hymenoptera: Siricidae), vespa-da-madeira. ao esterilizar as fêmeas do inseto, atinge níveis de Parasitismo próximos a 100%, com média de 70%. o monitoramento da eficiência do nematóide tem sido realizado pela avaliação da sua presença no aparelho reprodutor de machos e fêmeas do inseto. porém, esse processo é exaustivo e antieconômico quando aplicado a amostras muito grandes. o objetivo desta pesquisa foi testar a técnica da amostragem seqüencial para avaliação da eficiência do Parasitismo de Deladenus (Beddingia) siricidicola em adultos de Sirex noctilio, a qual se mostrou como uma alternativa viável, pois se baseia em um tamanho variável de amostra, definido em função dos resultados obtidos durante os levantamentos amostrais, resultando em redução do tamanho da amostra, dos custos da atividade e precisão nos resultados. foram também abordados aspectos do Parasitismo por Deladenus (Beddingia) siricidicola
Costa, José Nilton Medeiros - One of the best experts on this subject based on the ideXlab platform.
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Parasitismo na população da broca-do-café Hypothenemus hampei (Ferrari) (Coleoptera: Scolytidae), pelo parasitoide Cephalonomia stephanoderis Betrem (Hymenoptera: Bethylidae)
Entomologistas do Brasil, 2014Co-Authors: De Souza, Moisés Santos, Silva, Alexandre Almeida E, Teixeira, César Augusto Domingues, Costa, José Nilton MedeirosAbstract:A broca-do-café, Hypothenemus hampei (Ferrari) é responsável por grandes prejuízos em plantios de café, causando perdas de produtividade aos cafeicultores e danos quantitativos e qualitativos aos grãos. O controle biológico da praga tem sido principalmente à base de fungos entomopatogênicos. Em Rondônia, Brasil, as informações acerca dos parasitoides de H. hampei são escassas. O parasitoide Cephalonomia stephanoderis Betrem é um inimigo natural da broca do café e já é utilizado como agente de controle biológico em países da África e da América Latina. Constatou-se a presença desse parasitoide em cafezais de Rondônia. O objetivo do presente estudo foi investigar os níveis de ocorrência e Parasitismo do parasitóide em uma plantação de café no município de Ouro Preto D’Oeste, Estado de Rondônia. Foram analisados semanalmente frutos de café coletados diretamente das plantas e caídos sobre o solo, de janeiro a dezembro de 2004. Observou-se a ocorrência do parasitoide durante os meses de maior infestação da praga. Durante o período estudado, a taxa de Parasitismo nos diferentes microambientes variou de 2 a 24%. Parasitism in the Population of the Coffee Berry Borer Hypothenemus hampei (Ferrari) (Coleoptera: Scolytidae) by the Parasitoid Cephalonomia stephanoderis Betrem (Hymenoptera: Bethylidae) Abstract. The coffee berry borer, Hypothenemus hampei (Ferrari) attacks coffee plantations, greatly decreasing the production of coffee plants, causing quantitative and qualitative damage to the grains. Biological control of this pest has focused mostly on entomopathogenic fungi. In the state of Rondonia, studies on Parasitism levels of the parasitoids of H. hampei are scarce. The parasitoid Cephalonomia stephanoderis Betrem is a natural enemy of the coffee berry borer and is already used as an agent of biological control in countries of Africa and Latin America. The objective of the present study was to investigate the occurrence and Parasitism levels of the parasitoid in a coffee plantation in the municipality of Ouro Preto D’Oeste, State of Rondonia. Coffee beans collected directly from the plants and on the ground were analyzed weekly from January to December 2004. Parasitoid occurred in months of the highest pest infestation. During the studied period, Parasitism rate in different microenvironments ranged from 2 to 24%
