Evaluation of effects of two Lepidopteran larvae on the development and reproduction of Andrallus spinidens based on age-stage， two-sex life table

Objective This study aimed to clarify the effects of Spodoptera frugiperda and Mythimna separata as prey on the development， reproduction， and population parameters of Andrallus spinidens， with the goal of providing a theoretical basis for the mass rearing and field application of Andrallus spinidens.Method Under laboratory conditions， Andrallus spinidens was fed the larvae of Spodoptera frugiperda or Mythimna separata to determine biological para-meters， including developmental duration， survival rate， fecundity， egg hatching rate， and longevity. The effects of feeding on the larvae of two prey species were analyzed in terms of the population parameters of Andrallus spinidens using the age-stage， two-sex life table method.Result No significant difference was observed in the preadult stage of Andrallus spinidens fed on the larvae of two prey species （P>0.05， the same below）. However， the egg stage was significantly shorter for individuals fed on Mythimna separata （7.25 d） compared to those fed on Spodoptera frugiperda （8.50 d） （P<0.05， the same below）， and the 1^st instar nymphs developed faster （3.54 d）， leading to a significantly extended total lifespan （58.67 d）. Survival rates of Andrallus spinidens fed on Mythimna separata larvae were consistently higher than those fed on Spodoptera frugiperda larvae throughout development durations， with higher early survival rates and a more gradual decline in survival rate in older nymphs. No significant differences were found in pre-oviposition， total pre-oviposition， or oviposition stages of Andrallus spinidens fed on larvae of two prey species. However， female Andrallus spinidens fed on Spodoptera frugiperda produced significantly more eggs per female （221.17 eggs） than those fed on Mythimna separata （107.33 eggs）， with a more pronounced reproductive output during the mid-to-late adult stage. The female sex ratio of Andrallus spinidens was 0.22 （fed on Spodoptera frugiperda larvae） and 0.33 （Mythimna separata larvae）. No significant differences were detected in net reproductive rate， intrinsic rate of increase， finite rate of increase， or mean generation time between Andrallus spinidens fed on larvae of two prey species.Conclusion Mythimna separata enhances early development and population persistence of Andrallus spinidens， whereas Spodoptera frugiperda significantly improves the reproductive performance Andrallus spinidens， indicating complementary nutritional effects between the two prey species.