Fecundity and egg viability in relation to female body size in Neodiprion sertifer (Hymenoptera: Diprionidae)

Relationships between female size and fecundity, egg viability and embryonal development were studied in Neoriprion sertifer. Sawfly females, reared from the 1st instar larvae on Scots pine needles heavily affected by industrial pollutants or on relatively unpolluted needles, were induced to lay eggs parthenogenetically in the field in Finland. Females reared on polluted needles were smaller and oviposited an average of 68.8 eggs, and those reared on unpolluted needles 79.4 eggs per female. However, the higher egg viability in the former group masked the effect of reduced female size. This compensation was primarily related to the size of the females, larger individuals producing relatively fewer viable eggs in both groups.