| The lotus was generally planted in ponds and paddy fields, and also fish was stocked into ponds and paddy fields as a co-cultured object for utilization of the space and resources. For the purpose of preventing the pests on aquatic vegetables, impact of the fish-lotus co-culture both on ecosystem and beneficial was evaluated. Moreover, detailed research for Brachmia macroscopa Meyick, a fatal pest which found in the aquatic vegetables, was further explored. As a well-known leaf-eating pest, B. macroscopa, which belongs to the family Gelechiidae in Lepidoptera, has a wide distribution in the world. The pest has already leaded to severe crop failures and brought great economic losses. In severe cases, the rate of crop damage has reached 100% in the fields. Nevertheless, due to still little effort put on the basic study in this pest, biological control remains marginal, and chemical control, is still dominating pest management strategy. Aiming at developing potential biological control methods by exploiting the fundamental biology of B. macroscopa, in this study, the complete mitochondrial genome of B. macroscopa was determined, and the phylogenetic analysis base on the mtDNA data was constructed. Also, the age-stage, two-sex life table of B. macroscopa reared in different temperatures as well as the group fed with various host plants were established in the purpose of exploring the developmental fitness of B. macroscopa feeding on varies hosts and in different temperatures. The detailed results are summarized as follows:(1) The complete mitochondrial genome of B. macroscopa and its phylogenetic analysis: The complete mtDNA of B. macroscopa was featured as a 15,394 bp closed circle containing a putative A+T-rich region and encoded 37 genes. The 37 genes were organized by 13 PCGs, 22 tRNA genes and 2 rRNA genes. The complete mtDNA included 16 intergenic spacers and 10 overlaps. The longest spacers and overlaps were located in trnQ and nad2, nad and trnH, respectively. The nucleotide content of A+T was significantly biased (80.9%). The AT skew was 0.014 and GC skew was -0.188. Almost all of the PCGs started with ATN except for coxl, which started with CGA. Eleven of 13 PCGs encoded with TAA, except for cox2 with TA, and nad.4 with with a single T. Typical cloverleaf secondary structures were also found in this species, except for trnS(UCN) which lacked a dihydrouridine arm. The topological structures of the two trees (BI and ML) were almost identical. The Gelechioidea was nested within the clade Apoditrysia in the two trees. A sister relationship between Apodirtrysia and the Yponomeutoidea+Gracillarioidea was supported by a bootstrap value of 88% and a posterior probability of 1.00. The superfamily Gelechioidea, which includes Oegoconia novimundi, Endrosis sarcitrella, Ethimia eupostica, B. macroscopa, and Perimede sp. in this study, formed a monophyletic groupsupported by a posterior probability of 1.00.(2) Age-stage, two-sex life table of B. macroscopa fed in different temperatures: Development and fecundity of the B. macroscopa were recorded under six constant temperatures (21,24,27,30,33,36?). The eggs could not hatch out when reared in 36?. Within the range of 21-33?, the larval durations were shortened rapidly. The lowest larval survival rate was appeared in 27? group and the highest fecundity was observed in 21?. The 30? treatment proved to have the highest infinitesimal increase ratio (r) and finite increase ratio (?), while the 33? treatment calculated to be the lowest. According to the theoretically calculation, development threshold temperature for the egg, larvae, pupa and adult determined as 13.96,12.21,11.48,21.63?, respectively. The effective accumulated temperature for the four varied insect stage was 39.90,149.23,51.55, and 238.63 D·D. Development threshold temperature as well as effective accumulated temperature were figured up as 10.79? and 488.40D·D, respectively.(3) Age-stage, two-sex life table of B. macroscopa fed on different hosts:Development and fecundity of the B. macroscopa were measured on three different host plants (Ipomoea batatas (Linn.) Lam., Ipomoea aquatica Forsk. and Pharbitis perpurea (L.) Voigt) under constant temperatures (27+1?). The larval stage period fed on the diverse plants were significantly different (P<0.05), and the longest larval duration was on the I. batatas group while the shortest was observed on the I. aquatic group. The parameters for net reproductive rate (R0), gross reproduction rate (GRR), infinitesimal increase ratio (r), finite increase ratio (?) were found to be the highest in the I. aquatica treatment, while the P. perpurea treatment observed the lowest infinitesimal increase ratio (r) and finite increase ratio (?). |
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