Field studies were conducted to determine the flight response of the twig beetle Pityophthorus pubescens (Marsham) (Coleoptera: Curculionidae: Scolytinae) to the potential aggregation pheromone component, (E)-( )-pityol, and its racemic form, (E)-(±)-pityol, in different Pinus spp. L. (Pinales: Pinaceae) stands in the Basque Country (Northern Spain). Both (E)-( )-pityol and (E)-(±)-pityol equally attracted more males than females, and they were all significantly different from the blank controls. Data about P. pubescens gallery systems in naturally infested P. radiata D. Don branches are also provided. The presence of one male and one female was the most common gallery habitation found in debarked twigs. Current results suggest that P. pubescens may be monogynous and females might mediate the aggregation of mating partners.