Mites associated to Xylopia aromatica (Lam.) Mart. (Annonaceae) in urban and rural fragments of semidecidual forest

Ácaros associados a Xylopia aromatica (Lam.) Mart. (Annonaceae) em fragmentos urbano e rural de floresta estacional semidecidual. Plantas nativas podem abrigar uma grande diversidade de ácaros, entretanto o estado de conservação dos fragmentos onde estas plantas estão localizadas pode influenciar a estrutura da comunidade. em ambientes homogêneos a diversidade geralmente é menor devido à dominância de uma ou poucas espécies. O objetivo deste trabalho foi conhecer a acarofauna associada a Xylopia aromatica (Lam.) Mart. (Annonaceae) em dois fragmentos de floresta estacional semidecidual, sendo um rural e outro urbano. Amostramos mensalmente no período de abril de 2007 a março de 2008, sete indivíduos de X. aromatica em cada um dos dois fragmentos. Índices descritores de diversidade, dominância e de equitabilidade foram aplicados para verificar os padrões ecológicos da comunidade, além do Teste t de Student para comparar a abundância de ácaros entre os fragmentos. Foram coletados 27.365 ácaros de 37 espécies pertencentes a 11 famílias. Calacarus sp. (Eriophyidae) foi a espécie mais abundante, representando 73% do total amostrado. A abundância total foi maior no fragmento urbano (67,7%), com a diversidade atingindo somente 25% da máxima teórica prevista. Provavelmente, estes valores foram influenciados pela localização deste fragmento na área urbana, sendo mais homogêneo e submetido à presença de poluentes atmosféricos. Dessa forma, X. aromatica pode abrigar uma maior diversidade de ácaros quando inserida em um ecossistema conservado, visto que a maior diversidade de recursos disponíveis permite o estabelecimento de uma acarofauna mais rica e diversa.Mites associated to Xylopia aromatica (Lam.) Mart. (Annonaceae) in urban and rural fragments of semidecidual forest. Native plants can shelter a great diversity of mites. Notwithstanding, the conservation of the forest fragments where the plants are located can influence the structure of the mites community. Generally, in homogenous environments the diversity is lower due to the dominance of one or a few species. In this work, we studied the mite community on Xylopia aromatica (Lam.) Mart. (Annonaceae) in two fragments of semidecidual forest: one on rural and other on urban area. Seven individuals of X. aromatica were monthly sampled from April 2007 to March 2008, in each of these fragments. Descriptive indexes of diversity, dominance and evenness were applied to verify the ecological patterns of the mite community, besides the Student's t-test to compare the abundance between the fragments. We collected 27,365 mites of 37 species belonging to 11 families. Calacarus sp. (Eriophyidae) was the most abundant species, representing 73% of the total sampled. The abundance was greater in the urban fragment (67.7%), with the diversity index reaching only 25% of the theoretical maximum expected. Probably, these values might have been influenced by the location of this fragment in the urban area, being more homogeneous and submitted directly to the presence of atmospheric pollution. In this manner, X. aromatica is able to shelter a higher diversity of mites when inserted in preserved ecosystems, since the highest diversity of available resources allows the establishment of richer and most diverse mite community

Mites from Cerrado fragments and adjacent soybean crops: does the native vegetation help or harm the plantation?

Aiming to recognize the distribution patterns of the mite fauna in soybean crops and to determine the existence of similarity in the composition of species between Cerrado fragments and these plantations, samplings were carried out in 10 areas located in Brazilian Mid-Western and Southeastern regions. Each area was comprised of one fragment of Cerrado sensu stricto and one adjacent soybean crop plantation, with simultaneous samplings carried out on both of them. From the total sampled species, 111 were recorded in the Cerrado and 25 in soybean crops. About 68 % were common in both environments and only eight were exclusively found in soybean. All the species of Phytoseiidae recorded in soybean were also found in the Cerrado. The tetranychid mite Mononychellus planki (McGregor) was the most abundant species (96.3 % of the total individuals) and the only one recorded in every sampled crop. The main occurrence of M. planki was verified in soybean crops using the transgenic cultivar ANTA 82. In general terms, it has been observed that Cerrado fragments do not shelter pest species that may attack soybean and can contribute to the increase of possible predator species in this agroecosystem.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq