Identification,Synthesis And Field Evaluation Of The Female Sex Pheromone In The Nettle Caterpillar,Monema Flavescens Walker

The nettle caterpillar,Monema favescens Walker(Lepidoptera:Limacodidae),is a multivoltine,generalist moth whose larvae cause serious damage to trees.They exhibit window feeding on the lower leaf cuticle and sometimes even consume entire saplings,which seriously affects the growth of trees and reduces fruit yields.Presently,the principal method for controlling M.flavescens is spraying with chemical insecticides,but this method is drawing increasing concern because of potential environmental risks.So,the pattern of sexual behavior,the ulstructures of sex communication system,the chemical compositon and synthesis of sex pheromone,the evaluation of the sex pheromone attractiveness to the nettle caterpillar,M.flavescens were studied in this dissertation.The emergence period of M.flavescens of the overwintering was sustained about 50 days with a emergence peak at the mid-June and the daily emergence peak from 17:00 to 21:00 in the room.Calling behaviour and mating were correlated with virgin female age.About 34.5%of females initiated calling on the night they emerged(1-d-old),and a calling peak with 97.8%occurred in 2-d-old.But the male moths reached sexual maturity at the age of 3 days.The onset time of calling was advanced with the increase of female age.1-d-old females initiated calling activity 4 h after the onset of the scotophase,and 5-6-d-old females called during the first hour of the scotophase.The highest value of mating rate occurred at 3-d-old virgin female and at 4th to 6th hour in scotophase.The male antennae of M.flavescens displayed conspicuous responses to four components in the female pheromone extracts through GC-EAD analysis.Further GC-MS analyses of the EAG-active compounds in the gland extracts indicated that the four components were E-8-decen-l-ol(E8-10:OH),Z-7,9-decadien-l-ol(Z7,9-10:OH),Z-9,11?dodecadien-l-o1(Z9,11-12:OH),and Z-9,11-dodecadienal(Z9,11-12:Ald)respectively.The ratios of the components in baits were similar to those found in the per pheromone gland,this behavioral response and number of males trapped of a three-component blend of synthetic E8-10:OH,Z7,9-10:OH,and Z9,11-12:OH did not differ from the response to the four-component blend(E8-10:OH,Z7,9-10:OH,Z9,11-12:OH,and Z9,11-12:Ald)by wind tunnel and field trapping test.The compound Z9,11-12:A1d is inert,acting as neither a synergist nor an inhibitor of male attraction to M.flavescens in wind tunnel and field tests.This research result was differ to the test of the Japan population M.flavescens.Shibasaki et al.(2013)reported that lures baited with a 9:1 mixture of E8-10:OH and E7,9-10:OH attracted M.flavescens males in field tests and adding Z7,9-10:OH to the pheromone blend resulted in an antagonistic effect in trap catch.The idea that different geographic pheromone races exist in M.flavescens was supported by comparing our laboratory data with field test results.Female and male antennae were filiform and were on the front of the head between the compound eyes.The dorsal surface of the flagellomeres was covered by scales,whereas most of the various types of sensilla were on the ventral side.Eleven morphologically different types of sensilla were found on the antennae of male and female M.flavescens.Six types of likely chemosensory sensilla were identified:uniporous sensilla chaetica,multiporous sensilla trichodea,and four types of sensilla basiconica.The sensilla identified as likely mechanoreceptors included two subtypes of aporous sensilla chaetica,aporous sensilla coeloconica,and aporous sensilla styloconica.These mechanoreceptor,olfactory sensilla and gustatory(uniporous)sensilla are essential for insects to mate and locate hosts.In order to obtain a sufficient standard compounds for laboratory bioassay and field trapping,the sex pheromone of Z7,9-10:OH and Z9,11-12:OH were synthesized with the cheaper 1,?-diol compound as starting material through oxidation with PCC and Wittig reaction of phase transfer.The sex pheromone of E8-10:OH was synthesized via coupling reactions catalysed by Li2CuC14 starting from E-2-buten-l-ol and 6-chloro-l-hexanol.For practical field work,we recommend the use of sticky delta traps baited with a total of 650 ?g of a ternary blend of E8-10:OH,Z7,9-10:OH,and Z9,11-12:OH at a ratio 10:2:1(w/w/w),conveniently hung about 1.5 m above the ground.A new method provided the research could be used for integrated control M.flavescens in China.