Estimation of abundance and dispersal distance of the sugarcane click beetle Melanotus sakishimensis Ohira (Coleoptera: Elateridae) on Kurima Island, Okinawa, by mark-recapture experiments

The absolute population density and natural mean dispersal distance of the sugarcane click beetle Melanotus sakishimensis Ohira (Coleoptera: Elateridae) were estimated by using mark-recapture experiments in an agricultural area (180 ha) on Kurima Island, Miyakojima, Okinawa in mid-February, from 2002 to 2006. Funnel-vane traps with synthetic sex pheromone were uniformly placed along field roads at 100 points to capture adult males. Estimates of population densities of males that were obtained by the Jolly-Seber and Yamamura methods from 2002 to 2006 were 33,761, 29,727, 14,960, 11,360 and 8,634, respectively. The Yamamura method was adopted in 2004 and 2005 when the survival rates estimated by Jolly-Seber method became larger than 1. The estimate of lifetime natural mean dispersal distance ( SE) that was calculated by eliminating the influence of artificial trap removal was 193.8 +/- 11.0 m. The estimate of the male removal rate (and the 95% profile likelihood confidence interval) was 0.131 (0.117-0.147), indicating that the amount of male removal was not sufficient for the population control in this experiment.