Flight capacity and wingbeat frequency of Mythimna loreyi (Lepidoptera: Noctuidae)

The maize caterpillar, Mythimna loreyi (Duponchel, 1827) (Lepidoptera: Noctuidae), is an important migratory pest for agricultural production in Asia, but its flight performance remains poorly understood. Here, we utilized a computer-monitored flight mill system and a stroboscope to assess how adult age, sex, temperature, and relative humidity affect the flight capacity of M. loreyi. The results indicated that the flight ability of M. loreyi was most highly developed in 2-day-old adults and decreased significantly with age. Two-day-old adults under conditions of 24 °C and 80% relative humidity throughout a 12-h scotophase recorded a total flight distance of 23.5 ± 2.8 km for males and 27.2 ± 2.6 km for females, suggesting that M. loreyi has a strong potential for long-distance migration. Temperature and relative humidity had significant effects on the flight performance of M. loreyi, with the maximum flight capacity in the range 20 to 28 °C and 50% to 85% relative humidity. In addition, the wingbeat frequencies of M. loreyi adults ranged from 22.6 to 57.6 Hz and 18.6 to 56.8 Hz among different age groups and temperatures. The highest wingbeat frequency (46.0 ± 0.8 Hz) was recorded for 6-day-old moths. Wingbeat frequency increased with temperature, with maximum (47.0 ± 0.6 Hz) recorded at 36 °C. Wingbeat frequency of male moths was significantly higher than that of female moths. These findings provide a foundation for understanding M. loreyi's migration behavior and can guide the improvement of regional monitoring strategies.