Incursion and range expansion in the bluetongue vector Culicoides imicola in the Mediterranean basin: a phylogeographic analysis

D. V. Nolan, J. F. Dallas, S. B. Piertney, A. J. Mordue (Luntz)

Research output: Contribution to journalArticle

18 Citations (Scopus)

Abstract

The bluetongue (BT) vector Culicoides imicola Kieffer (Diptera: Ceratopogonidae) has undergone widespread range expansion across most of the Mediterranean basin, concomitant with the largest BT epizootic outbreaks on record. Knowledge of the substructure of this vector expansion would be useful for identifying specific source-expansion systems. To this end we analysed the haplotype diversity of the mitochondrial cytochrome oxidase I gene in 273 C. imicola from 88 Mediterranean sites and outgroups. All the C. imicola haplotypes (n = 26) formed a single, distinct clade in comparison with haplotypes of four other species of the Imicola group from southern Africa, confirming C. imicola as a single phylospecies. Haplotype distribution showed extreme differentiation across the Mediterranean basin, with four common haplotypes each predominating in different areas. Eastern and western areas characterized by distinct BT incursions accounted for most of the molecular variance in haplotype composition. Shared common haplotypes identified one area of incursion and expansion encompassing the western half of the Mediterranean basin, with evidence of population growth, and another system encompassing Anatolian Turkey, the Aegean Islands and mainland Greece. A third area of range expansion was identified in the central Mediterranean, with a possible source in Algeria and unsampled parts of central North Africa. We conclude that the expansion of C. imicola in the Mediterranean basin consists of at least three incursions followed by expansions and that the western system experiences conditions promoting high population growth.

Original languageEnglish
Pages (from-to)340-351
Number of pages12
JournalMedical and Veterinary Entomology
Volume22
Issue number4
Early online date21 Nov 2008
DOIs
Publication statusPublished - Dec 2008

Keywords

  • culicoides imicola
  • cytochrome oxidase I gene
  • mitochondrial DNA
  • polymerase chain reaction (PCR)
  • range expansion
  • Mediterranean
  • African horse sickness
  • spatial-distribution
  • statistical tests
  • population-growth
  • Balearic-Islands
  • 1913 diptera
  • virus
  • obsoletus
  • midges
  • Europe

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