Oviposition traits generate extrinsic postzygotic isolation between two pine sawfly species

Emily E. Bendall, Kim L. Vertacnik, Catherine R. Linnen

Research output: Contribution to journalArticlepeer-review

16 Scopus citations


Background: Although empirical data indicate that ecological speciation is prevalent in nature, the relative importance of different forms of reproductive isolation and the traits generating reproductive isolation remain unclear. To address these questions, we examined a pair of ecologically divergent pine-sawfly species: while Neodiprion pinetum specializes on a thin-needled pine (Pinus strobus), N. lecontei utilizes thicker-needled pines. We hypothesized that extrinsic postzygotic isolation is generated by oviposition traits. To test this hypothesis, we assayed ovipositor morphology, oviposition behavior, and host-dependent oviposition success in both species and in F1 and backcross females. Results: Compared to N. lecontei, N. pinetum females preferred P. strobus more strongly, had smaller ovipositors, and laid fewer eggs per needle. Additionally, we observed host- and trait-dependent reductions in oviposition success in F1 and backcross females. Hybrid females that had pinetum-like host preference (P. strobus) and lecontei-like oviposition traits (morphology and egg pattern) fared especially poorly. Conclusions: Together, these data indicate that maladaptive combinations of oviposition traits in hybrids contribute to extrinsic postzygotic isolation between N. lecontei and N. pinetum, suggesting that oviposition traits may be an important driver of divergence in phytophagous insects.

Original languageEnglish
Article number26
Pages (from-to)1-15
Number of pages15
JournalBMC Evolutionary Biology
Issue number1
StatePublished - Jan 19 2017

Bibliographical note

Funding Information:
This work was supported by the University of Kentucky and the National Science Foundation (DEB-1257739).

Publisher Copyright:
© 2017 The Author(s).


  • Diprionidae
  • Ecological speciation
  • Host adaptation
  • Neodiprion
  • Phytophagous insect
  • Reproductive barriers

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics


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