Chinese white pine beetle, Dendroctonus armandi (Coleoptera: Scolytinae), population density and dispersal estimated by mark-release-recapture in Qinling Mountains, Shaanxi, China

The population density and dispersal of adult Chinese white pine beetle in Qinling Mountains, Shaanxi, China, were estimated by mark-release-recapture at the peak period of its diffusion in 2008 and 2009. Before this study, laboratory trials implemented using a self-regulating crisper and flight mill system showed that marking the beetles with spray paint had no effect on its survival and flight behavior. Our results showed that the female recapture rate (infested success rate) was 23.7%, 24.9%, 20.3%, 28.4% and 27.5%, respectively, in five released plots and positively correlated with crown density. The attacking sequence of the beetles was from south and west to north and east in every host tree. Meanwhile, the distance was not the foremost factor in the natural process of beetles selectively attacking Pinus armandi Franch. After all beetles had been simultaneously released in the center of both Plots D and E, the attack time ranged from 1 to 9 d and 10 d, respectively, with peak appearing in 3-6 d, and the dispersal distances varied from 0 to 32 m and 34 m, with the distribution being leptokurtic, with most observations around the mean mark-release-recapture distance of 17.4 m and 17.3 m.