{"id":512492,"date":"2024-05-23T11:23:49","date_gmt":"2024-05-23T14:23:49","guid":{"rendered":"https:\/\/revistapesquisa.fapesp.br\/?p=512492"},"modified":"2024-05-23T11:23:49","modified_gmt":"2024-05-23T14:23:49","slug":"parasites-that-turn-spiders-into-zombies","status":"publish","type":"post","link":"https:\/\/revistapesquisa.fapesp.br\/en\/parasites-that-turn-spiders-into-zombies\/","title":{"rendered":"Parasites that turn spiders into zombies"},"content":{"rendered":"

In mid-forest tree foliage about 1 meter (m) off the ground, whitish stains may, at a distance, be taken for bird droppings. Upon closer inspection they are, in fact, velvety mounds, which at times carry the features of a spider that once lived, and at others take on minuscule, alien-like forms. These, then, are the reproductive structures of fungi that specialize in inhabiting spiders as parasites. A similar phenomenon in ants was the inspiration for The Last of Us<\/em>, a computer game featuring ravenous creatures affected by a mutant fungus, which became a television series this year.<\/p>\n

\u201cThe parasite manipulates the behavior of its hosts to confer a considerable advantage upon the fungus,\u201d explains biologist Arist\u00f3teles G\u00f3es Neto, coordinator of the Laboratory of Molecular and Computer Biology of Fungi at the Federal University of Minas Gerais (UFMG). The manipulation generally causes the spiders to ascend the trees and settle on higher leaves than they normally would, to die there. \u201cThey are like real-life zombies,\u201d quips the researcher. From this position the reproductive structures of the fungi release spores that fall in a shower of microscopic dust, scattering down to the next victims on lower leaves.<\/p>\n

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Jober Sobczak\u2009\/\u2009Unila<\/span><\/a> With its genitalia destroyed, it can be impossible to identify a parasite-infested spiderJober Sobczak\u2009\/\u2009Unila<\/span><\/p><\/div>\n

In April this year the group published a study into the parasite genus Gibellula<\/em> in the Journal of Fungi<\/em>, the doctoral research of biologist Thairine Mendes Pereira in her contribution to exploring the association. \u201cThis is one of the only fungus genera that exclusively inhabit spiders,\u201d says G\u00f3es Neto. In addition to bibliographical research, the fieldwork involved a survey of vegetation in Rio Doce State Park, located in the southeastern state of Minas Gerais, and in the Santa L\u00facia Biological Station and the Augusto Ruschi Biological Reserve, the latter two in the state of Esp\u00edrito Santo.<\/p>\n

The biologist also sought out parasite-inhabited spiders in northeastern state Cear\u00e1, in partnership with ecologist Jober Sobczak, of the University for International Integration of the Afro-Brazilian Lusophony (UNILAB). In the municipal area of Pacoti they identified a fungus which, on occupying the spider, coats it in gold-colored hyphae (fungus filaments), coining the name G. aurea<\/em>, as described in a 2022 article in Phytotaxa<\/em>. \u201cIt is difficult to identify the spider after the spores are formed because the fungus destroys the host\u2019s body,\u201d Sobczak elaborates. When it is possible to count the legs, the researchers can distinguish arachnids from insects, but more detailed identification of spiders usually depends on examination of their genitalia.<\/p>\n

The phenomenon has been studied in depth in insects, but is still broadly unknown in respect of spiders. \u201cThis area of mycology [the study of fungi] is still very much uncharted, but a sizeable proportion of the research is being produced in Brazil through the work of professors Ari, of UFMG, and Jober Sobczak in Cear\u00e1,\u201d says Brazilian mycologist Jo\u00e3o Ara\u00fajo, curator of fungi at the New York Botanical Garden in the US. Ara\u00fajo has collaborated with Brazil-based groups to describe species, define taxonomic connections between them, and elucidate their biology and evolution. \u201cWe are still taking baby steps in terms of understanding the real biodiversity in terms of these fungi.\u201d<\/p>\n

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Thiago Kloss\u2009\/\u2009UFV<\/span><\/a> It is difficult to discern the host on the underside of G. leiopus<\/em> reproductive structuresThiago Kloss\u2009\/\u2009UFV<\/span><\/p><\/div>\n

He goes on to say that Brazil is home to some of the world\u2019s most significant diversity of fungi with parasitic habits. \u201cAmazonia and the Atlantic Forest are \u2018goldmines\u2019 for those studying these fungi,\u201d he says. \u201cSometimes most of a day\u2019s samples are of as-yet undiscovered species.\u201d<\/p>\n

Sobczak notes that findings in the Brazilian Northeast have made it clear that there is a forest-wide connection between the South and the North. \u201cWe have found the same fungus species associated to the same host in Cear\u00e1, Amazonas, and Vale do Ribeira between the states of S\u00e3o Paulo and Paran\u00e1,\u201d he explains. The primary site for his research is the Baturit\u00e9 mountain range, an area of Atlantic Forest in northeastern Cear\u00e1 in the middle of a region where semiarid scrubland (Caatinga) predominates. \u201cWe have discovered a high incidence of parasitism on the underside of leaves and on bromeliads,\u201d reports the ecologist. \u201cWe have seen wasps, ants, beetles, and crickets\u2014there is evidence of this being an area with a significant wealth of entomopathogenic [insect] and araneopathogenic [spider] fungi.\u201d<\/p>\n

Once the inventories are compiled, work begins on understanding the as-yet undefined mechanisms of action. The consistency in causes of death, however, evidences a likely adaptive advantage for the fungus. \u201cRegardless of the species, all the spiders die in similar locations, stuck to the underside of leaves.\u201d The researcher states that a study coordinated by him and conducted by ecologist \u00cdtalo Arruda, from the Federal University of Cear\u00e1, provides convincing evidence that the fungus causes the spiders to climb to the highest vegetation. On average, the parasite-infested arachnids die splayed out on the leaves about 1 m off the ground, while those not affected spin their webs at a height of 75 centimeters, as described in a 2021 article in the Canadian Journal of Zoology<\/em>.<\/p>\n

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Jober Sobczak\u2009\/\u2009Unila\u2002<\/span><\/a> A Macrophyes pacoti<\/em> spider coated in the gold-colored hyphae of G. aurea<\/em>Jober Sobczak\u2009\/\u2009Unila\u2002<\/span><\/p><\/div>\n

Researchers are yet to confirm exactly how the fungus advances through the spiders\u2019 organisms after infection, but G\u00f3es Neto deduces that the process is similar to that observed and documented in insects, where the fungus produces compounds that act on the neurons of the invertebrates and alters their behavior. \u201cWe have sequenced the full genome of G. pulchra<\/em>, the most widely distributed species of fungus, and found several genes possibly involved in attacking the nervous system,\u201d he says of the ongoing work.<\/p>\n","protected":false},"excerpt":{"rendered":"Infected by fungi, invertebrates climb higher to die","protected":false},"author":3,"featured_media":512497,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"categories":[159],"tags":[209,224,266],"coauthors":[1601],"class_list":["post-512492","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-science","tag-biology","tag-ecology","tag-zoology"],"acf":[],"_links":{"self":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/512492","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/comments?post=512492"}],"version-history":[{"count":4,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/512492\/revisions"}],"predecessor-version":[{"id":512655,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/512492\/revisions\/512655"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/media\/512497"}],"wp:attachment":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/media?parent=512492"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/categories?post=512492"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/tags?post=512492"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/coauthors?post=512492"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}