We explored the origin of all-female broods resulting from male death in a Hokkaido population of Lymantria dispar through genetic crosses based on the earlier experiments done by Goldschmidt and by testing for the presence of endosymbionts that are known to cause male killing in some insect species. The mitochondrial DNA haplotypes of the all-female broods in Hokkaido were different from those of normal Hokkaido females and were the same as those widely distributed in Asia, including Tokyo (TK). Goldschmidt obtained all-female broods through backcrossing, that is, F1 females obtained by a cross between TK females (L. dispar japonica) and Hokkaido males (L. dispar praeterea) mated with Hokkaido males. He also obtained all-male broods by mating Hokkaido females with TK males. Goldschmidt inferred that female-and male-determining factors were weakest in the Hokkaido subspecies and stronger in the Honshu (TK) subspecies. According to his theory, the females of all-female broods mated with Honshu males should produce normal sexratio broods, whereas weaker Hokkaido sexes would be expected to disappear in F1 or F2 generations after crossing with the Honshu subspecies. We confirmed both of Goldschmidt's results: in the case of all-female broods mated with Honshu males, normal sex-ratio broods were produced, but we obtained only all-female broods in the Goldschmidt backcross and obtained an all-male brood in the F1 generation of a Hokkaido female crossed with a TK male. We found no endosymbionts in all-female broods by 4, 0 6-diamidino-2-phenylindole (DAPI) staining. Therefore, the all-female broods observed in L. dispar are caused by some incompatibilities between Honshu and Hokkaido subspecies.

Functional foods that inhibit α‐amylase and α‐glucosidase activity are effective for regulating the blood glucose level and preventing hyperglycemia. Extracts of adzuki beans (ABs, Vigna angularis), widely eaten in East Asia, can inhibit α‐amylase and α‐glucosidase activity. In this study, we identified and evaluated the components in an AB water extract (ABWE) after boiling, which is an essential process for cooking ABs. The ABWE before boiling inhibited α‐amylase and α‐glucosidase activity and the boiled ABWE showed slightly stronger inhibitory effects. High‐performance liquid chromatography, liquid chromatography‐mass spectrometry, and nuclear magnetic resonance analyses identified (+)‐catechin 7‐O‐β‐d‐glucopyranoside (C7G), (+)‐epicatechin 7‐O‐β‐d‐glucopyranoside (E7G), and (+)‐catechin as the bioactive components in boiled ABWE. Interestingly, the quantity of E7G significantly increased after boiling (from 0% to 17.1 ± 1.3%). E7G showed stronger inhibition of α‐amylase and α‐glucosidase than C7G; the IC50 values for α‐amylase were 0.74 ± 0.04 mg/mL (C7G) and 0.40 ± 0.09 mg/mL (E7G), and for α‐glucosidase the IC50 values were 0.085 ± 0.032 mg/mL (C7G) and 0.051 ± 0.007 mg/mL (E7G). Our findings suggest that C7G and E7G are the main active components in ABWE as they inhibit α‐amylase and α‐glucosidase and their inhibitory effect is not lost after boiling. These results support the effectiveness of boiled ABs in the promotion of health. Practical Application We identified (+)‐catechin 7‐O‐β‐d‐glucopyranoside (C7G), (+)‐epicatechin 7‐O‐β‐d‐glucopyranoside (E7G), and (+)‐catechin in adzuki bean extracts and commercially available boiled adzuki bean products. Interestingly, the E7G content was increased by boiling, and this compound showed strong inhibitory activity toward α‐amylase and α‐glucosidase. These results support the consumption of boiled adzuki beans to prevent acute rises in blood glucose level.