Efecto de las arañas (Arachnida: Araneae) como depredadoras de insectos plaga en cultivos de alfalfa (Medicago sativa) (Fabaceae) en Argentina

Abstract

Effect of spiders (Arachnida: Araneae) as predators of insect pest in alfalfa crops (Medicago sativa) (Fabaceae) in Argentina. Spiders are predators that reduce insect pest populations in agroecosystems. Trials were conducted to measure the selectivity against different insect preys, the daily consumption, effect of predators alone and together with a known number of preys, and the indirect effect of predators on vegetation. For this, experimental units (1x1m) were used covered with a fine plastic mesh. Misumenops pallidus, Oxyopes salticus and Araneus sp. were used as generalist predators, and aphids, weevils, locusts, chrysomelids and Lepidoptera larvae as their potential preys. Among the preys offered, the spiders preferred Lepidoptera larvae compared to the other two pests groups (weevils and aphids). The maximum consumption rate was of 93.33% for Lepidoptera larvae, 25.33% for aphids and 11.67% for weevils. The Q Index values for the three species of spiders showed a positive selectivity only for defoliating larvae. O. salticus showed the highest values of consumption rates while Rachiplusia nu was the most consumed. The maximum value of consumption in 24 hours was showed by O. salticus on R. nu (C)=2.8. The association of several species of predatory spiders increased the total number of insects captured, and also showed that the addition of spiders caused a decrease in the number of leaves damaged by the effect of lepidopterous larvae.

The diet of the black widow spider Latrodectus mirabilis (Theridiidae) in two cereal crops of central Argentina

“…There are several studies of diet and feeding behavior involving Latrodectus species all over the world (Shulov, 1940;Ross, 1981;Mackay, 1982;Nyffeler et al, 1988;Rocha Dias & Kobler, 1999;Hódar & Sánchez-Piñero, 2002;Bertani et al, 2008;Johnson et al, 2011;Salomon, 2011). However, in Argentina, studies on diet composition and prey selection are scarce; highlighting that from Thomisidae, Lycosidae, Araneidae and Oxyopidae, conducted with species in soybean and alfalfa crops (Cheli et al, 2006;González et al, 2009;Armendano & González, 2011). Nonetheless, these studies did not involve diet composition at the field.…”

Diversidad espacial y temporal de arañas en microhábitats de cultivos de Citrus sinensis, (Rutaceae) Corrientes, Argentina

“…Particularmente Uloboridae también fue poco abundante en otros cultivos (Dean, Sterling & Horner, 1982) y no se registró en alfalfa y algodón (Armendano & González, 2011;Almada et al, 2012). No obstante abundan en el follaje de los cultivos de Citrus en la India (Keswani, 2014) y en otros ambientes como en las selvas tropicales (Florez, 2000), en los bosques del Distrito Oriental Húmedo del Chaco (Avalos et al, 2009;Escobar et al, 2012) y en plantaciones de pinos (Avalos et al, 2018).…”

“…Entre estos organismos, las arañas adquieren cada vez mayor importancia debido a su capacidad de regular y evitar daños producidos por los diversos fitófagos que atacan a los cultivos (Barrientos, Villalba, Alvis-Davila, & Garcia-Mar, 2010). De este modo, en los sistemas agrícolas los estudios referidos a Araneae han ido incrementándose progresivamente (Riechert & Lockley, 1984;Nyffeler, Sterling, & Dean, 1994;Lee & Kim, 2001;Armendano & González, 2011;Almada, Sosa, & González, 2012). Particularmente en cultivos de cítricos se pueden citar los realizados por Carroll, 1980;Mansour & Whitecomb, 1986;Van Den Berg, Dippenaar-Schoeman, Deacon, & Anderson, 1992;Breene, Dean, & Meagher, 1993;Benamú Pino, 2004;Avalos, Bar, Oscherov, & González, 2013; que focalizan la fauna completa de arañas lo cual cobra importancia para el control de las poblaciones de algunos fitófagos (Foelix, 1996).…”

Impact ofCheiracanthium pelasgicum(Araneae: Miturgidae) andChrysoperla carnea(Neuroptera: Chrysopidae) intraguild predation on the potential control of cotton pestHelicoverpa armigera(Lepidoptera: Noctuidae)

“…crab spiders; Thomisidae). Previous reports have noted the importance of cursorial spiders (Miturgidae, Philodromidae, Anyphaenidae, Oxyopidae and Salticidae families) in woody and arable crops (Armendano & González, 2011;Chen, You, & Chen, 2011;Mansour & Whitecomb, 1986;Morris, Symondson, Kidd, & Campos, 1999;Pekár & Kocourek, 2004). In cotton crops, cursorial species appear to be among the most abundant spider groups (Mansour, 1987;Warui, Villet, & Young, 2004), preying not only on lepidopteran cotton-pest larvae but also on eggs (Pfannenstiel, 2008).…”