Archive for the ‘Migratory insects’ Category

Continuous long tracking of migrating insects

By flying with hawkmoths during migration, scientists reveal that insects employ sophisticated flight strategies similar to vertebrates

Date:August 11, 2022Source:Max-Planck-GesellschaftSummary:By flying with hawkmoths during migration, scientists reveal the insects employ sophisticated flight strategies similar to vertebratesShare:


Insects are the world’s smallest flying migrants, but they can maintain perfectly straight flight paths even in unfavorable wind conditions, according to a new study from the Max Planck Institute of Animal Behavior (MPI-AB) and the University of Konstanz. Researchers radio tracked migrating hawkmoths for up to 80 kilometers—the longest distance that any insect has been continuously monitored in the wild. By closely following individuals during migration, the world-first study unlocks a century-old mystery of what insects do over their long-range journeys. The study, published in Science, confirms that hawkmoths can accurately maintain straight trajectories over long distances, employing sophisticated strategies to counter and correct for unfavorable wind conditions. The findings reveal that insects are capable of accurate navigation, confirming that an internal compass guides them on their long journeys.

With trillions of individuals migrating every year, insects are some of the most common migrating animals on Earth. They include species of renown, such as the monarch butterfly, as well as species of enormous societal and environmental importance, such as locusts, mosquitos, and bees. But even though insect migrants far outnumber better-known migrants, such as birds or mammals, their migration is the least understood form of long-range animal movement.

The problem, for the most part, has been methodological. “Studying insects on the move is a formidable challenge,” says first author Myles Menz, who conducted the research at MPI-AB and is now a lecturer at James Cook University in Australia. “They’re usually too numerous to mark and find again, and too small to carry tracking devices.”

Much of what we know about insect migration has come from studies that sample insects at a single moment in time, such as through radar or direct observation, which has left vast blank spots in our knowledge. “Understanding what insects do during migration, and how they respond to weather, is a last frontier in migration science,” says Menz.

The current study, which followed radio-tagged individuals in a light aircraft, is the first to continuously study nocturnal migrating insects in the wild and represents the longest distance over which any insect has been continuously tracked in the field. The team, which includes researchers from the MPI-AB and University of Konstanz in Germany and the University of Exeter in the UK, focused on the death’s-head hawkmoth—a large, nocturnal migrant that travels up to 4000 kilometers between Europe and Africa every year. Like many insects, the species is a multi-generational migrant, which means that no individual knows the entire route.

At the MPI-AB in Konstanz, Germany, the team reared caterpillars until adulthood in the laboratory to ensure that individuals were naïve. When moths emerged as adults, they were fixed with radio tags weighing 0.2 grams—less than 15% of adults’ body weight. “The moths would probably eat more weight than that in a night, so these tags are extremely light for the insects,” says Menz.

The researchers released the tagged moths and waited for flight to begin, after which they chose a single individual to follow at a time. The team followed 14 moths each for up to 80 kilometers or 4 hours—a stretch long enough to be considered migratory flight—using antennas mounted on a Cessna airplane to detect precise locations every five to 15 minutes. Insects were followed in the south-south-west direction from Konstanz into the Alps, which follows the route taken by hawkmoths towards the Mediterranean and Northwest Africa.

Due to practical constraints of flying in an aircraft, the scientists tracked moths continuously until the insects stopped on route. “When you’re in an airplane, it becomes extremely difficult to wait for the insects to begin migrating again because you would have to be in the air when this happens, which could be anytime in the night,” says senior author Martin Wikelski, a movement ecologist from the MPI-AB and University of Konstanz, who piloted the plane during the study.

The results show that moths maintained perfectly straight trajectories for long distances during flight. This was not because they waited for favorable tailwinds. Rather, they employed a range of flight strategies to buffer against prevailing winds, allowing them to hold their course throughout the night. When winds were favorable, they flew high and slow, allowing the air to carry them. But during harsh headwinds or cross winds, they flew low to the ground and increased speed to keep control of their path.

Says Menz: “For years it was assumed that insect migration was mostly about getting blown around. But we show that insects are capable of being great navigators, on par with birds, and are far less vulnerable to wind conditions than we thought.”

“By showing that it is technically possible to continuously monitor individual insects over migration, and to observe their flight behavior in detail, we hope to inspire more studies to answer many more big questions in this area.”

For the study authors, the next step is to answer the question of how moths are able to maintain such straight lines. “Based on past lab work, it’s possible that the insects are using internal compasses, both visual and magnetic, to chart their way around the world,” says Menz.

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Materials provided by Max-Planck-GesellschaftNote: Content may be edited for style and length.

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Journal Reference:

  1. Myles H. M. Menz, Martina Scacco, Hans-Martin Bürki-Spycher, Hannah J. Williams, Don R. Reynolds, Jason W. Chapman, Martin Wikelski. Individual tracking reveals long-distance flight-path control in a nocturnally migrating mothScience, 2022; 377 (6607): 764 DOI: 10.1126/science.abn1663

Cite This Page:

Max-Planck-Gesellschaft. “Continuous long tracking of migrating insects: By flying with hawkmoths during migration, scientists reveal that insects employ sophisticated flight strategies similar to vertebrates.” ScienceDaily. ScienceDaily, 11 August 2022. <www.sciencedaily.com/releases/2022/08/220811143026.htm>.

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Minimizing Further Insect Pest Invasions in Africa

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Esther Ngumbi

Jun 20, 2018

Photo: Tamzin Byrne/ICIPE

This was written by Esther Ngumbi, and appeared on Sci Dev Net

USAID recently offered prize money for the best digital tools that can be used to help combat the fall armyworm (FAW), an invasive pest that has spread across Africa. The winners will be announced in the coming months.
Identified in over 35 African countries since 2016, the FAW is expected to continue to spread, threatening food security and agricultural trade in African countries.

Map of areas affected by Fall Armyworm (as of January 2018) Credit: FAO

But this is not the first invasive pest the African continent is dealing with. Just a few years ago, African smallholder farmers battled the invasive South American tomato moth, Tuta absoluta. According to recent research, five invasive insect pests including T. absoluta cost the African continent US$ 1.1 billion every year.
Around the world, invasive pests are causing US$ 540 billion in economic losses to agriculture each year despite the fact that many countries are doing their best to prevent insect invasions now and into the future.

Tackling invasive pests reactively

To deal with invasive insects, African countries assisted by other stakeholders, including aid agencies such as USAID, research institutions such as the International Center for Insect Physiology and Ecology, the Center for Agriculture and Bioscience International (CABI, the parent organization of SciDev.Net) and the United Nations Food and Agriculture Organization (UN FAO) have repeatedly taken a reactive rather than a proactive approach in tackling the invasive pests only after they have established a foothold and caused considerable damage.
Ghana, for example, established a National Taskforce to control and manage FAW after the worms had invaded local fields. This taskforce mandate includes sensitizing farmers and making them aware of the symptoms of armyworm attacks so they can report infestations to authorities and undertake research aimed at finding short and long term solutions to combat the spread of FAW.

“While many of these strategies are working, one cannot help but wonder what it would take for African governments to get ahead of this problem.”

Esther Ngumbi, University of Illinois

Malawi’s government prioritized the use of pesticides as an immediate and short-term strategy to fight the FAW after many of their smallholder farmers lost crops to this invasive insect. Further, the government intensified training and awareness campaigns about this pest and installed pheromone traps to help monitor the spread only after the pest had established a foothold.
The FAO, a leader in the efforts to deal with invasive pests in Africa, has spearheaded many efforts including bringing together experts from the Americas, Africa and other regions to share and update each other on FAW. The FAO has launched a mobile phone app to be used as an early warning system tool. But again, many of these efforts happened after the first detection of the FAW.
While many of these strategies are working, one cannot help but wonder what it would take for African governments to get ahead of this problem. How can aid agencies such as USAID, UN FAO and other development partners that are currently spending billions to fight the invasive FAW help Africa to take the necessary steps to ensure that it is better prepared to deal with invasive insects now and into the future?

Anticipate and prepare

Recent research predicts that threats from invasive insects will continue to increase with African countries expected to be the most vulnerable. African governments must anticipate and prepare for such invasions using already available resources.
Early this year, CABI launched invasive species Horizon Scanning Tool (beta), a tool that allows countries to identify potential invasive species. This online and open source tool supported by United States Department of Agriculture and the UK Department for International Development allows countries to generate a list of invasive species that are absent from their countries at the moment but present in “source areas,” which may be relevant because they are neighboring countries, linked by trade and transport routes, or share similar climates. Doing so could allow African countries to prepare action plans that can be quickly rolled out when potential invaders actually arrive.

Learn from other regions

Africa can learn from other regions that have comprehensive plans on dealing with invasive insects and countries that have gone through similar invasions. The United States and Australia are examples of countries that have comprehensive plans on preventing and dealing with insect invasions, while Brazil has gone through its own FAW invasion.

“African governments must learn to be proactive rather than reactive in dealing with invasive insects.”

Esther Ngumbi, University of Illinois

Through workshops and training programs that help bring experts together, African countries can learn how to prevent and deal with future insect invasions. Moreover, key actors should help organize more workshops and training programs to enable African experts to learn from their counterparts overseas. At the same time, the manuals, and all the information exchanged and learned during such workshops, could be stored in online repositories that can be accessed by all African countries.   

Strengthen African pest surveillance

A recent Feed the Future funded technical brief, which I helped to write, looked at the strength of existing African plant protection regulatory frameworks by examining eight indicators including the existence of a specified government agency mandated with the task of carrying out pest surveillance.
It reveals that many African countries have weak plant protection regulatory systems and that many governments do not carry out routine pest surveillance which involves the collection, recording, analysis, interpretation and timely dissemination of information about the presence, prevalence and distribution of pests.
The International Plant Protection Convention offers a comprehensive document that can help African countries to design pest surveillance programs. Also, the convention offers other guiding documents that can be used by African countries to strengthen their plant protection frameworks. African countries can use these available documents to strengthen national and regional pest surveillance abilities.

Set up emergency funds

Invasive insects know no borders. Thus, African countries must work together. At the same time, given the rapid spread of invasive insect outbreaks, the African continent must set up an emergency fund that can easily be tapped when insects invade. In dealing with the recent FAW invasion, it was evident that individual African countries and the continent did not have an emergency financing plan. This must change.

By anticipating potential invasive insects and learning from countries that have comprehensive national plant protection frameworks, Africa can be prepared for the next insect invasion. African governments must learn to be proactive rather than reactive in dealing with invasive insects.
Doing so will help safeguard Africa’s agriculture and protect the meaningful gains made in agricultural development. Time is ripe.
Esther Ngumbi is a distinguished postdoctoral researcher with the Department of Entomology at the US-based University of Illinois at Urbana Champaign, a World Policy Institute Senior Fellow, Aspen Institute New Voices Food Security Fellow and a Clinton Global University Initiative Agriculture Commitments Mentor and Ambassador. She can be contacted at enn0002@tigermail.auburn.edu 
This piece was produced by SciDev.Net’s Sub-Saharan Africa English desk. 


[1] USAID: Fall Armyworm Tech Prize (USAID, 2018). 
[2] Briefing note on FAO actions on fall armyworm in Africa (UN FAO, 31 January 2018) 
[3] Corin F. Pratt and others  Economic impacts of invasive alien species on African smallholder livelihoods (Global Food Security, vol 14, September 2017).
[4] Abigail Barker Plant health-state of research (Kew Royal Botanic gardens, 2017).
[5] US Embassy in Lilongwe United States assists Malawi to combat fall armyworm. (US Embassy, 13 February 2018).
[6] Joseph Opoku Gakpo Fall armyworm invasion spreads to Ghana (Cornell Alliance for Science, 19 May 2017). 
[7] Kimberly Keeton Malawi’s new reality: Fall armyworm is here to stay (IFPRI, 26 February 2018).
[8] Malawi’s farmers resort to home-made repellents to combat armyworms (Reuters, 2018). 
[9] Fall Armyworm (UN FAO, 2018). 
[10] FAO launches mobile application to support fight against Fall Armyworm in Africa (UN FAO, 14 March 2018).
[11] Dean R. Paini and others Global threat to agriculture from invasive species (Proceedings of the National Academy of Sciences of the United States of America, 5 July 2016).
[12] CABI launches invasive species Horizon Scanning Tool (CABI, 2018).
[13] United States Department of Agriculture Animal and Plant Health Inspection Service(USDA APHIS, 2018).
[14] Australia Government Department of Agriculture and Water Resources (Australia Government, 2018).
[15] Plant protection EBA data in action technical brief (USAID FEED THE FUTURE, 26 January 2018).
[16] Guidelines for surveillance (International Plant Protection Convention, 2016)FILED UNDER:AGRICULTURAL PRODUCTIVITYMARKETS AND TRADEPOLICY AND GOVERNANCERESILIENCE

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Over the past two years, locusts have ravaged swathes of East Africa. But the cure for the problem may also have dire consequences


A farmer walking through a swarm of locusts

A farmer walking through a swarm of locusts in Meru, Kenya, on 9 February 2021

Yasuyoshi Chiba/AFP via Getty Images

Most of the time, the desert locust, Schistocerca gregaria, is an innocuous grasshopper: a green or brown short-winged insect that lives a solitary life in the deserts of Africa, Arabia and Asia. But in certain conditions – when there’s lots of moisture and vegetation flourishes – these locusts enter a “gregarious phase”, and undergo a remarkable transformation.

Their brains change, they turn yellow and black, and their wings grow. Most importantly, they become attracted to each other and start joining together in swarms which can reach a density of 15 million insects per square mile, and travel up to 90 miles in a day. Since late 2019, vast clouds of these locusts have devastated parts of the Horn of Africa, devouring crops and pasture, triggering a huge operation to track and kill them.

Where did the locusts come from?

In 2018, two unusual cyclones – linked to climate change – deposited rain in the remote Empty Quarter of the Arabian peninsula, which led to an 8,000-fold increase in locust numbers there.

In 2019, strong winds blew the growing swarms first into Yemen, then across the Red Sea into Somalia, Ethiopia, Eritrea and Kenya, where their populations were further boosted by a wet autumn, and a cyclone in Somalia – paving the way for a major emergency last year. Billions of the insects swept on, into Uganda, South Sudan and Tanzania, going on to affect a total of 23 countries, from Sudan to Iran to Pakistan.

How big were the plagues?

In Kenya, they were the worst in 70 years. When they arrived in East Africa, witnesses said it was “like an umbrella had covered the sky”. “The first swarms we saw were massive – three or four kilometres wide and a thousand metres deep,” Mark Taylor, a farmer in the Laikipia region of northern Kenya, told The Sunday Times.

A swarm of desert locusts

A swarm of desert locusts pictured after an aircraft sprayed pesticide in Meru, Kenya

Yasuyoshi Chiba/AFP via Getty Images

When the locusts settled on trees, there were “so many of them that branches broke under the weight”. Locust swarms can vary from less than one square kilometre to several hundred square kilometres. There can be at least 40 million and sometimes as many as 80 million locust adults in each square kilometre. One swarm in northern Kenya was reported to have reached 2,400 square kilometres in size – an area the size of Luxembourg.

How bad was the damage?

Locusts eat their body weight in food every day; a small swarm covering one square kilometre can eat the same amount as 35,000 people. So when they descended on East Africa, vast swathes of vegetation were consumed within minutes. “They attacked everything,” says Mark Taylor. “Fifty-four hectares [133 acres] were destroyed just like that.”

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Monarch butterflies may be thriving after years of decline. Is it a comeback?

The North American species is seeing an exponential increase in California, but the population is far short of normal

A western monarch butterfly lands on a plant iln Pismo Beach, California.
Western monarch butterflies have returned to Pismo Beach in increasing numbers this month. Photograph: Gabrielle Canon/The Guardian

Gabrielle Canon@GabrielleCanonSun 21 Nov 2021 06.00 EST

  • On a recent November morning, more than 20,000 western monarch butterflies clustered in a grove of eucalyptus, coating the swaying trees like orange lace. Each year up to 30% of the butterfly’s population meets here in Pismo Beach, California, as the insects migrate thousands of miles west for the winter.

Just a year ago, this vibrant spectacle had all but disappeared. The monarch population has plummeted in recent years, as the vibrant invertebrates struggled to adapt to habitat loss, climate crisis, and harmful pesticide-use across their western range.

Last year less than 200 arrived at this site in 2020 – the lowest number ever recorded – and less than 2,000 were counted across the California coast.

But ahead of the official annual count that takes place around Thanksgiving, early tallies show monarchs may be thriving once again across California. The rise has sparked joy and relief, but the researchers, state park officials, and advocates say that doesn’t mean the species is safe.

Western monarch butterflies gather in the branches of a eucalyptus tree in Pismo Beach.
Up to 30% of the western monarch butterfly population converges on Pismo Beach each winter. Photograph: Gabrielle Canon/The Guardian

Even with the exponential increase, the population is still far short of once-normal numbers. It’s still unclear whether the butterflies are making a dramatic comeback or will continue to decline.AdvertisementThe New Face of Small BusinessR sundae infused with Black history: howRabia Kamara is changing the dessert worldhttps://imasdk.googleapis.com/js/core/bridge3.489.0_en.html#goog_346656178https://imasdk.googleapis.com/js/core/bridge3.489.0_en.html#goog_370564443https://imasdk.googleapis.com

“The takeaway is that the migration isn’t gone, which some people really feared last year,” says Emma Pelton, the senior conservation biologist for the Xerces Society, an organization dedicated to protecting pollinators and other invertebrates. Between 4 million and 10 million butterflies once graced the California coasts before dropping to just over a million at the end of the 1990s. In the decades that followed, the population plateaued at about 200,000.

Then, in 2017, the numbers crashed to fewer than 30,000 butterflies at the annual counts. Monarchs are resilient and adaptive but they continue to face challenges. This year’s uptick is small when put in perspective with past population levels, but “the good news is that it is not too late”, Pelton adds.

A remarkable migration

There’s still a fair amount of mystery surrounding the western monarchs and their incredible annual migration. Each year, they follow a celestial compass and head west from the Rocky Mountains to the coast. Remarkably, each generation of butterflies often returns the same groves along the coast each year, sometimes even a particular tree, without ever having been there before.

Generally, they arrive in California around November and disembark in the spring, heading east as the weather warms. A separate population of monarchs spends the winter in Mexico, coming from Canada and the eastern United States.

Stephanie Little, a scientist with California state parks, uses binoculars to look up in the trees and count butterflies in Pismo Beach.
Stephanie Little, a scientist with California state parks, counts butterflies in Pismo Beach. Photograph: Gabrielle Canon/The Guardian


Their dedication to routine makes them easier to count each year. But the process isn’t exactly simple, especially when the numbers are low and they are harder to spot. In the Pismo Beach grove, which usually hosts the largest gathering, there are three state parks officials tasked with tallying them before the Thanksgiving count that relies on help from volunteers.

Armed with binoculars, butterfly counters estimate the numbers based on clusters that can be seen in the branches, roughly 50ft (15 meters) from the ground. California state parks has partnered with advocacy organizations to produce a welcoming environment for them. That means planting more of the non-native eucalyptus trees, which the butterflies love to roost in.

The reasons behind this sharp increase remain a mystery. Monarchs that live in the west tend to have three or four generations each year, each with a different role to play in the migration that can span thousands of miles, and there are opportunities at each stage for big shifts.

Monarch butterflies gather in the branches of a eucalyptus tree, roughly 50 ft from the ground.
Monarch butterflies gather in the branches of a eucalyptus tree, roughly 50ft from the ground. Photograph: Gabrielle Canon/The Guardian

But what’s driving their precipitous decline is clear. Their historic habitats in grassland ecosystems across the US are being destroyed. Commercial agriculture is eating away at their range which is increasingly laced with deadly pesticides. And, susceptible to both fluctuations and extremes in temperatures, monarchs are vulnerable to climate change. That’s partly why they are considered a so-called “indicator species” revealing the devastating toll taken on other insects and ecosystems.

“The butterflies are just very adaptable and strong,” David James, an entomologist at Washington State University who has spent decades studying the species says. “But they are giving us a warning too – and we need to take heed of that,” he adds. “Their decline is going to affect other organisms.”

‘There’s still time to act’

The butterflies have also felt the impact of extreme heat, fires, and drought, as well as the severe winter storms on the California coast where they spend the winter. “Some of those storms have ripped the trees out and thrown butterflies to the ground,” James says.

But he also believes last year’s extremely low numbers may have been the result of dispersion, not necessarily death.

“When we only had 2,000 overwintering at the traditional sites, at the same time there were many reports inland in San Francisco and the LA area of monarch butterflies reproducing in people’s backyards and parks and gardens throughout the winter,” he says, noting that this spread makes them tricky to count.

But even if last year’s low numbers can be attributed to behavior changes, that’s still a sign climate crisis is causing problems. “They are indicating to us that things are going wrong,” James says.

Visitors look for butterflies at the Pismo Beach Butterfly Grove.
Visitors look for butterflies at the Pismo Beach Butterfly Grove. Photograph: Gabrielle Canon/The Guardian

Individuals can make a difference by planting native nectar plants, including the milkweed that monarchs lay their eggs on and limiting the use of pesticides. Members of the public can also volunteer to monitor monarchs across the west. And, according to Xerces’ Emma Pelton, the promising numbers show that small changes can have a big impact.

“The main message to me is that there’s hope,” she says, noting the way monarchs have inspired the public to reimagine how they see insects and the role that everyone can play in their conservation. “The insect apocalypse narrative and the very real biodiversity crises that we are facing, those can feel really dark” she says. “But the issue is not intractable and we can make a difference. There is still time to act.”

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Monarchs evolved mutations to withstand milkweed toxins; so did their predators

by University of California – Berkeley

What it takes to eat a poisonous butterfly
A cluster of monarch butterflies overwintering in California. Credit: Mark Chappell, UC Riverside

Monarch butterflies and their close relatives thrive on poisonous milkweed, thanks to genetic mutations that block the effects of the plant’s toxins while allowing the poisons to accumulate in the caterpillar or adult insects as deterrents to hungry predators.

Turns out some of those insect-eating predators evolved similar mutations in order to feast on monarchs.

In a study appearing this week in the journal Current Biology, researchers at the University of California, Berkeley, and UC Riverside report monarch-like genetic mutations in the genomes of four organisms that are known to eat monarchs: the black-headed grosbeak, a migratory bird that snacks on the butterflies at their overwintering home in Mexico; the eastern deer mouse, a close relative of the Mexican black-eared deer mouse that feeds on butterflies that fall to the ground; a tiny wasp that parasitizes monarch eggs; and a nematode that parasitizes insect larvae that feed on milkweed.

All four organisms have evolved mutations in one or more copies of a gene for the sodium-potassium pump—the same mutations, in fact, as milkweed butterflies, and ones that the researchers and their collaborators showed two years ago were critical to the monarch’s ability to eat milkweed without succumbing to its toxins.

The toxins are cardiac glycosides that interfere with this pump, which helps enable heartbeats and nerve firing. It’s so important in humans that we use a third of all the energy we generate from food to power the pump. It’s not surprising, then, that when the toxins throw a wrench in the pump, the heart and other organs stop, too. Even horses and humans can die of cardiac arrest if they consume enough of the milkweed toxins, which are still used as an arrow poison by hunter-gatherer groups in Africa. Until recently, small amounts of related chemicals from foxglove were widely used to treat congestive heart failure.

“The toxins move up the food chain from plants—what biologists call the first trophic level—to insect herbivores, the second, and then to predators and parasitoids—a third trophic level,” said evolutionary biologist Noah Whiteman, UC Berkeley professor of integrative biology and of molecular and cell biology. “In response, the predators and parasitoids have evolved resistance to the toxins at the same sites that we discovered were changing in the monarch, and sometimes to the same amino acids. This might be the first time that the same resistance mutations have been found in the third and second trophic levels that evolved in response to the latter feeding on toxic plants. “

“It’s remarkable that convergent evolution occurred at the molecular level in all these animals,” said co-author Simon “Niels” Groen, assistant professor of evolutionary systems biology in UC Riverside’s nematology department and a former UC Berkeley postdoctoral fellow. “Plant toxins caused evolutionary changes across at least three levels of the food chain.”

What it takes to eat a poisonous butterfly
In places like Mexico where monarch butterflies overwinter by the thousands to millions, the black-headed grosbeak is one of few birds that can eat them without vomiting. Researchers discovered that the bird has evolved similar genetic mutations as those found in the monarch that allow both to handle milkweed toxins, which accumulate in the butterfly and are deterrents to most predators. Credit: Mark Chappell, UC Riverside

Birds do it, wasps do it. Even nematodes do it.

Since the 1980s, biologists have known that monarchs and a few other butterflies, and even some beetles, aphids and other insects, have adapted to feeding on milkweed plants and storing the toxins in their bodies—even through metamorphosis—to deter predators. In the last decade, geneticists tracked down the actual genetic mutations that allowed this, all of which were in the sodium pump and allowed the pump to work, despite the toxins. Whiteman speculated that those animals that eat the butterflies must have evolved resistance mutations as well. But were they the same?

When the genome of the black-headed grosbeak was published last year, Whiteman and Groen immediately looked for and found sodium pump mutations nearly identical to those that evolved in the monarch. The researchers subsequently expanded the study, scanning previously sequenced genomes from other monarch-eating animals, and found similar mutations.

The black-headed grosbeak (Pheucticus melanocephalus), a summer resident of California, migrates to Mexico and is known for gobbling up monarchs at the places where they overwinter in the mountains of Michoacán state. One study found that the black-headed grosbeak and another bird, the black-backed oriole (Icterus abeillei), consumed hundreds of thousands to 1 million monarchs over a single winter.

It was evident from their behavior, however, that the two birds were not equally resistant to the milkweed toxins stored in the butterfly’s body. While the grosbeak would tear off the wings and consume the abdomen whole, the oriole would gut the abdomen after de-winging the butterfly and eat only the insides. The outside, or cuticle, has a higher concentration of cardiac glycoside toxins, as do the wings. Orioles also discarded monarchs with higher levels of cardiac glycosides.

The new study reveals how the grosbeak can tolerate the toxins in the monarch: It has evolved single-nucleotide mutations in its sodium pump genes in two of the same three locations where monarchs evolved mutations that help make them the most resistant organism to the milkweed’s cardiac glycosides. None of the other 150 or so sparrow-related “passerine” birds whose genomes are known has these mutations in both of the most widely expressed copies of the sodium pump gene. The oriole’s genome has yet to be sequenced.

What it takes to eat a poisonous butterfly
This graphic shows how milkweed toxins move from the plant through monarch caterpillars and butterflies into the black-headed grosbeak that feasts on them. To become resistant to the toxins, the grosbeak evolved mutations in its sodium pump (lower left) that are identical to two of the three mutations the monarch itself developed to make it resistant. Credit: UC Berkeley image by Julie Johnson

“It solves this mystery from 40 years ago where the biology was pretty well worked out, but we just couldn’t go down to the lowest level of organization possible, the genome, to see how grosbeaks are doing this,” Whiteman said. “It looks like, amazingly, they are evolving resistance using the same kind of machinery in the same places in the genetic code as the monarch and the aphids, the bugs and the beetles, that feed on milkweeds, as well.”

The biologists found that the wasp (Trichogramma pretiosum) also has two mutations in the same place as the monarch in the sodium pump gene. The nematode (Steinernema carpocapsae) has changes at all three locations in the sodium pump gene that also evolved in the monarch butterfly, including the one location that confers the most resistance. These nematodes have been found in the soil around milkweed plants in New York and may parasitize the grubs of beetles that feed on milkweed roots and presumably the larvae of other insects, including butterflies.

The fact that the eastern deer mouse (Peromyscus maniculatus)—a close relative of the black-eared deer mouse (P. melanotis), a monarch-feeding specialist—has all three mutations in its most widely expressed copies of the sodium pump gene was already known and not surprising, Whiteman said. The rat and other rodents have mutations in their sodium pump genes that allow them to resist cardiac glycosides and other substances that would be toxic to other mammals.

It’s unclear whether there are additional adaptations that help the black-headed grosbeak and other monarch predators like the black-eared deer mouse deal with the toxins, Groen said. He is planning to explore this question in future studies. Whiteman suspects that other organisms in the food chain that starts with milkweed will be found to have mutations similar to those found in the monarch.

“My guess is, there are other parasitoids out there, and predators that have also evolved resistance mutations that are interacting with monarchs, and it’s just a matter of time before they’re discovered,” he said. “We know that this isn’t the only way to evolve resistance to cardiac glycosides, but it seems to be the predominant way—targeting this particular pump.”

Explore furtherScientists recreate in flies the mutations that let monarch butterfly eat toxic milkweed with impunity

More information: Convergent evolution of cardiacglycoside resistance in predators and parasites of milkweed herbivores, Current Biology (2021). doi.org/10.1016/j.cub.2021.10.025Journal information:Current BiologyProvided by University of California – Berkeley

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Milkweeds for Monarch Butterfly Habitat in the Southwestern U.S.

Showy milkweed flowers, buds and foliage

Milkweeds are an iconic pollinator plant, with seventy-three native species that can be found in most habitats across the United States. These plants are in the genus Asclepias and are mostly composed of herbaceous perennials with milky sap and showy flowers. The plants are prolific nectar producers, providing nourishment for scores of native bees, flies, butterflies, hummingbirds, and many other animals. Milkweeds are perhaps most famous for their association with the life cycle of the monarch butterfly (Danaus plexippus). Milkweeds are vital to the monarch’s survival as the larvae feed exclusively on milkweed plants. Monarch butterflies are divided into two migratory populations, the eastern population overwinters in Mexico while the western population overwinters on the California coast.

Unfortunately, milkweed populations nationwide have been in significant decline due to habitat loss because of invasive weeds, urbanization, and agriculture. In addition to these stresses, milkweeds are often viewed as a weed, and are actively eradicated from roadsides, ditches, and agricultural areas. The reduction in milkweeds has been identified as a major contributing factor to the dramatic decline in monarch populations over the past few decades. The Western Monarch Thanksgiving Count offsite link image     is an annual population census that has counted over-wintering monarchs in California since the 1980’s. In 1997, they counted over 1.2 million individuals. In 2020, they counted a record low of 1,914 monarchs: a decline of over 99.9% since then.

The Southwestern Plant Materials Centers, located in Lockeford, California (CAPMC); Fallon, Nevada (NVPMC); Tucson, Arizona (AZPMC), and Los Lunas, New Mexico (NMPMC), have conducted studies and developed publications to enhance milkweed conservation in their respective areas. Much of this work has been in collaboration with the Xerces Society, Universities, and other partners.  The CAPMC evaluated the propagation and establishment of Asclepias speciosa, A. eriocarpa, and A. fascicularis by seed, rhizomes and transplants detailed in a series of three reports titled Milkweed Establishment in California’s Central Valley.  The NVPMC published a technical note on milkweed pollination biology and a report on the fourteen milkweed species that occur in the Great Basin. The AZPMC published a technical note on the forty-one milkweed species found in the Mojave, Sonoran, and Chihuahaun deserts. Milkweed conservation work conducted at the NMPMC included seed production trials of A. speciosa, A. latifolia, and A. asperula.

A monarch caterpillar on a woollypod milkweed

Additional resources and assistance programs to support monarch butterfly conservation are available on the Plant Materials Monarch Conservation and the NRCS Monarch Butterfly webpages.

Technical information and guidance on the use of conservation plants to address resource concerns is available on the Plant Materials Program website or contact the nearest Plant Materials Center or plant materials specialist. For additional information on species of plants mentioned, please see the USDA PLANTS database.

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Successful Farming



Kansas State University

An entomologist at Kansas State University urges winter wheat farmers to hold off on planting the crop due to an unusual infestation of fall armyworm that can quickly wipe out lush green wheat.

Jeff Whitworth, Extension agronomist at KSU, says farmers in Kansas are seeding winter wheat now, or will begin soon. With fall armyworm populations thriving, young wheat plants could be eradicated as soon as they emerge, he says.

“I would delay wheat planting as long as possible,” Whitworth says. “If there is any green wheat, these worms have the potential to do a great deal of damage.”

Delaying wheat planting is advised because insecticide seed treatments do not work on armyworms, Whitworth says. “We have tested this several times and they simply don’t work,” he emphasizes. Therefore, growers have two options to prevent damage. One, delay planting until after the Hessian fly-free date. Option two is to plant wheat as planned and monitor for damage. When the threshold gets to five or six armyworms per square foot, spray an insecticide over the top of the wheat crop. Insecticide options include products with active ingredients including pyrethroids, alpha-cypermethrin, beta-cyfluthrin, cyfluthrin, gamma-cyhalothrin, lambda-cyhalothrin, permethrin and zeta cypermethrin, organophosphates, choloropyrifos and carbamates, carbaryl and methomyl.PAID CONTENThttps://api.sele.co/iframe/v4.html?id=3903e723-938c-49bc-878a-55414ad7721d&_sm_xdm=true&use_xdm=1&autoStart=true&auto_start=1&start_muted=true&start_paused=1&disable_tab=1#https://www.agriculture.com/march-of-the-armyworms


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For the latter option, “…there are insecticides that work for armyworms, but is it worth the cost when growers could just delay planting?” Whitworth says.

There are two types of armyworms:

  • Fall armyworms feed on a wide range of host plants, including soybeans, sorghum, alfalfa, and corn. They have four spots on the top of the last abdominal segment, forming a square. They do not overwinter in most High Plains states.
  • True armyworms feed mostly on grasses. They don’t have have the spots fall armyworms possess.

Both species will feed on any plant material if they are hungry enough; they also have the same life cycle.

“Armyworms may continue to cycle through another generation, or even two, as they overwinter in Kansas,” Whitworth says. “Ultimately it will probably take a hard frost or freeze to stop them.”

Bob Wright, Extension entomologist at UNL, agrees. “Given the populations of fall armyworms to the south of us, it is likely moths will continue to be present in southern Nebraska for a while. Fall armyworms have a broad host range and can feed on broadleaf and grassy crops. Be sure to get out and monitor newly seeded alfalfa and wheat as seedling plants can be killed rapidly by caterpillars feeding on them,” Wright says.


The 2021 armyworm infestations have been particularly brutal. From Texas north to Nebraska and as far east as Michigan, insects have marched through farm fields, chewing through tender growth of plants and leaving fields bare in their wake.

Armyworms infest primarily grasses (sorghum, corn, brome pastures, lawns, etc.) and often this time of year, wheat, but occasionally alfalfa. Thus, if armyworms are the problem, they could be around through another generation or maybe even two depending upon the weather. If armyworms are relatively small they will probably feed for another 10 to 14 days, then pupate (stop feeding). If they are relatively large, however, they will probably pupate in the next three to seven days. There will probably be at least one more generation of armyworms.

“Hopefully, they will be heading south after these larvae finish feeding and become moths,” Whitworth says.

Also, in the next 30 to 60 days, army cutworm moths should have returned from their summer Rocky Mountain retreat to deposit eggs throughout at least the western two/thirds of the state and thus, these tiny worms will start feeding on wheat and/or alfalfa all winter.Read more about Crops

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Protecting Plants Will Protect People and the Planet

ISA Inerpress News Agency

By Barbara WellsReprint |         |  Print | Send by email

ROME, Jul 26 2021 (IPS) – Back-to-back droughts followed by plagues of locusts have pushed over a million people in southern Madagascar to the brink of starvation in recent months. In the worst famine in half a century, villagers have sold their possessions and are eating the locusts, raw cactus fruits, and wild leaves to survive.

Barbara WellsInstead of bringing relief, this year’s rains were accompanied by warm temperatures that created the ideal conditions for infestations of fall armyworm, which destroys mainly maize, one of the main food crops of sub-Saharan Africa.

Drought and famine are not strangers to southern Madagascar, and other areas of eastern Africa, but climate change bringing warmer temperatures is believed to be exacerbating this latest tragedy, according to The Deep South, a new report by the World Bank.

Up to 40% of global food output is lost each year through pests and diseases, according to FAO estimates, while up to 811 million people suffer from hunger. Climate change is one of several factors driving this threat, while trade and travel transport plant pests and pathogens around the world, and environmental degradation facilitates their establishment.

Crop pests and pathogens have threatened food supplies since agriculture began. The Irish potato famine of the late 1840s, caused by late blight disease, killed about one million people. The ancient Greeks and Romans were well familiar with wheat stem rust, which continues to destroy harvests in developing countries.

But recent research on the impact of temperature increases in the tropics caused by climate change has documented an expansion of some crop pests and diseases into more northern and southern latitudes at an average of about 2.7 km a year.

Prevention is critical to confronting such threats, as brutally demonstrated by the impact of the COVID-19 pandemic on humankind. It is far more cost-effective to protect plants from pests and diseases rather than tackling full-blown emergencies.

One way to protect food production is with pest- and disease-resistant crop varieties, meaning that the conservation, sharing, and use of crop biodiversity to breed resistant varieties is a key component of the global battle for food security.

CGIAR manages a network of publicly-held gene banks around the world that safeguard and share crop biodiversity and facilitate its use in breeding more resistant, climate-resilient and productive varieties. It is essential that this exchange doesn’t exacerbate the problem, so CGIAR works with international and national plant health authorities to ensure that material distributed is free of pests and pathogens, following the highest standards and protocols for sharing plant germplasm. The distribution and use of that germplasm for crop improvement is essential for cutting the estimated 540 billion US dollars of losses due to plant diseases annually.

Understanding the relationship between climate change and plant health is key to conserving biodiversity and boosting food production today and for future generations. Human-driven climate change is the challenge of our time. It poses grave threats to agriculture and is already affecting the food security and incomes of small-scale farming households across the developing world.

We need to improve the tools and innovations available to farmers. Rice production is both a driver and victim of climate change. Extreme weather events menace the livelihoods of 144 million smallholder rice farmers. Yet traditional cultivation methods such as flooded paddies contribute approximately 10% of global man-made methane, a potent greenhouse gas. By leveraging rice genetic diversity and improving cultivation techniques we can reduce greenhouse gas emissions, enhance efficiency, and help farmers adapt to future climates.

We also need to be cognizant that gender relationships matter in crop management. A lack of gender perspectives has hindered wider adoption of resistant varieties and practices such as integrated pest management. Collaboration between social and crop scientists to co-design inclusive innovations is essential.

Men and women often value different aspects of crops and technologies. Men may value high yielding disease-resistant varieties, whereas women prioritize traits related to food security, such as early maturity. Incorporating women’s preferences into a new variety is a question of gender equity and economic necessity. Women produce a significant proportion of the food grown globally. If they had the same access to productive resources as men, such as improved varieties, women could increase yields by 20-30%, which would generate up to a 4% increase in the total agricultural output of developing countries.

Practices to grow healthy crops also need to include environmental considerations. What is known as a One Health Approach starts from the recognition that life is not segmented. All is connected. Rooted in concerns over threats of zoonotic diseases spreading from animals, especially livestock, to humans, the concept has been broadened to encompass agriculture and the environment.

This ecosystem approach combines different strategies and practices, such as minimizing pesticide use. This helps protect pollinators, animals that eat crop pests, and other beneficial organisms.

The challenge is to produce enough food to feed a growing population without increasing agriculture’s negative impacts on the environment, particularly through greenhouse gas emissions and unsustainable farming practices that degrade vital soil and water resources, and threaten biodiversity.

Behavioral and policy change on the part of farmers, consumers, and governments will be just as important as technological innovation to achieve this.

The goal of zero hunger is unattainable without the vibrancy of healthy plants, the source of the food we eat and the air we breathe. The quest for a food secure future, enshrined in the UN Sustainable Development Goals, requires us to combine research and development with local and international cooperation so that efforts led by CGIAR to protect plant health, and increase agriculture’s benefits, reach the communities most in need.

Barbara H. Wells MSc, PhD is the Global Director of Genetic Innovation at the CGIAR and Director General of the International Potato Center. She has worked in senior-executive level in the agricultural and forestry sectors for over 30 years.https://platform.twitter.com/widgets/follow_button.f88235f49a156f8b4cab34c7bc1a0acc.en.html#dnt=false&id=twitter-widget-0&lang=en&screen_name=IPSNewsUNBureau&show_count=false&show_screen_name=true&size=l&time=1629524871809

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Fall armyworms eating rice leaves in a flooded field. Entomologists seek emergency-use exemption to help rice growers in ‘epic’ battle against armyworms.

Mary Hightower, U of A System Division of Agriculture | Jul 22, 2021SUGGESTED EVENT

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University of Arkansas System Division of Agriculture entomologists are seeking an emergency exemption to allow for the use of Intrepid to help control armyworms that threaten the state’s 1.24 million acres of rice. 

“This is the biggest outbreak of fall armyworm situation that I’ve ever seen in my career,” Gus Lorenz, extension entomologist for the Division of Agriculture, said Wednesday. “They’re in pastures, rice, soybeans, grain sorghum. It’s epic.”https://d4100051ff2b64e2ac90e81feaf8c9c5.safeframe.googlesyndication.com/safeframe/1-0-38/html/container.html

Lorenz said the Section 18 request to enable use of Intrepid should be submitted to the Arkansas State Plant Board by Friday.

Intrepid is a growth regulator that’s approved for use in just about every other row crop but is not labeled for use in rice.

“This armyworm thing started about three to four weeks ago,” he said. “It’s continued to build from that time. It’s from the Boot heel of Missouri down to Louisiana.”

Eaten to the ground

Gus Lorenz51326207237_6519faedbd_o.png

Sweep net full of armyworms. Taken July 21, 2021.Lorenz said he received a call from a producer in “south Arkansas, that they’d eaten his bermudagrass pasture to the ground. It was a 30- to 40-acre pasture. And he wasn’t even calling about the pasture. He was calling about his rice crop. He said his rice was being eaten to the ground.”

“Fall armyworm is a particularly voracious caterpillar,” said Jarrod Hardke, extension rice agronomist for the Division of Agriculture. “They have a tendency to surprise us because adults lay very large egg masses but the earliest instar larvae eat very little. It’s not until they get older and start to spread out that they consume most of the food in their life cycle.

“This is why we go from zero to TREAT seemingly overnight,” Hardke said.

Why a Section 18?

51327145063_f633537f6a_o.jpgExtension entomologist Nick Bateman examines a rice field in Jefferson County on July 21, 2021 for fall armyworms. (U of A System Kurt Beaty)

Typically, armyworms can be managed well using pyrethroids, but Lorenz said “when this outbreak first started, we got reports out of Texas and Louisiana that they weren’t getting control. We’re getting failures.”

Lorenz said he and colleagues ran some quick tests, spraying this year’s armyworms with pyrethroids “and we got 48% control.”

In cattle-heavy parts of the state producers use another insect growth regulator called Dimilin to manage armyworms, but in row crop country, “they just don’t carry it. It’s just not available,” Lorenz said.

Fellow extension entomologist Nick Bateman said, “another problem with using Dimilin is the pre-harvest interval. The pre-harvest interval on Dimilin is 80 days which will lead to major harvest issues.”

“We’re limited on the options in control for rice,” he said. “It’s not just a problem of row rice. We are also seeing them in flooded rice, all through the field. They are eating rice all the way down to the waterline.”

Lorenz said rice growers in California sought and received a Section 18 exemptions over the last three years. “We felt like that was our best option.”

Arkansas farmers who managed to replant after the floods and heavy rain in June have young, tender plants that are highly attractive to armyworms.

“Those crops are extremely susceptible to damage from armyworms,” Lorenz said.

What’s next

“My concern is that if we get another generation of them, the next wave could be unbelievable,” he said.

The first generation of armyworms matured into moths in Texas and Louisiana and flew northward. Now that they’re in Arkansas, “We’re making our own generation, which is what makes it so dangerous,” Lorenz said.

There’s also a chance that, depending on the environment, “the population could collapse,” he said. “There are some natural controls out there. When you get a big buildup a lot of things can happen. There are a lot of naturally occurring pathogens that can help control them.”

Some agents in southwest Arkansas found armyworms that had fallen victim to a naturally occurring virus. Lorenz is hoping that virus may provide another option for control in the future.

Arkansas is the nation’s leading rice producer. 

Use of product names does not imply endorsement.Source: University of Arkansas System Division of Agriculture, which is solely responsible for the information provided and is wholly owned by the source. Informa Business Media and all its subsidiaries are not responsible for any of the content contained in this information asset.

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Butterflies cross the Sahara in longest-known insect migration


Weather conditions shown to have big influence on migration numbers




A species of butterfly found in Sub-Saharan Africa is able to migrate thousands of miles to Europe, crossing the Saharan Desert, in years when weather conditions are favourable, scientists have found.

The striking Painted Lady (Vanessa cardui) butterfly has been shown for the first time to be capable of making the 12,000-14,000km round trip – the longest insect migration known so far – in greater numbers, when wetter conditions in the desert help the plants on which it lays eggs.

The international research team’s findings increase understanding of how insects, including pollinators, pests and the diseases they carry could spread between continents in future as climate change alters seasonal conditions.

Professor Tom Oliver, an ecologist at the University of Reading and co-author of the study, said: “We know that the number of Painted Lady butterflies in Europe varies wildly, sometimes with 100 times more from one year to the next. However, the conditions that caused this were unknown, and the suggestion the butterflies could cross the Sahara desert and oceans to reach Europe was not proven.

“This research shows this unlikely journey is possible, and that certain climate conditions leading up to migration season have a big influence on the numbers that make it. It demonstrates how the wildlife we see in the UK can transcend national boundaries, and protecting such species requires strong international cooperation”.

As well as answering long-asked questions about butterfly migrations, the findings could help predictions of the movements of other insects that affect people, such as the locusts currently plaguing East Africa, or by malaria-carrying mosquitoes.

Professor Oliver said: “We enjoy seeing the beautiful Painted Lady butterflies in our gardens in Europe, but climate change will also lead to shifts in invasive species that are crop pests or those that spread diseases. Food shortages in East Africa are a reminder that the impacts of climate change can be much more dramatic than a few degrees of warming might first seem.”

The Painted Lady migrates during the spring, following a winter breeding season. Researchers used long-term monitoring data from thousands of trained volunteer recorders, along with climate and atmospheric data in regions of Sub-Saharan Africa and Europe to learn about their movement.

The study, published in the Proceedings of the National Academy of Sciences journal, found that increased vegetation in the African Savanna during the winter and in North Africa in the spring, combined with favourable tail winds, are the three most important factors in the number that migrate to Europe.

Painted Lady caterpillars feed on the leaves of plants that thrive in wetter winter conditions in the Savannah and Sahel regions of sub-Saharan Africa, causing population numbers to explode. They migrate across the Sahara, and when there are also wet and green spring conditions in North Africa these allow further breeding and swell the numbers that cross the Mediterranean Sea to reach Europe.

Simulations by the scientists also showed that there are regularly favourable tailwinds between Africa and Western Europe, offering insects opportunities for transcontinental travel.

The team calculated that the butterflies must fly non-stop during the day and rest during night to cross the Sahara, making stops to feed on nectar. This is similar to the pattern in which night-flying songbirds migrate.

They concluded the butterflies must fly up to 1-3km above sea level to take advantage of favourable tailwinds, as their maximum self-powered flying speed of around 6 metres per second would make a Sahara crossing extremely difficult.

The researchers used observations of similar butterfly species to calculate that Painted Ladies have enough body fat after metamorphosis to sustain 40 hours of non-stop flying, and keep this topped up by feeding on nectar whenever possible in order to cross the Sahara.

The findings may help improve predictions of which insect species might be found in different regions in future due to climate change, and the numbers they could arrive in.


Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.

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Iran’s battle against migratory desert locusts successful

Mehr News Agency

Iran's battle against migratory desert locusts successful

TEHRAN, May 23 (MNA) – Director of the Plant Protection Organization of Iran, has said that the country has successfully repelled two swarms of desert locusts so far through taking necessary measures.

“So far, there have been two attacks by deserts locusts invading the country, which have been repelled and the country’s farms have not been damaged,” the head of the Plant Protection Organization of the I.R. Iran, Keikhosrow Changlvaei, said. 

He added, “Of course, the danger has not been eliminated yet and according to the reports of international organizations, in July and November of this year, the country will be exposed to the swarms of desert locusts again.”

“Desert locusts are originated from Saudi Arabia, the Indian subcontinent, and the Horn of Africa, and from these areas they move towards other countries, including Iran, in order to find suitable food and soil,” said Changlvaei.

The Chairman of the Plant Protection Organization added that these locusts have been fought well in the countries of their origin and the sizes of their dangers have been lowered.

Changlvaei added that Iran has prepared for fighting this pest, underlining that “We are ready in terms of facilities, pesticide, and well-trained personnel.”

He also said that his organization also receives help from the country’s military in the fight against migratory desert locusts.

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