Environmental factors affecting spittlebug egg survival during the dry season in Central Brazil

Abstract

Spittlebug egg survival and hatching was compared in pastures where differences occurred in vegetative characteristics and grazing intensity. Egg samples were placed in pastures at the start of the dry season and recovered before hatching began. Significantly (P<0.05) more eggs were recovered from areas where litter was present than from bare soil areas. Mortality from predators and scavengers was estimated at 73%. An additional 34% of the eggs were desiccated and 35% were nonviable. Egg survival was estimated to be 8.5% and was greater in pastures with the following characteristics: 1) canopy height > 30 cm; 2) abundant litter; 3) plant cover > 50%; 4) minimal or no grazing. More predators, especially spiders (Araneida) were also collected from these types of pastures. At one site more eggs hatched in a high grass pasture (74%) than in a low grass pasture (59%). Although high grass may receive less damage from spittlebug feeding the disadvantages of maintaining grass > 30 cm appear to outweigh the advantages.