Genetic studies on eight populations of eight locust species from Shanxi Province, China.

The genetic structure of eight locust species in three families (Catantopidae, Oedipodidae and Arcypteridae) from Shanxi Province in China was compared using allozyme analysis with horizontal starch gel electrophoresis. Among 17 loci identified in zymograms, Ao-1, Est-3, G3pd-1, Idh-2 and Mdh-2 had low variability with a few alleles. High polymorphism was observed at Ldh-1, Me-1 and Gpi-1. Each of the eight species demonstrated high percentage of polymorphic loci (P = 64.7%-94.1%) but low observed heterozygosity (H0 = 0.024-0.087) due to heterozygote deficiency. It was noted that the migratory locusts usually had higher percentage of polymorphic loci (P = 88.2%-94.1%) than non-migratory species (P = 64.7%-94.1%). The only exception is Oxya chinensis(P = 94.1%). It is reasoned that the higher polymorphism is necessary for migratory species to cope with the environments that might be drastically different from the habitats before migration. The taxon relationships using cluster analysis based on Nei's genetic identity (I) and Roger's genetic distance (D) were the same at species and genus levels. The differences were found at family level, possibly due to the alternative algorithms. The cladogram using Roger's genetic distance (D) overlapped the relationship obtained from karyotypic analyses, which demonstrated that the species examined in Catantopidae displayed somewhat closer relationship to those in Oedipodidae than to those in Arcypteridae. It is suggested that the allozyme analysis is useful as molecular marker for locusts in phylogenetic reconstruction at the species and genus level, while additional data from other studies are necessary when used for higher taxa.