Estimation of population density and dispersal parameters of the adult sugarcane wireworm, Melanotus okinawensis Ohira (Coleoptera: Elateridae), on Ikei Island, Okinawa, by mark-recapture experiments

Density and dispersal distance of the sugarcane wireworm, Melanotus okinawensis Ohira (Coleoptera: Elateridae), were estimated by conducting mark-recapture experiments over an agricultural field (81.4 ha) on Ikei Island (158.3 ha) in early April and late April 2000. Funnel-vane traps with synthetic sex pheromone were uniformly set at 250 points in the field to recapture adult males. The estimated population densities in early April and late April were, respectively, 148.0/ha and 13.8/ha, by the Jolly-Seber method, and 171.0/ha and 13.0/ha by the Yamamura method. Estimated two-day survival rates in early April and late April were, respectively, 0.50 and 0.30 by the Jolly-Seber method, and 0.58 and 0.28 by the Yamamura method. For the population that was released in the center of the island, the relation between the distance (r) from the release point and the proportion of settled individuals (p) was described by a Wallace model, ln(p)=-8.068-0.392rootr as a result of AIC selection. The estimated mean and median dispersal distances were 130.1 m and 87.7 m, respectively.