The Content Of Amino Acids In Artificial Diet Influences The Development And Reproduction Of Brown Planthopper, Nilaparvata Lugens (St(?)L)

Early nutrition has profound effects on phenotype, energy metabolism, immunesystem, lifespan and reproduction of insect. In this work, the research object is brownplanthopper (BPH), Nilaparvata lugensSt l, it has piercing-sucking mouthparts andfeed monophagously on rice plant’s phloem. Control nymphs were maintained on thestandard medium, the experimental nymphs were fed on amino acid deficient medium(AADM), it was prepared with amino acids present at40%of standard medium. Theamount of each amino acid of rice’s phloem was assayed, the ration of each aminoacid in the rice plant was referred to change D-97into a simulative diet D-98. Themain results are as follows:1. Deficient amino acid of larval period has significant effect on BPH’s phenotype:shorter larval period (20.78/23.09d) and higher brachypterous forms(34.06/16.52%). The interpretation is that BPHs accelerated their growth rate inanticipation of improving conditions and the poor reproductive performance ofadult females because of the inability to begin ovarian development during the latelarval stages. I interpreted the increased brachypterous forms in terms ofnutritional ecology. Artificial rearing systems cannot convey information about theenvironment to BPHs and it necessarily follows that the insects do not respond tosimple one-dimensional change in nutritional quality in the same way they response to changes in nutritional quality coupled with broader information abouttheir environment.2. Female had poor reproduction when it’s nymph was reared on AADM: extendedpreoviposition period (11.41/13.45d), declining number of laid eggs (2.27/37.44,p<0.01), ovarian dysplasia and shorter lifespan compared with control group.Females were fed back on standard medium after emergency still featured withpoor fertility, which means that the harm to reproduction from nymphs’ deficientamino acid diet is permanent. The interpretation is that this impeded thesynthetization of some specific protein needed for ovary’s development.3. Mean total lipids (39.26/41.38μmol/g) and protein (112.68/107.83μg/mg) storageof each newly eclosion female from control and experimental group showed nosignificant difference. The interpretation is that the carbohydrate components ofthe control and AADM provide sufficient energy to support lipids and proteinbiosynthesis and storage.4. The ration of most amino acids in rice plant phloem are different from that inD-97, the assayed data was referred to changeD-97into a simulative diet D-98.The change didn’t show any superiority, but reduced the reproduction of females.The reason maybe is that the new amino acid ratio broke the balance betweenamino acids and other nutrition, which may affected the synthetization of somespecific protein needed for ovary’s development.In conclusion,N. lugens makes a physiological trade-off between survival andreproduction by suppressing ovarian development. This is probably a commonstrategy during times of nutritional deficiency in nature.