Life cycle and morphology of Anisops sardeus Herrich-Schaeffer, 1849 (Heteroptera: Notonectidae)

[Display omitted] •Total developmental time is shorter in the wet season than that in the dry season.•Nymphs were larger in the dry season than that in the wet season.•Synthlipsis uniformly increased from instar I to instar V males and females.•WL/WW, WL/BL, HL/BL, FE2L/TI2L, S/HW and V/S can be used for separating instars. The life cycle of Anisops sardeus was studied by rearing individuals from egg to adult stage in laboratory conditions at a water temperature of 23.2 ± 1.4 °C during the wet season (May-June) and 19 ± 1.8 °C during the dry season (December-February). The incubation period averaged 8 ± 0.8 and 11.5 ± 1.7 days during the wet and dry seasons, respectively. Duration of the five instars averaged 3.4 ± 0.5, 4.4 ± 0.5, 4.8 ± 0.8, 5 ± 0.7, and 6.9 ± 0.7 days, respectively during the wet season, and 4.9 ± 0.7, 6.5 ± 1.1, 7.5 ± 1.1, 8.1 ± 0.7, and 9.4 ± 1.1 days, respectively during the dry season. Total developmental time averaged 32.5 ± 2 and 47.9 ± 2.8 days in the wet and dry seasons, respectively. The average period of incubation and developmental time of the five instars were shorter in the wet season as compared to those in the dry season. But individuals were larger in the dry season. The variations in morphometric ratios of different characteristic features of laboratory reared specimens among different developmental stages in both the wet and dry seasons, and field collected specimens in the wet season were highly significant as revealed by one-way MANOVA (F = 95.45, p