Male pheromone releasing behavior in Mythimna separata (Walker)
Author of the article:
Author's Workplace:
Key Words:
Abstract: [Objectives] To describe the surface ultrastructure and rhythmic movement of hair-pencils in male Mythimna
separata (Walker) and the period of pheromone release. [Methods] The surface structure of different regions of hair-pencils
was observed under a scanning electron microscope. Gas chromatography-mass spectrometry (GC-MS) was used to detect the
content of benzyl alcohol in extracts from hair-pencils at two different positions at different times, and changes in
benzaldehyde content in hair-pencils after mating were analyzed. [Results] Male moths have a hair-pencil on each side of
the anterior abdomen. The interior of the hair stem is hollow and reticulate and the surface of the proximal shaft has
longitudinal ridges and punctate holes. There is a transition area in which the longitudinal ridges are gradually replaced by
holes of different sizes. The end of the surface was “honeycomb” shaped. 6.67% of hair-pencils began to retract from the
second internode of the abdomen into pockets on the 3-4 segments 8h after males had emerged. 96.67% of hair-pencils
retracted within their pockets 24 h after emergence. 80% of males produced benzyl alcohol, which was detected on hair-pencils
after these had been retracted into their pockets for 2 h. Benzyl alcohol was also detected at the internode membrane,
especially 24 h after male emergence. There was no significant decrease in the benzaldehyde detected on hair-pencils after
mating. [Conclusion] The generation of male pheromone depends on changing the position of hair-pencils. Hormone begins
·818· 应用昆虫学报 Chinese Journal of Applied Entomology 55 卷
to be generated as hair-pencils are retracted from the intersegmental membrane into their pockets, rather than after hair-pencils
are fully retracted into their pockets. Eversion of hair-pencils during courtship and mating behavior was not observed, rather
males released pheromone by pressing their anterior abdomen to open the edge of their hair-pencil pockets.