The winter mortality of eggs of Chortoicetes terminifera (Walk.) (Orthoptera: Acrididae) during the outbreak of 1955.

Abstract

Migratory swarms of Chortoicetes terminifera established egg beds in New South Wales, South Australia, and Victoria during the autumn of 1955. Samples of eggs were taken from a number of districts in New South Wales and Victoria during the winter and the mortality rate was determined. Scelio fulgidus was the only parasite present but it was very widespread with a median percentage parasitization of 5%. Mortality from other causes had a median of 39%. Winter rainfall during 1955 was considerably above average and in some situations waterlogging of the soil in which the eggs were laid may have been one of the factors affecting survival. Low temperature seems more likely to have been the factor of importance at the higher altitudes in north-eastern Victoria where hatching was particularly poor.