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Arms race between ants and fungi has echoes of The Last of Us

Insects are fighting off fungal invaders, but the fungi have some tricks up their sleeve

• 10 FEB 2023
• 3:50 PM
• BYCLAUDIA LOPEZ LLOREDA

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There’s an arms race going on between a disease-causing fungus and its host, and it’s not the one portrayed in HBO’s postapocalyptic series The Last of Us. Researchers have found that, with a bit of grooming, ants can help their comrades fight off multiple fungal invaders—but that these fungi have also found a way to fight back. Such battles could influence the evolution of pathogens found in a wide range of species, including humans.

“The study is capturing evolution in action,” says Trine Bilde, an evolutionary biologist at Aarhus University who was not involved with the work. “That’s so cool.”

Ants, like people, are social. They live in giant colonies, with each individual invested in the others’ survival. Worker ants don’t just sacrifice themselves for the queen, they groom each other for parasites, similar to how chimpanzees pick fleas and ticks off their companions.

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To see whether such comradeship helps the insects fight off fungi, researchers at the Institute of Science and Technology Austria turned to Argentine ants (Linepithema humile), a small, brown species native to South America. In the wild, these ants live with thousands of other pathogens and are often infected with multiple fungi at once.

The scientists infected the insects with six different types of related fungal pathogens in the lab. Then they watched as the different fungi evolved as they infected ants over multiple generations.

When the insects were alone, one of the six fungus strains usually won out. The winning strain burrowed into the ant, infecting it and killing it to continue reproducing its spores, whereas the other fungus strains died off. But with friends around, the balance of power shifted. As the insects groomed each other, the six types of fungi duked it out among themselves, with no clear winner taking over, the team reports this month in Nature Ecology & Evolution.

The fungi also appeared to be evolving to become less lethal. But they hadn’t completely given up the fight. Further experiments revealed the pathogens were releasing less of a molecule called ergosterol, which made them visible to the ants. The less ergosterol the fungi produced, the less the insects groomed each other.

That could allow the fungi to hide out from the grooming ants while they evolve new ways to fight back—a strategy not previously seen, says Yoko Ulrich, an evolutionary biologist at the Max Planck Institute for Chemical Ecology who was not involved with the study. Humans don’t groom each other like ants do, she notes, but we do engage in other behaviors to fight off disease, such as using hand sanitizer.

What impact might that have on the evolution of the microbial invaders that threaten us? Stay tuned for future science—or perhaps the next HBO series.

doi: 10.1126/science.adh1159

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ABOUT THE AUTHOR

Claudia Lopez Lloreda

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Potential use of entomopathogenic and mycoparasitic fungi against powdery mildew in aquaponics

Aquaponics has the potential to produce sustainable and accessible quality food through the integration of hydroponics and aquaculture. Plants take up dissolved nutrients in fish wastewater, allowing water reuse for fish. However, the simultaneous presence of fish and plants in the same water loop has made phytosanitary treatments of diseases such as powdery mildew problematic due to risks of toxicity for fish and beneficial bacteria, limiting its commercialization.

Entomopathogenic and mycoparasitic fungi have been identified as safe biological control agents for a broad range of pests. This study aimed to investigate the efficacy of entomopathogenic fungi, Lecanicillium attenuatum (LLA), Isaria fumosorosea (IFR), and mycoparasitic fungus Trichoderma virens (TVI) against Podosphaera xanthii. Also, we investigated the possible harmful effects of the three fungal biocontrol agents in aquaponics by inoculating them in aquaponics water and monitoring their survival and growth. The findings showed that the three biocontrol agents significantly suppressed the powdery mildew at 107 CFU/ml concentration.

Under greenhouse conditions (65-73% relative humidity (RH)), a significant disease reduction percentage of 85% was recorded in L. attenuatum-pretreated leaves. IFR-treated leaves had the least AUDPC (area under disease progress curve) of ~434.2 and disease severity of 32% under 65-73% RH. In addition, L. attenuatum spores were the most persistent on the leaves; the spores population increased to 9.54 × 103 CFUmm-2 from the initial 7.3 CFUmm-2 under 65-73%. In contrast, in hydroponics water, the LLA, IFR, and TVI spores significantly reduced by more than 99% after 96 hrs. Initial spore concentrations of LLA of 107 CFU/ml spores were reduced to 4 x 103 CFU after 96 hrs. Though the results from this study were intended for aquaponics systems, the relevance of the results to other cultivation systems are discussed.

Read the complete research at www.researchgate.net.

Folorunso, Ewumi Azeez & Bohata, Andrea & Kavkova, Miloslava & Gebauer, Radek & Mraz, Jan. (2022). Potential use of entomopathogenic and mycoparasitic fungi against powdery mildew in aquaponics. Frontiers in Marine Science. 9. 10.3389/fmars.2022.992715. 

Publication date: Wed 9 Nov 2022

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Home | Arts + Culture | Wild Things

Bold jumping spiders will attack larger prey, leaping four times the length of their body

By Jeanine Farley

Saturday, November 5, 2022

Bold jumping spiders are very hairy, with four pairs of eyes. (Photo: Claire O’Neill/Earthwise Aware)

What’s small and hairy and jumps? Perhaps a bold jumping spider, which is one of the most common jumping spiders in North America. These spiders are not dangerous. If you pick one up, for example, it probably will not bite you (but I make no guarantees). If it did bite you, its fangs would probably not penetrate your skin, and if they did pierce the skin, the venom is too weak to cause harm to humans.

The legs of adult bold jumping spiders sport bands of silver hairs, while juveniles have orange or yellow bands. (Photo: Joe MacIndewar/Earthwise Aware)

These spiders (Phidippus audax) are so named because they are fearless and quick to jump on and attack prey that is larger than they are. “Audax” is from the word audacity, meaning “bold” or “daring.” They prey on many insect pests, including mosquitoes. These little critters (one-quarter to three-quarters of an inch) are also able to jump four times their body length.

Probably the most prominent feature of jumping spiders is that they are hairy. Bold jumping spiders are mostly black with a white or reddish triangle and two small dots on their abdomens. Their fangs or mouthparts(chelicerae) are metallic green – a feature sometimes more noticeable on males.

Bold jumping spiders display metallic green fangs or mouthparts that are more pronounced in males. (Photo: Claire O’Neill/Earthwise Aware)

Bold jumping spiders hunt during the day. They sneak up on their prey and pounce, injecting venom that paralyzes their prey. We all know that spiders have eight legs; most spiders, including bold jumping spiders, also have eight eyes. This gives them the sharp vision they need to stalk their prey. In fact, jumping spiders – with eyes in a semicircle around the head, each pair of a different size, with the two in the middle being the largest – have the sharpest vision of all spiders. These two largest eyes give the spider good three-dimensional vision, while the other six eyes provide it with 360-degree views of the surroundings.

Bold jumping spiders are the state spider of New Hampshire, but this spider hunts on Prospect Hill in Somerville. (Photo: Claire O’Neill/Earthwise Aware)

Jumping spiders do not spin webs, but before they jump they attach a strand of silk to the surface they are on. If they jump and miss, they are still tethered to the tree or wall from which they jumped. They also use silk to make a cocoonlike resting place (in dried leaves, under rocks, in tree crevices) where they, eat their prey and protect their eggs.

Birds and dragonflies and small mammals prey on bold jumping spiders. If you have ever seen a bird digging an insect out from a tree fissure, you might have witnessed the demise of a bold jumping spider.

Juvenile bold jumping spiders have an orange-tinted triangle and two small dots on their abdomens. These spots become whiter in adults. (Photo: Joe MacIndewar/Earthwise Aware)

Similar to snakes, spiders shed their outer skin as they grow larger. Bold jumping spiders stop the process in the fall as adolescents and overwinter as sub-adults. In the spring, they finish growing to adulthood. They breed from spring to early summer; the female bold jumping spider produces an egg sac containing 30 to 170 eggs. (With six to eight egg sacs per season, that’s a lot of baby spiders.) She guards the egg sac until the baby spiders hatch; then the babies are on their own.

The spiders prefer flat vertical surfaces where they can see and easily pounce on their prey. Therefore, these spiders like broad-leaved plants such as milkweed, for example, or tree trunks, fenceposts and house siding. If you should happen to see a bold jumping spider inside your cellar or on your lawn furniture, let it be; it is shy and harmless, will most likely run or jump away if it detects you, and can help control insect pests.

Bold jumping spiders like this one in the Cambridge Highlands can detect vibrations from a great distance and jump four times its body length. (Photo: Claire O’Neill/Earthwise Aware)

A bald eagle is spotted in Ball Square, Somerville, in mid-October. Its unusual left eye identifies it as KZ, the male of the nesting pair on the Mystic Lakes. (Photo: Jeanine Farley)

Have you taken photos of our urban wild things? Send your images to Cambridge Day, and we may use them as part of a future feature. Include the photographer’s name and the general location where the photo was taken.

Jeanine Farley is an educational writer who has lived in the Boston area for more than 30 years. She enjoys taking photos of our urban wild things.

November 11, 2022

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Biopesticides and Biocontrols 

‘Wonder weevils’ released in Yorkshire waterways in fight against invasive floating pennywort

 November 16, 2022  Delhi Bureau  0 Comments CABI  3 min read

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16 November 2022, America: Specialist weevils from South America have been introduced to two sites in West Yorkshire to control an invasive non-native plant choking waterways.

The floating pennywort weevils have been introduced on the Aire and Calder Navigation and one of the tributaries of the River Holme, in a collaboration by CABI, Yorkshire Water, Leeds City Council, River Holme Connections and a private landowner.

As reported by PA Media and syndicated to over 114 UK news outlets including the London Evening Standard, Belfast Telegraph, Glasgow Times and Oxford Mail, the bugs, which have evolved to only feed and develop on floating pennywort (Hydrocotyle ranunculoides), will target the plant where it is clogging up the waterways.

Floating pennywort is native to Central and South America, and was brought to the UK in the 1980s as an ornamental pond plant, but escaped into natural habitats where it can grow up to 20cm a day.

Back in May, CABI revealed how its research has been the forefront of a world-first after the weevil – a more than 10 years under study – started to be released in England to sustainably fight the floating pennywort.

The release was timed to coincide with Invasive Species Week 2022. Invasive Species Week is an annual national event to raise awareness of the impacts of invasive non-native species, the simple things that everyone can do to prevent their spread, and some of the fantastic work taking place across the UK, Ireland, Jersey, Guernsey and Isle of Man to protect the environment and reduce their impacts.

Since 2011, CABI, with Defra funding, has been investigating the potential use of a biocontrol agent for floating pennywort which has the ability to grow up to 20 centimetres each day. It forms dense rafts over rivers and harms native plant, fish and invertebrate species, through competition and cutting oxygen levels in water.

Floating pennywort – an ornamental pond plant originating from North America – also impedes navigation routes, disrupts recreational activities like fishing and canoeing and exacerbates flood risk.

Dr Steph Bradbeer, invasive species and biosecurity adviser at Yorkshire Water, said: “Invasive non-native species pose a very real risk to Yorkshire’s environment and wildlife.

“They can also impact on our ability to treat and distribute water to homes and return wastewater safely to the environment.

“Floating pennywort, if unchecked, can cause significant problems in slow-flowing watercourses and impact drainage systems.

“We hope the release of these specialist weevils will provide a way of tackling it without the need for mechanical or chemical intervention.”

Djami Djeddour, senior project scientist at CABI, said: “These weevil releases are the culmination of over a decade of collaboration with South American scientists and comprehensive safety and efficacy testing in our quarantine facilities, so it is thrilling to finally get them out into the wild.”

The weevils will be closely monitored, with their impact on the spread of floating pennywort carefully monitored.

It is hoped they will help improve local wildlife and water quality, reduce the plant’s impact on flood defences and control the spread of floating pennywort in rivers.

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DLNR NEWS RELEASE – NEW VIDEO HIGHLIGHTS HOW BIOCONTROL SAVED NATIVE WILIWILI TREES

Posted on Nov 16, 2022 in Latest Department News, Newsroom

(HONOLULU) – A new animated video highlights the success story of how biocontrol, a process where a carefully selected living organism is used to control an invasive species, helped to save the native Wiliwili tree. The video, produced by the DLNR Division of Forestry and Wildlife (DOFAW) in collaboration with the Coordinating Group on Alien Pest Species, also shows how biocontrol can continue to be an important tool in managing invasive species in Hawaiʻi.

In 2005, a new pest, the erythrina gall wasp, made its way to Hawaiʻi and rapidly spread across the state, killing or severely damaging nearly all wild Wiliwili populations. “The sudden arrival of the erythrina gall wasp caught us all by surprise,” says Chipper Wichman, President of the National Tropical Botanical Garden. “Wiliwili is a keystone species in our dry forests, and nearly every part of this special tree is used by cultural practitioners. The impact of losing this species would have been profound.”

However in 2008, after extensive exploration in Africa for predators of the gall wasp and testing to make sure those predators didn’t impact other species, scientists were able to safely release a biocontrol agent: an even smaller parasitic wasp that preys on the gall wasp. The biocontrol agent successfully reduced the pest wasp numbers to levels that did not kill Wiliwili trees, saving them from the edge of extinction.

“Invasive species cost the state millions by reducing watershed benefits, degrading agricultural lands, threatening human infrastructure, and are one of the main drivers of the loss of biodiversity and native ecosystems in our state,” DOFAW Protection Forester Rob Hauff said. “Biocontrol has proven to be a safe, cost-effective, and essential tool. The success of the Wiliwili gall wasp biocontrol is one example of what we can expect if we continue to support this type of work.”

Prior to releasing a biocontrol agent, researchers perform years of exploration and analysis to ensure it won’t impact any species other than the target invasive species. Proposed biocontrols are also subject to careful review by specialists and regulatory officials, as well as the public. Since the focus on safety was implemented in Hawaiʻi in the 1970s, the biocontrol program has had a stellar record, with no non-target damages from any biocontrol released in the last 50 years.

Given the ongoing impacts of many invasive species currently in Hawaiʻi, new, updated facilities are needed to expand the capacity for biocontrol research. A coalition of state and federal agencies, including DLNR, the Hawaiʻi Department of Agriculture (HDOA), the University of Hawaiʻi, and the United States Forest Service and Agricultural Research Service, are currently discussing options for new facilities that can serve Hawaiʻi and other Pacific island neighbors, who often deal with similar invasive species.

While discussions on new facilities are ongoing, there are still new biocontrol agents that may be ready for release in the near future. Two insects, including a caterpillar targeting the weed miconia (Miconia calvescens), and a beetle targeting the weed cane tibouchina (Tibouchina herbacea), may be ready for release in Hawaiʻi within the year.

# # #

RESOURCES

(All images/video courtesy: DLNR)

Animated Video – Wiliwili Trees in Hawaiʻi: A Biocontrol Success Story: https://vimeo.com/764310295/75668bbed2

Photographs – Wiliwili Trees: https://www.dropbox.com/sh/26iq4inb956i1zc/AACHgND3m0E2RBeeUS0YsNRJa?dl=0

Biocontrol Hawaiʻi webpage: www.biocontrolhawaii.org

Media Contact:

Madison Rice

Communications Specialist

Hawai’i Dept. of Land and Natural Resources

Dlnr.comms@hawaii.gov

808-587-0396

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