Phylogeny of Neotropical Sicarius sand spiders suggests frequent transitions from deserts to dry forests despite antique, broad-scale niche conservatism.

Phylogenetic niche conservatism (PNC) shapes the distribution of organisms by constraining lineages to particular climatic conditions. Conversely, if areas with similar climates are geographically isolated, diversification may also be limited by dispersal. Neotropical xeric habitats provide an ideal system to test the relative roles of climate and geography on diversification, as they occur in disjunct areas with similar biotas. Sicariinae sand spiders are intimately associated with these xeric environments, particularly seasonally dry tropical forests (SDTFs) and subtropical deserts/scrublands in Africa (Hexophthalma) and the Neotropics (Sicarius). We explore the role of PNC, geography and biome shifts in their evolution and timing of diversification. We estimated a time-calibrated, total-evidence phylogeny of Sicariinae, and used published distribution records to estimate climatic niche and biome occupancy. Topologies were used for estimating ancestral niches and biome shifts. We used variation partitioning methods to test the relative importance of climate and spatially autocorrelated factors in explaining the spatial variation in phylogenetic structure of Sicarius across the Neotropics. Neotropical Sicarius are ancient and split from their African sister-group around 90 (57-131) million years ago. Most speciation events took place in the Miocene. Sicariinae records can be separated in two groups corresponding to temperate/dry and tropical/seasonally dry climates. The ancestral climatic niche of Sicariinae are temperate/dry areas, with 2-3 shifts to tropical/seasonally dry areas in Sicarius. Similarly, ancestral biomes occupied by the group are temperate and dry (deserts, Mediterranean scrub, temperate grasslands), with 2-3 shifts to tropical, seasonally dry forests and grasslands. Most of the variation in phylogenetic structure is explained by long-distance dispersal limitation that is independent of the measured climatic conditions. Sicariinae have an ancient association to arid lands, suggesting that PNC prevented them from colonizing mesic habitats. However, niches are labile at a smaller scale, with several shifts from deserts to SDTFs. This suggests that PNC and long-distance dispersal limitation played major roles in confining lineages to isolated areas of SDTF/desert over evolutionary history, although shifts between xeric biomes occurred whenever geographical opportunities were presented.

Niche modelling of the Chilean recluse spider Loxosceles laeta and araneophagic spitting spider Scytodes globula and risk for loxoscelism in Chile.

In Chile, all necrotic arachnidism is attributed to the Chilean recluse spider Loxosceles laeta (Nicolet) (Araneae: Sicariidae). It is predated by the spitting spider Scytodes globula (Nicolet) (Araneae: Scytodidae). The biology of each of these species is not well known and it is important to clarify their distributions. The aims of this study are to elucidate the variables involved in the niches of both species based on environmental and human footprint variables, and to construct geographic maps that will be useful in estimating potential distributions and in defining a map of estimated risk for loxoscelism in Chile. Loxosceles laeta was found to be associated with high temperatures and low rates of precipitation, whereas although S. globula was also associated with high temperatures, its distribution was associated with a higher level of precipitation. The main variable associated with the distribution of L. laeta was the human footprint (48.6%), which suggests that this is a highly invasive species. Similarly to other species, the distribution of L. laeta reaches its southern limit at the Los Lagos region in Chile, which coincides with high levels of precipitation and low temperatures. The potential distribution of L. laeta in Chile corresponds to the distribution of cases of loxoscelism.

Chromosomal characteristics and karyotype evolution of Oxyopidae spiders (Araneae, Entelegynae).

We made a cytogenetic analysis of four species of Oxyopidae and compared it with the karyotype data of all species of this family. In Hamataliwa sp, the mitotic cells showed 2n♂ = 26+X(1)X(2) and telocentric chromosomes. The 2n♂ = 28, which has been described for only one oxyopid spider, is the highest diploid number reported for this family. Peucetia species exhibited distinct karyotype characteristics, i.e., 2n♂ = 20+X(1)X(2) in P. flava and 2n♂ = 20+X in P. rubrolineata, revealing interspecific chromosome variability within this genus. However, both Peucetia species exhibited telocentric chromosomes. The most unexpected karyotype was encountered in Oxyopes salticus, which presented 2n♂ = 10+X in most individuals and a predominance of biarmed chromosomes. Additionally, one male of the sample of O. salticus was heterozygous for a centric fusion that originated the first chromosomal pair and exhibited one supernumerary chromosome in some cells. Testicular nuclei of Hamataliwa sp and O. salticus revealed NORs on autosomal pairs, after silver impregnation. The majority of Oxyopidae spiders have their karyotype differentiated by both reduction in diploid number chromosome number and change of the sex chromosome system to X type; however, certain species retain the ancestral chromosome constitution 2n = 26+X1X2. The most remarkable karyotype differentiation occurred in O. salticus studied here, which showed the lowest diploid number ever observed in Oxyopidae and the second lowest registered for Entelegynae spiders.

Influence of Urban Landscape on Ants and Spiders Richness and Composition in Forests.

As large amounts of natural environments are lost due to urbanization, the role of remnant native vegetation in the preservation of biodiversity has become even more significant. Remnant native forest patches are essential refugia for flora and fauna and are crucial for the maintenance of ecosystem processes in urbanized landscapes. We evaluated the influence of landscape structure on ants and spiders associated with Atlantic Forest remnants in urban landscapes. We sampled 14 forest areas in the Metropolitan Region of Salvador and tested the effect of the landscapes' proportion of forest cover, mean landscape isolation, and mean landscape shape complexity on the taxonomic and functional richness and the community composition of both groups. The species collected were classified into functional groups based on behavioral attributes and environmental preferences. Overall, there were strong adverse effects of forest loss, decreased connectivity, and an increase in edge effects associated with the mean shape complexity of the forest remnants. However, the spiders responded to all three landscape structure characteristics whereas the ants only responded to the landscape mean shape complexity. Our findings indicate that the maintenance of urban forest habitats is essential for the conservation of biodiversity in the Metropolitan Region of Salvador and the preservation of ecological functions performed by species within the forest areas.

Cytogenetic study in sand spiders (Sicariidae) from the brazilian Caatinga: sex chromosome system diversity in closely related species / Estudio citogenético en arañas de arena (Sicariidae) de la Caatinga brasileña: diversidad del sistema de cromosomas sexuales en especies estrechamente relacionadas

ABSTRACT In this study, we investigated the chromosomes of three species of Sicarius spiders from the Brazilian Caatinga, using classical and molecular cytogenetic techniques. Based on the phylogenetic approach, we also discussed about the variation of diploid number, types of sex chromosome system and changes in the localization of ribosomal genes of Scytodoidea. Sicarius are Synspermiata spiders that together with the genera Loxosceles and Hexophthalma constitute the family Sicariidae. In this group, the available cytogenetic data showed a low diploid number range (2n♂=18 to 2n♂=23) and the presence of only multiple sex chromosome systems (X1X2Y and X1X20). Mitotic metaphase cells exhibited 2n♂=16+X1X2Y for Sicarius cariri and S. ornatus, and 2n♂=18+XY for S. tropicus. In these species, silver impregnation revealed nucleolar organizer region (Ag-NOR) on the terminal region of pair 1. In S. ornatus and S. tropicus, the results obtained with fluorescent in situ hybridization (FISH) using 18S rDNA probe were similar to Ag-NOR, however in S. cariri, the ribosomal sites were localized in the terminal region of the X1 sex chromosome. In this work, we presented the first description of a simple sex chromosome system for Sicariidae, helping to understand how the XY sex chromosome system evolved from the X1X2Y system. Additionally, FISH data incongruous with Ag-NOR indicate that the cytogenetic studies in Sicariidae allow investigating the relation between the karyotype evolution and the distribution and the activity of rDNA genes.

RESUMEN En este estudio, investigamos los cromosomas de tres especies de arañas Sicarius de la Caatinga brasileña, utilizando técnicas de citogenética clásica y molecular. Usando un enfoque filogenético, también discutimos la variación del número diploide, los tipos de sistema cromosómico sexual y los cambios en la localización de los genes ribosómicos en Scytodoidea. Los Sicarius son arañas Synspermiata que, junto con los géneros Loxosceles y Hexophthalma, constituyen a la familia Sicariidae. En este grupo, los datos citogenéticos disponibles mostraron un rango de número diploide bajo (2n♂=18 a 2n♂=23) y únicamente la presencia de sistemas de cromosomas sexuales múltiples (X1X2Y y X1X20). Las células mitóticas en metafase mostraron 2n♂=16+X1X2Y para Sicarius cariri y S. ornatus, y 2n♂=18+XY para S. tropicus. En estas especies, la impregnación de plata reveló la región organizadora nucleolar (Ag-NOR) en la región terminal del par 1. En S. ornatus y S. tropicus, los resultados obtenidos con la hibridación in situ fluorescente (FISH) utilizando la sonda de ADNr 18S fueron similares a los de Ag-NOR, sin embargo, en S. cariri los sitios ribosomales se localizaron en la región terminal del cromosoma sexual X1. En este trabajo, presentamos la primera descripción de un sistema cromosómico sexual simple para Sicariidae, ayudando a entender cómo el sistema cromosómico sexual XY evolucionó a partir del sistema X1X2Y. Además, los datos de FISH incongruentes con Ag-NOR indican que los estudios citogenéticos en Sicariidae permiten investigar la relación entre la evolución del cariotipo y la distribución y la actividad de los genes de ADNr.

Spider prey (Araneae) of Trypoxylon (Trypargilum) rogenhoferi (Hymenoptera: Sphecidae) in southeastern Brazil.

Fifty five nests and 216 cells of Trypoxylon (Trypargilum) rogenhoferi were obtained from trap-nests (cut bamboo canes) in Santa Carlota Farm (Itaoca Section = IS and Santana Section = SS), Cajuru and on the São Paulo University Campus, Ribeirão Preto (= RP), both in the State of São Paulo, Brazil (Sept. 1993-Oct. 1995). The prey (spiders) of 40 cells from IS, 58 from SS and 39 from RP were identified. The greatest nesting frequency occurred during the hot and wet season (September to April). T. rogenhoferi preyed upon individuals of five spider families, with Araneidae (orb-weaver spiders) being the most frequent (99.6%). Alpaida aff. negro (58%) was the most frequently collected species in IS, followed by A. alto (24.8%); in SS (59.6%) and RP (64.7%) the most frequent species was A. veniliae, followed in SS by A. aff. negro (14.9%) and in RP by A. leucogramma (13.5%). The size of reproductive niches, H' = 1.25 (IS), H' = 1.30 (SS) and H' = 1.29 (RP) were not significantly different. There was a positive correlation between the reproductive niche width (H') and evenness.

Prey selection in the trap-nesting wasp Trypoxylon (Trypargilum) opacum Brèthes (Hymenprtera; Crabronidae).

The purpose of our research was to document and discuss the temporal patterns of prey use shown by the trap-nesting wasp Trypoxylon opacum in two different habitats in Southern Brazil. It was carried out from December 2001 to December 2004. Twenty nine species belonging to five families of spiders were captured by T. opacum. Araneidae was the most captured family and has been strongly represented by the genus Eustala. Through Bray-Curtis s coefficient and the unweighted pair group method average (UPGMA), the spiders can be divided into three groups: the smaller group includes the most abundant species (Alpaida sp2, Bertrana rufostriata, Eustala sp1, Eustala sp2, Eustala sp3 and Eustala sp4), the second group includes species with intermediate abundance (Alpaida, Alpaida gracia and Mangora sp2), and the third and largest group includes the less abundant species, (Acacesia villalobosi, Alpaida argenata, Alpaida sp1, Araneus blumenau, Araneus sicki, Crysometa boraceia, Crysometa sp3, Eustala sp8, Eustala sp11, Larinia t-notata, Mangora sp1, Ocrepeira aff gnomo, Sanogasta sp., Sanogasta sp2, Sanogasta sp3, Salticidae sp2, Theridion sp1, Theridion sp2, Wagneriana eupalaestris, Wagneriana iguape). Of 1,053 identified spiders, 362 were captured in the grassland areas and 691 in the swamp, since T. opacum built nests only in these two habitats. The diversity, richness and evenness of spiders in T. opacum nests were higher in grassland than in the swamp.

Patterns of prey selection of Trypoxylon (Trypargilum) lactitarse Saussure (Hymenoptera: Crabronidae) in southern Brazil.

This study was carried out in the Parque Municipal das Araucárias, in the municipality of Guarapuava, southern Brazil. A total of 449 T. lactitarse nests were collected using trap-nests of different diameters. Fifty three species of spiders belonging to 7 families were captured by T. lactitarse. Araneidae was the most captured family and has been strongly represented by the genus Eustala. Through Bray-Curtis's coefficient and the unweighted pair group method average (UPGMA), the spiders species can be divided into 3 groups: the smaller group includes the most abundant species (Eustala sp1, Eustala sp2, Acacesia villalobosi, Alpaida sp1 and Araneus corporosus), the second group includes species with intermediate abundance (Wagneriana iguape, Araneus omnicolor, Eustala sp4, Alpaida grayi, Eustala sp3, Larinia t-notata, Mangora sp1 and Wagneriana iguape), and the third and largest group includes the least abundant species (Aysha gr. brevimana 1, Eustala sp5, Wagneriana eupalaestra, Alpaida scriba, Alpaida veniliae, Araneus aff. omnicolor, Araneus sicki, Eustala sp8, Mangora sp2, Mangora sp3, Wagneriana juquia, Alpaida sp2, Araneus blumenau, Eustala sp6, Eustala sp7 and Ocrepeira galianoae). Of 2,029 identified spiders, 1,171 were captured in the Araucaria forest, 612 in grassland areas and 246 in the swamp. Grassland and swamp areas evidenced greater similarity between them than to the Araucaria Forest, regarding presence-absence of spider species in T. lactitarse's diet, as well as regarding species abundance in these habitats. The juvenile number (56%) was significantly higher than the female (38%) and male (6%) percentages.

Prey selection in the trap-nesting wasp Trypoxylon (Trypargilum) opacum Brèthes (Hymenprtera; Crabronidae) / Seleção de presas por vespa que nidifica em ninhos-armadilha Trypoxylon (Trypargilum) opacum Brèthes (Hymenprtera; Crabronidae)

The purpose of our research was to document and discuss the temporal patterns of prey use shown by the trap-nesting wasp Trypoxylon opacum in two different habitats in Southern Brazil. It was carried out from December 2001 to December 2004. Twenty nine species belonging to five families of spiders were captured by T. opacum. Araneidae was the most captured family and has been strongly represented by the genus Eustala. Through Bray-Curtis´s coefficient and the unweighted pair group method average (UPGMA), the spiders can be divided into three groups: the smaller group includes the most abundant species (Alpaida sp2, Bertrana rufostriata, Eustala sp1, Eustala sp2, Eustala sp3 and Eustala sp4), the second group includes species with intermediate abundance (Alpaida, Alpaida gracia and Mangora sp2), and the third and largest group includes the less abundant species, (Acacesia villalobosi, Alpaida argenata, Alpaida sp1, Araneus blumenau, Araneus sicki, Crysometa boraceia, Crysometa sp3, Eustala sp8, Eustala sp11, Larinia t-notata, Mangora sp1, Ocrepeira aff gnomo, Sanogasta sp., Sanogasta sp2, Sanogasta sp3, Salticidae sp2, Theridion sp1, Theridion sp2, Wagneriana eupalaestris, Wagneriana iguape). Of 1,053 identified spiders, 362 were captured in the grassland areas and 691 in the swamp, since T. opacum built nests only in these two habitats. The diversity, richness and evenness of spiders in T. opacum nests were higher in grassland than in the swamp.

O objetivo desta pesquisa foi documentar e discutir o padrão temporal de uso de presas por Trypoxylon opacum em dois ambientes diferentes no Sul do Brasil. Ela foi realizada de dezembro de 2001 a dezembro de 2004. Vinte e nove espécies de aranhas pertencentes a cinco famílias foram capturadas por Trypoxylon opacum. Araneidae foi a família mais capturada e foi fortemente representada pelo gênero Eustala. Pelo coeficiente de Bray-Curtis e pela análise de agrupamento, (UPGMA) as aranhas foram divididas em três grupos: o menor deles, incluindo as aranhas mais abundantes na dieta de T. opacum (Alpaida sp2, Bertrana rufostriata, Eustala sp1, Eustala sp2, Eustala sp3 and Eustala sp4); o segundo com as espécies cujas abundâncias foram intermediárias (Alpaida, Alpaida gracia and Mangora sp2); e o terceiro e maior grupo com as espécies pouco abundantes (Acacesia villalobosi, Alpaida argenata, Alpaida sp1, Araneus blumenau, Araneus sicki, Crysometa boraceia, Crysometa sp3, Eustala sp8, Eustala sp11, Larinia t-notata, Mangora sp1, Ocrepeira aff gnomo, Sanogasta sp., Sanogasta sp2, Sanogasta sp3, Salticidae sp2, Theridion sp1, Theridion sp2, Wagneriana eupalaestris, Wagneriana iguape). Das 1.053 aranhas identificadas, 362 foram capturadas em área de campos naturais e 691 em área de várzea, visto que T. opacum fundou ninhos apenas nestes ambientes. A diversidade, a riqueza e a equitabilidade de aranhas nos ninhos de T. opacum foram maiores nas áreas de campos do que naquelas de várzeas.

Patterns of prey selection of Trypoxylon (Trypargilum) lactitarse Saussure (Hymenoptera: Crabronidae) in southern Brazil / Padrões de seleção de presas por Trypoxylon (Trypargilum) lactitarse Saussure (Hymenoptera: Crabronidae) no sul do Brasil

This study was carried out in the Parque Municipal das Araucárias, in the municipality of Guarapuava, southern Brazil. A total of 449 T. lactitarse nests were collected using trap-nests of different diameters. Fifty three species of spiders belonging to 7 families were captured by T. lactitarse. Araneidae was the most captured family and has been strongly represented by the genus Eustala. Through Bray-Curtis's coefficient and the unweighted pair group method average (UPGMA), the spiders species can be divided into 3 groups: the smaller group includes the most abundant species (Eustala sp1, Eustala sp2, Acacesia villalobosi, Alpaida sp1 and Araneus corporosus), the second group includes species with intermediate abundance (Wagneriana iguape, Araneus omnicolor, Eustala sp4, Alpaida grayi, Eustala sp3, Larinia t-notata, Mangora sp1 and Wagneriana iguape), and the third and largest group includes the least abundant species (Aysha gr. brevimana 1, Eustala sp5, Wagneriana eupalaestra, Alpaida scriba, Alpaida veniliae, Araneus aff. omnicolor, Araneus sicki, Eustala sp8, Mangora sp2, Mangora sp3, Wagneriana juquia, Alpaida sp2, Araneus blumenau, Eustala sp6, Eustala sp7 and Ocrepeira galianoae). Of 2,029 identified spiders, 1,171 were captured in the Araucaria forest, 612 in grassland areas and 246 in the swamp. Grassland and swamp areas evidenced greater similarity between them than to the Araucaria Forest, regarding presence-absence of spider species in T. lactitarse's diet, as well as regarding species abundance in these habitats. The juvenile number (56 percent) was significantly higher than the female (38 percent) and male (6 percent) percentages.

Este estudo foi realizado no Parque Municipal das Araucárias, município de Gurarapuava, Sul do Brasil. Através de ninhos armadilhas de diferentes diâmetros, foram coletados 449 ninhos de Trypoxylon lactitarse. Cinqüenta e três espécies de aranhas pertencentes a 7 famílias foram capturadas por T. lactitarse. Araneidae foi a família mais freqüente, sendo fortemente representada pelo gênero Eustala. Através do índice de Bray-Curtis e do método de agrupamento (UPGMA), as espécies de aranhas foram divididas em três grupos: o primeiro e menor deles, formado pelas espécies abundantes (Eustala sp1, Eustala sp2, Acacesia villalobosi, Alpaida sp1 e Araneus corporosus); o segundo, pelas espécies intermediárias (Wagneriana iguape, Araneus omnicolor, Eustala sp4, Alpaida grayi, Eustala sp3, Larinia t-notata, Mangora sp1 e Wagneriana iguape); e o terceiro e maior deles, pelas espécies menos abundantes (Aysha gr. brevimana 1, Eustala sp5, Wagneriana eupalaestra, Alpaida scriba, Alpaida veniliae, Araneus aff. omnicolor, Araneus sicki, Eustala sp8, Mangora sp2, Mangora sp3, Wagneriana juquia, Alpaida sp2, Araneus blumenau, Eustala sp6, Eustala sp7 e Ocrepeira galianoae). Das 2.029 aranhas identificadas, 1.171 foram capturadas na mata de araucárias, 612 no campo e 246 na várzea. As áreas de campo e várzea foram as mais similares entre si, tanto com relação à presença e ausência, quanto com relação à abundância de espécies de aranhas na dieta de T. lactitarse. O número de jovens (56 por cento) foi significativamente maior que a de fêmeas (38 por cento) e de machos (6 por cento).

Cytogenetic analysis of the neotropical spider Nephilengys cruentata (Araneomorphae, tetragnathidae): standard staining, NORs, C-bands and base-specific fluorochromes

O objetivo deste trabalho é caracterizar Nephilengys cruentata em relação ao número diplóide, à morfologia cromossômica, ao tipo de sistema cromossômico de determinação sexual, aos cromossomos portadores de Regiões Organizadoras de Nucléolo (RONs), padrão de bandas C e seqüências AT ou GC repetitivas. As preparações cromossômicas foram submetidas à coloração convencional (Giemsa), à impregnação pelo nitrato de prata, técnica de obtenção de bandas C e à coloração com fluorocromos base-específicos. A análise das células mostrou 2n = 24 e 2n = 26 cromossomos nos embriões e 2n = 26 nas células ovarianas, sendo todos cromossomos acrocêntricos. O braço longo dos pares 1, 2 e 3 apresentou extensa região heteropicnótica negativa quando as metáfases mitóticas foram coradas com Giemsa. Os cromossomos sexuais não mostraram características diferenciais que permitissem distingui-los dos outros cromossomos do complemento. Considerando os números diplóides encontrados em N. cruentata e a predominância do sistema cromossômico de determinação sexual do tipo X1X2 em Tetragnathidae, N. cruentata parece contar com 2n = 24 = 22 + X1X2 nos machos e com 2n = 26 = 22 + X1X1X2X2 nas fêmeas. Os pares 1, 2 e 3 mostraram RONs coincidentes com as regiões heteropicnóticas negativas. Utilizando a técnica de obtenção de bandas C, a região pericentromérica dos cromossomos revelou pequena quantidade ou até mesmo ausência de heterocromatina constitutiva, diferindo do padrão de bandas C descrito em outras espécies de aranhas. Em N. cruentata, os fluorocromos DAPI/DA, DAPI/MM e CMA3/DA revelaram que a heterocromatina constitutiva é rica em bases AT e as RONs apresentam seqüências repetidas de bases GC.