RESUMEN
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.
Asunto(s)
Animales , Citrus/parasitología , Ácaros/clasificación , Arañas/clasificación , BrasilRESUMEN
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 m(2)). 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%) and Chrysso pulcherrima (Mello-Leitão) (Theridiidae) (9.9%). Autumn exhibited the greatest abundance of young and adults of Araneae (29.2%) 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%) and Amblyseius saopaulus Denmark & Muma (Phytoseiidae) (30%). Autumn was the season richest in mite species (eight). The highest abundance (47%) was observed on winter and the lowest (0.88%) 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.
Asunto(s)
Citrus/parasitología , Ácaros/clasificación , Arañas/clasificación , Animales , BrasilRESUMEN
A study was conducted about the Auchenorrhyncha assembly of grassland area with earthmounds of forests at Viamão County, Rio Grande do Sul State from November, 1996 to November, 1997. Forty-four samples were taken with the aid of a square mouth sweeping net. The collections were alleatory made, employing the method of transects. In total 5350 individuals were collected belonging to 38 species and seven families: Cicadellidae (3074), Issidae (1870), Membracidae (379) Dictyopharidae (9), Cercopidae (7), Cixiidae (6) and Delphacidae (1). The commonest species was Nubithia grisescens Stal (Issidae) with 1669 (31.2%) specimens. The homopterans showed a highest density in August (3.38 ind/m³) and the lowest in April (0.32 ind./m³). A total richness of 45 species was estimated by "Jacknife" procedure. Shannon-Wiener's heterogenity index was 2.18. Pielou's homogenity index was 0.60.
Estudou-se a comunidade de auquenorrincos em uma área de campos com capões de mata do município de Viamão, RS no período de novembro de 1996 a novembro de 1997. Realizaram-se 44 coletas semanais utilizando-se uma rede-de-varredura de secção quadrada sobre transectos escolhidos aleatoriamente. No total foram coletados 5350 indivíduos pertencentes a 38 espécies distribuídos em sete famílias: Cicadellidae (3078), Issidae (1870), Membracidae (379), Dictyopharidae (9), Cercopidae (7), Cixiidae (6) e Delphacidae (1). A espécie mais abundante foi Nubithia grisescens Stal (Issidae) com 1669 (31,2%) exemplares coletados. As cigarrinhas apresentaram a maior média de densidade populacional no mês de agosto (3,48 ind/m³) e a menor no mês de abril (0,32 ind/m³) com média anual de 1,61 ind/m³. A estimativa do total de morfoespécies que podem ser encontradas na área, obtida através do cálculo do "Jacknife" foi de 45 morfoespécies. Para o índice de heterogeneidade de Shannon-Wiener obteve-se 2,18. O valor de homogeneidade de Pielou foi de 0,60.