Laboratory evaluation of flight activity of Dendroctonus armandi (Coleoptera: Curculionidae: Scolytinae)

Dendroctonus armandi Tsai and Li is an important native pest of Chinese white pine (Pinus armandii Franch. (Pinaceae)) in the Qin ling Mountains of Shaanxi Province, People's Republic of China. Populations can reach epidemic levels and cause widespread mortality of trees in forest ecosystems. We studied the flight behaviour of D. armandi collected under controlled conditions using a flight-mill system to gather information to aid in its management. Our results indicate that D. armandi has three distinct flight patterns (intermittent flight, short-burst flight, and sustained uninterrupted flight). There were no significant differences in flight performance between males and females. Median daily values for total distance traveled, total flight time, and maximum uninterrupted flight time were 275.1 m day-1, 815 s day-1, 40 s day-1, (n = 148). Individuals displayed positive phototactic behaviour: total flight distance and total flight time were greater under artificial illumination than in natural light or darkness. The level of flight activity increased throughout the morning, remained high during the afternoon (1400-1600), dropped considerably at 1800, and was lowest at midnight. There was no significant difference in flight distance or flight time between the first and second generations. From the data collected, it is clear that the phototactic response is an important factor in the flight behaviour of D. armandi and may influence its spatial dispersal.