'Antelope perfume' keeps flies away from cows

Researchers involved in research that shows how the tsetse fly can be tricked in Africa

Date:  October 20, 2017

Source:  University of Bonn

Summary:

In Africa, tsetse flies transfer the sleeping sickness also to cattle. The damage is estimated to be about 4.6 billion US dollars each year. Experts have developed an innovative way of preventing the disease. Tsetse flies avoid waterbucks, a widespread antelope species in Africa. The scientists imitated the smell of these antelopes.

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Ancient African herders used ‘no fly zones’ to migrate south

March 10, 2015

Chuck Bednar for redOrbit.com – @BednarChuck

Experts have long believed that it was one little but dangerous insect, the tsetse fly, that halted the southward migration of ancient herders thousands of years ago. But new research published Monday in the Proceedings of the National Academies of Science now suggests otherwise.

As Dr. Fiona Marshall, a professor of anthropology at Washington University in St. Louis, and her colleagues explain in the new study, herders migrated from eastern to southern Africa about 2,000 years ago, but only in small numbers. The tsetse fly, a disease-carrying insect known for spreading sleeping sickness, was long believed to have impeded their migration.

“Archaeologists have argued that the presence of tsetse flies around Lake Victoria, Kenya, created a barrier that prevented migration and forced subsistence diversification,” the authors wrote. “This study, using stable isotope analysis of animal teeth, reveals the existence of ancient grassy environments east of Lake Victoria, rather than tsetse-rich bushy environments.”

Overturning previous assumptions

By analyzing animal remains from a nearly 2,000-year-old settlement located near Gogo Falls in the modern woodlands of southern Kenya, the Marshall and her colleagues report that they have discovered evidence that contradicts previous assumptions about the conditions of the era.

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Eradicating fatal sleeping sickness by killing off the tsetse fly

Date:

July 17, 2014

Source:

Brigham Young University

Summary:

A professor of biology has lent his expertise in understanding insect movement to help shape a UN-sanctioned eradication effort of the tsetse fly -- a creature that passes the fatal African sleeping sickness to humans, domestic animals, and wildlife. The tsetse fly is the main vector for Human African Trypanosomiasis (aka sleeping sickness), and spreads the disease by biting humans or animals. The disease affects the central nervous system and is fatal if untreated. For some forms of the disease, victims can reach the terminal stage before symptoms even start to show.

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Decoded fly genome offers clues about sleeping sickness

Tsetse gene sequence adds to researchers' knowledge of the fly's biology and behaviour.

Jessica Morrison

24 April 2014

An estimated 70 million people remain at risk for sleeping sickness, which is carried by the tsetse fly.

Public-health workers are one step closer to stamping out a debilitating and potentially fatal disease known as sleeping sickness following the sequence of its carrier, the tsetse fly. The 366-million-base sequence of Glossina morsitans morsitans offers clues to the insect's diet, vision and reproductive strategies, researchers say.

“This really accelerates our ability to do basic research on this fly”, says lead author Geoffrey Attardo of the Yale School of Public Health in New Haven, Connecticut. The work was published today in Science1.

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Spermless mosquitoes hold promise to stop malaria

Scientists have created spermless mosquitoes in an effort to curb the spread of malaria.


Experts say that this is an important first step toward releasing sterile males into the wild to reduce the size of mosquito populations.

Malaria kills around one million people worldwide every year, and in Africa alone, accounts for 20% of all childhood deaths.

The work is reported in Proceedings of the National Academy of Sciences.

Insect sterilisation isn't new: scientists have attempted to control the sleeping sickness-carrying tsetse fly by exposing them to radiation to render them sterile.

A similar approach has been successfully used against the potatoes weevil in Japan and the tropical screwworm that attacks cattle.

Frail fly
However, exposing mosquitoes to radiation has tended to leave male mosquitoes frail, and unable to compete in the frenzied mating aerobatics that Anopheles gambiae - the world's most efficient malaria vector - enjoys.

Now scientists have developed an alternative route to mosquito sterility.

Entomologist Flaminia Catteruccia from Imperial College London enlisted the help of her graduate student Janis Thailayil in the search for how to make male mosquitoes sterile but leave them otherwise unharmed.

Mr Thailayil injected 10,000 mosquito embryos with tiny fragments of RNA designed to turn off a gene - called zpg - that is essential for normal sperm development.

After months of laborious work, the researchers created around 100 spermless mosquitoes, and showed that females were just as willing to mate with these males as with fertile ones.

Dr Catteruccia explains that female mosquitoes mate only once in their lives. If scientists can trick them into thinking that they have successfully mated, then they will continue to lay their eggs without knowing that they have not been fertilised.

"You [could] in principle release large numbers of sterile males over many generations… and eventually all the females will have mated with the sterile males and…you can really reduce the number of mosquitoes," explained Dr Catteruccia.

This would gradually reduce the number of hatching mosquitoes. And hopefully help eradicate what many consider to be the single most dangerous insect species for mankind.

However, Dr Catterucci warns that this is only a proof of principle. The method her team used to create the spermless males would be far too labour-intensive to flood wild populations with enough spermless males to have any effect on their numbers.

However, knowing that females don't notice whether they are receiving sperm or not is still an important step, she said.


By Jennifer Carpenter

Science reporter, BBC News


http://www.bbc.co.uk/news/science-environment-14422440