A study of the effects in immature Cryptolestes turcicus of density and food quantity upon the rate of development, survival and the weight of newly-formed adults has allowed the following conclusions:—
- (a) rate of development, survival and adult weight are highly correlated;
- (b) as food quantities per larva become smaller, so these values are reduced;
- (c) three intermediate density factors are recognised, one attributed to cannibalism, one to changes in the food medium brought about by the larvae themselves and a third which may be called disturbance. It is postulated that at least these three, acting independently or interdependently produce the response which is recognised as being due to density.
Comparison with C. ferrugineus and C. ugandae shows that the former species is more susceptible than C. turcicus in response to high densities, whereas the latter is rather similar.