Effects of moth age and rearing temperature on the flight performance of the loreyi leafworm, Mythimna loreyi (Lepidoptera: Noctuidae), in tethered and free flight

Authors: QIN, JIANYANG - Chinese Academy Of Agricultural Sciences; LIU, Y - Chinese Academy Of Agricultural Sciences; ZHANG, LEI - Chinese Academy Of Agricultural Sciences; CHENG, YUNXIA - Chinese Academy Of Agricultural Sciences; Sappington, Thomas; JIANG, XINGFU - Chinese Academy Of Agricultural Sciences

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/1/2018
Publication Date: 4/7/2018
Citation: Qin, J., Liu, Y., Zhang, L., Cheng, Y., Sappington, T.W., Jiang, X. 2018. Effects of moth age and rearing temperature on the flight performance of the loreyi leafworm, Mythimna loreyi (Lepidoptera: Noctuidae), in tethered and free flight. Journal of Economic Entomology. 111(3):1243-1248. https://doi.org/10.1093/jee/toy076.
DOI: https://doi.org/10.1093/jee/toy076

Interpretive Summary: The loreyi leafworm has suddenly emerged as a serious agricultural pest of several crops, including corn, in China. It is a close relative of the true armyworm in North America and the oriental armyworm in Eurasia, which have long been major pests of corn and other crops. To develop efficient and effective management strategies for any new insect pest requires an understanding of its ecology and population dynamics. Because it is closely related to other armyworms which are known long-distance migrants, laboratory flight experiments were conducted to examine the flight potential of M. loreyi. Both tethered-flight and free-flight experiments showed that M. loreyi adults have very high flight propensity and capacity during days 2 through 5 after emergence from the pupa, corresponding to the pre-reproductive period of females, a strong indication that this species is probably migratory. Larval rearing temperature significantly affected flight performance of adults, suggesting that a decision to disperse or remain a resident as an adult is probably a facultative decision made during the larval stage. This information will be used by university, government, and industry scientists to understand the population dynamics of this new and serious pest, with ramifications for better understanding and management of closely related species in the U.S. and worldwide.

Technical Abstract: To understand the migratory flight behaviors of the loreyi leafworm, Mythimna loreyi, both tethered (flight distance, time and velocity) and free flight activity (flight action, duration and frequency) of adults at different ages, sexes and temperatures were investigated using computer-controlled insect flight mills and an autonomous flight monitoring system. Tethered flight activity differed significantly among ages and rearing temperature, but not sex. Newly emerged adults (the first day after emergence) displayed the lowest flight time, distance, and speed. However, flight performance increased with age, peaking at 3 days. Relatively strong flight performance was maintained up to 5 days post-emergence, and then declined significantly by day 6. There was no significant difference in flight performance between sexes for 3-day-old moths. Adults reared as larvae at 24 degrees C averaged significantly longer flight duration and distance than those reared at other temperatures. Both lower and higher rearing temperatures negatively affected tethered flight. Similar results among age and rearing temperature treatments and were observed in autonomous free-flight tests. During 12-hour free-flight tests, flight activity peaked from 6 to 10 hours after beginning of darkness. Free-flight activity of 1 and 6-day-old adults was significantly less than that of 3, 4, and 5-day-old adults. Adults reared at 24 degrees C showed significantly greater free flight action, duration, and frequency than those reared at other temperatures. The results suggest M. loreyi may be a migratory species.