In The Fight Against Tsetse Flies, Blue Is The New Black: Goats and Soda: NPR

In The Fight Against Tsetse Flies, Blue Is The New Black

If you were a tsetse fly, you would be irresistibly attracted to these blue flags. Courtesy of J.Esterhuizen/LSTM Tsetse Project hide caption

If you were a tsetse fly, you would be irresistibly attracted to these blue flags.

Courtesy of J.Esterhuizen/LSTM Tsetse Project

Walk along one of the many streams and rivers in the West Nile region of Uganda, and you’ll notice something funny. All along the riverbanks, you’ll see small pieces of blue cloth, attached to wooden stakes in the ground. There’s one every 50 yards or so.

No, this isn’t some half-baked public art project. These dinky contraptions are actually flytraps, designed to lure and kill tsetse flies, whose bites transmit a parasitic disease called sleeping sickness, which, like rabies, drives victims mad before it kills them.

Sleeping sickness is a scourge of sub-Saharan Africa — around 7,000 cases were reported in 2013. It can be cured with drugs, if it’s detected early. But it’s usually difficult to diagnose. Early symptoms are vague: headaches, joint pain and bouts of fever. By the time people realize they’re infected, the parasite has often made its way to the brain, causing rapid mood swings and confusion. As the name suggests, the disease in its later stages also affects sleep, making it impossible to rest at night and impossible to stay awake during the day.

«People don’t understand what is happening to them. They think it’s witchcraft, or they are cursed,» says Charles Waiswa, a veterinarian at Makerere University in Kampala, Uganda, who directs a regional initiative against sleeping sickness. Treatment is expensive — the drugs can cost hundreds of dollars, though the World Health Organization distributes them for free. Plus, residents of rural villages often have trouble getting to hospitals where treatment is offered. And even those who survive are sometimes left physically or mentally impaired.

«The worst part is the disease affects the communities that are already suffering the most, the poorest of the poor,» Waiswa says. These rural communities heavily depend on the rivers where tsetse flies breed. «These people have to go to the river to collect firewood, do the wash and of course, to collect water, because unlike those who live in the cities, they don’t have access to tap water.»

And tsetse flies don’t just bite humans. They also transmit disease to cattle and other animals, which can devastate agriculture. So scientists have been looking for ways to cut down the tsetse population. And they’ve discovered that the flies’ Achilles heel is the color blue.

«When the tsetse flies are looking for targets to bite, they’re generally looking for something that contrasts with the green vegetation,» explains Steve Torr, an entomologist at the University of Liverpool in the U.K. «They’re attracted to bright colors, and for some reason they’re especially attracted to bright blue.»

With that in mind, Torr and his colleagues set out to design the ultimate flytrap. It consists of a small piece of blue cloth, «about the size of a handkerchief,» Torr says, plus a panel of fine netting covered in insecticide.

The blue material catches the flies’ interest. As the tsetses circle the blue cloth, mesmerized, they hit the poisoned netting, which they can’t see. The insecticide kills them within three minutes.

Since last November, Torr’s research team — with help from local health workers — has installed some 17,500 traps, covering about 1,500 square miles in northern Uganda.

The researchers’ early estimates show the strategy is working: The tsetse population in the region is down by almost 90 percent. «That’s because tsetse flies breed very slowly,» Torr says. Unlike mosquitoes, which lay hundreds of eggs all at once, tsetse flies give birth just once every nine days — so it’s relatively easy to quickly reduce their numbers.

Still, traps aren’t perfect: they have to be replaced every six months and can get washed away during heavy rains. But they are relatively cheap; it costs about $240 to set traps across one square mile of land. Spraying areas with insecticide, in contrast, can cost several times that. And while dousing cattle in insecticide is just as effective as setting traps, it’s not an option for communities that don’t raise livestock.

«Of course, we’re not trying to kill off the tsetse flies altogether, we just want to kill off those that carry the sleeping sickness parasite,» Torr says. About one in 1,000 flies carries the parasite — so if all goes well, the traps could weed out all the disease-carrying tsetse over the course of five or six years.

Thanks to a concerted effort by the World Health Organization and local governments, cases of sleeping sickness are already on the decline. During the height of the most recent sleeping sickness epidemic, in the late 90s, the World Health Organization estimated that about 300,000 people were infected yearly. Last year, the number of confirmed cases was down to fewer than 10,000.

Since the blue traps were installed, researchers have been testing the blood of locals and closely tracking cases of sleeping sickness in northern Uganda.

Combined with amped up treatment efforts, the traps could help eliminate sleeping sickness for good, says Dr. Charles Wamboga, who works with Uganda’s Ministry of Health and isn’t involved in the fly trap initiative. Over the course of his medical career, Wamboga has treated hundreds of infected patients.

«Already there are fewer cases than there used to be. And the cases we are seeing are not so bad,» Wamboga says. «It will take a lot of resources to maintain this reduction, but we are doing well so far. And if we keep it up, I think we can do it — we can eliminate this terrible disease.»

www.npr.org

UN urges people to eat insects to fight world hunger

Related Stories

Eating more insects could help fight world hunger, according to a new UN report.

The report by the UN Food and Agriculture Organization says that eating insects could help boost nutrition and reduce pollution.

It notes than over 2 billion people worldwide already supplement their diet with insects.

However it admits that «consumer disgust» remains a large barrier in many Western countries.

Insect nutritional value /100g

Source: Montana State University

Wasps, beetles and other insects are currently «underutilised» as food for people and livestock, the report says. Insect farming is «one of the many ways to address food and feed security».

«Insects are everywhere and they reproduce quickly, and they have high growth and feed conversion rates and a low environmental footprint,» according to the report.

The authors point out that insects are nutritious, with high protein, fat and mineral content.

They are «particularly important as a food supplement for undernourished children».

Insects are also «extremely efficient» in converting feed into edible meat. Crickets, for example, need 12 times less feed than cattle to produce the same amount of protein, according to the report.

Most insects are are likely to produce fewer environmentally harmful greenhouse gases than other livestock.

The ammonia emissions associated with insect-rearing are far lower than those linked to conventional livestock such as pigs, says the report.

Insects are regularly eaten by many of the world’s population, but the thought may seem shocking to many Westerners.

The report suggests that the food industry could help in «raising the status of insects» by including them in new recipes and adding them to restaurant menus.

It goes on to note that in some places, certain insects are considered delicacies.

For example some caterpillars in southern Africa are seen as luxuries and command high prices.

Most edible insects are gathered in forests and serve niche markets, the report states.

It calls for improved regulation and production for using insects as feed.

«The use of insects on a large scale as a feed ingredient is technically feasible, and established companies in various parts of the world are already leading the way,» it adds.

www.bbc.com

Coronavirus: Birdsong seems louder and the ravens are more relaxed

Lockdown enabling people to engage with ‘calm and quiet’ natural world

Research is ongoing to see if a drop in noise levels improves birds’ ability to attract a mate. Photograph: James Crombie/Inpho

Hits on the Birdwatch Ireland website are up 350 per cent as a society in shutdown takes more notice of the natural world.

The spike in interest comes at a time when not just birds but plants, marine life, insects and even our skies are all affected by the sudden reduction of human activity prompted by the fight against coronavirus.

“I’ve noticed the ravens are more relaxed,” says Matthew Jebb, director of the National Botanic Gardens in Dublin, which are closed as part of the Government’s containment measures.

“At weekends on a good day, [there] could be up to four or five thousand people, and the birds are never, ever, comfortable or settled. But now it’s so quiet, they won’t see a person all day, and it just gives them that added confidence in going about their nesting.”

There is a lot of research going on, he says, about the effect of traffic noise on birds’ efforts to lure a mate. Birds sing early in the morning to mark their territory and to attract partners, but unfortunately this usually coincides with both the early morning rush hour and early morning flights.

“Now the noise levels in Dublin have dropped by almost one-third and it has become very calm and quiet.”

The unusual calm and quiet in cities means people are becoming more aware of the nature around them

Air quality

The cleaner air we are experiencing will be good for plants, as newly emerging leaves will be subject to far less day-to-day pollution, says Jebb. “The delicate new leaves get a cleaner sweep, and a much better start in life.”

“A lot of people are asking us has the lockdown produced more birds, and the answer is no,” says Niall Hatch of Birdwatch Ireland. “The number of birds is the same as it has always been. It is just people are more aware of them than they have normally been.”

People are spending more time in their own gardens, if they have one, and the unusual quiet in cities means that birdsong is more noticeable. It is also the case that because of the quiet, sound travels more.

The shutdown has also had an impact on some, though not all, catches of marine life covered by the EU quota system.

Fishing for prawns, crabs and lobsters, as well as demersal, such as whiting, haddock and monkfish, is below what it would normally be for this time of year (with 10 per cent, rather than 25 per cent, of quotas used). However the fishing of blue whiting, mackerel and horse mackerel continues at normal levels.

The closure of markets for some product has hit the Irish fishing industry hard, but scientists will be closely monitoring the effect on marine population levels off our shores.

Climate science

The drop in economic activity has also provided a type of enormous laboratory experiment for scientists involved in studying the related issues of cloud formation, dirty air and climate change.

Data from Eurocontrol show flights across Europe, as of earlier this week, were down by approximately 90 per cent, with the figure for Ireland, including overflights, being 92 per cent down.

In the immediate wake of the 9/11 attacks in the United States, all non-military flights over US airspace were grounded for a number of days. Scientists in Wisconsin were able to study the behaviour of contrail cirrus cloud – the cloud created by the vapour from jet engines – left by military flights travelling across otherwise empty skies.

“They were able to track contrails associated with very specific military flights,” says Rowan Fealy, who lectures on climate science in the geography department of Maynooth University. “They found that the contrails associated with just six military aircraft were able to fan out to cover a region of about seven and a half thousand square miles. These can impact for a number of hours after they have formed.”

Climate scientists find this interesting because of the “energy balance” impact high-level clouds can have on global warming. Contrail cirrus cloud can keep energy out during the day, and keep energy in at night when the earth is cooling down.

“Now we have potentially a much, much bigger data sample beyond that of 9/11,” Fealy says. “In spite of the tragic circumstances of the global pandemic, we do have some really interesting opportunities in the sense that we have real-world conditions that we can now look at and analyse.”

‘Global dimming’

Another big issue for climate scientists is “global dimming”, or the impact of air pollution on the ability of the sun’s light or energy to reach the earth’s surface. Recent figures from Nasa, the US space agency, have shown huge drop-offs in air pollution over major cities.

Global dimming may have the effect of constraining the temperature increases caused by greenhouse gases.

Hannah Hamilton, communications manager with Coillte Nature, says it is a bit early to speak about the effect of the shutdown on wildlife, though undoubtedly there will be less roadkill, and it is well known that noise pollution affects animals negatively.

“The key thing is not the effect on wildlife so much as the extent to which we are noticing more. We are living slower lives, limited in the places we are going, and we are noticing what is around us in a way that we don’t normally do.”

This, she says, is exactly what scientists and naturalists do all of the time. A positive aspect of the shutdown is that more people are now having the opportunity to “take pause and just look around.”

She is hoping that, once the awfulness of the pandemic has passed, people will have an increased “natural literacy” and that this increased engagement with the natural world will endure.

www.irishtimes.com

How to Treat Termites in Walls?

Subterranean termite is a crafty pest. The insect prefers concealed, damp and dark out-of-sight places, that is why sometimes it is rather complicated to find the presence of termites’ colony nest inside a house and the problem of termites’ infestation becomes serious and sometimes irretrievable.

Termites have gone further in their eating “habits”: it is easier for them to eat cellulose than to devour just the wood pieces, that is why termites have become a frequent “guest” in walls, no matter what material they are made of.

Can one be absolutely sure that there are no these nasty insects somewhere except basement, furniture or other wooden structures? Are termites beginning to eat everything they are able to find? Today we will try to answer these questions and give you some necessary information how to avoid and get rid of these insects inside your house.

What Treatment Measure Is the Most Effective One?

Subterranean termites live inside the soil and reach above-ground level food sources via special tunnels that workers build of saliva, mud and their feces.

Walls can draw these nasty insects in case they are in direct contact with the ground (soil).

Wall damage also tends to go undiscovered for long periods of time, as it may begin so far below the level a human can see.

The total surface area of walls that is exposed to the soil is extensively larger than other parts of a house. This large surface area attracts termites as a food source, as many insects can feed on the same piece of wood without having to travel and forage too far beyond their nest.

Fortunately, there are a lot of treatment measures against termites in walls today. We will speak about the most effective measures, as well as “organic fight” against these dangerous insects in a house’s walls.

If pest damage is limited to one or two walls (in case they are made of sheetrock that is easy to replace), it can be replaced in sections.

Advantage: fast repair without using chemicals.

Disadvantage: if termites caused damage to a sheetrock, they may have damaged wall studs or ceiling joists near this very sheetrock. In this case, it will be very difficult to repair.

If there is no opportunity to replace wall materials (walls are made of solid material, brick, for example), you can use the so called “baiting station”. It uses the termites’ natural behaviors to cause the nest and colony to die of starvation (i.e. without cellulose and moisture).

The process uses a special baiting system to kill the workers responsible for feeding the entire colony. The “bait” contains cellulose food the ingredient called “sulflurimid” (or other chemicals) that is fed to the termites. As a result, working termites die, so they are no longer able to feed their colony, so it dies of starvation.

Advantage: when one use baiting system there is no need to scatter dangerous chemicals all around the house to control the termites.

Disadvantage: it takes time for termites to eat out the stake. It also will take a long period of time for colony to die. Besides, they can produce a new worker caste.

Fumigation. For termite species that don’t travel on the soil or for killing working or flying stages of termites, this method of eradication is usually required.

Gas or heat fumigation of a house is a perfect way to treat termites that fly and can nest in the attic and ceiling of a house.

Advantage: kills adult termites on contact. Can eliminate other nasty insects in a house.

Disadvantage: very difficult process performed only by a specialist. Do not deal with underground colony and eggs.

Another alternative is to treat infested walls with Termidor or Premise (in foam, spray, liquid). These chemicals are applied into the wall voids and exterior soil near the problem wall.

Also, the process involves drilling holes into slabs to apply the liquid underneath the home and create an adequate barrier of protectability.

Advantage: Termidor and Premise kill termites on contact. It means, that the adult insects will die immediately (in 12-24 hours).

Disadvantage: these chemicals have nothing to do with underground nest with their eggs. It means, that there is no use of single treatment, since in a month or two termites will restore their population.

Since termites are discovered, it is very important to take a combination of measures against these nasty pests: it is recommended immediate spraying of Termidor or Premise into the wall voids and exterior soil near the problem drywall before installing bait stations.

Advantage: Termidor/Premise plus baiting station inside a house is the best solution ever. It will deal with termites that are already inside the wall and with those under the soil level. This method is considered to be the most effective one.

Disadvantage: one should carefully check baiting station and the overall situation with termites in a house.

Is It Possible to Lead “Organic War” Against Termites in A Wall?

Today there is a tendency to use natural materials and substances in all areas.

Termite elimination is not an exception to the rule. But are these organic treatment measures so effective as non-organic chemicals? Let’s have a look at these treatment ways:

Orange oil (or other essential oils with distinctive scent) is more or less effective due to the active ingredient that can eliminate a great variety of insects, by means of dissolving their exoskeleton and destroying their cell membranes, thus leading to insects’ death.

Drill small holes into the infested wall and spray the oil-water mixture into the hollow spaces.

Effectiveness: it will not solve an already serious problem. Can be true for other insect, but not for termites.

Boric acid. This natural insecticide destroys their nervous system and dehydrates them. You can make DIY baiting stations for your house based on cellulose and boric acid and place them near infested walls.

Effectiveness: more or less effective. Needs regular observation and replacement.

Salt. Soak cotton balls with water-salt mixture and put them into the drilled holes in the walls. This mixture will scare the termites away.

Here you can learn more information about termite bait systems: Advance, Green, CSIRO, Nemesis, Exterra, Firstline, Terminate. Also find out how to make baits by yourself and how to refill them?

How Long Does It Take to Get Rid of Termites Inside a Wall?

It is a rather difficult question to give a precise answer.

This time depends on various factors: the overall humidity level in a building and temperature, used treatment measures, disposition and condition of vent system and water pipes, the material of walls and density of termites in the area.

Approximately, to get rid of termites using the most effective treatment measure (liquid termicide plus baiting system) will take from 3 months to 1 year (one treatment will not solve this problem entirely, you will need 2-3 treatments).

Here you can learn more information about effective treatment method called tenting (fumigation): dangers for termites, preparing for fumigation and cleaning after, how long does this procedure last?

Useful articles

If you interested in more information of termites we recommend you to read the following articles:

Conclusion

Termites is a very serious problem that badly needs the work of a specialist. We recommend you not to rely on DIY treatment measures and always try to consult with a specialist.

Once neglected, termites’ colony can rapidly grow and invade the whole house destroying all necessary house structures as ceilings, walls and floors. Do not forget about annual inspection that is also better to entrust to a specialist.

pests.guru

Genetically engineered moths can knock down crop pests, but will they take off?

By Erik Stokstad Jan. 30, 2020 , 10:50 AM

Diamondback moths love broccoli. They’re also fond of cabbage, cauliflower, and related crops. And they quickly evolve resistance to insecticides and crops genetically modified to kill them. But frustrated farmers might get a new weapon against them: genetically engineered versions of the moths that mate with wild pests and cause half their offspring to die. Yesterday, researchers reported that these moths, developed by the biotechnology company Oxitec, survive well on actual farms.

“This is important,” says Max Scott, an entomologist at North Carolina State University who was not involved in the study. The technology, he says, “has excellent potential.” But it’s unclear what happens next with the moths, as Oxitec says it is only “evaluating potential opportunities.”

The approach is a version of sterile insect technology, which has been used for decades to control and eradicate a fly known as screwworm, a livestock parasite, and a few other pests. The insects are blasted with x-rays, making them sterile. Then, the neutered males are released to find females and when the insects mate, there are no offspring.

One challenge is that large numbers are required because the radiation leaves the males less vigorous than their wild rivals. “Radiating insects is like a using sledgehammer,” says Tony Shelton, an entomologist at Cornell University who studies the diamondback moth and led the current study. “You can get the same result by just tweaking genes, and they will behave normally.”

That tweaking was done by Oxitec, which also funded the new field trial. The company is more famous for its mosquitoes, which it has tested in Brazil and other tropical countries to combat dengue fever and other diseases. (In October 2019, the city of Indaiatuba, Brazil, began to use the Oxitec insects to help reduce its mosquito populations.) The moths were engineered in the same way: Researchers at the company assembled a “lethality gene” called tetracycline transcriptional activator variant (tTAV), by combining DNA from the bacterium Escherichia coli and the herpes simplex virus; then they added it to the insects.

The idea is that when modified males mate with females in the wild, they pass on their tTAV gene. The gene prevents the female offspring from developing, and they die as larvae. But male offspring survive and half inherit tTAV. After these males grow up and mate with other wild insects, the next generation of female offspring also dies, further shrinking the population. The Oxitec insects carry a gene for a fluorescent marker as well, allowing them to be identified in the wild.

The modified males have another attractive trait. They could help maintain the effectiveness of insecticides and genetically modified crops the diamondback moth has evolved resistance to. That’s because the modified males added to a field don’t have the resistance genes, as they were bred in the lab from a susceptible strain.

In 2015, Shelton and his colleagues showed in a greenhouse study that the modified moths could knock down a population in three generations. The new trial—started in 2017—was to evaluate the behavior of the insect in a real field, where weather and predators can make life more challenging.

The researchers released several thousands of Oxitec moths in a cabbage field in New York. They then placed traps with scented lures throughout the field to see how far the insects might travel. The modified moths behaved the same as normal moths; 95% ventured less than 35 meters from where they were released, meaning that they stayed in the field. They also lived as long as normal moths, the team reported on 29 January in Frontiers in Bioengineering and Biotechnology .

The scientists did not measure the ability of the moths to reduce the population in the field. But in lab experiments, they determined that the modified moths were just as good at finding mates, and these females laid as many eggs. A mathematical model based on these data suggested the modified moths will be effective at controlling pests, Shelton says.

A drawback of this approach is that releasing insects is more complicated to use than simply spraying insecticides, and probably more expensive as well, Scott notes. In addition, organic farmers, who are a large market for biological control because they aren’t allowed to spray synthetic insecticides, can’t use genetically modified insects.

The next step would be to test the moths in warmer locations that have larger infestations of diamondback moths. Shelton won’t be around to see that, as he plans to retire. “I’ve taken this as far as I can,” he says. “I hope some other scientists continue the work with the diamondback moth and other insects.”

Neil Morrison, who directs agricultural research at Oxitec, said in a statement that the company is “evaluating potential opportunities in regions where diamondback moth management is challenging for farmers.” But, he added, the research has shown “significant promise.” Meanwhile, the company is continuing to research the technology to control two other major pests. One is a moth called the soybean looper that has evolved resistance to insecticides in Brazil, where it also damages cotton and corn. The other is the fall armyworm, which is even more omnivorous and a rapidly growing problem in Africa.

www.sciencemag.org

See also:  Cutworms: How To Destroy Noctuidae Caterpillars In Your Garden
Share:
No comments

Добавить комментарий

Your e-mail will not be published. All fields are required.

Adblock
detector
Food source Protein (g) Calcium (mg) Iron (mg)