Where do conifer insects come from?

Phytophagous insects nearly always specialize in feeding on specific tissues of the plants with which they are associated, ranging from roots to stems, twigs, leaves or seeds, but sometimes vary widely in how many species they attack. For comparative studies, phytophagous insects associated with a plant group can be assigned to feeding guilds, assemblages that are generally considered to share a feeding niche. Conifers are an ancient lineage of seed plants attacked by a wide range of insect orders. Because they also constitute an economic resource for wood, paper, resins and many other commodities, one in which insects are the major factor in reducing economic value, their insect pests and associated pathogens are known in some detail. In this study, the composition of insect guilds on a member of the conifer genus Pinus is analyzed using a review of known associations and field observation. A framework of phylogenetic niche conservatism is utilized to evaluate two dimensions of feeding niche in different guilds of insects: host taxonomic range and tissues utilized. This approach allows for elucidation of the macroevolutionary model underlying phylogenetically conserved associations with more ancient conifer lineages, as well as other Pinus species. A perspective on the relative lability of associations informs considerations of the community structure, niche composition, and potential for competition within the conifer insect guilds. Knowledge of pest and pathogen guild evolutionary dynamics is relevant to the management and sustainability of this valuable economic resource.