Studies On The Sex Pheromone Of Haemaphysalis Longicornis Neumann (Acari: Ixodidae)

A series of experiments were conducted on Haemaphysalis longicornis Neumann, components of body surface secretion are analyzed by modern biology technology including GC, GC/MS, bioassay, X-ray etc., then the functional components which play important roles in mating are indentified. Their structure, content changes, and the role in mating of sex pheromones are also researched deeply. The present research will provide foundation for tick reproductive biology, chemical ecology and behavior ecology. The main results were as follows:1. In H. longicornis, reproductive behaviour can be divided into 7 steps. The following steps of male activity in the mating process were recognised: (1) excitation and localization of female as an source of sexual attractant, (2)contacting the female, (3)mounting on her dorsal surface, (4)crawling over the female opisthosoma to the ventral surface, (5)location of female gonopore, (6)stretching out the palps and inserting chelicerae and hypostome into the gonopore, (7)the male genital opening ejaculation of a spermatophore, fixation of the spermatophore into the female gonopore.2. The results of GC and bioassay analysis showed that 2,4-DCP is a noval effective component of attractant sex pheromone in H. longicornis, and which regulates the reproductive behaviour during earlier stage together with 2,6-DCP.3. The content of 2,4-DCP changed along with developmental stages. 2,4-DCP in unfed female is minimum(49.38ng), then increased after feeding, reached its maximum at mating stage (98.09ng), and decreased 75.97ng (after mating) and 54.55ng (after engorgement). The changes of 2,6-DCP is silimar to 2,4-DCP, unfed (14.41ng), feeding (16,14ng, 27.88ng), mating (30.04ng), after mating (22.22ng) and engorgement (16.22ng).4. The results of X-ray analysis in female body surface at diverse development stages is similar to the change of the contents of sex pheromone along with developmental stages. The results of X-ray analysis at different region in female body surface showed that attractant sex pheromone is mostly excreted at the middle region of female body surface.5. Male perceives attractant sex pheromones through Haller's organ, and in the later stage of mating behavior, palpal receptor is the main receptor.The above result showed that in H. longicornis, reproductive behaviour is regulated by sex pheromones, and the components of attractant sex pheromones are 2,4-DCP and 2,6-DCP. Haller's organ is the main receptor of attractant sex pheromones.