Mitochondrial COI gene fragments of five Bombyx mandarina populations from the islands of Tsushima, Yakushima, Tanegashima, Nakanoshima and Akusekijima were analyzed. These populations shared specific haplotypes apparently different from those found on the Japanese main islands. In the five island populations, different levels of genetic divergences were observed; Tsushima and Tanegashima populations share common haplotypes in similar frequencies, while Yakushima population has unique haplotypes. Nakanoshima and Akusekijima populations also share a common haplotype which is different from those found on the other three islands.

 We investigated the effect of sericin powder extracted from cocoons of the mulberry silkworm, Bombyx mori, and the non-mulberry silkworm, Antheraea yamamai, on lymphocyte proliferation. Sericin from A. yamamai (AS) elicited significant proliferation of B-lymphocytes. B. mori sericin (BS) and AS extended the lifespan of Caenorhabditis elegans. Transcriptome analysis revealed that AS increased the expression of CD86 and CD69, along with the proinflammatory cytokine IL-1βand the regulatory cytokine IL-10, in mouse spleen cells. The immunostimulatory effect of AS suggests that it has therapeutic value.