Non-consumptive effects of the predatory Sycanus falleni (Hemiptera: Reduviidae) on Spodoptera frugiperda (Lepidoptera: Noctuidae) based on age-stage two-sex life table

Non-consumptive effects induced by predators have significant potential applications in pest management. Sycanus falleni is an important predatory natural enemy with biological control value.

This study aimed to elucidate the potential impacts of S. falleni on the major invasive pest Spodoptera frugiperda.

Laboratory experiments were conducted to investigate the non-consumptive effects of S. falleni on the whole developmental period of S. frugiperda. A systematic evaluation was performed using the age-stage two-sex life table.

The results showed that the egg period of S. frugiperda was significantly prolonged, while the development of 2^nd and 5^th instar larvae was significantly accelerated under the non-consumptive stress of S. falleni. The preoviposition period of adult females was significantly prolonged, with reduced fecundity and survival rate, although the pupation rate, weight of male and female pupae, and sex ratio of S. frugiperda were not affected by the non-consumptive stress. Population prediction curves showed that the population growth rate of S. frugiperda under the non-consumptive stress of S. falleni was lower than that of the normal-growing population. In addition, the population parameters of S. frugiperda under the non-consumptive stress of S. falleni showed negative trends, although these were not significant overall.

In conclusion, the non-consumptive effects of S. falleni can inhibit the growth and development of S. frugiperda to some extent, but have a lesser impact on the fecundity of S. frugiperda. This study provides a theoretical basis for the field application of S. falleni to controlling S. frugiperda.