Assessment and Models of Insect Damage to Cones and Seeds of in the Sierra Madre Occidental, Mexico.

Insect damage to cones and seeds has a strong impact on the regeneration of conifer forest ecosystems, with broader implications for ecological and economic services. Lack of control of insect populations can lead to important economic and environmental losses. is the most widespread of the white pines in Mexico and is widely distributed throughout the mountains of northern Mexico. Relatively few studies have examined insect damage to the cones and seeds of these pines, especially in Mexico. In this study, we therefore analyzed insect damage to cones and seeds of in Mexico by using X-ray and stereomicroscopic analysis. The specific objectives of the study were (a) to characterize insect damage by measuring external and internal cone traits, (b) to assess the health of seeds and cones of in the Sierra Madre Occidental, Mexico, and (c) to estimate the relative importance of the effects of different environmental variables on cone and seed damage caused by insects. We found that 80% of seeds and 100% of the tree populations studied had damage caused by insects. Most seeds were affected by , and the Lepidoptera complex (which includes , and ). The cones of all tree populations were affected by some type of insect damage, with Lepidoptera causing most of the damage (72%), followed by (15%), the hemipteran (7%), and the wasp (6%). The proportion of incomplete seeds in at the tree level, cone damage by and seed damage in were associated with various climate and soil variables and with crown dieback. Thus, cone and seed insect damage can be severe and potentially impact seed production in and the reforestation potential of the species. The study findings will enable managers to better identify insects that cause damage to cone and seeds. In addition, identification of factors associated with damage may be useful for predicting the levels of insect predation on seeds and cones.