The Effect of Larval Diet on the Flight Capability of the Adult Moth Athetis lepigone (Möschler) (Lepidoptera: Noctuidae)

Abstract

Athetis lepigone (Möschler) (Lepidoptera: Noctuidae) is a polyphagous insect which has caused severe damage to corn seedlings in recent yr in the summer corn region of China. It is suggested that this is a migrant species, which annually produces 4 different host-fed generations, but the discovery of its flight performance on each host has been elusive. The effects of 4 host plants - corn, peanut, soybean, and wheat - on the survival ratio of larvae and on the flight performance of A. lepigone moths were investigated under laboratory conditions. The results indicate that wheat was the comparatively preferred diet for larvae. The flight distance of A. lepigone moths increased from 1 d old to a peak level at 3 d and then declined after 4 d old within a 24 h limited flight time. The positive larval-nutrition relationship in terms of flight capability of A. lepigone moths also resulted in the furthest distance and longest duration from the preferred wheat. The maximum distance covered by a single individual fed on wheat for 24 h was 44.55 km. The max duration of an individual was 21.46 h. However, A. lepigone moths had a comparatively higher maximum immediate speed (max speed) when larvae fed on non-preferred host plants such as corn and peanut. The sex of the moths from different hosts had no effect on flight distance, duration, or max speed. There were 2 peaks in flight duration of all 3 to 4 d old tested moths, which meant 2 groups: short flight and long flight duration. The difference between hosts in terms of distance, duration, and max speed as previously mentioned occurred only in the long flight duration group. All these results enhance understanding of the seasonal population dynamics of this migratory moth in the agricultural ecosystem in China. They also have important implications for natural environments in terms of migration and outbreaks.