A comparison of the numbers and distribution of aphid species flying over Eastern Australia in two successive years.

Abstract

The results of the two year's operations, using Moericke aphid traps at 12 sites in eastern Australia, are compared. The basic stability of the aphid fauna flying in successive years is established in terms of primary effects of geographical distribution and seasonal phenology in association with climate. The causes of variability of the magnitude and timing of flights of aphids are discussed in terms of properties of species and of local variations in the weather pattern. There appears to be a latitudinal pattern of areas where aphid catches were highly consistent and of areas where consistency was low. A study of the consistency of occurrence of individual species in the two years, shows that the numbers of some species appear inherently more stable than of others. A large overall effect in the collecting performance of the traps seems to be traceable to a climatic difference between the two years.