Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


A clearer picture of how assassin bugs evolved

UC Riverside entomologists reconstruct the evolutionary history of assassin bugs; new work fine-tunes the Tree of Life

Assassin bugs, so named because these insects lie in ambush for prey that they attack with speed and precision, are found all over the world.

This photo shows a representation of the diversity of blood-feeding kissing bug species in the world.

Credit: W. S. Hwang, Weirauch Lab, UC Riverside.

Nearly 140 species of these bugs are blood-sucking; because they can bite humans around the mouth, they are also called kissing bugs. All kissing bugs can spread Chagas disease, a neglected tropical disease that imposes an economic burden on society.

Surprising, then, that scientists' understanding of the evolutionary history of assassin bugs is riddled with difficulty. The data are incomplete. Fossils, which exist for only a few groups of assassin bugs, are young, providing only patchy information on how these bugs evolved.

Now entomologists at the University of California, Riverside have produced a clearer snapshot of the entire evolutionary history of assassin bugs by integrating molecular, paleontological, behavioral and ecological data into their analyses. The result of their painstaking work is a new phylogeny — the representation of the evolutionary relationships between species — for assassin bugs. It includes the most number of assassin bugs to date and represents the most number of subfamilies.

"We can now zoom in on specific groups within the phylogeny to examine specific aspects of the evolution of that group," said Christiane Weirauch, an associate professor of entomology who reconstructed the assassin bug phylogeny with her Ph.D. graduate student Wei Song Hwang. "Our phylogeny significantly improves our knowledge about relationships within assassin bugs and will guide future research work in understanding how some of the interesting prey specialization behaviors and prey capture techniques have evolved."

Study results appeared last month in PLoS ONE.

"One significant improvement is the addition of several assassin bug species from the subfamily Reduviinae, the second largest subfamily of assassin bugs," said Hwang, the first author of the research paper. "Previous phylogenies have a very limited representation of Reduviinae, which means the overall interpretation of the phylogeny is of limited value."

Assassin bugs are estimated to have originated during the Middle Jurassic (~178 million years ago), making them a relatively old group of insects. They diversified significantly in the Late Cretaceous (~97 million years ago); indeed, nearly 90 percent of the existing species diversity we see today in assassin bugs started to diversify from this time onwards. The cause of this diversification remains unknown.

Blood-feeding kissing bugs

Weirauch and Hwang also determined that kissing bugs originated just 27-32 million years ago, the previous estimate being 107 million years ago. Mostly found in Central and South America, these bugs have evolved to feed on vertebrate blood — lizards, birds, opossums, armadillos, bats, etc., and humans — and can be found in diverse environments, from the Sonoran desert to the Amazon rainforest.

"The previous estimate of 107 million years ago linked the diversification of kissing bugs with the splitting of South America from Antarctica and provided a longer time-span for kissing bugs to speciate and spread across the continent and adapt," Hwang said. "Our research shows that this is not the case. By including more data and improving estimation methods, our younger estimate of 27-32 million years ago matches the time when the hosts, mainly mammals and birds, were diversifying at a rapid rate in South America."

The researchers caution that as natural environments get altered, more kissing bugs may be seen adapting to new environments and hosts rather than going extinct.

"The colonization of human settlements by wild kissing bugs we are witnessing now is thus likely to increase in intensity as more natural environments are replaced by human activities," Hwang said.

With their comprehensive sampling of assassin bugs and large molecular dataset, Weirauch and Hwang also show that the blood-feeding kissing bugs either have a single origin or two separate but close origins. Until now, the possibility of two separate but close origins of kissing bugs had not been hypothesized nor demonstrated.

"The possibility that there are two separate lineages implies that there will be shared traits among the lineages, but also slight differences we need to be aware of when developing different preventative strategies," Hwang explained. "A single origin, on the other hand, means we can expect common traits shared among all kissing bugs that can be targeted for control or monitoring."

Building the Tree of Life

The current research is part of the scientific endeavor to reconstruct the entire Tree of Life — the biological concept that all living organisms are related and can be traced back to a single ancestor representing the origin of life on Earth.

"Reconstructing a phylogeny, a framework from which we can infer the evolutionary history of any group of organisms, is thus the first step towards understanding how life evolved, how different species relate to one another, how specific traits evolved over time, and why biodiversity occurs the way it does today," Weirauch said.

The study was financially supported by the Partnership for Enhancing Expertise in Taxonomy (PEET) program of the National Science Foundation, the UCR Department of Entomology, a UCR Graduate Division Dissertation Year Program Award and an American Museum of Natural History Collection Study Grant.

The University of California, Riverside is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California's diverse culture, UCR's enrollment has exceeded 20,500 students. The campus will open a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of more than $1 billion. A broadcast studio with fiber cable to the AT&T Hollywood hub is available for live or taped interviews. UCR also has ISDN for radio interviews. To learn more, call (951) UCR-NEWS.

Iqbal Pittalwala | EurekAlert!
Further information:

More articles from Life Sciences:

nachricht North and South Cooperation to Combat Tuberculosis
22.03.2018 | Universität Zürich

nachricht Researchers Discover New Anti-Cancer Protein
22.03.2018 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Researchers Discover New Anti-Cancer Protein

An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.

The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...

Im Focus: Researchers at Fraunhofer monitor re-entry of Chinese space station Tiangong-1

In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.

Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...

Im Focus: Alliance „OLED Licht Forum“ – Key partner for OLED lighting solutions

Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.

They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...

Im Focus: Mars' oceans formed early, possibly aided by massive volcanic eruptions

Oceans formed before Tharsis and evolved together, shaping climate history of Mars

A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...

Im Focus: Tiny implants for cells are functional in vivo

For the first time, an interdisciplinary team from the University of Basel has succeeded in integrating artificial organelles into the cells of live zebrafish embryos. This innovative approach using artificial organelles as cellular implants offers new potential in treating a range of diseases, as the authors report in an article published in Nature Communications.

In the cells of higher organisms, organelles such as the nucleus or mitochondria perform a range of complex functions necessary for life. In the networks of...

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Virtual reality conference comes to Reutlingen

19.03.2018 | Event News

Ultrafast Wireless and Chip Design at the DATE Conference in Dresden

16.03.2018 | Event News

International Tinnitus Conference of the Tinnitus Research Initiative in Regensburg

13.03.2018 | Event News

Latest News

Modular safety concept increases flexibility in plant conversion

22.03.2018 | Trade Fair News

New interactive map shows climate change everywhere in world

22.03.2018 | Earth Sciences

New technologies and computing power to help strengthen population data

22.03.2018 | Earth Sciences

Science & Research
Overview of more VideoLinks >>>