Evidence for Semiochemical Divergence Between Sibling Bark Beetle Species: Dendroctonus brevicomis and Dendroctonus barberi

Brian T. Sullivan, Amanda M. Grady, Richard W. Hofstetter, Deepa S. Pureswaran, Cavell Brownie, Daniel Cluck, Tom W. Coleman, Andrew Graves, Elizabeth Willhite, Lia Spiegel, Dwight Scarbrough, Andrew Orlemann, Gerardo Zúñiga

Research output: Contribution to journalArticlepeer-review

Abstract

We investigated geographic variation in the semiochemistry of major disturbance agents of western North American pine forests, Dendroctonus brevicomis Le Conte and Dendroctonus barberi Hopkins (Coleoptera: Curculionidae: Scolytinae), species separated by the Great Basin in the USA that until recently were synonymous. At 15 sites in the western USA and northern Mexico, beetle populations were examined to determine (1) pheromone production by solitary, mining females, (2) male electroantennogram amplitudes in response to known semiochemicals for the genus, or (3) relative attractiveness of two female-produced pheromone components (endo- and exo-brevicomin) and two host odors (alpha-pinene and myrcene) to beetles in the field. Compared to female beetles collected east of the Great Basin (D. barberi), western females (D. brevicomis) produced a consistently higher proportion of, and male antenna were correspondingly more sensitive to, the exo- than the endo-isomer of brevicomin. With the exception of one sampling location (where no preference was observed), beetles west of the Great Basin were more attracted to exo- than endo- brevicomin trap lures, whereas eastern beetles displayed the reverse preference. In contrast, there was not a consistent difference between these populations regarding relative attraction or olfactory response to myrcene or alpha-pinene, although some geographic variability was evident. These data show that the semiochemical systems of D. brevicomis and D. barberi have diverged and corroborate genetic and morphological evidence that they are distinct, allopatric species.

Original languageEnglish (US)
Pages (from-to)10-27
Number of pages18
JournalJournal of Chemical Ecology
Volume47
Issue number1
DOIs
StatePublished - Jan 2021

Keywords

  • Geographic variation
  • Host odor
  • Pheromone
  • Southwestern pine beetle
  • Speciation
  • Western pine beetle

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Biochemistry

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