Diversidade de aranhas de solo em cultivos de milho (Zea mays)

Abstract

ResumoEstudos sobre a diversidade e abundância de aranhas podem prover uma rica base de informações sobre o grau de integridade dos sistemas agrícolas em que se encontram. No milho transgênico as proteínas de Bacillus thuringiensis são expressas em grandes quantidades nos tecidos verdes das plantas, podendo afetar a comunidade de artrópodes. Portanto, o objetivo deste trabalho foi identificar a diversidade de aranhas associadas às cultivares de milho transgênico e convencional. Foram realizadas coletas com pitfall em talhões de milho Transgênico e Convencional durante todo o ciclo da cultura, em Cruz Alta, RS. Foram coletadas 559 aranhas, sendo 266 aranhas no milho transgênico e 293 aranhas no milho convencional. Foi determinado um total de 11 famílias e os indivíduos adultos distribuídos em 27 morfoespécies. As famílias com o maior número de representantes foram Linyphiidae (29,70%), Theridiidae (5,72%) e Lycosidae (5,01% AbstractStudies carried out on the diversity and abundance of spiders may provide a rich information base on the degree of integrity of agricultural systems where they are found. In transgenic corn, Bacillus thuringiensis proteins are expressed in great amounts in plant tissues and may affect arthropod communities. Thus, the main goal of this work was to identify the spider diversity associated to transgenic and conventional corn hybrids. Pitfall collections were performed in conventional and transgenic corn plots during the 2010/2011 crop season, at the experimental field of the Agronomy Course of the University of Cruz Alta, RS. A total of 559 spiders were collected, from which 263 were adults and 296 young individuals. In the transgenic corn 266 spiders were collected and in the conventional one 293. Eleven families were determined and the adult individuals grouped in 27 morphospecies. Families with the largest number of representatives were Linyphiidae (29.70%), Theridiidae (5.72%) and Lycosidae

Spider community responds to litter complexity: insights from a small-scale experiment in an exotic pine stand

“…The spider community colonizing our experiment from this stand was mostly represented by spiders displaying web-building strategy, more specifically space web weavers (Linyphiidae and Theridiidae; Dias et al, 2012), and by ground hunters (Salticidae) in a little diminished proportion. Analogous pattern regarding these dominant ground families was also registered in Da Silva et al (2014) for corn plantations, and Rodrigues et al (2010) for Eucalyptus plantations in Rio Grande do Sul. In this former study, similarly to our results, a species of Thymoites (Linyphiidae) was also found to be very abundant in the leaflitter, being frequent in all sampled sites.…”

“…Specifically in South Brazil, some attempts were done in order to compare spider diversity patterns between agroecosystems and adjacent native ecosystems, such as the studies of Baldissera et al (2008) in tree plantations, including pine, and native Araucaria forest, Rodrigues et al (2009) in rice field, grassland and native forest, and Rodrigues et al (2010) in Eucalyptus plantations and natural grasslands. Other studies in agroecosystems in South Brazil describe spider assemblages, for example, in olive groves (Ricalde et al, 2016), corn plantations (Da Silva et al, 2014), citrus groves (Ott et al, 2007) and irrigated rice (Rodrigues et al, 2008). Here we also expect to contribute with a very first view of the ground spider assemblages inhabiting pine plantations in the state of Rio Grande do Sul.…”

Natural enemies in alternative plants during the soybean and corn offseason in Cruz Alta, Rio Grande do Sul

“…Lycosa spp. is considered an important biological controller of the general type, being present in several environments including crops such as maize (Silva, Ribeiro, & Lúcio, 2014). A. bicornis had the highest population density followed by E. angustifolium and C. distichophylla.…”

Field evaluation of sweet corn varieties for their potential as a trap crop forHelicoverpa zeaunder tropical conditions

“…We mainly observed hunting spiders. We expected to find wolf spiders (Lycosidae) and jumping spiders (Salticidae) in our sweet corn plots because our study site was the same as that used for a study by Mollot et al (2014) on ground-dwelling predators in banana (Nyffeler 1999;Pfannenstiel 2008;Da Silva et al 2014). Predation of a closely related species, Helicoverpa armigera, by spiders was also suggested by Ratnadass et al (2014).…”