Natural colonization and adaptation of a mosquito species in Galápagos and its implications for disease threats to endemic wildlife

Abstract

Emerging infectious diseases of wildlife have been recognized as a major threat to global biodiversity. Endemic species on isolated oceanic islands, such as the Galá pagos, are particularly at risk in the face of introduced pathogens and disease vectors. The black salt-marsh mosquito (Aedes taeniorhynchus) is the only mosquito widely distributed across the Galá pagos Archipelago. Here we show that this mosquito naturally colonized the Galá pagos before the arrival of man, and since then it has evolved to represent a distinct evolutionary unit and has adapted to habitats unusual for its coastal progenitor. We also present evidence that A. taeniorhynchus feeds on reptiles in Galá pagos in addition to previously reported mammal and bird hosts, highlighting the important role this mosquito might play as a bridge-vector in the transmission and spread of extant and newly introduced diseases in the Galá pagos Islands. These findings are particularly pertinent for West Nile virus, which can cause significant morbidity and mortality in mammals (including humans), birds, and reptiles, and which recently has spread from an introductory focus in New York to much of the North and South American mainland and could soon reach the Galá pagos Islands. Unlike Hawaii, there are likely to be no highland refugia free from invading mosquito-borne diseases in Galá pagos, suggesting bleak outcomes to possible future pathogen introduction events.Aedes ͉ disease vector ͉ phylogenetics ͉ West Nile virus

How to save the rarest Darwin's finch from extinction: the mangrove finch on Isabela Island

“…Additionally, because several wild animal diseases require insects as vectors Kilpatrick et al 2006;Deem et al 2008;Bataille et al 2009), the recent establishment of the mosquito Culex quinquefasciatus in Galápagos (Thiel et al 2005), which spreads Avipoxvirus spp. and is a potential vector for avian malaria and West Nile virus, represents a major risk to the island's native avifauna (van Riper et al 2002;Pollock 2008).…”

West Nile Virus Vector Competency of Culex quinquefasciatus Mosquitoes in the Galápagos Islands

“…21 Three species of mosquito are currently resident in Galápagos. Aedes taeniorhynchus is ubiquitous and naturally colonized the archipelago approximately 200,000 years ago 22 (Eastwood G, unpublished data). Aedes aegypti is a recently introduced anthropophilic mosquito that because of its associations with dengue viruses has been largely controlled.…”

Ascension Island: a survey to assess the presence of Zika virus vectors

“…Although insular systems are more isolated, pathways of IMS introductions do exist and there are many historical examples of establishment and spread of IMS on islands. Early discussions on passive transport of mosquitoes by road, ship and rail pathways are provided by Howard et al 3 and Hughes and Porter,4 but there are also recent examples of mosquito introductions to island systems by human transport (aeroplanes or tourist boats), for example, the establishment of Culex quinquefasciatus in the Galápagos Islands posing risks to the archipelago's endemic fauna,5 the introduction and establishment of Aedes japonicus on the island of Hawaii6 and the recent introduction of Aedes aegypti to Madeira in 2004 7…”