3,544 research outputs found

    \u3ci\u3ePolistes Dominulus\u3c/i\u3e (Hymenoptera: Vespidae) Found in Michigan

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    (excerpt) On 25 May 1995, a single foundress colony of Polistes dominulus (Christ) was discovered on a study site at Oakland University in Rochester, Michigan (Oakland County). This is the first record of Polistes dominulus in the state of Michigan

    Vespidae (Insecta: Hymenoptera) of Puerto Rico, West Indies

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    The vespid fauna of Greater Puerto Rico is reviewed (Hymenoptera: Vespidae). Three new species are described, Ancistrocerus isla Carpenter, Euodynerus jeitita Carpenter and Genaro, and Omicron aridum Carpenter and Genaro. Polistes crinitus americanus (Fabricius, 1775) and P. crinitus multicolor (Olivier, 1792) are both reduced to synonyms of nominotypical P. crinitus (Felton, 1765), revised status; Zeta abdominale hispaniolae (Bequaert and Salt, 1931) and Zeta abdominale ornatum (de Saussure, 1855) are both reduced to synonyms of nominotypical Zeta abdominale (Drury, 1770), revised status; and Zethus rufinodus monensis Bohart and Stange, 1965, and Zethus rufinodus virginicus Bohart and Stange, 1965, are both reduced to synonyms of nominotypical Zethus rufinodus (Latreille, 1806), revised status. Parancistrocerus obliquus (Cresson, 1865) is newly recorded from Puerto Rico. The presence of Pachodynerus guadulpensis (de Saussure, 1853) in Puerto Rico is confirmed. An analysis of the composition of the Puerto Rican vespid fauna is presented.Se revisa la fauna de avispas de Puerto Rico e islas adyacentes (Hymenoptera: Vespidae). Se describen tres ESPECIES NUEVAS: Ancistrocerus isla Carpenter, Euodynerus jeitita Carpenter y Genaro, y Omicron aridum Carpenter y Genaro. Polistes crinitus americanus (Fabricius, 1775) y P. crinitus multicolor (Olivier, 1792) son reducidas a nombres sinónimos de la especie nominotipica P. crinitus (Felton, 1765), ESTADO REVISADO; Zeta abdominale hispaniolae (Bequaert and Salt, 1931) y Zeta abdominale ornatum (de Saussure, 1855) son reducidas a sinonimia de la especie nominotipica Zeta abdominale (Drury, 1770), ESTADO REVISADO; Zethus rufinodus monensis Bohart y Stange, 1965, y Zethus rufinodus virginicus Bohart y Stange, 1965, son reducidas a nombres sinónimos de la especie nominotipica Zethus rufinodus (Latreille, 1806), ESTADO REVISADO. Parancistrocerus obliquus (Cresson, 1865) se registra nuevamente para Puerto Rico. Se confirma la presencia de Pachodynerus guadulpensis (de Saussure, 1853) en Puerto Rico. Se analiza la composición de la fauna de véspidos de Puerto Rico

    When attempts at robbing prey turn fatal

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    Because group-hunting arboreal ants spreadeagle insect prey for a long time before retrieving them, these prey can be coveted by predatory flying insects. Yet, attempting to rob these prey is risky if the ant species is also an effective predator. Here, we show that trying to rob prey from Azteca andreae workers is a fatal error as 268 out of 276 potential cleptobionts (97.1 %) were captured in turn. The ant workers hunt in a group and use the “Velcro®” principle to cling firmly to the leaves of their host tree, permitting them to capture very large prey. Exceptions were one social wasp, plus some Trigona spp. workers and flies that landed directly on the prey and were able to take off immediately when attacked. We conclude that in this situation, previously captured prey attract potential cleptobionts that are captured in turn in most of the cases

    Protoplanetary Disk Masses in the Young NGC 2024 Cluster

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    We present the results from a Submillimeter Array survey of the 887 micron continuum emission from the protoplanetary disks around 95 young stars in the young cluster NGC 2024. Emission was detected from 22 infrared sources, with flux densities from ~5 to 330 mJy; upper limits (at 3sigma) for the other 73 sources range from 3 to 24 mJy. For standard assumptions, the corresponding disk masses range from ~0.003 to 0.2Msolar, with upper limits at 0.002--0.01Msolar. The NGC 2024 sample has a slightly more populated tail at the high end of its disk mass distribution compared to other clusters, but without more information on the nature of the sample hosts it remains unclear if this difference is statistically significant or a superficial selection effect. Unlike in the Orion Trapezium, there is no evidence for a disk mass dependence on the (projected) separation from the massive star IRS2b in the NGC 2024 cluster. We suggest that this is due to either the cluster youth or a comparatively weaker photoionizing radiation field.Comment: ApJ, in pres

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

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    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

    Incomplete Punishment Networks in Public Goods Games: Experimental Evidence

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    Abundant evidence suggests that high levels of contributions to public goods can be sustained through self-governed monitoring and sanctioning. This experimental study investigates the effectiveness of decentralized sanctioning institutions in alternative punishment networks. Our results show that the structure of punishment network significantly affects allocations to the public good. In addition, we observe that network configurations are more important than punishment capacities for the levels of public good provision, imposed sanctions and economic efficiency. Lastly, we show that targeted revenge is a major driver of anti-social punishment

    Debris Disks of Members of the Blanco 1 Open Cluster

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    We have used the Spitzer Space Telescope to obtain Multiband Imaging Photometer for Spitzer (MIPS) 24 um photometry for 37 members of the ~100 Myr old open cluster Blanco 1. For the brightest 25 of these stars (where we have 3sigma uncertainties less than 15%), we find significant mid-IR excesses for eight stars, corresponding to a debris disk detection frequency of about 32%. The stars with excesses include two A stars, four F dwarfs and two G dwarfs. The most significant linkage between 24 um excess and any other stellar property for our Blanco 1 sample of stars is with binarity. Blanco 1 members that are photometric binaries show few or no detected 24 um excesses whereas a quarter of the apparently single Blanco 1 members do have excesses. We have examined the MIPS data for two other clusters of similar age to Blanco 1 -- NGC 2547 and the Pleiades. The AFGK photometric binary star members of both of these clusters also show a much lower frequency of 24 um excesses compared to stars that lie near the single-star main sequence. We provide a new determination of the relation between V-Ks color and Ks-[24] color for main sequence photospheres based on Hyades members observed with MIPS. As a result of our analysis of the Hyades data, we identify three low mass Hyades members as candidates for having debris disks near the MIPS detection limit.Comment: Accepted to Ap

    CLEAR I: Ages and Metallicities of Quiescent Galaxies at 1.0<z<1.8\mathbf{1.0 < z < 1.8} Derived from Deep Hubble Space Telescope Grism Data

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    We use deep \textit{Hubble Space Telescope} spectroscopy to constrain the metallicities and (\editone{light-weighted}) ages of massive (logM/M10\log M_\ast/M_\odot\gtrsim10) galaxies selected to have quiescent stellar populations at 1.0<z<1.81.0<z<1.8. The data include 12--orbit depth coverage with the WFC3/G102 grism covering \sim 8,000<λ<11,5008,000<\lambda<11,500~\AA\, at a spectral resolution of R210R\sim 210 taken as part of the CANDELS Lyman-α\alpha Emission at Reionization (CLEAR) survey. At 1.0<z<1.81.0<z<1.8, the spectra cover important stellar population features in the rest-frame optical. We simulate a suite of stellar population models at the grism resolution, fit these to the data for each galaxy, and derive posterior likelihood distributions for metallicity and age. We stack the posteriors for subgroups of galaxies in different redshift ranges that include different combinations of stellar absorption features. Our results give \editone{light-weighted ages of tz1.1=3.2±0.7t_{z \sim 1.1}= 3.2\pm 0.7~Gyr, tz1.2=2.2±0.6t_{z \sim 1.2}= 2.2\pm 0.6~Gyr, tz1.3=3.1±0.6t_{z\sim1.3}= 3.1\pm 0.6~Gyr, and tz1.6=2.0±0.6t_{z\sim1.6}= 2.0 \pm 0.6~Gyr, \editone{for galaxies at z1.1z\sim 1.1, 1.2, 1.3, and 1.6. This} implies that most of the massive quiescent galaxies at 168168\% of their stellar mass by a redshift of z>2z>2}. The posteriors give metallicities of \editone{Zz1.1=1.16±0.29Z_{z\sim1.1}=1.16 \pm 0.29~ZZ_\odot, Zz1.2=1.05±0.34Z_{z\sim1.2}=1.05 \pm 0.34~ZZ_\odot, Zz1.3=1.00±0.31Z_{z\sim1.3}=1.00 \pm 0.31~ZZ_\odot, and Zz1.6=0.95±0.39Z_{z\sim1.6}=0.95 \pm 0.39~ZZ_\odot}. This is evidence that massive galaxies had enriched rapidly to approximately Solar metallicities as early as z3z\sim3.Comment: 32 pages, 23 figures, Resubmited to ApJ after revisions in response to referee repor

    Atmospheric phase correction using CARMA-PACS: high angular resolution observations of the FU Orionis star PP 13S*

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    We present 0".15 resolution observations of the 227 GHz continuum emission from the circumstellar disk around the FU Orionis star PP 13S*. The data were obtained with the Combined Array for Research in Millimeter-wave Astronomy (CARMA) Paired Antenna Calibration System (C-PACS), which measures and corrects the atmospheric delay fluctuations on the longest baselines of the array in order to improve the sensitivity and angular resolution of the observations. A description of the C-PACS technique and the data reduction procedures are presented. C-PACS was applied to CARMA observations of PP 13S*, which led to a factor of 1.6 increase in the observed peak flux of the source, a 36% reduction in the noise of the image, and a 52% decrease in the measured size of the source major axis. The calibrated complex visibilities were fitted with a theoretical disk model to constrain the disk surface density. The total disk mass from the best-fit model corresponds to 0.06 M_⊙, which is larger than the median mass of a disk around a classical T Tauri star. The disk is optically thick at a wavelength of 1.3 mm for orbital radii less than 48 AU. At larger radii, the inferred surface density of the PP 13S* disk is an order of magnitude lower than that needed to develop a gravitational instability
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