Study On Summer Nectar Plants Flower-visited And Nectar-sucked By Mythimna Separata

Mythimna separata(Walker)is a long-distance migratory pest.Its larvae mainly harm gramineous crops,and its adults need supplementary nutrition to complete reproduction and migration.It is known that Astragalus sinicus is the main nectar source plant to supplement nutrition during the migration period of armyworm adults in spring.The planting area of Astragalus sinicus is closely related to the occurrence area of the first generation armyworm larvae.There are many kinds of nectar plants in summer,which is far more than Guo Pei’s(2017)research?Is Vitex negundo var.heterophylla,a widely distributed Vitex negundo var.heterophylla,a supplementary nutritional host for the adults of M.separata?Do adults of M.separata have learning behaviors when they choose plants to improve their nectar intake efficiency?In this study,the learning behavior of armyworm(Mythimna separata)was determined by the combination of phenylacetaldehyde and benzyl acetate;The pollen carried by the beak of M.separata was detected by scanning electron microscope(SEM).The species of nectar plants visited by M.separata in summer were identified and analyzed by morphological and ecological methods;According to the types of pollen adhered to the inner side of the beak tube of M.separata,combined with the ovarian development level of female and whether they mate(with sperm),the summer nectar sources of M.separata were analyzed.The main results are as follows:1.The learning behavior of armyworm moth:the adults were trained with 3%phenylacetaldehyde and 2%benzyl acetate to simulate the flower scent and 5%sucrose solution,and the behavioral response of adults to the flower scent was determined.The results showed that there was no significant difference in the selection frequency of flower odor and agar gel between the two groups.The only contact with flower odor could not induce the learning behavior of armyworm,but the joint contact with flower odor and 5%sucrose solution could induce the learning behavior of armyworm.From the perspective of gender difference,the male has a stronger ability to learn the relationship between flower odor and sucrose solution than the female.2.Species of nectar plants visited by Mythimna separata in summer:(1)after detecting the beaks of 2230 Mythimna separata captured from 2018 to 2019,45 species of pollen were identified.A total of 587 slime moths were trapped under high-altitude searchlights in Xinyang City,and pollen of 16 genera were detected.Toona was the highest,accounting for 57.33%,Betula was the second,accounting for 6.67%;1368 slime moths were trapped under high-altitude searchlights in Mengzhou City,and pollen of 37 different genera were detected.Ligustrum was the highest,accounting for 51.45%,and Toona was the highest In Mengzhou City,230 army worm moths were trapped under black light,and the pollen of 12 different genera were detected.Pinus was the highest,accounting for 39.47%,Toona was the second,accounting for 26.68%.In Gongzhuling City,45 armyworm moths were trapped under high-altitude searchlight,and the pollen of 3 different genera were detected,namely Echinochloa Beauv.,Ambrosia and Alnus mill.(2)The results showed that the pollen carrying rates of male and female moths were 12.58%and 12.98%respectively in Xinyang,25.63%and 24.62%respectively in Mengzhou,and 17.58%and 12.50%respectively in Mengzhou.(3)The results showed that the pollen carrying rates of myxomycetes trapped by Xinyang high altitude lamp,Mengzhou black light lamp and Mengzhou high altitude lamp were 12.78%,16.52%and 25.15%respectively.The pollen carrying rates of myxomycetes trapped by Mengzhou high altitude lamp and Xinyang high altitude lamp were significantly different.The pollen carrying rates of Myxomycetes trapped by Mengzhou high altitude lamp and Mengzhou black light lamp were significantly different.3.Nectar plant species of armyworm in summer:(1)there were 45 armyworm captured by Mengzhou high altitude lamp,and pollen of 6 species were detected inside the beak tube,accounting for 13.08%of the total pollen.The proportion of pollen carried by female was slightly higher than that of male,but there was no significant difference between them.(2)Pollen of 11 species were detected in the beak of female moths with sperm beads.The results of different trapping methods showed that whether the female moths with pollen beads carried pollen had nothing to do with different trapping methods;whether the female moths with pollen beads had sperm beads had something to do with different trapping methods;the female moths with pollen beads trapped under black light were easier to detect sperm beads.(3)The beak pollen carrying rates of stage Ⅰ,Ⅱ,Ⅲ and Ⅳ of ovary development were 25.00%,29.63%,10.53%and 46.15%,respectively.There was no significant difference in beak pollen carrying rate among the female nests of stage Ⅱ,Ⅲ,Ⅳ and Ⅴ,which were 20.00%,16.04%,13.79%and 33.33%respectively.All the slime worms with ovarian development Ⅰ,Ⅱ and Ⅲ carry the pollen of Ligustrum,Toona and Pinus.