Sublethal Effect Of Phosphine On Sex Pheromone Communication System Of Liposcelis Entomophila

Liposcelis entomophila(Enderlein)is one kind of the stored products pests, which is very small but damaging seriously. In this study, several sublethal resistant generations of L. entomophila to phosphine were selected by continuous fumigation with sublethal dosage LC50. On one hand, the influence of sublethal dosage phosphine on different resistant generations’ reproductive capability were studied; On the other hand, female sex pheromone’s release、extraction and identification、allure to male and male perception to female sex pheromone were studied. The main results are as followes:1 Without the treatment of phosphine, the F0 was obtained. Under the phosphine Continuous fumigation with dosage LC50, sublethal resistant generation F4 was selected. Whose virulence equations were y=5.86+2.39 x, and y=4.90+4.32 x respectively. Each generation was fumigated by phosphine with dosage LC20 and LC50. after the treatment of LC20, the egg laying amounts of both generations increased insignificantly(P>0.05), and the spawning peak period hasn’t changed, which suggested that the low sublethal dosage fumigation could increase the reproductive capability of L. entomophila. After the treatment of phosphine with dosage LC50, egg laying amounts of both generations decreased significantly(P<0.05), and the spawning peak period delayed. In comparison with the F0 generation, egg laying amounts of F4 inceased insignificantly(P>0.05), and the spawing peak period was brought forward. While, the egg hatch rate and offspring nymph emergence rate of F4 were decreased significantly(P<0.05). Reproductive capability of F4 was lower than F0,which may suggested that phosphine fumigation with sublethal dosage make fitness cost to reproductive ability of L. entomophila.2 The mating peak period of L. entomophila started from the third day of female emergencing. The mating behavior was started from the female: female ones released sex pheromone, sensed by male, male ones directional searched female ones, ultimately they mated successfully. By the solvent extracting method and analysis of GC-MS, the sex pheromone was detected contain two main components and which were preliminarily identified as Hexadecanoic acid and Z-6-Octadecenoic acid. Using the biological activity assay and GC-MS analysis, the purchased standard components had the same chemical composition and biological activity as the female sex pheromone extract.3 Under phosphine continuous fumigation with the sublethal dosage LC50, sublethal resistant generation of F6 was selected, whose virulence equation was y=1.55+4.96 x. Through analysis of the sex pheromone releasing of F0、F4、F6 generations, the releasing peak period was found at the same day, the third day after female emergence; the sex pheromone release amount decreased with the increase of the generation resistance. Through the analysis of allure ability of F0、F4、F6generations’ female and female extracts to male ones, allure ability of female and female’s extracts decreased with the increase of generation resistance. Through the analysis of F0、F4、F6 generations’ male reponse to female and female’s extract, the male’ reponse decreased with the increase of generation resistance. These results suggested phosphine fumigation with sublethal dosage LC50 could restrain sex pheromone releasing and allure ability of female, sensory ability of male significantly(P<0.05), which showed that phosphine fumigation with sublethal dosage LC50 had signigicantly affection on sex pheromone communication system of L. entomophila.