Comparative Studies on the Fecundity of Three Aphidophagous Coccinellids (Coleoptera : Coccinellidae)

Abstract

Three species of aphidophagous coccinellids, Coccinella septempunctata brucki, Propylea japonica and Scymnus (Neopullus) hoffmanni were studied on their fecundity in laboratory condition (25°C, 14L-10D). The values of the net reproduction (R0), the mean length of one generation (T) and the intrinsic rate of natural increase (r) were calculated as 575.4, 43.8 and 0.145 for C. septempunctata, 179. 8, 27. 8 and 0.187 for P. japonica, and 126. 9, 20.5 and 0.236 for S. hoffmanni, respectively. The oviposition was continued for 66 days and 1,660 eggs were laid in C. septempunctata, 77 days and 1,481 eggs in P. japonica, and 49 days and 110 eggs in S. hoffmanni, respectively. It is interesting to note that the females of S. hoffmanni showed protecting behavior of their eggs, covering them with exuviae of their prey aphids. The hatchability was 40-60% for C. septempunctata and P. japonica and 60% for S. hoffmanni. © 1985, JAPANESE SOCIETY OF APPLIED ENTOMOLOGY AND ZOOLOGY. All rights reserved.