Host preference and attack pattern of Dendroctonus rhizophagus (Coleoptera: Curculionidae: Scolytinae): a bark beetle specialist on pine regeneration.

Pine seedlings and saplings are seldom attacked by bark beetles of the genus Dendroctonus. However, Dendroctonus rhizophagus (Coleoptera: Curculionidae: Scolytinae) Thomas and Bright specifically attacks pine seedlings and causes conspicuous mortality in naturally regenerated stands in the Sierra Madre Occidental, northern Mexico. We evaluated the host preference and attack of D. rhizophagus under field conditions. We tried to establish any relationship between tree growth or host size and the number of attacking beetles. Generally, only one pair of beetles attacked each of the seedlings regardless of host size; however, a significant positive linear relationship between host size and adult brood size was observed. We found that this species preferred the best growing seedlings in our study sites.