Ecological notes and annotated checklist of the grasshoppers (Orthoptera - Acridoidea) of the Savanna ecosystem project study area, Nylsvley.

Abstract

An annotated checklist is given of 60 species of Acridoidea which were found on the Nylsvley Nature Reserve. The density of a species may change greatly over small distances, altering the population species composition. Vegetation structure seems to be the main determinant of this. Changes also occur with time because of different breeding strategies. Most species are univoltine but exhibit considerable flexibility and asynchrony in breeding. All species examined are polyphagous but diets can be distinguished according to the physical characteristics of the preferred food plants. The amount of grass production removed by grasshoppers in a year varied between 9 and 24%. The effect of feeding and the extent to which grasshoppers were in competition with other grazers was less than these figures suggest. The passage of a grass fire in spring caused only a 30% loss of grasshopper biomass but post-fire mortality of nymphs was high.