Genetic variation and digestive physiology of various populations of Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae)

Golikhajeh, Neshat and Naseri, Bahram and Razmjou, Jabraeil and Hosseini, Reza (2016) Genetic variation and digestive physiology of various populations of Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae). Doctoral thesis, University of Mohaghegh Ardabili.

Text (تنوع ژنتیکی و فیزیولوژی گوارشی جمعیت¬های مختلف کرم برگخوار چغندرقند Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae)) Neshat Golikhajeh.pdf Download (605kB)

Abstract

Abstract: The beet army worm, Spodoptera exigua Hübner, is one of the important pests of sugar beet in Iran and the World. In this research, genetic variation of beet army worm collected from sugar beet from 7 regions (Sabzvar, Moghan, Miandoab, Zarghan, Kalpish, Gonbad, Esfahan) and its digestive physiology and biological parameters (Moghan, Miandoab and Kalposh regions) on four sugar beet cultivars (Dorothea, Rozier, Persia, Perimer) were evaluated. Among 8 microsatellite locuses, only locus Spe 15 could not proliferated. But other locuses indicated polymorphism. These locuses showed 45 polymorphic bands in ranges 143-230 base pair. The number of bands per locus varied from 4-8 bands. The value of F showed high genetic differentiation, so that the mean of Fst was 0.21. Significant difference was observed between observed heterozygosity and expected heterozygosity in all locuses. Lower observed heterozygosity than expected heterozygosity indicated that heterozygosity in these populations were low. Deviation from Hardy- Wienberg equilibrium was observed in all locuses. One of reasons for this deviation might be due to shortage of heterozygosity. Genetic variation within populations was higher than between populations indicating that individuals of populations had long migrations. Moghan- Miandoab populations had shortest genetic distance; whereas, Moghan-Gonbad populations had longest genetic distance. In dendrogram section, Sabzvar population was placed in separate group; whereas, other populations were placed in another group. Difference between Sabzvar population with other populations might be due to isolation of this population from the others. The results of digestive physiology and biological parameters of beet army worm confirmed the results of genetic variation, and indicated significant differences between three geographic populations. The present study showed that biological parameters and digestive physiology of geographic populations were different on various sugar beet cultivars. Moreover, populations when fed on local host plant, showed higher enzymatic activity and feeding responses than when fed on non local host plant. These results indicated that S. exigua adapted with local host plant. Although it is expected that host plant quality affecting activity of the enzymes and larval feeding performance of beet army worm, but in comparison with role of geographic origin, effect of geographic origin was higher.

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