Evidence for regular ongoing introductions of mosquito disease vectors into the Gala ´ pagos Islands Arnaud Bataille 1,2,3, *, Andrew A. Cunningham 2,4 , Virna Ceden ˜o 4,5,6 , Marilyn Cruz 4 , Gillian Eastwood 1,2 , Dina M. Fonseca 7 , Charlotte E. Causton 8 , Ronal Azuero 8 , Jose Loayza 8 , Jose D. Cruz Martinez 8 and Simon J. Goodman 1,4, * 1 Institute of Integrative and Comparative Biology, University of Leeds, Leeds LS2 9JT, UK 2 Institute of Zoology, Zoological Society of London, Regent’s Park, London NW1 4RY, UK 3 NERC Molecular Genetics Facility (Sheffield ), Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK 4 Gala ´pagos Genetics, Epidemiology and Pathology Laboratory, Gala ´pagos National Park, Universidad de Guayaquil, Puerto Ayora, Gala ´pagos Islands, Ecuador 5 Concepto Azul, Cdla. Vernaza Norte Mz 10 Villa 34, PO Box 09-02-142A, Guayaquil, Ecuador 6 Biotechnology Program, Universidad de Guayaquil, Guayaquil, Ecuador 7 Center for Vector Biology, Rutgers University, New Brunswick, NJ 08901, USA 8 Charles Darwin Research Station, Puerto Ayora, Gala ´pagos Islands, Ecuador Wildlife on isolated oceanic islands is highly susceptible to the introduction of pathogens. The recent establishment in the Gala ´pagos Islands of the mosquito Culex quinquefasciatus, a vector for diseases such as avian malaria and West Nile fever, is considered a serious risk factor for the archipelago’s endemic fauna. Here we present evidence from the monitoring of aeroplanes and genetic analysis that C. quinquefasciatus is regularly introduced via aircraft into the Gala ´pagos Archipelago. Genetic population structure and admixture analysis demonstrates that these mosquitoes breed with, and integrate success- fully into, already-established populations of C. quinquefasciatus in the Gala ´pagos, and that there is ongoing movement of mosquitoes between islands. Tourist cruise boats and inter-island boat services are the most likely mechanism for transporting Culex mosquitoes between islands. Such anthropogenic mosquito movements increase the risk of the introduction of mosquito-borne diseases novel to Gala ´pagos and their subsequent widespread dissemination across the archipelago. Failure to implement and maintain measures to prevent the human-assisted transport of mosquitoes to and among the islands could have catastrophic consequences for the endemic wildlife of Gala ´pagos. Keywords: Gala ´pagos; Culex quinquefasciatus; emerging infectious disease; West Nile virus; population genetics; aircraft monitoring 1. INTRODUCTION Human-aided transport and human-induced environ- mental changes have dramatically increased the capacity of disease vectors, such as mosquitoes, to reach, establish and spread in previously inaccessible areas, triggering emergence and epidemics of vector-borne diseases across the globe (Lounibos 2002). Disease vector intro- ductions in recent history are closely linked with the development of global transportation links such as the Worldwide Airline Network (Tatem et al. 2006). Recent outbreaks of West Nile fever in the USA (Kramer et al. 2008) and of Chikungunya disease throughout the Indian Ocean region (Chevillon et al. 2008) are striking examples of the impacts of globalization on human and animal health. Recently, emerging infectious diseases that have wildlife host reservoirs have been highlighted as threats to human health, the global economy and bio- diversity (Daszak et al. 2000; Jones et al. 2008). Wildlife endemic to isolated oceanic islands is particularly suscep- tible to the introduction of infectious diseases (Matson 2006). For example, the co-introduction of the southern house mosquito Culex quinquefasciatus Say (Diptera: Culicidae) and avianpoxvirus in Hawaii, followed by a later introduction of avian malaria, precipitated dramatic declines and extinctions among Hawaiian endemic birds (Warner 1968; Van Riper et al. 1986, 2002). In contrast to Hawaii, Gala ´pagos remains one of the most pristine archipelagos on Earth, with much of its endemic fauna intact (Tye et al. 2002; Watkins & Cruz 2007). The introduction of new pathogens and disease vectors could have devastating effects on the Gala ´pagos biodiver- sity (Wikelski et al. 2004; Kilpatrick et al. 2006), and because of this, the establishment of C. quinquefasciatus * Authors and address for correspondence: Institute of Integrative and Comparative Biology, Faculty of Biological Sciences, University of Leeds, L.C. Miall Building, Clarendon Way, Leeds LS2 9JT, UK (bgyaba@leeds.ac.uk, s.j.goodman@leeds.ac.uk). Electronic supplementary material is available at http://dx.doi.org/10. 1098/rspb.2009.0998 or via http://rspb.royalsocietypublishing.org. Proc. R. Soc. B (2009) 276, 3769–3775 doi:10.1098/rspb.2009.0998 Published online 12 August 2009 Received 9 June 2009 Accepted 21 July 2009 3769 This journal is q 2009 The Royal Society on December 21, 2016 http://rspb.royalsocietypublishing.org/ Downloaded from