A Study on the Bionomics and Predatory Effect of Camponotus japonicus to Dendrolimus punctatus

Camponotus japonicus Mayr nests under ground. In one colony, there are eggs from 0 to 953, larvae from 29 to 2 302, pupae from 0 to 1 357, workers from 42 to 4 012 and dealate females from 1 to 3. The males and females usually appear in autumn and they will come out for marriage flight from last ten days of April to the first ten days of May next year. The growth time from egg to adult is as follows: 16 to 19 days for eggs, 10 to 28 days for larvae, 6 to 7 days for prepupae and 14 to 19 days for pupae. Placing larvae of the Dendrolimus punctatus Walker in the near of the ant, the ratio of 1 to 3 instar larvae by ants is 70%, 23.3% and 10% respectively. When the first and second instar larvae on trees were found by the ant, they will be preyed by 48% and 10% respectively. After 14 days experiment, the populations of the D. yunctatus in trees with ants decreased than those without ants by an average rate of 23.7%.