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Factors influencing the diversity of tenebrionid beetles in arid, high-altitude environments in the northwest of Argentina are little-known. Using pitfall traps and suction sampling in 30 sites, we collected these beetles in Altos Andes (AA) and Puna (PU) ecoregions and evaluated how local and regional factors influenced their assemblages. During each sampling date, we registered variables related to climate, vegetation, and soil in each sampling site. In total, we recorded 270 individuals from 21 species, richness of species was higher in PU than in AA, but without a statistically significant difference. Twelve species were present exclusively in PU, while two in AA. Tenebrionid assemblages in both ecoregions had different dominant species, in PU, Psectrascelis cariosicollis while Epipedonota interandina in AA. Beta diversity between ecoregions was moderate and we recorded a high beta diversity and high turnover of species in each ecoregion. The geographical distance between the sites influenced the similarity of the assemblages inside and between ecoregions, therefore, an increase in the geographical distance between sites determined a decrease in the similarity of the assemblages. The increase in elevation of the sampled sites did not produce significant changes in the abundance and richness of Tenebrionidae. There is no individual factor responsible for the darkling beetle communities structuration in these high-altitude environments. Different combinations of both local (soil and vegetation) and regional (climate and geographical distance) environmental factors together explain the ecoregional tenebrionid assemblages. We suggest including them among the focus groups in conservation studies to evaluate anthropogenic activities in this area.

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Studies under constant temperatures are the most common to estimate the Postmortem Interval (PMI). It is imperative that forensic sciences have data from studies carried out in the field. Therefore, this work aims to: (1) evaluate the parameters (weight, length, development time) associated with the life cycles of Lucilia ochricornis (Wiedemann) (Diptera: Calliphoridae) and Lucilia purpurascens (Walker) under experimental conditions in the field considering fluctuating temperatures, and (2) compare these results with those known and published by the same authors for cultures realized in the laboratory under constant temperatures; which will permit us to contrast the most widely used existing methodologies for forensic application in estimating the minimum postmortem interval (PMImin). For each season of the year, cultures of both species were made in the field, collecting information on temperature, humidity, and photoperiod to perform laboratory cultures, later comparing: development time, length, weight, and Accumulated Degree-Hours (ADH) in both types of cultures. Methods for estimating the PMI were obtained and validated with the information of the cultures grown in the field. The two types of cultures showed differences between each other for both species. The forensic use methods to estimate PMI were enhanced and their precision increased when maximum larval length data were used, and it was also concluded that feeding larval stages are the most accurate to be used in making estimates because the larva is growing. The estimation of the PMI through the use of necrophagous flies development remains reliable for obtaining the PMImin.

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Obtaining the specific development time of each species of forensic interest is crucial for the estimation of an accurate and reliable Minimum Postmortem Interval (PMImin). In Argentina, Lucilia ochricornis (Wiedemann) and Lucilia purpurascens (Walker) (Diptera: Calliphoridae) were masked under the name Lucilia cluvia (Walker) for a long time still in forensic expertise. For this reason, the objective of this work is to deepen the study of the development time of these species and utilize this relevant information in the generation of different associated methods that can be used in forensics to estimate the PMI. Immature stages of L. ochricornis and L. purpurascens were reared in a brood chamber according to the following temperature treatments: 13.4, 15.1, 22.3, and 23.6°C. The development time of each stage/state of these flies was recorded as well as the resulting accumulated degree-hours (ADH), to build isomorphen diagrams and thermal summation models for each species. The development time and ADH were different between both species and their development stages. On the other hand, the methods provided for estimating PMImin provide the forensic entomologist more tools to reach accurate and reliable estimates.

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The early arrival and colonization of species belonging to the family Calliphoridae (Insecta: Diptera) on a corpse represent one of the most reliable means of estimating minimum postmortem interval (PMImin). However, information on the development and life cycles of some Argentine species in this family is not complete. The objective of this work was to contribute new information regarding the larval body size of neotropical species that allow, through the construction of forensic methods, the estimation of a more precise and specific PMImin. This work was conducted on laboratory cultures of larvae of Lucilia ochricornis (Wiedemann) and Lucilia purpurascens (Walker) using as average temperatures: 13.4, 15.1, 22.6, and 23.3°C, which represent the four seasons of the year for the province of Salta. With this information, we constructed isomegalen diagrams and growth models for the obtained variables of larval length and body weight. The mean values of length and body weight differ between both species, indicating that L. purpurascens exceeded L. ochricornis in both variables. In contrast, within each species the mean length and weight remained unchanged between culture temperatures for the three larval instars. Isomegalen diagrams can be used for the entire range of temperatures worked in the laboratory, but the body size entered is approximate. The growth models allow the use of point data but are specific for each culture temperature used.

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The invasive Argentine ant causes ecological and economic damage worldwide. In 2011, this species was reported in vineyards of Cafayate, a wine-producing town in the Andes, Argentina. While the local xeric climate is unsuitable for Argentine ants, populations could establish in association with vineyards where human activity and irrigation facilitate propagule introduction and survival. In 2013-2014, we combined extensive sampling of the area using ant-baits with monitoring of the change in land use and vineyard cultivated area over the past 15 years. Our results revealed that the species has thus far remained confined to a relatively isolated small area, owing to an effective barrier of dry shrublands surrounding the infested vineyards; yet the recent expansion of vineyard acreage in this region will soon connect this encapsulated area with the rest of the valley. When this happens, vulnerable ecosystems and the main local industry will be put at risk. This case provides a rare opportunity to study early invasion dynamics and reports, to the best of our knowledge, for the first time, the Argentine ant in high altitude agroecosystems.

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This study examined arthropod community patterns over an altitudinal ecoregional zonation that extended through three ecoregions (Yungas, Monte de Sierras y Bolsones, and Puna) and two ecotones (Yungas-Monte and Prepuna) of Northwestern Argentina (altitudinal range of 2,500 m), and evaluated the abiotic and biotic factors and the geographical distance that could influence them. Pitfall trap and suction samples were taken seasonally in 15 sampling sites (1,500-4,000 m a.s.l) during one year. In addition to climatic variables, several soil and vegetation variables were measured in the field. Values obtained for species richness between ecoregions and ecotones and by sampling sites were compared statistically and by interpolation-extrapolation analysis based on individuals at the same sample coverage level. Effects of predictor variables and the similarity of arthropods were shown using non-metric multidimensional scaling, and the resulting groups were evaluated using a multi-response permutation procedure. Polynomial regression was used to evaluate the relationship between altitude with total species richness and those of hyperdiverse/abundant higher taxa and the latter taxa with each predictor variable. The species richness pattern displayed a decrease in species diversity as the elevation increased at the bottom wet part (Yungas) of our altitudinal zonation until the Monte, and a unimodal pattern of diversity in the top dry part (Monte, Puna). Each ecoregion and ecotonal zone evidenced a particular species richness and assemblage of arthropods, but the latter ones displayed a high percentage of species shared with the adjacent ecoregions. The arthropod elevational pattern and the changes of the assemblages were explained by the environmental gradient (especially the climate) in addition to a geographic gradient (the distance of decay of similarity), demonstrating that the species turnover is important to explain the beta diversity along the elevational gradient. This suggests that patterns of diversity and distribution of arthropods are regulated by the dissimilarity of ecoregional environments that establish a wide range of geographic and environmental barriers, coupled with a limitation of species dispersal. Therefore, the arthropods of higher taxa respond differently to the altitudinal ecoregional zonation.

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Beta-diversity, defined as spatial replacement in species composition, is crucial to the understanding of how local communities assemble. These changes can be driven by environmental or geographic factors (such as geographic distance), or a combination of the two. Spiders have been shown to be good indicators of environmental quality. Accordingly, spiders are used in this work as model taxa to establish whether there is a decrease in community similarity that corresponds to geographic distance in the grasslands of the Campos & Malezales ecoregion (Corrientes). Furthermore, the influence of climactic factors and local vegetation heterogeneity (environmental factors) on assemblage composition was evaluated. Finally, this study evaluated whether the differential dispersal capacity of spider families is a factor that influences their community structure at a regional scale. Spiders were collected with a G-Vac from vegetation in six grassland sites in the Campos & Malezales ecoregion that were separated by a minimum of 13 km. With this data, the impact of alpha-diversity and different environmental variables on the beta-diversity of spider communities was analysed. Likewise, the importance of species replacement and nesting on beta-diversity and their contribution to the regional diversity of spider families with different dispersion capacities was evaluated. The regional and site-specific inventories obtained were complete. The similarity between spider communities declined as the geographic distance between sites increased. Environmental variables also influenced community composition; stochastic events and abiotic forces were the principal intervening factors in assembly structure. The differential dispersal capacity of spider groups also influenced community structure at a regional scale. The regional beta-diversity, as well as species replacement, was greater in high and intermediate vagility spiders; while nesting was greater in spiders with low dispersion capacity. Geographic distance, among other factors (climate, and active and passive dispersion capacity), explains assembly structure and the decrease spider community similarity between geographically distant sites. Spiders with the highest dispersal capacity showed greater species replacement. This may be due to the discontinuity (both natural and anthropic) of the grasslands in this ecoregion, which limits the dispersal capacity of these spiders, and their close dependence on microhabitats. The dispersal capacity of the least vagile spiders is limited by geographic distance and biotic factors, such as competition, which could explain the nesting observed between their communities.

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Se conoce poco sobre la biología y la ecología de la especie mirmecófaga Leprolochus birabeni Mello-Leitão, 1942 (Zodariidae), el único representante de este género en la Argentina. Esta especie es típica de ambientes áridos del norte del país, y su estudio en el Chaco Seco es relevante, por ser una ecorregión altamente perturbada con uno de los pocos bosques subtropicales secos del mundo. El objetivo de este trabajo es estudiar la demografía de la especie teniendo en cuenta su variación estacional en ambientes nativos, y sí la ganadería y la agricultura, dos de las actividades antropogénicas más comunes de la ecorregión Chaco Seco en la provincia de Salta (Argentina) producen cambios en sus poblaciones. Se consideraron tres tipos de ambientes: nativo (NA); afectados por el ganado vacuno y caprino (NP); y afectados por la agricultura (NC). Este último correspondió a parches de vegetación nativa en medio de una matriz agrícola. En cada tipo de ambiente se consideraron tres sitios de muestreo donde se realizaron muestreos estacionales utilizando trampas de caída durante el otoño, invierno y primavera de 2006 y el verano de 2007. Se recolectaron 549 ejemplares de L. birabeni , siendo la mayoría juveniles con el 64,12% de la abundancia total, seguidos por machos (26,41%) y hembras (9,47%). A nivel de paisaje, la primavera presentó el mayor número de individuos, llegando al 44,99% de la abundancia total; mientras que el otoño mostró el porcentaje más bajo (7,83%). El incremento de los juveniles durante el invierno podría indicar una adaptación de los estadios de desarrollo a las condiciones ambientales. El mismo patrón se observó en ambientes NA y NC, pero no en los NP. Estos últimos mostraron una disminución en la abundancia de adultos a lo largo del año; mientras que las poblaciones NC mostraron un incremento en la abundancia de los machos durante la primavera, con una fuerte reducción de las hembras y los juveniles durante todo el año. [...](AU)

Little is known about the biology and ecology of the myrmecophagic species Leprolochus birabeni Mello-Leitão, 1942 (Zodariidae), the only representative of this genus in Argentina. This species is typical of arid environments of the north of Argentina, and their study in the Chaco Seco is relevant, because is a highly disturbed ecoregion and one of the few with dry subtropical forests in the World. The aim of this work is to study the demography of this species, considering its seasonal variation in native environments, and if the livestock grazing and the agriculture, two of the most common anthropogenic activities of the Chaco Seco ecoregion, produce changes in their populations in the province of Salta (Argentina). We consider three type of environments: native (NA); affected by cattle and goats (NP); and affected by agriculture (NC). The latter corresponds to patches of native vegetation in an agricultural matrix. Three sampling sites were selected on each type of environment, where seasonal samplings using pitfall traps were performed during autumn, winter and spring (2006) and summer (2007). We collected 549 spiders of L. birabeni , with the juveniles reaching until the 64.12% of total abundance, followed by males (26.41%) and females (9.47%). At landscape level, spring season showed the highest number of individuals, reaching 44.99% of the total abundance, while autumn reported the lowest percentage (7.83%). The juveniles increase observed during the winter would indicate an adaptation to environmental conditions. The same pattern was observed in NA and NC environments, but not in NP ones. The later environments showed a decrease in the adult abundances across the seasons, while the NC populations showed an increase of male abundances during spring season with a sharp reduction of females and juveniles throughout the year. [...](AU)

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Se conoce poco sobre la biología y la ecología de la especie mirmecófaga Leprolochus birabeni Mello-Leitão, 1942 (Zodariidae), el único representante de este género en la Argentina. Esta especie es típica de ambientes áridos del norte del país, y su estudio en el Chaco Seco es relevante, por ser una ecorregión altamente perturbada con uno de los pocos bosques subtropicales secos del mundo. El objetivo de este trabajo es estudiar la demografía de la especie teniendo en cuenta su variación estacional en ambientes nativos, y sí la ganadería y la agricultura, dos de las actividades antropogénicas más comunes de la ecorregión Chaco Seco en la provincia de Salta (Argentina) producen cambios en sus poblaciones. Se consideraron tres tipos de ambientes: nativo (NA); afectados por el ganado vacuno y caprino (NP); y afectados por la agricultura (NC). Este último correspondió a parches de vegetación nativa en medio de una matriz agrícola. En cada tipo de ambiente se consideraron tres sitios de muestreo donde se realizaron muestreos estacionales utilizando trampas de caída durante el otoño, invierno y primavera de 2006 y el verano de 2007. Se recolectaron 549 ejemplares de L. birabeni , siendo la mayoría juveniles con el 64,12% de la abundancia total, seguidos por machos (26,41%) y hembras (9,47%). A nivel de paisaje, la primavera presentó el mayor número de individuos, llegando al 44,99% de la abundancia total; mientras que el otoño mostró el porcentaje más bajo (7,83%). El incremento de los juveniles durante el invierno podría indicar una adaptación de los estadios de desarrollo a las condiciones ambientales. El mismo patrón se observó en ambientes NA y NC, pero no en los NP. Estos últimos mostraron una disminución en la abundancia de adultos a lo largo del año; mientras que las poblaciones NC mostraron un incremento en la abundancia de los machos durante la primavera, con una fuerte reducción de las hembras y los juveniles durante todo el año. [...]

Little is known about the biology and ecology of the myrmecophagic species Leprolochus birabeni Mello-Leitão, 1942 (Zodariidae), the only representative of this genus in Argentina. This species is typical of arid environments of the north of Argentina, and their study in the Chaco Seco is relevant, because is a highly disturbed ecoregion and one of the few with dry subtropical forests in the World. The aim of this work is to study the demography of this species, considering its seasonal variation in native environments, and if the livestock grazing and the agriculture, two of the most common anthropogenic activities of the Chaco Seco ecoregion, produce changes in their populations in the province of Salta (Argentina). We consider three type of environments: native (NA); affected by cattle and goats (NP); and affected by agriculture (NC). The latter corresponds to patches of native vegetation in an agricultural matrix. Three sampling sites were selected on each type of environment, where seasonal samplings using pitfall traps were performed during autumn, winter and spring (2006) and summer (2007). We collected 549 spiders of L. birabeni , with the juveniles reaching until the 64.12% of total abundance, followed by males (26.41%) and females (9.47%). At landscape level, spring season showed the highest number of individuals, reaching 44.99% of the total abundance, while autumn reported the lowest percentage (7.83%). The juveniles increase observed during the winter would indicate an adaptation to environmental conditions. The same pattern was observed in NA and NC environments, but not in NP ones. The later environments showed a decrease in the adult abundances across the seasons, while the NC populations showed an increase of male abundances during spring season with a sharp reduction of females and juveniles throughout the year. [...]

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RESUMEN Se conoce poco sobre la biología y la ecología de la especie mirmecófaga Leprolochus birabeni Mello-Leitão, 1942 (Zodariidae), el único representante de este género en la Argentina. Esta especie es típica de ambientes áridos del norte del país, y su estudio en el Chaco Seco es relevante, por ser una ecorregión altamente perturbada con uno de los pocos bosques subtropicales secos del mundo. El objetivo de este trabajo es estudiar la demografía de la especie teniendo en cuenta su variación estacional en ambientes nativos, y sí la ganadería y la agricultura, dos de las actividades antropogénicas más comunes de la ecorregión Chaco Seco en la provincia de Salta (Argentina) producen cambios en sus poblaciones. Se consideraron tres tipos de ambientes: nativo (NA); afectados por el ganado vacuno y caprino (NP); y afectados por la agricultura (NC). Este último correspondió a parches de vegetación nativa en medio de una matriz agrícola. En cada tipo de ambiente se consideraron tres sitios de muestreo donde se realizaron muestreos estacionales utilizando trampas de caída durante el otoño, invierno y primavera de 2006 y el verano de 2007. Se recolectaron 549 ejemplares de L. birabeni , siendo la mayoría juveniles con el 64,12% de la abundancia total, seguidos por machos (26,41%) y hembras (9,47%). A nivel de paisaje, la primavera presentó el mayor número de individuos, llegando al 44,99% de la abundancia total; mientras que el otoño mostró el porcentaje más bajo (7,83%). El incremento de los juveniles durante el invierno podría indicar una adaptación de los estadios de desarrollo a las condiciones ambientales. El mismo patrón se observó en ambientes NA y NC, pero no en los NP. Estos últimos mostraron una disminución en la abundancia de adultos a lo largo del año; mientras que las poblaciones NC mostraron un incremento en la abundancia de los machos durante la primavera, con una fuerte reducción de las hembras y los juveniles durante todo el año. La abundancia de L. birabeni en ambientes NA fue mayor (41,06% de la abundancia total), siendo los valores mínimos registrados en NC (24,67%). Las dos actividades antropogénicas más comunes que afectan al Chaco Seco de la provincia de Salta modifican tanto los cambios estacionales como la representación de las diferentes etapas de desarrollo y sexos de las poblaciones nativas de L. birabeni , siendo la modificación de los ambientes nativos por la agricultura, el factor más perjudicial.

Abstract Little is known about the biology and ecology of the myrmecophagic species Leprolochus birabeni Mello-Leitão, 1942 (Zodariidae), the only representative of this genus in Argentina. This species is typical of arid environments of the north of Argentina, and their study in the Chaco Seco is relevant, because is a highly disturbed ecoregion and one of the few with dry subtropical forests in the World. The aim of this work is to study the demography of this species, considering its seasonal variation in native environments, and if the livestock grazing and the agriculture, two of the most common anthropogenic activities of the Chaco Seco ecoregion, produce changes in their populations in the province of Salta (Argentina). We consider three type of environments: native (NA); affected by cattle and goats (NP); and affected by agriculture (NC). The latter corresponds to patches of native vegetation in an agricultural matrix. Three sampling sites were selected on each type of environment, where seasonal samplings using pitfall traps were performed during autumn, winter and spring (2006) and summer (2007). We collected 549 spiders of L. birabeni , with the juveniles reaching until the 64.12% of total abundance, followed by males (26.41%) and females (9.47%). At landscape level, spring season showed the highest number of individuals, reaching 44.99% of the total abundance, while autumn reported the lowest percentage (7.83%). The juveniles increase observed during the winter would indicate an adaptation to environmental conditions. The same pattern was observed in NA and NC environments, but not in NP ones. The later environments showed a decrease in the adult abundances across the seasons, while the NC populations showed an increase of male abundances during spring season with a sharp reduction of females and juveniles throughout the year. The abundance of L. birabeni in NA environments was higher (41.06% of total abundance) and the least value was reported in NC environments (24.67%). The two most common anthropogenic activities affecting the Chaco Seco of the province of Salta modify both the seasonal changes as the representation of the different developmental stages and sexes of the native populations of L. birabeni , being the most damaging factor the modification of the native environments by the agriculture.

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Spiders are a megadiverse group that can be useful indicators of the overall species richness and health of biotic communities. The spider diversity in subtropical forests of the Neotropical region are not yet well known, especially in Argentinean subtropical forests where systematic fieldwork has not been done until recently. The Great Chaco is very important as the unique dry subtropical forest of the earth, but it is suffering increasing degradation by the advance of agriculture. Spider communities have been shown to be more directly influenced by vegetation architecture than vegetation species composition. In this study, we aim to assess whether spider diversity and assemblages change in adjacent habitats with different types of vegetation. We compare the diversity and spider assemblages in two different contiguous protected habitats (hygrophilous woodland and savannah parkland) of the Mburucuyá National Park, (Humid Chaco ecoregion). Seasonal samples were obtained using three types of sampling methods: pitfall trapping, beating, and manual litter extraction. The spider assemblages were different in the studied areas, and the abundance, diversity, evenness, and species richness were higher in the hygrophilous woodland than the savannah parkland. These differences in spider diversity and assemblages indicate that both types of habitats are important if the biodiversity is to be conserved in the Chaco ecoregion, where different types of habitat are shown as a patchy distribution.

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