Egg Mortality in Pterostichus oblongopunctatus (Fabricius) (Col., Carabidae)

Summary

Eggs of the carabid beetle Pterostichus oblongopunctatus kept under ‘optimum’ conditions in petri dishes had a mean mortality of 8% (n=200), while the mortality of eggs incubated in fresh litter was 83% (n=250). Heating the litter up to 70° C and thus eliminating other organisms from the litter fauna reduced mortality to 18% (n=250). When eggs were deposited by the females themselves in a perspex cylinder containing an undisturbed soil sample, the mean egg mortality was 70% (n≈235), but when predators had been eliminated the mortality was only 7% (n≈235). The assumption of Grüm (1975) that egg mortality can be neglected does not hold for P. oblongopunctatus. The predators of the eggs must be common species, but it is not yet known to which family they belong.