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In many animal species, females are faced with at least 2 reproductive options: independent or cooperative breeding. Some individuals in cooperative groups choose to help in rearing the broods of conspecific females. Through observations of how females of Polistes simillimus Zikán, 1951 (Hymenoptera: Vespidae) started new nests in the field, we investigated whether ecological constraints and the geographic variations explain group formation in this species. The founding of nests was studied between 1996 and 2000 in various localities of 2 states of southeastern Brazil. Weekly observations were carried out on 109 pre-worker nests. We kept track of 40 colonies in Minas Gerais State and 69 in São Paulo State, each started either by a single female or by an association of females. There was a chance that worker production would become numerically similar in both solitary and associative colonies in both states. An increased number of foundresses did not improve the chance of colony success in Minas Gerais State, but it improved this chance in São Paulo State, so that colonies each with 3 or more foundressess were always successful. In colonies in both states, nest cell productivity was higher with a greater number of associated females per nest. Females were able to start building nests alone, being the only reproductive, or 2 or more females could cooperate to found a nest, thus increasing worker production. However, the type of environment chosen to establish the nest (anthropogenic or natural) seemed to influence strongly the choice of the founding strategy. [ABSTRACT FROM AUTHOR]

Soybean aphid, Aphis glycines Matsumura (Hemiptera: Aphididae), is an important soybean pest in North America. In this study, A. glycines was fed on detached leaves of Glycine max (L.) Merrill (Fabaceae) at 20, 23, 26, 29, and 32 °C under 3 rearing methods: leaf-disc method, filter paper method, and moisturized cotton method. Aphis glycines life parameters, including nymph stage duration, adult lifespan, adult fecundity, adult body size, and intrinsic rate of increase were measured. There were no significant differences in nymph stage duration among these rearing methods at 20 to 32 °C. Within this temperature range, the filter paper method and the moisturized cotton method resulted in similar or greater adult lifespans, adult fecundities, adult body sizes, and intrinsic rates of increase in comparison to the leaf-disc method. When nymphs of A. glycines were reared at 20 to 29 °C, the experimental labor required for the moisturized cotton method was less than that for the filter paper method and the leaf-disc method. Considering the development, reproduction, and experimental labor, the moisturized cotton method is recommended as a good detached leaf method for rearing individual A. glycines. These conclusions will be useful and informational for researchers who study A. glycines, especially when selecting methods to rear A. glycines individually in the laboratory. El pulgón de la soja, Aphis glycines Matsumura (Hemiptera: Aphididae), es una plaga importante de la soja en América del Norte. En este estudio, A. glycines fue alimentado con hojas desprendidas de Glycine max (L.) Merrill (Fabaceae) a 20, 23, 26, 29 y 32 °C bajo 3 métodos de crianza: método de disco de hoja, método de papel de filtro y método de algodón humedecido. Se midieron los parámetros de vida del A. glycines, incluyendo la duración de la estadio del ninfa, la duración de vida de los adultos, la fecundidad, el tamaño corporal adulto y la tasa intrínseca de aumento. No hubo diferencias significativas en la duración del estadio de ninfa entre estos métodos de crianza a 20 a 32 °C. Dentro de este rango de temperatura, el método del papel de filtro y el método del algodón humedecido dieron resultados similares o mayores sobre la duración de vida de los adultos, la fecundidad, el tamaño corporal de adultos y la tasa intrínseca de aumento en comparación con el método del disco de hoja. Cuando se criaron las ninfas a una temperatura de 20 a 29 °C, el trabajo experimental requerido para el método del algodón humedecido fue menor que los métodos del papel de filtro y del disco de hoja. Teniendo en cuenta el desarrollo, la reproducción y el trabajo experimental, se recomienda el método del algodón humedecido como un buen método de hojas sueltas para criar los individuales de A. glycines. Estas conclusiones serán útiles e informativas para los investigadores que estudian A. glycines, especialmente al seleccionar métodos para criar A. glycines individualmente en el laboratorio. [ABSTRACT FROM AUTHOR]

The European paper wasp, Polistes dominula (Christ) (Hymenoptera: Vespidae), directly competes with native Polistes and is a safety concern for workers and homeowners. A previous investigation of Polistes behavior found that a portion of wasps died after consuming a solution of pear ester, a compound commonly found in fruits that is considered non-toxic to humans. The goal of our study was to corroborate those preliminary observations and investigate the toxicity of pear ester to P. dominula. Two experiments were performed. First, 3 wasp castes were fed 17% sugar water, or sugar water mixed with 0.5%, 1.0%, 5.0%, or 10.0% (w/v) solutions of pear ester. Mortality after 24 h ranged from 0% among wasps fed sugar water only, to >10% among wasps that were fed pear ester. Mortality increased logarithmically with pear ester concentration. Pear ester toxicity differed among wasp castes, with <5% mortality recorded among fall gynes to >10% mortality among workers. The second experiment attempted to define the relationship between morbidity and volume of pear ester consumed by P. dominula workers. Although results confirmed that ingestion of pear ester causes death or paralysis of P. dominula workers, there was no clear relationship between volume of ingested pear ester and wasp morbidity. About 80% of P. dominula were unaffected by pear ester despite consuming large quantities of the solution. This is the first study to demonstrate lethal effects of pear ester compound and may indicate its potential as an insecticide for paper wasps. La avispa cartonera europea, Polistes dominula (Christ) (Hymenoptera: Vespidae), compite directamente con las Polistes nativas y, además, es una preocupación de seguridad para trabajadores y familias en sus casas. Una investigación previa sobre el comportamiento de Polistes, encontró que algunas de las avispas morían después de consumir una solución de éster de pera, un compuesto comúnmente encontrado en frutas y que no es considerado tóxica para humanos. El objetivo de nuestro estudio fue corroborar esas observaciones preliminares e investigar la toxicidad del éster de pera para P. dominula. Se realizaron 2 experimentos. Primero, 3 castas de avispas fueron alimentadas con soluciones de 17% agua azucarada, o agua mezclada con 0.5%, 1.0%, 5.0% y 10.0% (p/v) con éster de pera. La mortalidad después de 24 horas varió desde 0% entre avispas alimentadas solamente con agua azucarada, a >10% entre avispas a las cuáles se les dio éster de pera. La mortalidad aumentó logarítmicamente con la concentración de éster de pera. La toxicidad del éster de pera varió entre las castas de avispas, con una mortalidad registrada <5% entre hembras reproductivas de otoño a >10% entre obreras. El segundo experimento intentó definir la relación entre morbilidad y volumen de éster de pera consumido por obreras de P. dominula. Aunque los resultados confirmaron que la ingesta de éster de pera causa la muerte o parálisis de obreras de P. dominula, no hubo una relación clara entre el volumen ingerido de éster de pera y morbilidad. Cerca del 80% de P. dominula no fue afectado por el éster de pera, a pesar, de haber consumido grandes cantidades de la solución. Este es el primer estudio que demuestra que la ingestión de éster de, pero por un insecto causa parálisis o muerte. Este es el primer estudio que demuestra efectos letales del compuesto de éster de pera y puede indicar su potencial como insecticidas para avispas papeleras. [ABSTRACT FROM AUTHOR]

Attractants are sought for trapping of Polistes spp. paper wasps when they are pestiferous. The serendipitous capture of Polistes metricus Say and Polistes bellicosus Cresson in traps baited with a wine/vinegar mixture for spotted wing drosophila, Drosophila suzukii (Matsumura) prompted experiments to determine the nature of the wasp response. Both wasp species were captured in subsequent field tests in traps baited with the same mixture of wine plus vinegar, and not in unbaited traps. Polistes bellicosus responses to wine, vinegar, ethanol (as a major volatile of wine), and acetic acid (as a major volatile of vinegar) were evaluated using a Y-tube olfactometer. In the olfactometer, P. bellicosus wasps were attracted to wine and not to vinegar. They also preferred wine alone to wine with vinegar, and were attracted to ethanol. Female wasps were deterred by acetic acid. In field tests comparing traps baited with wine, vinegar and a combination of the 2 materials, P. bellicosus and Polistes fuscatus (Fab.) were captured in traps baited with wine, but were not trapped with vinegar. The inclusion of vinegar with wine did not improve bait attractiveness in the field. We conclude that the paper wasp response to the D. suzukii bait of wine plus vinegar was largely the result of the wasp response to wine. This work constitutes the first demonstration of an attractive bait that can be used to trap P. bellicosus and P. metricus in situations where they are pestiferous, and suggests a potential source of a chemical attractant based on wine volatiles. [ABSTRACT FROM AUTHOR]

We report a likely range expansion of the introduced social wasp Polistes major major Palisot de Beauvois (Hymenoptera: Vespidae) from Florida into southern Georgia, USA, as well as the first records of Polistes apachus de Saussure from Georgia. We also review what is known of the history of these species in the southeastern United States. [ABSTRACT FROM AUTHOR]