| Opisina arenosella Walker is an important pest damaging palm plants,which was first found in Wanning City,Hainan Province in 2013.Coconut moth has certain migratory ability,which poses a serious threat to palm plant industry in China.It has seriously affected the development of coconut planting industry and urban green space landscape in Hainan Province.In order to carry out long-term effective prevention and control of Opisina arenosella and clarify the occurrence regularity and early warning of invasion information of Opisina arenosella,this paper studies the population dynamics and genetic differences of geographical populations of Opisina arenosella,which is of great significance to reveal the occurrence regularity and prevention and control strategies of Opisina arenosella.The main results of this study are as follows :1.To reveal the insect source information of O.arenosella invading China by the analysis of the distribution characteristics of haplotypes of O.arenosella in the native and invaded zones.A total of 172 samples from 16 geographical populations were analyzed by mitochondrial COI gene,and the genetic relationship of O.arenosella from India and invading areas(China,Malaysia and Thailand)was compared in the study.The results showed that a total of 12 haplotypes were identified in 172 sequences with fragment length of 625 bp.The haplotype alignment showed that 15 variation sites were detected and 2obvious haplotype branches were formed,one of which was composed of 11 haplotypes IN1～IN11 and they were all from Indian populations.Haplotype IN1 was shared by six O.arenosella populations from India.IN2～IN11 were exclusive haplotypes and were not shared with other populations.The other branch was haplotype HAP.The populations from China,Malaysia and Thailand all shared this haplotype,indicating that the O.arenosella in these invading areas came from the same genotype type or had the same invasion source.There were 4 variation sites between HAP and 11 haplotypes IN1～IN11 from India,which suggested that the population of O.arenosella could produce new mutations or hybrids in new habitats under the pressure of environmental selection.2.The results of field experiments showed that Opisina arenosella Walker can occur in a year and frequent activities.In the second half of Hainan Province,the Highest monthly temperature was 28.9 °C in October,and the average humidity was about 89 %.There was an outbreak period,during which the number of pests increased sharply.3.Under laboratory conditions,when the humidity was controlled at 75%,the developmental duration of Opisina arenosella Walker population shortened with the increase of temperature.The lowest number of second generation hatching was 177.67 at 35°C,which indicated that high temperature could hinder the second generation hatching.When the temperature was controlled at 28°C,the longevity of the Opisina arenosella decreased with the increase of humidity.In this experiment,the pupation rate,eclosion rate and the number of second generation hatching were the highest when the humidity was 80 %,indicating that the optimum humidity was 80 % of the Opisina arenosella.4.When the humidity was constant at 75%,the parasitism rates of Habrobracon hebetor Say and Chouioia cunea Yang at 30°C were significantly higher than those at other temperatures of 91.12% and 86.67%,respectively.At 35°C,the parasitic rates of the two parasitoids were 44.25% and 13.33%,respectively.When the temperature was constant at28 °C and the humidity was 65 %,the best parasitic rates of Habrobracon hebetor and Chouioia cunea on the O.arenosella populations were 86.71 % and 73.33 %,respectively.It indicated that when the temperature was 30 °C and the humidity was 65 %,the number of the three populations could be inhibited to some extent.But in the natural environment,the inhibitory effect on the O.arenosella populations is poor. |
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