The Development Of Polymorphic Microsatellite Loci And Sperm Competition Pattern Of Octodonta Nipae(Maulik)

Octodonta nipae(Maulik)(Coleoptera:Chrysomelidae)is an importent invasive pest on palm plants in southern China.Based on existing transcriptome data,polymorphism SSR loci were identified,which developed the paternity identification technology of O.nipae.Integrated with observation of mating behavior,internal reproductive system and genetic differentiation of filial generation,sperm competition model of O.nipae was discussed,the results were as follows:(1)In total,1274 SSR loci were identified from the 49919 unigenes.The majority of them contained mono-,dinucleotide-and trinucleotide-motifs(43.56%,26.14%and 28.18%,respectively),in which A/T(41.21%)and AT/TA(15.86%)were the most abundant motifs.104 pairs of the SSR primers produced amplification bands of expected sizes in O.nipae,in which 51 pairs of them also produced amplification band in Brontispa longissima.(2)80 pairs of SSR primers were tested randomly for polymorphism,and 9 loci of them were polymorphic,their PIC(polymorphic information content)are between 0.062 and 0.582(0.38 in mean of PIC,which shows medium polymorphic).In those 9 SSR loci,On 2 can be used for rapid species identification,and On 9 can be used for sex diagnosis,Combined with five loci of them can complete the paternity identification and genetic differentiation analysis of O.nipae(3)According to the results of P2 value,the sperm competition pattern of O.nipae shows precedence from the sperm of last male,with the mean value of P2 in 94.6±1.4%.(4)In female O.nipae,the spermatheca is highly ossified and the meatus connected spermatheca and genital chamber is long and narrow,so those sperm came from two males will make sperm stratification,sperm displacement may occur only in genital chamber,the unique female reproductive structures is one of the important factors causing the last male sperm precedence.O.nipae had two kinds sperms,eupyrene sperm and apyrene sperm.(5)In P2 value experiments,the first mating time is 61.8±11.9 min,and the second mating time is 124.7±19.3 min,the former was significantly shorter than the latter,which indicated the final mating male will get advantages in sperm competition by lengthening the mating duration.In this paper,those SSR transcriptome data can provide invaluable resource for SSR development,population genetics research,invasion and expansion mechanism,paternity testing and other research on O.nipae and its related species.Meanwhile,this study explains the mechanism of sperm competition from internal reproductive structure and mating behavior,which will lead to a comprehensive understanding of mating habits,breeding strategy,mechanism of invasion and provide a scientific basis for pest sexual interference technology.