{"id":79856,"date":"2026-10-14T15:09:59","date_gmt":"2026-10-14T22:09:59","guid":{"rendered":"https:\/\/in.nau.edu\/news\/?p=79856"},"modified":"2026-10-14T15:12:51","modified_gmt":"2026-10-14T22:12:51","slug":"tiger-beetles","status":"publish","type":"post","link":"https:\/\/in.nau.edu\/news\/tiger-beetles\/","title":{"rendered":"The mystery behind a flightless beetle’s transatlantic journey"},"content":{"rendered":"

They can\u2019t fly, they can\u2019t swim, so why do their closest relatives appear on different continents?<\/span>\u00a0<\/span><\/p>\n

Grey Gustafson, <\/span><\/b>an associate professor in the Department of Biological Sciences, discovered through DNA sequencing that the ancestors of some of today\u2019s tiger beetles existed in South America and Africa before the two continents separated. What\u2019s more, North America\u2019s largest tiger beetles are related to these ancestral South American giant tiger beetles.\u00a0<\/span>\u00a0<\/span><\/p>\n

Gustafson and his colleagues recently published their findings in <\/span>Proceedings of the Royal Society B<\/span><\/a>.<\/span>\u00a0<\/span><\/p>\n

Gustafson\u2019s research began with two groups of tiger beetles found in the western U.S.: the genus <\/span>Amblycheila<\/span><\/i>, called the giant tiger beetles, and the genus <\/span>Omus, <\/span><\/i>the night stalking tiger beetles. The previous hypothesis was that both groups belong to the tribe Manticorini \u2013 named for the mythical chimeric monster, which also contains large-bodied, flightless tiger beetles found in the Southern Hemisphere. <\/span>\u00a0<\/span><\/p>\n

If that were true, Gustafson said, it begs the question: How and why did tiger beetles end up in North America when most species of the tribe live in Sub-Saharan Africa, with the only other close relative being found in South America?<\/span>\u00a0<\/span><\/p>\n

\u201cWe wanted to know how a large-bodied, flightless beetle could get across the ocean to South America and then better yet, how our North American beetles fit into this tribe,\u201d Gustafson said.<\/span>\u00a0<\/span><\/p>\n

The process<\/span><\/b>\u00a0<\/span><\/h3>\n

Scientists have done substantial research to better understand the biology, classification, life history and conservation of tiger beetles, but they\u2019ve done comparatively little to understand the evolutionary history of these insects. So as part of a four-year National Science Foundation grant, Gustafson spent three years generating data that could reveal more about the evolutionary history of North American manticorine tiger beetles. With help from colleagues, Gustafson collected and compared DNA sequences from across their entire genomes.<\/span>\u00a0<\/span><\/p>\n

\u201cWe assembled genomic sequences from both freshly collected material in the western U.S., ethanol-preserved frozen material from colleagues and specimens held in natural history collections in the U.S. and Europe,\u201d Gustafson said.<\/span>\u00a0<\/span><\/p>\n

The research team then used the data to produce a family tree to understand the most recent common ancestors. With this information, researchers were able to trace when they diverged from one another.<\/span>\u00a0<\/span><\/p>\n

\u201cThe exciting thing we found was that the group is actually older than when the continents were separated, so they didn’t actually get across the oceans,\u201d Gustafson said, \u201cThey originated before an ocean separated South America from Africa on a supercontinent called Gondwana.\u201d<\/span>\u00a0<\/span>\u00a0<\/span><\/p>\n

An ancient lineage<\/span><\/b>\u00a0<\/span><\/h3>\n

Gustafson and his colleagues found that not only are the giant tiger beetles of North America most closely related to the South American tiger beetle, but together these tiger beetles were most closely related to those found in southern Africa. The family tree produced by DNA sequencing revealed the Manticorini tribe evolved during a time when South America and Africa were part of a landmass known as Gondwana, which later separated into the distinct continents we know today.<\/span>\u00a0<\/span><\/p>\n

\u201cBecause of the size of the supercontinent, many biologists hypothesized that lineages with lots of closely related modern diversity in Africa and South America likely originated when the continents were still part of Gondwana,\u201d Gustafson said. \u201cThis hypothesis has especially been used to explain how animals that are unable to fly but have close relatives on either side of the Atlantic Ocean could be distributed on two landmasses currently separated by an ocean.\u201d<\/span>\u00a0<\/span><\/p>\n

The geographical phenomenon, known as vicariance, occurs when a barrier is formed, splitting different populations of the same species between the land on either side. While not limited to tiger beetle research, vicariance continues to be part of a larger ecological narrative regarding evolution. Similar to the rheas of South America and the ostriches of Africa, these tiger beetles are large, flightless and separated by an ocean. However, unlike these birds, the ancient manticorine tiger beetles now serve as a well-supported example of Gondwanan vicariance.\u00a0<\/span>\u00a0<\/span>\u00a0<\/span><\/p>\n

\u201cThe answer to our question of how these giant beetles got across the ocean was that they actually didn’t,\u201d Gustafson said. \u201cAs the continents separated, they took their giant tiger beetles with them.\u201d\u00a0<\/span>\u00a0<\/span><\/p>\n

\"Northern<\/a>Ishana Grant | NAU Communications<\/p>\n","protected":false},"excerpt":{"rendered":"

They can\u2019t fly, they can\u2019t swim, so why do their closest relatives appear on different continents?\u00a0 Grey Gustafson, an associate professor in the Department of Biological Sciences, discovered through DNA sequencing that the ancestors of some of today\u2019s tiger beetles existed in South America and Africa before the two continents separated. What\u2019s more, North America\u2019s…<\/a><\/p>\n","protected":false},"author":2880,"featured_media":79858,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[11],"tags":[],"class_list":["post-79856","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-research-academics"],"acf":[],"_links":{"self":[{"href":"https:\/\/in.nau.edu\/news\/wp-json\/wp\/v2\/posts\/79856","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/in.nau.edu\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/in.nau.edu\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/in.nau.edu\/news\/wp-json\/wp\/v2\/users\/2880"}],"replies":[{"embeddable":true,"href":"https:\/\/in.nau.edu\/news\/wp-json\/wp\/v2\/comments?post=79856"}],"version-history":[{"count":2,"href":"https:\/\/in.nau.edu\/news\/wp-json\/wp\/v2\/posts\/79856\/revisions"}],"predecessor-version":[{"id":79859,"href":"https:\/\/in.nau.edu\/news\/wp-json\/wp\/v2\/posts\/79856\/revisions\/79859"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/in.nau.edu\/news\/wp-json\/wp\/v2\/media\/79858"}],"wp:attachment":[{"href":"https:\/\/in.nau.edu\/news\/wp-json\/wp\/v2\/media?parent=79856"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/in.nau.edu\/news\/wp-json\/wp\/v2\/categories?post=79856"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/in.nau.edu\/news\/wp-json\/wp\/v2\/tags?post=79856"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}