Sex pheromone composition of the cotton caterpillar, Palpita indica (Lepidoptera: Pyralidae), in Korea

Abstract

This study was conducted to investigate the sex pheromone composition of Palpita (= Diaphania) indica (Saunders) (Lepidoptera: Pyralidae) in Korea. Two sex pheromone components, E11-16:Al and E,E-10,12-16:Al, were identified by GC and GC-EAD analysis of sex pheromone gland extracts. The mean ratios of the two components, E11-16:Al and E,E-10,12-16:Al, were about 6.5:3.5 and 7.5:2.5 in gland extracts and in SPME collection, respectively. In field bioassays, maximum attraction occurred in traps baited with a 7:3 ratio of E11-16:Al and E,E-10,12-16:Al. The head extracts of P. indica stimulated the sex pheromone production of P. indica, as well as Hez-PBAN and PssPT, indicating that a PBAN-like substance exists in the head extracts of P. indica. Whole-mount immunocytochemistry showed that three groups of neurosecretory cells showed PBAN-like immunoreactivity in the SEG of P. indica. The PBAN-like immunoreactivity connected to the Corpora Cardiaca, a neurohemal organ. Also, PBAN-like immunoreactivity was found in the brain and in the thoracic and third/fourth abdominal ganglia. The addition of sex pheromone components of Peridroma saucia to the sex pheromone of P. indica greatly improved the attraction of P. indica males. The mixing of the sex pheromone components of S. exigua did not significantly increase the catches of P. indica, while the sex pheromone of H. armigera completely inhibited the attractiveness.