The Study On Flight Ability Among Different Geographic Populations Of Asian Gypsy Moth, Lymantria Dispar In China

The gypsy moth, which is divided by genetic markers into European gypsy moth (EGM) and Asian gypsy moth (AGM), can attack a number of different forest types around the globe. In North America, EGM has successfully invaded and brought tremendous damages to several economically and environmentally important tree species. Compared with EGM, the AGM females have greater flight ability and pose a higher potential risk to forestry industries. Therefore, AGM has already been listed as top threat by U.S. and Canadian quarantine agents and become a great obstacle for Chinese international trading. The research reared AGM with artificial diets to ensure equivalent vigor for seven geographic populations, and used flight mill system to study the influence of gender, age and mating status on different geographic groups (Beijing, Hebei, Inner Mongolia, Jiangsu, Anhui, Guizhou and Liangning). The scientific questions for the research are:how to quantify flight ability for AGM females from different geographic populations? What is the dominant factor to this capacity? A series of experiments and analysis have been systematically carried to approach the research questions:1. The AGM females and males (Hebei and Inner Mongolia groups) were used to examine flight speed, flight distance and flight duration for24-hour flight test. The results showed:AGM male has much stronger flight ability than AGM female. The flight ability of both genders reached peak at the1-day age, and female linearly decreased along with age. Egg-laying in mated moths had a negative influence on flight capability,while males haven’t been influenced by mating status.2. The AGM females from seven geographic groups (Beijing, Hebei, Inner Mongolia, Jiangsu, Anhui, Guizhou and Liangning) were used for8-hour flight test. The results showed:53%of all females undertook short flights (a longest single flight less than5km). All females have best performance at1-day old. The Liaoning and Guizhou groups showed relatively stronger flight ability with average flight distance of6.63km and7.50km in1-day old. While Inner Mongolia and Hebei groups are weaker with average flight distance of3.95km and4.03km in1-day old. The virgin female from all groups did better in flight distance, flight duration and flight speed than mated ones. Among the mated females, Liangning group has stronger flight performance than others.3. The study employed flight distance, flight duration, flight muscle strength and largest distance for a single flight as variables to Cluster-analyze the flight ability of AGM females from seven geographic groups. The results showed:seven geographic groups can be categorized by flight ability into three groups:1) Beijing, Hebei and Inner Mongolia;2) Jiangsu, Anhui and Guizhou;3) Liaoning, which has strongest flight ability.