Pityogenes bidentatus or Pityogenes quadridens galleries in Scotch pine wood. Both species are found competing
for bark on branches of Scotch pine. Both species have a polygamous mating system where the male bores the entrance hole and
tunnel to the nuptial chamber and produced aggregation pheromone. Several females usually join the male and they make the
galleries leading away from the nuptial chamber, while laying eggs along the sides of their gallery. Note the nuptial chamber (made by the
male) and the 3 galleries (3 females) leading away from the center of the photo.
Images © 2000 by John A. Byers, Chemical Ecology.