Inter- and intraspecific acoustic communication in bark beetles

Many bark beetle species have similar life histories and aggregation pheromones, but often segregate temporally or spatially within trees or habitats. However, in Arizona several Dendroctonus species are known to colonize trees and occupy phloem resources in the same area of the tree bole. We investigated whether acoustic calls are distinct between the southern and western pine beetle, and whether these calls are used by beetles for heterospecific and conspecific recognition during colonization and mating. Although much variation existed among and between individuals of each species, we found differences among the call patterns and frequencies between the two species that suggest that acoustic calls could be used for mate recognition and species isolation. Species-specific calls may relax the requirement for distinct pheromones in sympatric species and allow for interspecific cooperation during tree colonization, but still provide reproductive isolation within the tree. Further studies of allopatric populations of these two species compared to sympatric populations, may provide insight into the evolution and selection pressures that shape acoustic calls of these species.