A review of the South American species of Heilus Kuschel, 1955 (Curculionidae: Molytinae: Molytini: Hylobiina) with emphasis on those from Brazil.

The fourteen described South American species of Heilus (Curculionidae, Molytinae, Molytini, Hylobiina) are reviewed for the first time. Eleven species are redescribed based on specimens (almost exclusively from Brazil) examined by us: H. bistigma (Hustache, 1938), H. faldermanni (Boheman, 1836), H. fasciculatus (Boheman, 1843), H. freyreissi (Boheman, 1836), H. inaequalis (Boheman, 1836) [= type species of the genus], H. iniquus (Kirsch, 1874), H. myops (Boheman, 1836), H. ochrifer (Boheman, 1843), H. pupillatus (Olivier, 1790), H. rufescens (Boheman, 1836), and H. tuberculosus (Perty, 1832). Diagnoses of one additional Brazilian species, Heilus admixtus (Hustache, 1938), and two additional South American species, H. asperulus (Erichson, 1847), and H. inornatus (Kirsch, 1874), are presented based on the literature and by examination of images of the type material. Integument texture and the variations in the patterns of maculation are the main characteristics used for species identification. Geographic distribution, descriptions of male and female genitalia are provided for eleven redescribed species, together with habitus photographs, and an identification key to the fourteen described South American species.

Vertical and time distribution of Pseudoscorpiones (Arthropoda: Arachnida) in a floodplain forest in the Brazilian Pantanal / Distribución vertical y temporal de Pseudoscorpiones (Arthropoda: Arachnida) en un bosque inundable del Pantanal brasileño

AbstractPseudoscorpions embrace a diverse group of arachnids with approximately 3 500 species that occur in various habitats, such as soil, leaf litter, caves and canopies. This study aimed at evaluating the relationship between the pseudoscorpion assemblages in soil, termite nests, tree trunks and canopies, as well as the temporal distribution as to the abundance and richness of species in these habitats. For this purpose different sampling techniques were applied in an integrated manner in distinct habitats of a seasonally flooded monodominant forest in the Northern Pantanal of Mato Grosso, Brazil. Data regarding the abundance and richness of assemblage species were organized by means of the Non-Metric Multidimensional Scaling (NMDS). A total of 2 068 Pseudoscorpiones distributed in seven families and 18 species were captured. Chernetidae (8 spp.) and Withiidae (5 spp.) predominated, while Atemnidae, Cheiridiidae, Geogarypidae, Lechytiidae and Olpiidae were present with only one species each. Terrestrial fauna was more abundant (1 035 ind.; 50.0 % of the total catch) with three families and 10 species. In the arboreal fauna (712 ind.; 34.4 %), four families and 13 species were found. Termite mounds (321 ind.; 15.6 %) corresponded to the habitat with the least number of individuals, however, five families and nine species were identified, including Parachernes sp. 2, Geogarypus sp. and Olpiolum sp., not found in other analyzed habitats in this forest. The analyses did not show any temporal variation as to abundance or richness of Pseudoscorpiones in each evaluated habitat; however, the analysis showed that the edaphic environment (soil + termite nests), tree trunks and tree canopies are distinct habitats in relation to the composition of the assemblage. The occurrence of typical terricolous (e.g. Parawithius sp., Withiidae gen. sp. and Parachernes sp.) and other arboricolous (e.g. Cheiridium sp., Americhernes sp. and Lustrochernes sp.) species highlights the vertical stratification of the assemblage present in this floodplain forest in the Pantanal of Mato Grosso.

ResumenLos Pseudoescorpiones comprenden un diversificado grupo de arácnidos con aproximadamente 3 500 especies que se han encontrado en varios hábitats como suelo, hojarasca, cuevas y copas de árboles. Este estudio tiene como objetivo evaluar la relación entre la comunidad de Pseudoscorpiones presentes en el suelo, nidos de termitas (termiteros), troncos y copas de árboles, así como también la distribución temporal de la abundancia y riqueza de especies en estos hábitats. Para esto, se usaron diferentes técnicas de muestreo en hábitats de un Bosque Monodominante Estacionalmente Inundado en la región norte del Pantanal, Estado Mato Grosso, Brasil. Datos referentes a abundancia y riqueza de especies del ensamble fueron ordenados por Escalamiento Multidimensional No Métrico (NMDS). Fueron capturados 2 068 Pseudoscorpiones distribuidos en siete familias y 18 especies. Chernetidae (8 spp.) y Withiidae (5 spp.) predominaron. Mientras Atemnidae, Cheiridiidae, Geogarypidae, Lechytiidae y Olpiidae fueron registradas con una especie en cada una. La fauna terrícola fue más abundante (1 035 ind.; 50.0 % de la captura total), con tres familias y 10 especies. Para la fauna arborícola (712 ind.; 34.4 %), cuatro familias y 13 especies fueron registradas. Los termiteros (321 ind.; 15.6 %) representaron el hábitat con menor número de individuos; sin embargo, fueron identificadas cinco familias y nueve especies, incluyendo Parachernes sp. 2, Geogarypus sp. y Olpiolum sp., que no se encuentra en otros hábitats analizados en este bosque. Los análisis estadísticos no evidenciaron variación temporal en la distribución de abundancia y riqueza de Pseudoscorpiones en cada hábitat evaluado; no obstante, demostraron que el ambiente edáfico (suelo y termiteros), troncos y copas de árboles son distintos en relación a la composición de la comunidad. La presencia de especies típicamente terrícolas (e.g. Parawithius sp., Withiidae gen. sp. y Parachernes sp.) y otras arborícolas (e.g. Cheiridium sp., Americhernes sp. y Lustrochernes sp.) evidencian una estratificación vertical de la comunidad de Pseudoscorpiones presente en Bosques Inundables del Pantanal brasileño.

Vertical and time distribution of Pseudoscorpiones (Arthropoda: Arachnida) in a floodplain forest in the Brazilian Pantanal

Pseudoscorpions embrace a diverse group of arachnids with approximately 3 500 species that occur in various habitats, such as soil, leaf litter, caves and canopies. This study aimed at evaluating the relationship between the pseudoscorpion assemblages in soil, termite nests, tree trunks and canopies, as well as the temporal distribution as to the abundance and richness of species in these habitats. For this purpose different sampling techniques were applied in an integrated manner in distinct habitats of a seasonally flooded monodominant forest in the Northern Pantanal of Mato Grosso, Brazil. Data regarding the abundance and richness of assemblage species were organized by means of the Non-Metric Multidimensional Scaling (NMDS). A total of 2 068 Pseudoscorpiones distributed in seven families and 18 species were captured. Chernetidae (8 spp.) and Withiidae (5 spp.) predominated, while Atemnidae, Cheiridiidae, Geogarypidae, Lechytiidae and Olpiidae were present with only one species each. Terrestrial fauna was more abundant (1 035 ind.; 50.0 % of the total catch) with three families and 10 species. In the arboreal fauna (712 ind.; 34.4 %), four families and 13 species were found. Termite mounds (321 ind.; 15.6 %) corresponded to the habitat with the least number of individuals, however, five families and nine species were identified, including Parachernes sp. 2, Geogalypus sp. and Olpiolum sp., not found in other analyzed habitats in this forest. The analyses did not show any temporal variation as to abundance or richness of Pseudoscorpiones in each evaluated habitat; however, the analysis showed that the edaphic environment (soil + termite nests), tree trunks and tree canopies are distinct habitats in relation to the composition of the assemblage. The occurrence of typical terricolous (e.g. Parawithius sp., Withiidae gen. sp. and Parachernes sp.) and other arboricolous (e.g. Cheiridium sp., Americhernes sp. and Lustrochernes sp.) species highlights the vertical stratification of the assemblage present in this floodplain forest in the Pantanal of Mato Grosso.

Functionality of the plastron in adults of Neochetina eichhorniae Warner (Coleoptera, Curculionidae): aspects of the integument coating and submersion laboratory experiments / Funcionalidade do plastrão em adultos de Neochetina eichhorniae Warner (Coleoptera, Curculionidae): aspectos do revestimento tegumentar e experimentos laboratoriais de submersão

The plastron theory was tested in adults of Neochetina eichhorniae Warner, 1970, through the analysis of the structure that coats these insects' integument and also through submersion laboratorial experiments. The tegument processes were recognized in three types: agglutinated scales with large perforations, plumose scales of varied sizes and shapes, and hairs. The experiments were carried out on 264 adult individuals which were kept submerged at different time intervals (n = 11) and in two types of treatment, natural non-aerated water and previously boiled water, with four repetitions for each treatment. The tests showed a maximum mortality after 24 hours of immersion in the previously boiled water treatment. The survival of the adults was negative and significantly correlated with the types of treatment employed and within the different time intervals. The values of oxygen dissolved in water (mg/l) differed significantly within the types of treatment employed. They were positively correlated with the survival of the adults in the two types of treatment, although more markedly in the treatment with previously boiled water. The mortality of adults after 24 hours of submersion in the treatment with previously boiled water may be associated with the physical-chemical conditions of the non-tested water in this study, such as low surface tension and concentration of solutes. These results suggest plastron functionality in the adults of this species.

A teoria plastrão foi testada em adultos de Neochetina eichhorniae Warner, 1970, por meio da análise da estrutura que reveste o tegumento destes insetos e em experimentos laboratoriais de submersão. Os processos tegumentares foram reconhecidos em três tipos: escamas aglutinadas e com perfurações largas; escamas plumosas de tamanhos e formas variadas; e pêlos. Os experimentos realizados com 264 indivíduos adultos os quais permaneciam submersos por diferentes intervalos de tempo (n = 11) e em dois tratamentos, água natural não aerada e água previamente fervida, com quatro repetições para cada tratamento, revelaram uma mortalidade máxima após 24 horas de mergulho no tratamento água previamente fervida. A sobrevivência dos adultos foi negativa e significativamente correlacionada com os tratamentos empregados e entre os diferentes intervalos de tempo. Os valores de oxigênio dissolvido (mg/l) na água diferiram significativamente entre os tratamentos aplicados, sendo positivamente correlacionado com a sobrevivência dos adultos nos dois tratamentos, embora mais acentuadamente no tratamento com água previamente fervida. A mortalidade dos adultos após 24 horas de mergulho no tratamento com água previamente fervida pode estar associada às condições físico-químicas da água não testadas neste estudo, como, por exemplo, baixa tensão superficial e concentração de solutos. Estes resultados sugerem uma funcionalidade do plastrão nos adultos desta espécie.

Comunidade edáfica de Araneae (Arthropoda, Arachnida) em uma floresta sazonalmente inundável na região Norte do Pantanal de Mato Grosso, Brasil / Community of ground Araneae (Arthropoda, Arachnida) in a seasonally flooded forest in the Northern region of Pantanal of Mato Grosso, Brazil

Este estudo teve como objetivo avaliar a composição da comunidade edáfica de Araneae de uma floresta sazonalmente inundável na região norte do Pantanal de Mato Grosso, tendo como base sua densidade de atividade e emergência. Foram empregadas armadilhas de solo tipo pitfall-trap para avaliação da atividade sobre o solo, e fotoecletores de solo para verificar a densidade de emergência ao longo de todos os períodos sazonais desta região, entre janeiro de 2004 e janeiro de 2005. Como resultado obteve-se um total de 2.233 aranhas, 1.314 indivíduos obtidos com armadilhas pitfall (29 famílias e 35 gêneros) e 919 com fotoecletores de solo (27 famílias e 22 gêneros). Oonopidae (335 ind.: 15,0 por cento), Corinnidae (310 ind.; 13,9 por cento), Gnaphosidae (289 ind.; 12,9 por cento) e Ctenidae (248 ind.; 11,1 por cento) corresponderam às principais representantes desta comunidade, bem como àquelas com maior densidade de atividade sobre a superfície do solo, enquanto Salticidae (177 ind.; 19,3 por cento), Oonopidae (126 ind.; 13,7 por cento) e Gnaphosidae (114 ind.; 12,4 por cento) foram aquelas com maior densidade de emergência. Doze agrupamentos de guildas comportamentais foram identificados, sete representaram aranhas caçadoras e cinco tecelãs. As análises referentes à variação temporal da atividade e emergência desta comunidade evidenciaram que a influência de fatores abióticos como a pluviosidade e a inundação da floresta são determinantes para sua estruturação, influenciando a ocorrência de táxons como Salticidae, Corinnidae e Oonopidae.

This study aimed to evaluate the community composition of ground dwelling Araneae in a seasonally flooded forest in the Northern region of Pantanal of Mato Grosso, based on its density and emergency activity. Pitfall traps were used to estimate the ground activity and ground photoeclectors to verify the density of emergency throughout the seasonal periods between January 2004 and January 2005. A total of 2,233 spiders were collected, 1,314 with pitfall traps (29 families and 35 genera) and 919 with ground photoeclectors (27 families and 22 genera). Oonopidae (335 ind.: 15,0 percent), Corinnidae (310 ind.; 13,9 percent), Gnaphosidae (289 ind.; 12,9 percent) and Ctenidae (248 ind.; 11,1 percent) were the main representatives of the community, as well as those with higher density of activity on the soil surface, while Salticidae (177 ind.; 19,3 percent), Oonopidae (126 ind.; 13,7 percent) and Gnaphosidae (114 ind.; 12,4 percent) were those with higher density of emergency. Twelve groups of behavioral guilds were identified, seven were hunting spiders and five were weavers. The analyses concerning temporal variation of the activity and emergence of this community demonstrate that the influence of abiotic factors, such as rainfall and flooding of the forest, are determinant to its structure, influencing the occurrence of groups as Salticidae, Corinnidae and Oonopidae.

Morphological aspects of the genitalia of seven species of Heilus Kuschel (Coleoptera, Curculionidae) / Aspectos morfológicos da genitália de sete espécies de Heilus Kuschel (Coleoptera, Curculionidae)

Morphological aspects of the male and female genitalia and their associated sclerites, abdominal tergite and sternite 8, are described, illustrated and discussed for seven species of Heilus Kuschel 1955 of tribe and subtribe Hylobiini-Hylobiina. The seven species are H. faldermanni (Boheman, 1836); H. fasciculatus (Boheman, 1843); H. freyreissi (Boheman, 1836); H. myops (Boheman, 1836); H. pupillatus (Olivier, 1790); H. rufescens (Boheman, 1836) and H. tuberculosus (Perty, 1832).

Aspectos morfológicos da genitália masculina e feminina e seus escleritos associados, tergito e esternito abdominal 8, de sete espécies de Heilus Kuschel 1955 da tribo e subtribo Hylobiini-Hylobiina, são descritos, ilustrados e discutidos. As sete espécies são H. faldermanni (Boheman, 1836); H. fasciculatus (Boheman, 1843); H. freyreissi (Boheman, 1836); H. myops (Boheman, 1836); H. pupillatus (Olivier, 1790); H. rufescens (Boheman, 1836) e H. tuberculosus (Perty, 1832).

Curculionídeos associados à Pistia stratiotes L. (Araceae) na Amazônia Central, com novos registros para Argentinorhynchus Brèthes (Coleoptera, Curculionidae) / Weevils associated with Pistia stratiotes L. (Araceae) in the Central Amazon Region, with new records for Argentinorhynchus Brèthes (Coleoptera, Curculionidae)

São apresentados, pela primeira vez para o Brasil, dados sobre a ocorrência de dez espécies de curculionídeos associadas à Pistia stratiotes L. (Araceae), provenientes da Ilha de Marchantaria, Manaus (Amazonas, Brasil). Durante o período de março a agosto de 2005 foram amostrados 809 espécimens de curculionídeos sobre P. stratiotes, distribuídos em nove espécies alocadas em cinco gêneros de Stenopelmini, e uma espécie não identificada pertencente à Cryptorhynchinae. Dentre os Stenopelmini, Argentinorhynchus breyeri Brèthes, 1910 (N = 665) foi a espécie dominante, com a maior abundância em julho (N = 189), e a menor em agosto (N = 11); Ochetina uniformis Pascoe, 1881 (N = 63), Neochetina bruchi Hustache, 1926 (N = 45), Neohydronomus pulchellus Hustache, 1926 (N = 15), Neohydronomus affinis Hustache, 1926 (N = 10), A. squamosus (Hustache, 1926) (N = 5), Neochetina eichhorniae Warner, 1970 (N = 4), A. minimus O'Brien & Wibmer, 1989b (N = 1) e Tanysphiroideus sp. (N = 1) apresentaram abundância inferior. Além disto, registra-se para o Brasil a co-ocorrência de A. breyeri, A. minimus e A. squamosus sobre P. stratiotes, e para o estado do Amazonas, o primeiro registro de A. minimus e A. squamosus.

Data on the occurrence of ten weevils species associated with Pistia stratiotes L. (Araceae), from Ilha de Marchantaria, Manaus (Amazonas, Brazil) are presented for the first time. During the period from March to August 2005, 809 weevils specimens were sampled on P. stratiotes, distributed across nine species allocated in five genera of Stenopelmini, in addition to one unidentified species in the Cryptorhynchinae. Among the Stenopelmini, Argentinorhynchus breyeri Brèthes, 1910 (N = 665) was the dominant species, with the highest abundance in July (N = 189) and the lowest in August (N = 11), while Ochetina uniformis Pascoe, 1881 (N = 63), Neochetina bruchi Hustache, 1926 (N = 45), Neohydronomus pulchellus Hustache, 1926 (N = 15), Neohydronomus affinis Hustache, 1926 (N = 10), A. squamosus (Hustache, 1926) (N = 5), Neochetina eichhorniae Warner, 1970 (N = 4), A. minimus O'Brien & Wibmer, 1989b (N = 1), and Tanysphiroideus sp. (N = 1) had lower abundances. In addition, the co-occurrences of A. breyeri, A. minimus, and A. squamosus on P. stratiotes were recorded for Brazil and the first records of A. minimus and A. squamosus were observed for the State of Amazonas.

Surface swimming behavior of the curculionid Ochetina uniformis Pascoe (Erirhininae, Stenopelmini) and Ludovix fasciatus (Gyllenhal) (Curculioninae, Erodiscini)

The swimming behavior exhibited by specimens of L. fasciatus and O. uniformis was analyzed frame-by-frame with video observation recorded with a digital camera, attached to a stereomicroscope. Adults of O. uniformis, an aquatic insect, swim with all three pairs of legs. During the process of swimming the majority of the abdomen and rostrum remain submerged, part of the fore and hind tibiae remain above the surface, while the mid tibiae remain submerged. The mesothoracic legs, during the power-stroke stage, provide the greatest thrust while the metathoracic legs provide the least forward propulsion. The prothoracic legs, extended forward, help to direct the swimming. The semi-aquatic specie L. fasciatus shows the same swimming style as O. uniformis, that is, with movement of all the three pairs of legs; the mesothoracic legs are responsible for the main propulsion. The insect body remains on the water surface during the process of swimming, while the legs remain submerged. Both species complete a swimming cycle in 0.33 and 0.32 seconds, respectively, with an average speed of 1.38 cm/s and a maximum and minimum swimming duration time of 11.15 and 5.05 minutes, respectively, for L. fasciatus. The swimming behavior exhibited by O. uniformis and L. fasciatus corresponds to the style known as a breast strokelike maneuver. This is the first record of this kind of swimming for both species here observed and increases to seven the number of genera of Curculionidae exhibiting this behavior.

O comportamento de nado exibido por indivíduos de L. fasciatus e O. uniformis foi analisado quadro a quadro através de imagens obtidas com o auxílio de uma câmera fotográfica digital com opção de vídeo, acoplada a um estereomicroscópio. Foi demonstrado que O. uniformis, espécie aquática, nada com o auxílio dos três pares de pernas. Durante este processo a maior parte do abdome e rostro localizam-se abaixo da superfície da água, parte das tíbias anteriores e posteriores acima da superfície, enquanto as médias permanecem submersas durante o nado. As pernas metatorácicas, durante a "braçada", impulsionam fracamente o inseto para frente, enquanto que as mesotorácicas são as responsáveis por uma maior propulsão. As pernas protorácicas, estendidas anteriormente, ajudam na orientação do nado. A espécie L. fasciatus, de hábito semi-aquático, apresenta o mesmo estilo de nado como em O. uniformis, também realizado com auxilio dos três pares de pernas, sendo as mesotorácicas, responsáveis pela maior propulsão. O corpo do inseto permanece na superfície da água durante todo o processo, porém as pernas encontram-se mergulhadas. Ambas as espécies, O. uniformis e L. fasciatus, completam um ciclo do nado em cerca de 0,33 e 0,32 segundos, respectivamente, com uma velocidade média de 1,38 cm/s e tempo máximo e mínimo de permanência de nado 11,15 e 5,05 minutos, respectivamente, para L. fasciatus. O comportamento de nado exibido por O. uniformis e L. fasciatus corresponde ao estilo de nado conhecido como manobra semelhante ao nado peito (breast strok-like maneuver). Trata-se do primeiro registro para ambas as espécies elevando para sete o número de gêneros de Curculionidae conhecidos com tal comportamento.