Tracing the Tiger: Population Genetics Provides Valuable Insights into the Aedes (Stegomyia) albopictus Invasion of the Australasian Region

Abstract

BackgroundThe range of the Asian tiger mosquito Aedes albopictus is expanding globally, raising the threat of emerging and re-emerging arbovirus transmission risks including dengue and chikungunya. Its detection in Papua New Guinea's (PNG) southern Fly River coastal region in 1988 and 1992 placed it 150 km from mainland Australia. However, it was not until 12 years later that it appeared on the Torres Strait Islands. We hypothesized that the extant PNG population expanded into the Torres Straits as an indirect effect of drought-proofing the southern Fly River coastal villages in response to El Nino-driven climate variability in the region (via the rollout of rainwater tanks and water storage containers).Methodology/Principal FindingsExamination of the mosquito's mitochondrial DNA cytochrome oxidase I (COI) sequences and 13 novel nuclear microsatellites revealed evidence of substantial intermixing between PNG's southern Fly region and Torres Strait Island populations essentially compromising any island eradication attempts due to potential of reintroduction. However, two genetically distinct populations were identified in this region comprising the historically extant PNG populations and the exotic introduced population. Both COI sequence data and microsatellites showed the introduced population to have genetic affinities to populations from Timor Leste and Jakarta in the Indonesian region.Conclusions/SignificanceThe Ae. albopictus invasion into the Australian region was not a range expansion out of PNG as suspected, but founded by other, genetically distinct population(s), with strong genetic affinities to populations sampled from the Indonesian region. We now suspect that the introduction of Ae. albopictus into the Australian region was driven by widespread illegal fishing activity originating from the Indonesian region during this period. Human sea traffic is apparently shuttling this mosquito between islands in the Torres Strait and the southern PNG mainland and this extensive movement may well compromise Ae. albopictus eradication attempts in this region.

Photoperiodic Diapause and the Establishment ofAedes albopictus(Diptera: Culicidae) in North America

“…In addition to ND5, analysis of mtDNA gene sequences including Cytb and COI has also been used to examine the phylogeography of Ae. albopictus (Mousson et al 2005, UsmaniBrown et al 2009, Kamgang et al 2011, Porretta et al 2012, Beebe et al 2013). Additionally, a recent study analyzing COI mtDNA variation strongly supports an Asian origin of Ae.…”

Aedes albopictus(Diptera: Culicidae) as a Potential Vector of Endemic and Exotic Arboviruses in Australia

“…albopictus recently has colonized the islands of the Torres Strait, the region that separates northern Australia from southern Papua New Guinea (Ritchie et al 2006, Beebe et al 2013. Considering its importance in DENV and CHIKV transmission cycles throughout the world, there is concern that if introduced to the Australian mainland, Ae.…”

Ability forAedes albopictus(Diptera: Culicidae) to Survive at the Climatic Limits of Its Potential Range in Eastern Australia

“…Despite the implementation of an eradication initiative, including a public awareness program, source reduction campaign, and application of insecticides, Ae. albopictus has since established itself on the inner islands of Waiben and Ngurupai, Ͻ30 km from the Australian mainland (Beebe et al 2013). In 2009, Ae.…”

“…Genetic analysis showed the populations of Ae. albopictus in the Torres Strait probably came from Indonesia (Beebe et al 2013). It was subsequently eliminated from the mainland, but the ongoing presence of Ae.…”