Spodoptera ornithogalli (Lepidoptera: Noctuidae): Biological parameters of immature stages under controlled conditions using an artificial larval diet

Abstract This study details some biological parameters of immature stages (eggs and larvae, including the prepupal period, and pupae) of Spodoptera ornithogalli (Guenée, 1852), including survival rates, stage duration, larval head capsule width, and pupal weight. Insects were kept under controlled conditions (25 ± 1 °C, 70 ± 10% RH, and a 14-h photophase) and reared on an artificial diet. The viability of the egg, larval, and pupal stages, and the prepupal period was 99.03%, 99.41%, 98.77%, and 97.61%, respectively. The average durations of the egg, larval, pupal stages, and the prepupal period were 3.00, 14.86, 11.93, and 1.68 days, respectively. All larvae developed through six instars. From the fourth instar onward, females exhibited larger head capsules than males, with a mean growth rate of 1.61 between successive instars. Female pupae were significantly heavier and exhibited protogyny. The rearing method and artificial diet previously developed for other congeneric species proved suitable for S. ornithogalli , enabling detailed observations of its biological cycle, particularly during the larval stage, and resulting in an overall survival rate of nearly 95%. The immature biological parameters of S. ornithogalli are discussed in comparison with data from previous studies involving the same species reared on different host plants, as well as with those reported for Spodoptera albula (Walker, 1857), Spodoptera cosmioides (Walker, 1858), Spodoptera dolichos (Fabricius, 1794), Spodoptera eridania (Stoll, [1782]), and Spodoptera frugiperda (J.E. Smith, 1797) kept under the same artificial larval diet and standardized rearing conditions.