2022 Volume 25 Issue 1 Pages 3-8
To contribute to conservation of Ranatra unicolor Scott, 1874, rearing experiments using only laboratory-bred food insects were conducted to elucidate the nymphal period of each instar stage of the hemipteran insect. The developmental period for each immature stage was as follows: first instar, 3–5 d (4.0±0.5 d, N=28); second instar, 3–5 d (4.0±0.5 d, N=27); third instar, 3–5 d (4.1±0.5 d, N=27); fourth instar, 4–7 d (5.5±0.7 d, N=26); and fifth instar, 9–11 d (9.6±0.6 d, N=21). The survival rate of nymphs to adults was 70％. The body length of the adult insects fed laboratory-bred prey did not significantly differ from that of field-collected adults. In this study, efficient rearing methods for this species are proposed.