Notes on the Mortality Rate of Traumatocampa (= Thaumetopoea) pityocampa D. & S. (Lepidoptera Thaumetopoeidae) Eggs and the Population of Oophagous Parasitoids in the Ronco-Bidente Valley

The mortality rate of Traumatocampa (= Thaumetopoea) pityocampa D. & S. (Lepidoptera Thaumetopoeidae) eggs (determined as the number of eggs per egg cluster from which larvae of the lepidopteron failed to emerge) was recorded in seven stations along the Ronco-Bidente valley during the three-year period 1990, '91, '92. Emergence failure percent values were found to be significantly higher during the second and third years as compared to the first. The trend was seen to be extremely variable and hence independent of the years and localities studied, with higher values being recorded in pinewoods at an elevation of 440 and 455 metres. The lay of these pine woods, at least for 1991 was seen to affect egg mortality rate that was found to be higher in those facing south-east and lower in those facing north-east.