Predation as a Mortality Factor in Populations of the Spittlebug, Deois flavopicta Stål (Homoptera: Cercopidae)

• Autor(a) principal: SUJII,EDISON R.
• Data de Publicação: 2002
• Outros Autores: GARCIA,MARIA A., FONTES,ELIANA M.G., O'NEIL,ROBERT J.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Neotropical entomology (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S1519-566X2002000400010
• topic: Insecta; insect community; population dynamics; survival curve

The spittlebug, Deois flavopicta Stål, is the main pest in cultivated pastures of the "Cerrados" (savanna) in the central region of Brazil. The insect has three discrete generations during the rainy season (September-April) and a synchronized population of diapausing eggs during the dry season (May-August). Experiments in cultivated pastures showed that nonspecific predators were able to affect significantly the mortality rates of diapausing eggs and nymphs of D. flavopicta. Predation was a density independent mortality factor that reduced diapausing eggs by approximately 60% and nymphs by 20% to 47%. The nymph mortality rate due to predation did not differ during the first and the second generations of the year. For the third generation however, the mortality rate was lower, related to a greater degree of nymphal aggregation in spatial refuges. Our direct observations indicate that among the types of predators in pastures, ants potentially make the greatest contribution to mortality, although their impact needs experimental verification. High rates of mortality of eggs and nymphs of D. flavopicta exposed to predators indicate that predation can be an important factor determining the size of adult populations. Therefore, management practices that disturb the predator community may increase the population densities of the spittlebug.