Abundância e sazonalidade do ácaro-rajado em cultivares de gérbera / Abundance and seasonality of two-spotted spider mite on gerbera cultivars

Neste estudo foi avaliada a abundância e a sazonalidade de Tetranychus urticae Koch, 1836 em três cultivares de Gerbera jamesonii Adlam., em cultivo comercial no sul do Brasil. Para avaliação destes parâmetros foram realizadas amostragens de abril de 2011 a fevereiro de 2012. Os ácaros foram obtidos a partir de flores e folhas retiradas de cada uma das cultivares. No total foram contabilizados 10.640 ácaros e de acordo com os testes, a cultivar "Pink Snow" apresentou maior abundância significativa. A análise estatística não evidenciou diferença entre o número de ácaros presentes nas folhas e flores. Em todas as variedades o maior número de T. urticae foi registrado na primavera.

In this study it was evaluated the abundance and seasonality of Tetranychus urticae Koch, 1836 in three varieties of Gerbera jamesonii Adlam. in a commercial cultivation at the south of Brazil. For the evaluation of these parameters samplings were accomplished from April 2011 to February 2012. The mites were obtained from flowers and leaves removed from each one of the studied varieties. A total of 10,640 mites were counted, and in agreement with the tests, there were a significant larger number of mites in the "Pink Snow" variety. The statistical analysis didn't evidence conclusive differences in the mite numbers between leaves and flowers. In all three varieties the largest number of T. urticae was registered in the spring.

Carabid beetle assemblages in three environments in the Araucaria humid forest of southern Brazil

Carabid beetle assemblages in three environments in the Araucaria humid forest of southern Brazil. Carabidae is composed mainly by ground-dwelling predator beetles. It is the fourth most diverse group within Coleoptera, but its diversity in the Neotropical region is understudied. Here we describe and analyze the diversity of carabid beetles in a region of subtropical rain forest dominated by Araucaria angustifolia with different landscapes. Three areas were chosen in an environmental integrity gradient: primary forests, secondary forests and old Pinus plantations. Pitfall traps were taken monthly, in a total of 14 samples per area. 1733 adult carabid beetles, belonging to 18 species, were sampled. There were differences in richness and abundance between the sampled areas. The total scores followed the same tendency: primary forests (14 species/747 individuals), secondary forests (13/631) and Pinus forests (10/355). An analysis of similarity shows differences in species composition, for both areas and seasons. Galerita lacordarei was the most abundant species for all samples and seasons. Carabid species show similar responses in accordance with habitat heterogeneity and disturbance. The abundance of Galerita lacordarei was influenced by temperature, for all sampled sites. Environmental changes affect the carabid assemblages and decrease diversity, possibly interfering in local dynamics. Seasonality patterns seem to indicate an increase in individual movement during summer, probably in search of resources. It is suggested that microhabitat patchiness is probably an important factor affecting carabid beetle diversity at small spatial scales.

Aranhas e ácaros predadores em copas de tangerineiras Montenegrina, mantidas sob manejo orgânico, em Montenegro, RS / Spiders and predatory mites in the canopies of organically managed Montenegrina tangerine trees, in Montenegro County, RS

O estudo objetivou o levantamento da fauna de aranhas e ácaros com hábito predador, em copas de tangerineiras (Citrus deliciosa var. Montenegrina) em pomar orgânico, situado em Montenegro, RS. Durante um ano, quinzenalmente 24 plantas eram sorteadas e avaliadas em duas regiões da copa, utilizando-se um pano-de-batida (1 m²). Capturou-se o total de 3.129 indivíduos, sendo 2.559 aranhas e 570 ácaros. Em Araneae foram reconhecidas 53 espécies adultas distribuídas em oito famílias, dentre estas, as mais abundantes foram Sphecozone sp. (Linyphiidae) (21,8 por cento) e Chrysso pulcherrima (Mello-Leitão) (Theridiidae) (9,9 por cento). No outono observou-se a maior abundância de jovens e adultos (29,2 por cento) e, na primavera, a maior riqueza de espécies (40). Na primavera também se registraram os maiores valores para os índices de Margalef e Shannon-Wiener, este último, porém, não diferiu significativamente dos das demais estações. Os valores de Simpson, em todas as estações foram semelhantes, indicando o mesmo grau de dominância das espécies. Em Acari registraram-se oito espécies, distribuídas em três famílias, as mais abundantes foram Leptus sp.1 (Erythraeidae) (59,4 por cento) e Amblyseius saopaulus Denmark & Muma (Phytoseiidae) (30 por cento). O outono foi a estação mais rica em número de espécies (oito). No inverno observou-se a maior abundância de indivíduos (47 por cento) e, no verão, a menor (0,88 por cento). Entre os ácaros, Phytoseiidae apresentou a maior riqueza. Entre as aranhas, Anyphaenidae foi a que apresentou a maior abundância e Theridiidae, a maior riqueza de espécies, seguindo assim o padrão já observado para o grupo.

A survey was conducted to study the spider and predatory mite fauna occurring in the canopies of tangerine trees (Citrus deliciosa Tenore, cultivar Montenegrina) of an organically managed orchard, at Montenegro County, RS. During a year, fortnightly, 24 randomly trees were selected and sampled in two canopies areas, by using a sheet of white cloth (1 m²). A total of 3,129 arachnids were collected, being 2,559 spiders and 570 mites. Based on the adults, 53 species of Araneae were recognized, belonging to eight families. Among those, the most abundant were Sphecozone sp. (Linyphiidae) (21.8 percent) and Chrysso pulcherrima (Mello-Leitão) (Theridiidae) (9.9 percent). Autumn exhibited the greatest abundance of young and adults of Araneae (29.2 percent) and spring was the season richest in species (40). Margalef and Shannon-Wiener diversity indexes also showed the highest values in spring. The latter index did not show differences among seasons. Simpson complementary index was equal among seasons, reflecting the same degree of species dominance. In Acari, eight species were identified in three families. The most abundant species were the mites Leptus sp.1 (Erythraeidae) (59.4 percent) and Amblyseius saopaulus Denmark & Muma (Phytoseiidae) (30 percent). Autumn was the season richest in mite species (eight). The highest abundance (47 percent) was observed on winter and the lowest (0.88 percent) on summer. Among mites, Phytoseiidae showed the highest richness. Among the spiders, Anyphaenidae was the most abundant and Theridiidae had the highest species richness, following the patterns observed for the group.

Araneofauna (Arachnida; Araneae) do Parque Estadual do Turvo, Rio Grande do Sul, Brasil / Araneofauna (Arachnida; Araneae) from Parque Estadual do Turvo, Rio Grande do Sul, Brazil

A região Neotropical é considerada pouco amostrada com relação à sua araneofauna, carecendo de inventários padronizados que possam servir de base para estudos de biodiversidade. As aranhas são consideradas como importantes componentes dos ecossistemas florestais e aparentam ser organismos ideais para estudos de padrões de biodiversidade. Neste estudo foi efetuado um levantamento da riqueza e composição da fauna de aranhas do Parque Estadual do Turvo, Rio Grande do Sul, Brasil, local que protege o único remanescente representativo da Floresta do Alto Uruguai no Brasil. Foram realizadas quatro expedições semestrais, durante dois anos, no outono e na primavera (2003-2005). Como principal técnica de coleta foi empregado o guarda-chuva entomológico, com o qual amostou-se a vegetação arbóreo-arbustiva da borda da floresta nas estradas internas do Parque. Adicionalmente, foram utilizadas armadilhas de solo, extratores de Winckler, coletas manuais noturnas e amostragens aleatórias. Índice de diversidade de Shannon-Wiener (H') e curvas de rarefação foram calculados para as coletas com o guarda-chuva entomológico. Incluindo todos os métodos, foram coletadas 8724 aranhas pertencentes a 37 famílias. Cerca de 34 por cento (2946) constituíram-se de aranhas adultas, pertencentes a 31 famílias, 157 gêneros e 447 morfoespécies. A maior riqueza de espécies foi registrada para Salticidae (23 por cento), seguida de Araneidae (18 por cento), Theridiidae (16 por cento) e Thomisidae (9 por cento). Nas amostragens com guarda-chuva entomológico foram registradas 29 famílias; as mais abundantes (incluindo jovens) foram: Salticidae (23 por cento), Araneidae (18 por cento), Thomisidae (14 por cento), Theridiidae (12 por cento) e Anyphaenidae (12 por cento). Dezenove espécies apresentaram abundância superior a 1 por cento do total de indivíduos adultos coletados com esta metodologia. As mais abundantes, foram Thwaitesia affinis O. P.-Cambridge, 1881 (Theridiidae),...

The araneofauna of the Neotropical region can be considered undersurveyed and lacking standardized inventories that can be used as a base for biodiversity studies. Spiders are recognized as important components of forest ecosystems and appear to be good organisms for studies concerning biodiversity standards. A survey was carried out in the Parque Estadual do Turvo, Rio Grande do Sul, Brazil to determine the richness and composition of the spider fauna. The Park is a protection area that includes the only remainder of the Floresta do Alto Uruguai in Brazil. Four expeditions were conducted over the period of two years, in Spring and Autumn (2003-2005). The main sampling technique was the beating tray, sampling the vegetation along the trails inside the park. Additionally, pitfall-traps, Winckler extractors, nocturnal manual collecting and random samplings were used. Shannon-Wiener (H') diversity indices and rarefaction curves were calculated for the beating tray samplings. A total of 8724 spiders belonging to 37 families were collected. Of these, 34 percent (2946) were adults, distributed in 31 families, 157 genera and 447 morphospecies. The richest families were Salticidae (23 percent) followed by Araneidae (18 percent), Theridiidae (16 percent) and Thomisidae (9 percent). In the beating tray samples 29 families were recorded. The most abundant families (including young individuals) were Salticidae (23 percent), Araneidae (18 percent), Thomisidae (14 percent), Theridiidae (12 percent) and Anyphaenidae (12 percent). Nineteen species presented a percentage higher than 1 percent of the total of collected adult individuals. The most abundant being Thwaitesia affinis O. P.-Cambridge, 1881 (Theridiidae), Tariona sp.1 (Salticidae) and Misumenops argenteus (Mello-Leitão, 1929) (Thomisidae). The Spring periods revealed more adult individuals and species and the Shannon-Wiener (H') diversity was considered higher in the periods of Autumn. The rarefaction...