Development and consumption capacity of Chrysoperla externa (Hagen) (Neuroptera, Chrysopidae) fed with Cinara spp. (Hemiptera, Aphididae) under three temperatures

• Autor(a) principal: Cardoso,Josiane T.
• Data de Publicação: 2003
• Outros Autores: Lazzari,Sonia M. N.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Revista Brasileira de Zoologia (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0101-81752003000400002
• topic: Biological control; giant conifer aphids; green lacewing; prey-predator relationship

The giant conifer aphids Cinara pinivora (Wilson, 1919) and Cinara atlantica (Wilson, 1919) (Hemiptera: Aphididae) are pests on Pinus spp. (Pinaceae) in the South and Southeast regions of Brazil. Larvae of Chrysoperla externa (Hagen, 1861) (Neuroptera, Chrysopidae) were observed feeding voraciously on these aphid colonies. In order to evaluate their potential as biological control agents, some biological parameters and their consumption capacity were studied in laboratory. Ten larvae were isolated in plastic vials and fed with aphids of small size (nymphs of 1st and 2nd instars) and 10 with aphids of medium size (nymphs of 3rd and 4th instars), maintained at 15ºC, 20ºC and 25ºC, under 12:12 h photoperiod and 70 ± 10% RH, and observed daily. The egg incubation period was nine days at 20ºC and four days at 25ºC. The mean larval development period for C. externa was 59.5 days; 22.3 days and 10.9 days, respectively at 15ºC, 20ºC and 25ºC. The pupal stage last 23.2 at 20ºC and 11.1 days at 25ºC. Unfortunately, data of egg and pupal development at 15ºC are not available because the rearing chamber overheated. The mortality rate from egg to adult was 46.2% 46.6% and 20.2% at 15ºC, 20ºC and 25ºC, respectively. The average aphid consumption of each C. externa larva to complete its development was 499.1; 341.7 and 215.1 small aphids, and 126.4; 105.6 and 67.0 medium aphids, at 15ºC, 20ºC and 25ºC, respectively. About 80% of the total food consumption was by the 3rd instar larvae. Although the development was faster and viability higher at 25ºC than at the other two temperatures, the consumption was the highest at 15ºC because the larval period was much longer. Therefore, the larvae of C. externa can be regarded as potential biological control agents of Cinara spp. throughout the year and even in cool areas of Southern Brazil during some periods o the year.