Growth rate and anticipated longevity of Chrysopa phyllochroma Wesmael (Neuroptera: Chrysopidae) larvae fed on Aphis gossypii Glover (Homoptera: Aphididae)

Abstract

The growth rate and anticipated longevity of Chrysopa phyllochroma fed on Aphis gossypii were determined to test the two following hypotheses: a) When prey is quite sufficient, predators show the maximum growth rate; b) without prey provided, predators have a constant anticipated longevity. Considering assimilative efficiency (k), a new model was suggested: G=G0[1-e -k(I-C)]. Fitted to the new model, the maximum growth rate (G 0), respiration threshold (C) and assimilative efficiency of larvae (I) were 15.256, 0.529, and 17.624, respectively. There were significant linear correlations between the maximum growth rate and the development day-age of larvae (D), the respiration threshold and D, except between assimilative efficiency and D. Under the condition of no prey, stage mortality curves of larvae were fitted by Normal Distribution Curve. The anticipated longevity of larvae at 0.5, 1, 2, 3, 4, and 5 day-age was 29.56, 38.97, 46.79, 48.73, 53.15, and 59.77 h, respectively. There was a significant logarithmic correlation between the anticipated longevity of larvae and D. The accumulated weight loss of larvae increased as the survival time of larvae was prolonged, and there was a significant logarithmic correlation between the accumulated weight loss and survival time.