Mark-recapture of Monochamus galloprovincialis with semiochemical-baited traps: population density, attraction distance, flight behaviour and mass trapping efficiency

Abstract

The pine sawyer Monochamus galloprovincialis is considered the most efficient vector in Europe of the pine wood nematode (PWN), the causal agent of the pine wilt disease. The detection of PWN in Europe generated great concern by the EU which, in response, implemented strong quarantine and phytosanitary measures. Among them, the improvement of monitoring and control of pine sawyer is imperative, for which better understanding of behavioural, ecological and operational factors affecting catchability is needed. In 2012–2013, we investigated with mark-recapture methods the population density, trap attraction distance, flight behaviour and mass trapping efficiency in M. galloprovincialis. Population density ranged from 96 to 474 adults ha−1. Trap attraction distance averaged 50 m. Lifetime adult dispersal was 107–122 m on average. A logarithmic diffusion model fitted to recapture data yielded a maximum dispersal of 464 m (95 per cent confidence limits: 121–2365 m). Sawyer flights were significantly more frequent downslope in the plot. Catch concentration (i.e. the ratio between the radius r of the effective trapping area S and the maximum dispersal distance rm) ranged from 0.32 to 0.41 depending on sex. Mass trapping efficiency (i.e. the ratio of the total number of adults caught in the plot (excluding recaptures) over the estimated population size) was consistently low (0.08–0.36). We conclude from an applied perspective that available lures and traps are highly effective for monitoring, but their implementation in mass trapping requires substantial improving.