The Sarcophagidae (Diptera) of the Coastline of Buenos Aires City, Argentina

Fil: Mariluis, Juan C. ANLIS Dr.C.G.Malbrán. Centro Nacional de Diagnóstico e Investigación en Endemo-Epidemias; Argentina.Fil: Schnack, Juan A. División Entomología, Museo de La Plata, Universidad Nacional de La Plata, La Plata; Argentina.Fil: Mulieri, Pablo R. ANLIS Dr.C.G.Malbrán. Centro Nacional de Diagnóstico e Investigación en Endemo-Epidemias; Argentina.Fil: Torretta, Juan P. Cátedra de Botánica Agrícola, Facultad de Agronomía, Universidad de Buenos Aires, Buenos Aires; Argentina.The flesh fly community was surveyed on the shoreline of Río de la Plata at an ecological reserve whose western border directly abuts downtown eastern Buenos Aires. Samples were taken at monthly intervals from September 2004 to August 2005. To attract the flies, dog faeces and rotten cow liver were used as bait. Overall number, species composition and sex ratio were referred to each chosen bait. Of the thirteen species captured during the sampling period, Helicobia aurescens (Townsend), Oxysarcodexia culmiforceps Dodge, Oxysarcodexia marina (Hall), Oxysarcodexia thornax (Walker), Sarcophaga (Lipoptilocnema) koehleri (Blanchard), S. (L.) lanei (Townsend) and Tricharaea (Sarcophagula) occidua (Fabricius) were recorded for the first time in Buenos Aires city. Regardless of species composition, higher number of flies were obtained on faeces. Tricharaea (S.) occidua, was highly dominant (78,35%) followed in abundance by Oxysarcodexia varia (7,82%), both species showing a strong preference for dog faeces. Microcerella muehni and Oxysarcodexia paulistanensis did not show any preference on either bait. Sex ratio was male biased for O. varia, while females were dominant for O. paulistanensis and T. (S.) occidua, and no differences were found for M. muehni. Bait's preference and sex ratio could not be estimated for the remaining species due to their low abundance

Descriptions of unknown sexes, new geographical records, and host associations for two South American species of Megachile (Hymenoptera: Megachilidae)

The cosmopolitan genus Megachile include many species described on the basis of only one sex. Sexual dimorphism is very pronounced in these taxa and therefore sexes are often difficult to associate, thus making species identification nearly impossible. The females of M. (Chrysosarus) concava and M. (Pseudocentron) variplantis are described and illustrated. Additional geographical and host records are provided as well as comments on their diagnostic features and identification based on existing keys.Fil: Durante, Silvana P.. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Entomología; ArgentinaFil: Torretta, Juan Pablo. Universidad de Buenos Aires. Facultad de Agronomia. Cátedra de Botanica General; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Colombo, María Guadalupe. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Entomología; Argentin

Are the floral morphology and anatomy of Galphimia australis, an atypical neotropical Malpighiaceae, associated to a new pollination syndrome?

The flowers of the species of Malpighiaceae in the Neotropical Region are relatively uniform in their morphology due to their dependence on oil-collecting bees as their main pollinators. However, many species of the genus Galphimia seem to have acquired a different floral syndrome, lacking markedly zygomorphic flowers and developed elaiophores in the calyx. Likewise, these species present anthers with great development, probably in response to the selection of pollinators that collect pollen. Galphimia australis incorporated some of these traits but also retained some residual characteristics typical of species pollinated by oil bees. This leads to many questions on how these flowers ensure their pollination. Inquiring about the reduction or modification of these characteristics allows us to understand how G. australis achieves a different pollination syndrome. In this research, we carry out a detailed morphological and anatomical study of the flowers and pollen grain devolvement of G. australis and floral visitors were observed and captured. Results were analyzed in order to determine how this species changed from the oil-floral syndrome, typical of neotropical Malpighiaceae, to one syndrome with pollen as the main reward.Fil: Gotelli, Marina María. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; ArgentinaFil: Aliscioni, Sandra Silvina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Botánica Darwinion. Academia Nacional de Ciencias Exactas, Físicas y Naturales. Instituto de Botánica Darwinion; ArgentinaFil: Kuo, P. T.. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; ArgentinaFil: Torretta, Juan Pablo. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Similarities and differences in the realized niche of two allopatric populations of a solitary bee under environmental variability

We studied the realized niche of two distant allopatric wool-carder bee populations (bee-plant interaction and reproductive biology in weather variability). In one population, we analyzed the direct and indirect effects of weather on bee-resource interactions. The two populations shared several niche characteristics but showed some differences. Anthidium vigintipunctatum is a specialist species, with plasticity to extend the individual niche pushed by resources availability and weather variability. In both regions, the bee’s response to weather condition was similar (nesting rates and the reproductive success). Causal analysis indicated climate directly determines bee’s reproductive success, and indirect resource availability effects are subtle. The immediate response to environmental conditions warms about A. vigintipunctatum sensitivity to expected changes in the regional climate which could be a negative pressure on bees’ survival.Fil: Vitale, Nydia Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; ArgentinaFil: Torretta, Juan Pablo. Universidad de Buenos Aires. Facultad de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; ArgentinaFil: Durante, Silvana Patricia. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Área Zoología; ArgentinaFil: Basilio, Alicia Mabel. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Vazquez, Diego P.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentin

Measurement of the Lifetime Difference Between B_s Mass Eigenstates

We present measurements of the lifetimes and polarization amplitudes for B_s --> J/psi phi and B_d --> J/psi K*0 decays. Lifetimes of the heavy (H) and light (L) mass eigenstates in the B_s system are separately measured for the first time by determining the relative contributions of amplitudes with definite CP as a function of the decay time. Using 203 +/- 15 B_s decays, we obtain tau_L = (1.05 +{0.16}/-{0.13} +/- 0.02) ps and tau_H = (2.07 +{0.58}/-{0.46} +/- 0.03) ps. Expressed in terms of the difference DeltaGamma_s and average Gamma_s, of the decay rates of the two eigenstates, the results are DeltaGamma_s/Gamma_s = (65 +{25}/-{33} +/- 1)%, and DeltaGamma_s = (0.47 +{0.19}/-{0.24} +/- 0.01) inverse ps.Comment: 8 pages, 3 figures, 2 tables; as published in Physical Review Letters on 16 March 2005; revisions are for length and typesetting only, no changes in results or conclusion

Zygostates alleniana (Orchidaceae: Epidendroideae: Cymbidieae: Oncidiinae): estructura floral relacionada con la polinización

The genus Zygostates Lindl. (Orchidaceae) comprises about 20 species of small Neotropical epiphytic plants, represented in its southernmost limit by the species Z. alleniana. In this paper, we studied morphological and anatomical floral characteristics of this species related to pollination mechanism. We confirmed the presence of the unicellular trichomes on the base of the lip and side lobes secreting oil, constituting a trichomal elaiophore. The oil is deposited beneath the cuticle at the apex of the trichomes forming small blisters. The oil could represent a reward for the species Lophopedia nigrispinis, which would be a potential pollinator of Z. alleniana in a natural area within the geographic range of this plant species. Moreover, we prove that the reconfiguration of the pollinaruim is due to the dehydration of the walls cell. This reconfiguration could favor cross-pollination mechanism already described for other species of the family Orchidaceae. Finally, we discuss the floral characters present in Z. alleniana with closely related species.El género Zygostates Lindl. (Orchidaceae) comprende aproximadamente 20 especies de pequeñas plantas epífitas con distribución neotropical, representado en su límite más austral por la especie Z. alleniana. En el presente trabajo se estudian morfológica y anatómicamente las características florales de esta especie relacionadas con el mecanismo de polinización. Se confirma la presencia de tricomas unicelulares en la base del labelo y lóbulos laterales que actúan secretando aceite, constituyendo un elaióforo tricomatoso. El aceite se deposita por debajo de la cutícula en el ápice de los tricomas formando pequeñas ampollas. El aceite podría representar una recompensa para la especie Lophopedia nigrispinis, la cual sería un posible polinizador de Z. alleniana en un área natural dentro del rango de distribución geográfica de esta especie vegetal. Por otro lado, se comprueba que la reconfiguración del polinario se debe a la deshidratación de las paredes celulares. Esta reconfiguración podría favorecer la polinización cruzada, mecanismo ya descrito para otras especies de la familia Orchidaceae. Por último, se discuten los caracteres florales presentes en Z. alleniana con otras especies estrechamente emparentadas

Nuevos registros de Messatoporus (Hymenoptera: Ichneumonidae) de la Argentina, con comentarios sobre su biología

Se presentan nuevos registros del género Messatoporus Cushman de la Isla Martín García, Argentina, y se menciona por primera vez la especie Messatoporus transversostriatus (Spinola) de la Argentina. La especie fue criada de nidos de Isodontia costipennis (Spinola) (Sphecidae), Pachodynerus guadulpensis (Saussure) y Monobia angulosa Saussure (Vespidae). Estos registros constituyen las primeras observaciones biológicas detalladas para un miembro del género Messatoporus en la Región Neotropical y representan la primera asociación del género con nidos de Sphecidae

First description of male of Megachile (Pseudocentron) gomphrenoides Vachal and redescription of female (Hymenoptera, Megachilidae)

Megachile is one of the largest genus of the family Megachilidae widely distributed in temperate and tropical areas of the world. Megachile (Pseudocentron) gomphrenoides was described by Vachal (1908) based on three female collected in Buenos Aires. Recently in a work about nest building of bees, we obtained females and males of this species in trap-nest. In this paper, the original description of the female is enlarged and the first description of the male is provided. Additionally, floral host and new record geographical are presented.Fil: Durante, Silvana P.. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Entomología; ArgentinaFil: Torretta, Juan Pablo. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Recursos Naturales y Ambiente. Cátedra de Botánica Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Redalyc.Flesh flies species (Diptera: Sarcophagidae) from a grassland and a woodland in a Nature Reserve of Buenos Aires, Argentina

Abstract: Temporal changes of flesh flies abundance were simultaneously recorded at monthly intervals during a year in a woodland and in a grassland at the "Reserva Ecológica Costanera Sur" (RECS), Buenos Aires city, Argentina. Samples were taken at monthly intervals (February 2004-January 2005. Hourly captures of adult flies (10:00 am -04:00 pm) were taken each sampling date with a hand net. Temperature was recorded at each hourly capture. The baits used were 200 g of rotten cow liver and 200 g of fresh dog faeces. Records of abundance included only species whose abundance was ≥30 individuals accumulated during the whole sampling period. Considering overall abundance, a non-parametric Chi-square test was used to estimate deviations of an expected habitat and bait preference ratios of 1:1. The same criterion was applied to include species in a contingency table to describe their seasonality. The final matrix included four species whose associations to seasons were analyzed by using a Correspondence Analysis. To normalize the data, a log 10 (n+1) transformation was applied prior to the analysis of correlation. Pearson product-moment correlations were used to examine the relationship between flesh-fly abundance with temperature and habitat preference. The entire sample accumulated 1 305 individuals and 18 species. The flies were more abundant in the grassland than in the woodland. Microcerella muehni, Oxysarcodexia paulistanensis, O. varia and Tricharaea (Sarcophagula) occidua exhibited the higher relative abundance, representing the remaining species less than 8 % of the entire sample. Most of the recorded species showed preference for faces as bait. Concerning the dominant species, all of them but M. muehni, a suggestively termophobic species, prevailed in late spring-summer. The observed species arrangement at both sites indicates low species diversity and equitability and high information per individual in the average. The referred community traits would indicate the possible effects of environmental disturbance due to the proximity of study sites to dense urban settlements. Rev. Biol. Trop. 56 (3): 1287-1294. Epub 200

Visitantes florales nocturnos del girasol (Helianthus annuus, Asterales: Asteraceae) en la Argentina Nocturnal floral visitors of sunflower (Helianthus annuus, Asterales: Asteraceae) in Argentina

El girasol (Helianthus annuus) es un cultivo oleaginoso, polinizado por Apis mellifera L. y otras abejas en distintas regiones del mundo. Sin embargo, sus flores también son visitadas por insectos de actividad nocturna. Durante tres campañas agrícolas, se determinó la diversidad de los visitantes nocturnos de capítulos de girasol, en cinco sitios de Argentina. También se estudió el comportamiento de forrajeo de los principales visitantes y la variación de la receptividad estigmática a lo largo del día, con el fin de establecer si estos visitantes contribuyen a la polinización. Al menos 67 especies o morfoespecies pertenecientes a cuatro órdenes de visitantes nocturnos fueron colectadas. El orden más rico y abundante fue Lepidoptera (44 especies o morfoespecies, cinco familias), seguido por Coleoptera (18 especies o morfoespecies, nueve familias), Orthoptera (tres morfoespecies, una familia) y Blattaria (dos especies, una familia). Los lepidópteros forrajearon exclusivamente por néctar, mientras que los individuos de los demás órdenes consumieron polen y/o partes florales. El estigma se encontró receptivo durante las horas de luz, con una receptividad máxima al mediodía (12:00 - 14:00). Llamativamente, las flores del girasol son visitadas por mayor número de polillas que de abejas. Debido a que las polillas consumen néctar y potencialmente transportan polen entre flores, en un momento del día en que los estigmas se encuentran menos receptivos, es improbable que polinicen efectivamente el cultivo.Sunflower (Helianthus annuus) is an oilseed crop pollinated by Apis mellifera L. and other diurnal bees in different regions of the world. However, their flowers are also visited by insects active at night. During three agricultural years, the diversity of nocturnal visitors to sunflower heads was assessed in five different sites in Argentina. The foraging behavior of the main visitors as well as the stigmatic receptivity variations along the day were also studied in order to determine whether or not these visitors contribute to pollination. At least 67 species or morpho-species belonging to four nocturnal visitor orders were recorded. The richest and most abundant order was Lepidoptera (44 species or morpho-species, five families), followed by Coleoptera (18 species or morpho-species, nine families), Orthoptera (three morpho-species, one family) and Blattaria (two species, one family). Lepidopterans foraged exclusively for nectar while species in other orders consumed pollen and/or floral parts. However, stigma receptivity was greater during the day, peaking at midday (12:00 - 14:00). Unexpectedly, moth species widely outnumbered bee species as sunflower visitors. Since moths potentially transfer pollen at a time of the day when stigmas are least receptive, it is unlikely that they do effectively pollinate sunflowers