Ml. Crowe, THE EFFECT OF SEASON AND GROUP-SIZE ON SURVIVORSHIP AND LARVAL GROWTHIN PLAGIODERA-VERSICOLORA, Ecological entomology, 20(1), 1995, pp. 27-32
1. The larvae of the multivoltine imported willow leaf beetle, Plagiod
era versicolora (Laicharting), are found in larval aggregations during
the first half of the larval stage. An experimental study was conduct
ed to test for seasonal (brood) and group size effects on larval fitne
ss. For each of the three broods, egg group sizes of 1, 4, 8, 16, 24 a
nd 32 were established in the field and monitored for the first 6 days
post-hatching. 2. There was no effect of group size on larval weight,
but there was a significant effect of group size on survival. Individ
uals from group size 16 had the highest survival, which coincides with
the mean natural cluster size of 15.3 eggs. 3. There were no signific
ant interactions between brood and group size. 4. The effect of larval
weight on adult fitness was determined in the laboratory and the fiel
d. Larval weight was correlated with egg production in the laboratory
but not in the field.