A new genetic study dispels the myth of the \u2018London Underground mosquito,\u2019 pointing to an older origin of this species in the Mediterranean region and explaining its evolution beyond the borders of the British capital.<\/p>\n
The idea that this mosquito originated specifically in London\u2019s tunnels during World War II arose in the context of bites while sheltering in underground stations. Over time, many biologists believed that the city\u2019s underground life and its constant humidity could have fostered the adaptation and evolution of the underground form molestus \u2013 one of the two manifestations of Culex pipiens.<\/p>\n
The mosquito, often called the \u2018northern house mosquito,\u2019 is linked to two forms in its existence: Culex pipiens form pipiens feeds mainly on birds and lives in the open air; the other form \u2013 Culex pipiens form molestus, from the Latin molestus meaning \u201cannoying\u201d \u2013 loves people and reproduces well underground.<\/p>\n
The second form was previously considered the one that could adapt to life in London\u2019s underground stations. <\/p>\n
\n\u201cThis theory was truly made famous by a genetic study published in 1999, which, in my view, was based on limited evidence, and asserted that the \u2018London Underground mosquito\u2019 allegedly evolved in situ from an above-ground population.\u201d<\/p>\n
\u2013 Yuki Haba\n<\/p><\/blockquote>\n
Results of the study and its context<\/p>\n
In the work of Haba and his colleagues, genetic sequences of hundreds of mosquitoes from different corners of the world were analyzed, including samples from the World War II era. The conclusion indicates that molestus did not rapidly evolve underground in London, but has a significantly older origin.<\/p>\n
\u201cThis predates the London Underground by a long way, and it seems to have evolved near the Mediterranean region, particularly in the Near East,\u201d said Yuki Haba, adding that the divergence between the terrestrial pipiens and the subterranean molestus could have arisen as far back as 10,000 years ago, but most likely between 3,000 and 2,000 years ago.<\/p>\n
\u201cEvolutionary analysis indicates that those ancestral molestus populations were above-ground, \u2013 added he, \u2013 and they gradually spread around the world, including to the London Underground.\u201d<\/p>\n
Methods of study and context of the data<\/p>\n
The team began rigorously testing the \u2018London Underground mosquito\u2019 hypothesis in 2018. \u201cWe literally searched for Culex pipiens using Google and sent letters to every author of every publication we found about this mosquito, saying that we needed samples to understand the origin and genetic diversity of the species,\u201d said Haba.<\/p>\n
Over the years thousands of emails and samples were collected: dead mosquitoes preserved in ethanol, from over 200 sources in 50 countries. Live specimens from the London Underground could not be obtained due to a refusal to grant permission to collect specifically in the tunnels. Instead, historical specimens preserved at the Natural History Museum in London and analyzed at the Wellcome Sanger Institute were used.<\/p>\n
In total, 357 modern mosquitoes and 22 historical samples were analyzed, and thanks to additional samples from another study the total number rose to about 800.<\/p>\n
\n\u201cOur data indicate that molestus descends directly from pipiens populations that still thrive in the Mediterranean region.\u201d<\/p>\n
\u2013 Lindi McBride\n<\/p><\/blockquote>\n
\u201cThis finding suggests that molestus evolved at Mediterranean latitudes, but more likely in the Near East, where the climate is drier for the avian-feeding variant,\u201d said McBride, adding that the gap between underground and above-ground populations occurred long before they appeared in other parts of the world.<\/p>\n
During roughly the same period, regional people began forming agricultural communities with irrigation systems, which created conditions for the mosquito to reproduce and allowed it to colonize arid regions, and later adapt to humans.<\/p>\n
Evidence is supported by the fact that molestus was first described as a species in 1775 in Egypt by naturalist Peter Forssk\u00e5l. \u201cProbably he was there at least a thousand years before that,\u201d McBride noted. \u201cThen it was documented in southern Europe in two places, in Croatia and Italy, in the 1800s, and the first mentions from underground structures in Northern Europe date to around 1920.\u201d<\/p>\n
These lines of inquiry hint that molestus could have travelled north and, encountering a climate that would not allow survival in open environments, sought shelter underground. McBride noted that they did not withstand cold winters, so they largely stayed in southern Europe, where underground structures for winter later appeared.<\/p>\n
There are more than 3,000 known species of mosquitoes that now inhabit almost all continents, with the exception of Antarctica. Recently in Iceland a mosquito was found that had previously been considered unlikely due to the country\u2019s cold.<\/p>\n
\n\u201cWe interpreted these results as evidence that some above-ground populations had previously adapted to the London Underground system and became reproductively isolated from others.\u201d<\/p>\n
\u2013 Richard Nichols\n<\/p><\/blockquote>\n
\u201cThis is an exciting and comprehensive study of the evolution of this globally significant mosquito,\u201d commented Cameron Webb, associate professor of medical entomology at the University of Sydney and NSW Health Pathology in Australia. \u201cAlthough it is often depicted as adapted specifically to the London Underground, the mosquito is actually well known for its underground ecosystems around the world,\u201d he added in a letter.<\/p>\n
\n\u201cThe London Underground mosquito underscores the need to better understand the biology of less-studied mosquitoes to assess how they might exploit a changing urban landscape and the related health challenges for populations\u201d<\/p>\n
\u2013 Cameron Webb\n<\/p><\/blockquote>\n
This study underscores the need to consider global sources of mosquito evolution in the context of urbanization and climate change, as our understanding of their biology helps better assess risks to public health in modern cities.<\/p>\n","protected":false},"excerpt":{"rendered":"A new genetic study dispels the myth of the \u2018London Underground mosquito,\u2019 pointing to an older origin of…\n","protected":false},"author":2,"featured_media":142520,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[272],"tags":[84384,18,247,458,19,17,84385,84383,84386,84387,84388,5,133,84389,84390],"class_list":{"0":"post-142519","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-genetics","8":"tag-culex-pipiens-molestus","9":"tag-eire","10":"tag-genetic-research","11":"tag-genetics","12":"tag-ie","13":"tag-ireland","14":"tag-london-underground-mosquito","15":"tag-london-underground-mosquito-culex-pipiens-molestus-mosquito-evolution-genetic-research-mediterranean-mosquito-origin-urban-mosquito-adaptation","16":"tag-mediterranean-mosquito-origin","17":"tag-mosquito-evolution","18":"tag-mosquito-genetics","19":"tag-news","20":"tag-science","21":"tag-urban-mosquito-adaptation","22":"tag-wwii-mosquito-myth"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@ie\/115428686918798041","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/142519","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/comments?post=142519"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/posts\/142519\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media\/142520"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/media?parent=142519"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/categories?post=142519"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/ie\/wp-json\/wp\/v2\/tags?post=142519"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}