Comunidad de arañas (Arachnida, Araneae) del cultivo de alfalfa (Medicago sativa) en Buenos Aires, Argentina

Abstract

Spider community (Arachnida, Araneae) of alfalfa crops (Medicago sativa) in Buenos Aires, Argentina. Over the last decades there has been an increasing interest in the use of natural enemies to control pest insects, including spiders. We studied a spider community in Argentina by sampling every two weeks during 2004-2006 in one-hectare lots. Soil stratum spiders were collected using nets and pitfall traps. A total of 6229 specimens were collected (15 families and 50 species). Seven families were found in the herbal stratum, the most abundant were Thomisidae (n=2012, 32.30%), Araneidae (n=1516, 24.33%) and Oxyopidae (n=604, 9.70%). The soil had 14 families, mainly: Lycosidae (n=629, 10.10%) and Linyphiidae (n=427, 6.85%). Hunting spiders predominated: ambushers (32.99 %); stalkers (11.77%) and ground-runners (10.84%) were less common. The most abundant web building spiders were the orb weavers (27.56%). The diversity indexes were: H´=2.97, Dsp=0.11 and J=0.79, evidencing a moderately diverse spider community with predominance of Misumenops pallidus, Oxyopes salticus, Lycosa poliostoma and L. erythrognatha. The spiders were present throughout the phenological development of the crop with abundance peaks in spring and summer. Rev. Biol. Trop. 58 (2): 757-767. Epub 2010 June 02.

Evaluation of the design effects of different agropastoral systems on the diversity and density of spiders

“…These families coincided partially with those recorded in crops of soybeans, alfalfa, wheat and cotton (Liljesthröm et al, 2002;Beltramo et al, 2006;Armendano & González, 2009Almada et al, 2012, respectively), where Anyphaenidae, Salticidae and Linyphiidae were the main families in terms of their abundance. These families are also represented with greater abundance in livestock systems (Toti et al, 2000;Warui et al, 2005), as well as in reserves and national parks (Corronca & Abdala, 1994;Rubio et al, 2004;Grismado, 2007;Avalos et al, 2009;Rubio, 2015).…”

“…The results showed that the communities of spiders in the North of Santa Fe are affected by the design of fields within agropastoral systems. The araneofauna registered in the studied area represents 43% of the total number of families cited in Argentina (World Spider Catalog, 2016), and the richness of collected species exceeds the values known to the province of Santa Fe in soybean crops (Beltramo et al, 2006) and cotton (Almada et al, 2012) and to that of other regions or other crops studied in the country (Liljesthröm et al, 2002;Armendano & González, 2009;Benamú Pino, 2010).…”

Diversidad de arañas (Araneae, Araneomorphae) en la selva de montaña: un caso de estudio en las Yungas Argentinas

“…Asimismo, la riqueza específica obtenida en esta investigación no difiere a las observadas en otros estudios realizados en selvas tropicales amazónicas (Höfer, 1990;Raizer et al, 2005;Machado Pinto-Leite et al, 2008;Ricetti & Bonaldo, 2008;Bonaldo & Dias, 2010;Carvalho & Avelino, 2010). Aunque en un marco menos comparable, en Argentina existen estudios sobre ecología de comunidades de arañas en agroecosistemas que revelaron niveles de riqueza más bajos, debido sin duda a la pérdida de la heterogeneidad del paisaje: cultivos de soja (Liljesthrom et al, 2002;Beltramo et al, 2006), y alfalfa (Armendano & González, 2010).…”

“…Los estudios sobre arañas exclusivamente en Argentina se enfocaron, en su mayoría, en aspectos taxonómicos y sistemáticos de algunas familias; siendo los trabajos de diversidad principalmente orientados en agroecosistemas con distintos manejos (Liljesthröm et al, 2002;Beltramo et al, 2006;Armendano & González, 2010;Avalos et al, 2013), muy pocos en áreas naturales protegidas (Rubio et al, 2008;Rubio & Moreno, 2010) o en ambientes degradados (Avalos et al, 2007). Aún hay mucho por conocer sobre la fauna nativa de arañas en Argentina, y en especial en áreas con un valor agregado (como las yungas) debido a la diversidad ambiental y biológica y al incremento de la pérdida de muchos de sus hábitats.…”

Spider fauna associated with wheat crops and adjacent habitats in Buenos Aires, Argentina

“…Only few data sets concerning the spider assemblages of arable lands are available. Minervino (1996), Liljesthröm et al (2002), and Beltramo et al (2006) have examined the spider community in soybeans fields, and Armendano and González (2010) in alfalfa crops. According to a recent bibliography of arachnological studies, the present research is the first to study the spider fauna of winter wheat in Argentina.…”