The Highly Divergent Mitochondrial Genomes Indicate That the Booklouse, <i>Liposcelis bostrychophila</i> (Psocoptera: Liposcelididae) Is a Cryptic Species.

The booklouse, Liposcelis bostrychophila is an important storage pest worldwide. The mt genome of an asexual strain (Beibei, China) of the booklouse, L. bostrychophila, comprises two chromosomes; each chromosome contains approximate half of the 37 genes typically found in animals. The mt genomes of two sexual strains of L. bostrychophila, however, comprise five and seven chromosomes respectively; each chromosome contains one to six genes. To understand mt genome evolution in L. bostrychophila and whether L. bostrychophila is a cryptic species, we sequenced the mt genomes of six strains of asexual L. bostrychophila collected from different locations in China, Croatia and USA. The mt genomes of all of the six asexual strains of L. bostrychophila collected in China, Croatia and USA have two chromosomes. Phylogenetic analysis of mt genome sequences divided nine strains of L. bostrychophila into four groups. Each group has a distinct mt genome organization and substantial sequence divergence (48.7-87.4%) from other groups. Furthermore, the seven asexual strains of L. bostrychophila including the published Beibei strain are more closely related to two other species of booklice, L. paeta and L. sculptilis, than to the sexual strains of L. bostrychophila Our results revealed highly divergent mt genomes in the booklouse, L. bostrychophila, and indicated that L. bostrychophila is a cryptic species.