Cryptic diversity, reproductive isolation and cytoplasmic incompatibility in a classic biological control success story

Marco Gebiola, Jennifer A. White, Bodil N. Cass, Amaranta Kozuch, Leanne R. Harris, Suzanne E. Kelly, Javad Karimi, Massimo Giorgini, Steve J. Perlman, Martha S. Hunter

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Molecular genetics and symbiont diagnostics have revolutionized our understanding of insect species diversity, and the transformative effects of bacterial symbionts on host life history. Encarsia inaron is a parasitoid wasp that has been shown to harbour two bacterial endosymbionts, Wolbachia and Cardinium. Known then as E. partenopea, it was introduced to the USA in the late 1980s from populations collected in Italy and Israel for the biological control of an ornamental tree pest, the ash whitefly, Siphoninus phillyreae. We studied natural populations from sites in the USA, the Mediterranean and the Middle East as well as from a Cardinium-infected laboratory culture established from Italy, with the aims of characterizing these populations genetically, testing reproductive isolation, determining symbiont infection status in their native and introduced range, and determining symbiont role. The results showed that the two Encarsia populations introduced to the USA are genetically distinct, reproductively isolated, have different symbionts and different host-symbiont interactions, and can be considered different biological species. One ('E. inaron') is doubly infected by Wolbachia and Cardinium, while only Cardinium is present in the other ('E. partenopea'). The Cardinium strains in the two species are distinct, although closely related, and crossing tests indicate that the Cardinium infecting 'E. partenopea' induces cytoplasmic incompatibility. The frequency of symbiont infection found in the native and introduced range of these wasps was similar, unlike the pattern seen in some other systems. These results also lead to a retelling of a successful biological control story, with several more characters than had been initially described.

Original languageEnglish
Pages (from-to)217-230
Number of pages14
JournalBiological Journal of the Linnean Society
Issue number2
StatePublished - Feb 1 2016

Bibliographical note

Publisher Copyright:
© 2016 The Linnean Society of London.


  • Cardinium
  • Cryptic species
  • Cytoplasmic incompatibility
  • Encarsia inaron
  • Encarsia partenopea
  • Invasive species
  • Molecular systematics
  • Parasitic wasps
  • Siphoninus phillyreae
  • Wolbachia

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics


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