Ecological Adaptability Research On Four Bamboo Shoot Borers

The four dominant shoot-boring noctuids,which are Kumasia kumaso, Oligia vulgaris, Apamea apameoides and Sapporia repetita(Butler) are main pests of bamboo forest in southern China. Reports on their morphological characters’ comparative studies are little, particularly for Apamea repetita conjuncta.And its classification status and evolutionary approach is still controversial. They are all bamboo borers.Their morphology differences are small, life cycle is very similar, and their niche is overlapped.Therefor, there would have a fiercely competition on resource utilization. This study used the morphology and genetic differentiation methods, ecological niche methods, feeding and oviposition behavior methods to interprete what kinds of survival strategies the four moths take to adapt this kind of competition.The main methods and conclusions were as follows:(1) The results show that there were not significantdifferences between them except Kumasia kumaso. This moth had different egg pattern, larvas color and external genitals. The rest of them had big difference in egg shell and larvas color. Others were not significant. In conclusion, its classification status and evolutionary approach can not be confirmed using morphological characters only. Morphological differentiation of the research results show that the four kinds of bamboo shoot moth have not significant differentiation difference on morphological characteristicsdue to ecological adaptation. It will providemorphology basis for four kinds of bamboo shoot moth by sympatric speciation.(2)Four 709 bp segments of cytochrome C oxidase subunit(COⅠ Ⅰ) gene were cloned from mitochondrial DNA of different bamboo shoot borers′individuals and compared with homologous sequences from other lepidopterous insects to analyze their base composition characteristics and phylogenetic evolution for accurate identication of bamboo shoot borers at molecular level.The results indicated that the average content of T,C,A and G in segments of mtDNA COⅠgene from the four bamboo shoot borers and other lepidopterous insects was 39.5%,14.8%,31.9% and 14. 6% respectively.The A + T content at the 3rd codon position was significantly higher than those at the 1st position and the 2nd position.The use of bases showed an obvious T bias(the average skew of AT was-0.1171).There were 21. 72% variable sites, 16.64% parsimony-informative sites and 5.07% singleton sites in the 709 bp segments.Base transition was higher than base transversion(R value was 12.6).The average genetic distance between mtDNA CO Ⅰgene from various insect species was 0. 055. In the four bamboo shoot borers, the genetic distanceof Sapporia repetita was highest between them,being higer than the interspecific genetic distance. The rest of them had a genetic distance similarly as the intraspecific distances.Phylogenetic tree displayed that Sapporia repetita had the closest relationship with genus Apamea. The other three bamboo shoot borers had the closest relationship with genus Enargia, Lithophane hemina(EU768944.1) and Ufeus faunus(GU828860.1), all of which formed a evolutionary group. It suggested that four kinds of bamboo shoot the moth genetic differentiation difference was not significant after different ecological adaptation, the results of the study provided demonstrable genetic basis for sympatric species evolutionary hypothesis.(3)The niche(temporal niche, trophic niche and niche types) were investigated on four bamboo species, Kumasia kumaso, Apamea apameoides, Oligia vulgaris and Sapporia repetita by field investigation. It was found that the population density of Apamea apameoides was the main species and temporal niche breadth of Apamea apameoides was the widest among four noctuids. While temporal niche similarity between Kumasia kumaso and Oligia vulgaris was higher than 0.7 while the interspecific competition coefficient was 0.9073 in anji. However, the population density of Sapporia repetita was the main species and temporal nich breadth of Apamea apameoides was the widest similarity with Oligia vulgaris among four noctuids in Guangdong province.The results indicated that the bamboo shoots of the moth have different occurrence period to may be a way of its less competitive.We also found that different bamboo shoots of the moth feed bamboo shoots in a different way in the same host, it was thought that bamboo shoot even show the moth by increasing decay to eat bamboo shoots way to increase their feeding niche and improve the competitiveness.The trophic niche showed that four bamboo shoots of the moth had different niche.The population density of Apamea apameoides and Kumasia kumaso were the main species and temporal nich breadth were wider than other noctuids, so it can increase improve the competitiveness in the feeding.In conclusion,The four bamboo shoots of the moth larvae avoided the intense interspecific competition through different feeding time and feeding and host on the same host feeding path to ensure its own reproduction smoothly. Kumasia kumaso was the dominant population of the four bamboo shoots of the moth.(4) Their oviposition behaviour selection of four hoot-boring noctuids were significantly different on different host plants, and Apamea apameoides and Oligia vulgaris only choose Roegneria kamoji to lay eggs,and all of them selected oviposition on the same plant which of the most site were the leaf surface, sheath and the root of Roegneria kamoj. Compared with the other two noctuids, Apamea apameoides and Oligia vulgaris spawned more eggs and amount of which were different significantly, and meanwhile the oviposition time of the four shoot-boring noctuids were different. Kumasia kumaso was the earliest oviposition moth among of them and its spawning process lasted for 10 days. The others were later(Sapporia repetita>Oligia vulgaris>Apamea apameoides) and overlap. In conclusion,The four bamboo shoots of the moth avoided the interspecific competition through oviposition time difference, host difference and position difference. And then the species differentiation comes into being.