Observations of the flight activity of Hylastes ater and Hylurgus ligniperda (Curculionidae: Scolytinae) in Pinus radiata forests in the central North Island, New Zealand.
Hylastes ater and Hylurgus ligniperda adults were trapped using Lindgren type funnel traps in Pinus radiata forests in the central North Island, New Zealand, from October 1998 through April 2000, to observe the annual flight activity of both species. The results of the trapping programme indicated that Hylurgus ligniperda might be bivoltine and Hylastes ater univoltine. Since the introduction of Hylurgus ligniperda into New Zealand, the peak period of Hylastes ater flight activity has shifted from mid-summer to late autumn, while Hylurgus ligniperda is the dominant species during the spring and summer months. Therefore, most of the habitat created by the harvesting of P. radiata is likely to be colonized by Hylurgus ligniperda. In the past Hylastes ater was the dominant bark beetle colonizing this material. These changes in seasonality may have resulted in a reduction in damage to P. radiata seedlings in some areas.