Preferencia alimentaria de arañas Misumenops pallidus (Keyserling) (Araneae, Thomisidae) sobre potenciales insectos presa en cultivos de alfalfa

CHELI, GERMÁN HORACIO; A. ARMENDANO; A. GONZALEZ

REVISTA DE BIOLOGíA TROPICAL

Universidad de Costa Rica

Lugar: San José; Año: 2006 vol. 54 p. 505 - 513

0034-7744

Abstract. Feeding preferences of the spider Misumenops pallidus (Araneae: Thomisidae) on potential prey insects from alfalfa crops. The spider Misumenops pallidus (Thomisidae) is commonly found in alfalfa crops. We studied its predatory preferences on potential insect prey, particularly regarding agroecosystems pests. Two kinds of tests were done under normal laboratory conditions: simultaneous presentation of prey (n= 215) and alternative prey test (n= 45). The spiders preferred insects that were mobile, small, without defensive glands and with thin exoskeletons. According to the amount of prey consumed, we established four predation levels: high (> 55%, on adult Drosophila melanogaster flies); intermediate (30% -55% on the defoliator larvae ofMisumenops pallidus (Araneae: Thomisidae) on potential prey insects from alfalfa crops. The spider Misumenops pallidus (Thomisidae) is commonly found in alfalfa crops. We studied its predatory preferences on potential insect prey, particularly regarding agroecosystems pests. Two kinds of tests were done under normal laboratory conditions: simultaneous presentation of prey (n= 215) and alternative prey test (n= 45). The spiders preferred insects that were mobile, small, without defensive glands and with thin exoskeletons. According to the amount of prey consumed, we established four predation levels: high (> 55%, on adult Drosophila melanogaster flies); intermediate (30% -55% on the defoliator larvae ofThe spider Misumenops pallidus (Thomisidae) is commonly found in alfalfa crops. We studied its predatory preferences on potential insect prey, particularly regarding agroecosystems pests. Two kinds of tests were done under normal laboratory conditions: simultaneous presentation of prey (n= 215) and alternative prey test (n= 45). The spiders preferred insects that were mobile, small, without defensive glands and with thin exoskeletons. According to the amount of prey consumed, we established four predation levels: high (> 55%, on adult Drosophila melanogaster flies); intermediate (30% -55% on the defoliator larvae ofDrosophila melanogaster flies); intermediate (30% -55% on the defoliator larvae of Rachiplusia nu and adult heteropterans: Horciasinus argentinus and Halticus spegazzinii); and low (10%- 30% on the chrysomelids Colapsis sp. and Diabrotica speciosa). The pentatomid Piezodorus guildinii, the curculionidand adult heteropterans: Horciasinus argentinus and Halticus spegazzinii); and low (10%- 30% on the chrysomelids Colapsis sp. and Diabrotica speciosa). The pentatomid Piezodorus guildinii, the curculionidColapsis sp. and Diabrotica speciosa). The pentatomid Piezodorus guildinii, the curculionid Naupactus sp. and the aphid Acyrthosiphom pisum were not accepted as food. Once the spider captured a prey item it did not accept another, independently of prey item species (82% of trials). Rev. Biol. Trop. 54(2): 505- 513. Epub 2006 Jun 01.sp. and the aphid Acyrthosiphom pisum were not accepted as food. Once the spider captured a prey item it did not accept another, independently of prey item species (82% of trials). Rev. Biol. Trop. 54(2): 505- 513. Epub 2006 Jun 01. Key words: araneae, Thomisidae, Misumenops pallidus, predation, prey preference, alfalfa.araneae, Thomisidae, Misumenops pallidus, predation, prey preference, alfalfa.