Effect of intraspecific competition on progeny production of Tomicus piniperda (Coleoptera : Scolytidae)

Intraspecific competition. in Tomicus piniperda (L.) was studied in Ascot, United Kingdom, with special emphasis on its effect on progeny adult (i.e., offspring) weight and progeny production. Although the weight of female pr ogeny adults was significantly decreased by increasing attack density (dens ity of colonization), the latter did nor significantly affect weight of mal e progeny adults. Similarly, increasing adult female weight was significant ly related to increasing egg gallery length, number of hatched eggs, and fi nal production of progeny adults. This production was also affected by host (tree) species. Females breeding in Pinus sylvestris (L.) showed a higher production of progeny adults than those in Pinus nigra variety maritima (Ai t.) Melville. Overall, increasing intraspecific competition appears to cont ribute to the regulation of T. piniperda populations through reduction of w eight and fecundity of female progeny.