Survival of larvae of Anoplognathus porosus (Dalman) and Sericesthis nigrolineata Boisd. (Coleoptera: Scarabaeidae).
Abstract
With the aid of a field plot layout of semi-controlled environments developed by R.L. Davidson, J.R. Wiseman & V.J. Wolfe to validate simulation models, the survival of larvae of Anoplognathus porosus (Dalm.) and Sericesthis nigrolineata (Boisd.) was compared in pastures in New South Wales in 1971 [cf. RAE/A 58, 2449; 61, 2337, etc.; 64, 4125]. Differences found in the laboratory were used to interpret the observed differences in mortalities between the 2 species. In a wet soil, larvae of A. porosus survived better than those of S. nigrolineata, but in a dry soil the reverse was the case. Larvae of S. nigrolineata were found deeper in the soil than those of A. porosus, the difference in vertical distribution being a significant factor in the observed mortalities. These results are discussed in relation to the prediction of the time, place and size of outbreaks of these species, the populations of which fluctuate widely from year, damage varying from negligible to the complete destruction of pastures. [Cf. next abstract, etc.]