Effect of hormones on total haemocyte count during the post-embryonic development of Corcyra cephalonica (Lepidoptera)

Abstract

Total haemocyte count increased gradually from the penultimate instar to late last instar larvae of Corcyra cephalonica. However, the cell number declined during prepupal stages. Decapitation and ligation behind the thoracic segments resulted in a decrease of the haemocyte number in the posterior part of the larvae. Injection of brain homogenate either from early last instar larvae of C. cephalonica or nymphs of Periplaneta americana into decapitated larvae, caused a significant increase in total haemocyte count. Injection of 5 μg of 20-hydroxyecdysone into the posterior half of thorax ligated larvae caused a significant increase in total haemocyte count, while application of juvenile hormone-I alone had no effect. However, juvenile hormone-I, when applied in conjunction with 20-hydroxyecdysone partially blocked the effect of 20-hydroxyecdysone.