3.1 Genetic diversity
A total of 300 COI and Cyt b gene datasets (2598 bp) were obtained of L. spadiceus from eight geographic locations (Figure 1). 94 polymorphic sites were detected among all individuals, including 28 parsimony information sites and 66 singleton variable sites (Table 1). The average nucleotide composition was 23.2% adenine (A), 27.3% thymine (T), 31.6% cytosine (C), and 17.9% guanine (G), with a slightly higher content of A+T (50.5%) than G+C (49.5%), showing a clear anti-G bias. The mutation of DNA was unsaturated for the transition/transversion (Ts/Tv) of bases in the COI and Cyt b gene datasets, which was 3.73. 95 haplotypes were identified (GenBank accession numbers: OQ970201-OQ970253 and OR428269-OR428309), the majority of which were unique haplotypes (89.47%). Only ten haplotypes were shared between populations (Hap_1, Hap_2, Hap_4, Hap_5, Hap_17, Hap_22, Hap_23, Hap_25, Hap_30, and Hap_65), and the most common Hap_1 (24.0%), Hap_2 (19.3%), and Hap_22 (11.0%) were found at each population (Figure 2).
Total haplotype diversity (H d) was high (H d = 0.874±0.013), while nucleotide diversity (π ) was low (π =0.00075±0.00058) (Table 1), showing the high haplotype diversity and low nucleotide diversity. The correlation between genetic diversity and longitude and latitude of sampling locations showed that the haplotype diversity (r = 0.29) and nucleotide diversity (r = 0.31) of L. spadiceus populations tend to rise with latitude but did not change significantly with longitude (r = 0.08 and 0.04, respectively) (Figure 3).