Changes in density optimum in ontogenesis of the Siberian moth Dendrolimus superans sibiricus (Lepidoptera, Lasiocampidae) larva
Kirichenko, N.I.; Baranchikov, Y.N.
Zoologicheskii Zhurnal 83(1): 54-60
The optimal density of larvae in the Siberian moth (Dendrolimus superans sibiricus) kept in chambers varied in ontogenesis: the larvae living in groups predominated in the 1st-4th instars, whereas those living alone, in the 6th instar. The critical moment equalizing feeding and growth parameters in single larvae and those grown in groups was observed in the 5th instar. The larval aggregation favoured the survival rate in the 1st-3rd instars and the developmental intensity in the 3rd-4th instars due to the higher efficiency of using food (ingested and digested) for growth. The relative growth rate and digestibility of food did not depend on the density of larval populations. The effects of density on feeding and growth parameters, as well as on the survival rate, were displayed even when three larvae were kept in one chamber. The increase of the number of larvae up to 20 did not change these effects.