On October 29th, 2017 we learned about

Fungus forces beetles to become sexy zombies and spread its spores

This should be obvious, but don’t try to mate with zombies. Even “sexy” zombies doing their best to convince you they’d really like to have kids. You will have no offspring, zombified or otherwise, because the only organism that’s going to be reproducing is the fungus that turned your supposed mate into a zombie in the first place.

Eating flowers, fearing fungi

As outlandish as the above advice may sound, it’s a real concern for Goldenrod soldier beetles (Chauliognathus pensylvanicus). The beetles live in meadows across North America, eating flowers as their main source of food. Conveniently, they also mate on flowers, since it’s a good place to run into another beetle. Amorous females can advertise their intentions by waiting on a flower with their wings open and extended, almost like they’re about to fly away. Unfortunately for the beetles, spores for the Eryniopsis lampyridarum fungus can also be found on these flowers, which is what kicks off a cycle of zombification and unintentional necrophilia.

When the fungus infects a beetle, it triggers some very specific physiological responses to bend the beetle’s body to it’s own ends. The beetle will be compelled to climb to a flower top as it’s body starts to give out. Once in position, the fungus ensures that its host doesn’t just fall off the flower once it’s dead, by forcing it to clamp onto the flower tightly with it’s mandibles. The corpse is just a means to an end though, which is where the beetles’ courtship behavior comes into play.

Making brain-dead bugs more attractive

An inert beetle clamped to a flower isn’t attractive on it’s own, but the fungus makes sure to pretty up its host, whether its male or female. After 15 to 22 hours, the wings will pop out to resemble the pose of a female looking to attract a mate. As an extra touch, the fungus causes the beetle’s abdomen to swell, which is an attractive look to male beetles that seem to prefer larger females in general. This attempt at sexiness doesn’t make zombified males all that enticing, but zombified females do draw a lot of attention from healthy males in the area. The resulting contact with those males is the fungus’ real goal, because that’s how new spores get spread from a zombie female to new flowers across the meadow.

This isn’t the only insect to have it’s brain and body taken over by a fungus, but there are still some questions particular to this pairing. Since the fungus already manipulates the beetles’ behavior, scientists are going to take the opportunity to measure exactly how big a role opened wings plays in courtship by gluing zombified wings shut. The zombie won’t object, and better yet, won’t do anything new that would add unwanted variables to the study.

Source: Fungus uses zombie female beetles to infect males by Bob Yirka, Phys.org

On August 8th, 2017 we learned about

Cocoa plants get protection from their healthy neighbors’ leftover leaves

The next time you’re about to enjoy a bite of chocolate, take a moment to thank the fungi and other microbiota that made it possible. Like the microbes humans start picking up at birth, organisms like Colletotrichum tropicale come to live on cocoa plants, helping them be more resilient to pathogens that would otherwise destroy the plant. Fortunately for farmers, and chocolate lovers, experiments suggest that this kind of fungal protection isn’t hard to spread between cocoa plants— sharing a bit of leaf litter from healthy neighbors should do the trick.

One of the biggest concerns for a cocoa, papaya and other tropical plants is Phytopthora palmivora, the “plant destroyer.” Once infected, a plant will start rotting at a variety of locations, from the roots to the fruit, and thus is a huge problem for farmers. The pathogen can be found in soil and water throughout tropical ecosystems, but fortunately protective fungi like C. tropicale aren’t too hard to come by either. Just as microbes can be shared between people when they touch, contact with leaf litter from healthy plants seems to be a good way to spread preferred microbes.

Testing leaf-based transmission

Researchers tested the effectiveness of leaf litter with cocoa plants initially grown from sterile seeds in sterilized chambers. Their leaves were verified as being fungus free before one-third of the plants had dead leaves from healthy cocoa plants placed in their pots. Other plants got mixed leaves from the forest, and some had none at all. They were all given a little time to grow outdoors in more “natural” conditions before purposely being exposed to P. palmivora. After three weeks, the plants with healthy cocoa leaves on their soil fared the best. DNA sequencing also confirmed that these plants leaves had a considerable population of the helpful fungus, C. tropicale.

While growing up in the leave litter of a healthy plant seems beneficial, there are limits to proximity. If a parent plant is infected, it can just as easily spread pathogens to its offspring. So cocoa farmers need to keep an eye on their plants to make sure the healthier plants are the ones dumping their leaves their neighbors.

Source: Litter Bugs May Protect Chocolate Supply, Scienmag

On July 10th, 2017 we learned about

Plants and fungi that spray, splatter and sling their seeds and spores

If the apple doesn’t fall too far from the tree, they both have a problem. The seeds in the apple may take root next to its parent where it will be forced to compete for nutrients and sunlight, possibly stunting its growth and wasting the investment the parent plant made in the seeds. Fortunately for apples, the seeds are packaged in yummy, sugar-filled fruit that animals eat, taking the seeds for a ride along the way. As those seeds are pooped or discarded elsewhere, the seeds have a chance to grow in new territory away from their parents. Not all plants make such attractive fruit though, and so many have had to find other ways to give their offspring a push to newer pastures. In some cases, that even means evolving mechanisms to squirt, eject or catapult seeds and spores to ensure a bit of distance between each generation.

Shooting spores

Starting small, many fungi have ways to launch their spores into the air when it’s time to reproduce. The Pilobolus mold, for instance, uses sap to build up pressure in a stalk called the sporangiophore. Once the pressure is too great to contain, the end of the sporangiophore bursts open, launching a payload of pinhead-sized spore capsules. Those tiny capsules are ejected at up to 55 miles per hour, sometimes traveling as far as six feet. For molds that grow less than half an inch high, that’s plenty of distance to ensure the spores end up on the grass they need to continue their life-cycle.

Slinging sori

On a larger scale, some plants throw their spores rather than fire them out of a fluid-powered cannon. The delicate ferns you find in shady forests have a two-stage life-cycle, and to get spores in a safe location to grow into gametophytes, the spores need to move away from the parent plant. To do this, clumps of spore pellets, called sori, grow on the underside of the fern’s leaves. Once the sori dry out, the a catapult mechanism flings them into the air where they can be carried on the wind, animal fur, or in local waterways.

Ferns don’t exactly look like catapults, but they can launch their spore in a process that takes less than a half-second to complete. A coiled group of cells called an annulus grows around spore capsules, bent in an arch to build a bit of mechanical tension. Once dried sufficiently, the annulus snaps forward to lob the spore capsule. To keep it from bending too far and flinging the spore back at the leaf, a tiny amount of water squeezes through pores in the annulus, blocking that forward movement and releasing the spore at an optimal trajectory. This tiny delivery structure can send spores flying at around 22 miles per hour once released.

Popping pods

Launching spores are one thing, but firing full-sized seeds into the air requires some heavier artillery. Various plants grow seed containers that dry out unevenly, squeezing the seeds from one side. For example, when gorse seed pods are sufficiently dried out, they fire seeds out at around 18 miles per hour. Gorse seeds usually only travel a few feet, but pinching seeds for propulsion is used by the Bauhinia tree to send seeds as far as 49 feet.

Self-firing fruit

The biggest payload to be propelled off a plant may be Ecballium elaterium, better known as the Squirting cucumber. Like the cucumber you put on your salad, this plant’s seeds grow in a protective, oblong fruit, although there’s a lot less flesh to actually eat. Instead the two-inch fruit fills mostly with fluid, with enough room for a 20 or so seeds to go flying away from the parent plant.

When filled with fluid, there’s enough pressure in a single cucumber to give it a bit of a hair trigger, ready for wind or a passing animal to kick things off. When “activated,” the cucumber will detach from the stalk it grows on, ejecting water and seeds into the air out of newly formed opening where the stem attached. Like a rocket booster, the cucumber shell will be pushed towards the ground while the seeds will fly as far as 20 feet away. It seems like this should make for the most exciting, kid-pleasing vegetable ever, but aside from being mostly water, Squirting cucumbers contain a lot of cucurbitacins, pest-deterring chemicals which are toxic if ingested. It seems that Squirting cucumbers are better to watch than to eat.

Source: An explosive start for plants: Plants get up to some ingenious tricks and aerial acrobatics to ensure their survival by Paul Simons, New Scientist

On February 6th, 2017 we learned about

Yeasts may let us cut cows out of the process of making milk

Milk is a substance that has, for millions of years, been made exclusively by mammals. Most species use the mix of water, proteins, minerals and sugar to feed their babies exclusively, but humans have have decided that it’s worth consuming dairy throughout our lives, even if we get it from other animals like cows and goats. With demand growing for dairy, but livestock requiring a lot of resources and space to raise, new sources of milk are being developed, even from well outside the animal kingdom.

Protein production

The newest form of milk should look a lot like what we’re used to getting from cows, but it will largely be sourced from yeasts. This isn’t to say that we’ll be directly milking yeasts, but that the yeasts will grow many of the crucial proteins, like casein, normally produced by cows. Researchers were able to isolate which genes are responsible for these proteins in the cows, and then inserted those genes into the yeast’s relatively simple genome.

With yeast producing these proteins, many of the other ingredients in bovine milk can also be sourced without actual cows. There are some things beyond the reach of yeast though, such as sugars like lactose (or some equivalent) and immunoglobins that help protect against bacteria like E. coli and Helicobacter pylori.

Alternatives to animals

Yeast-sourced milk isn’t the first cowless milk option, but it’s the closest you’ll find to the real thing. Soy and rice milks have been fairly decent analogs to bovine milk for a while, but yeast will offer something much closer to a mammalian food-source without involving too many large, resource-heavy mammals (unless you count the humans involved…) It will be a while before it can compete with the price of milk from cows, but as people become more sensitive to how much it costs the world to raise even a single cow, this might seem like a very efficient option.

Source: Your Breakfast Is About to Take a Weird Turn by Marta Zaraska, Mother Jones

On January 30th, 2017 we learned about

Parasitic fungus fetches increasingly high prices in Chinese markets

Rhinos and elephants have long been targeted by poachers for the keratin and ivory that grows from their heads. Horns and tusks are ground up and sold for imagined medicinal value, primarily in China, often at the cost of the animal’s life. The latest miracle cure to be sold in this way also grows out of an animal’s head, but in this case, it’s the growth itself that causes the animal’s death, not the poaching. That’s because the prize in question is a zombifying fungus that can only be found growing out of the heads of infected, dead caterpillars.

The fungus is known as Ophiocordyceps sinensis, a parasite that can be found on insects in Tibet and the Himalayas. Once a caterpillar is infected, the fungus slowly grows and takes over their body, making it increasingly rigid in the process. After hiding out in a caterpillar like Thitarodes damxungensis for the winter, the fungus will finally kill its host, growing a spore-filled stalk out of the caterpillar’s head. If other caterpillars are nearby, they’ll then be in range for subsequent rounds of infection by the spores.

Finding fewer fungi

However, finding infected caterpillars is becoming increasingly difficult. Rising prices on fungus-carrying caterpillars has been a big motivator for many people, and at this point the caterpillars have been so over-collected that the fungus O. sinensis has been designated an endangered species in China. Once on sale in China, the dead, infected caterpillars can sell for close to $9,000 a pound, although many people will by smaller helpings to cook into a soup or tea. While there are some similarities to other expensive fungi, like truffles, the market for dead caterpillars isn’t looking for a meal as much as a cure for everything from cancer to, of course, erectile dysfunction.

As the caterpillars and fungi continue to be harvested, some people are speculating that the market for these supposedly medicinal corpses may be crashing soon. That may require more enforcement of conservation laws, but it may come about on its own if there just aren’t enough dead caterpillars to sustain interest in misinformed public.

Source: The worms that cost $20,000 a kilo by Veronique Greenwood, BBC Future

On November 22nd, 2016 we learned about

Making leather from carefully cultivated mushrooms

The leather in any pair of new shoes is probably over two years old. That’s the time it takes to raise a cow from birth, feeding, watering and caring for its health, before slaughtering it, skinning it and treating the hide to be cut and sewn into a pair of loafers. We can get meat from the slaughtered cow, but overall it’s a slow, resource-intensive process that contributes to climate change in a variety of ways, and basically sucks for the cow. Mushrooms can beat all that, plus come in customized colors.

Familiar fungi

You’ve probably never considered the mushrooms in your salad as a possible fashion statement, but it turns out they could be wearable if grown under the right conditions. A startup company in San Francisco called MycoWorks has found that growing common mushrooms under the right conditions can yield amazing results, producing 27 square feet of fungal leather in as little as two weeks. Their species of choice, Ganoderma lucidum, was selected because it was so common. These mushrooms have been used in a variety of contexts for thousands of years, which hopefully means there are no health-related surprises left to discover for people wanting to wear them as clothing.

Flexible fibers

The not-so-secret ingredient in G. lucidum, and other fungi, is a fiber called mycelium. This structure, which makes up the bulk of any mushroom, has been found to be durable yet flexible. By changing growing conditions and food sources, MycoWorks has been able to produce leathers with varying degrees of rigidity, texture and even color. Skipping tanning and other treatments normally required of animal skin, fungal leather can be grown in specific shapes, with patterned textures, and even in unusual colors like blue and purple. If a blue leather coat with a cross-hatch texture isn’t your thing, mycelium can also be coaxed to grow into a much harder structure, and MycoWorks is also looking into growing fungi as a tree-free wood for use in furniture.

Fashion considerations aside, one of the most compelling aspects of wearing mushrooms over cow-skins the resources necessary to produce them. An adult cow needs 27 pounds of hay a day to produce a large hide, plus water, space and other resources. Fungi, on the other hand, can get by on our leftovers, consuming wood shavings, corn cobs, and seed husks. Various oils are added to guide the texture of each fungal “hide,” but overall mushrooms are much cheaper to produce than a cow, on top of the environmental and ethical considerations. The catch at this point is mainly to scale things up, so that a cow’s worth of fungal leather can be produced in even less time, making production that much cheaper. Cowboys may not have as much to do if fungal leather takes off, but they’ll at least have access to more amazing boots than ever before.

Source: The Fungi in Your Future by Chau Tu, Science Friday

On October 17th, 2016 we learned about

Bacteria may be frogs’ and toads’ best hope in their fight against a devastating fungus

Chytrids are some of the oldest fungi on Earth, and until recently nobody minded as they fed on dead or rotting material. In 1999 however, a species of chytrid was discovered that was passing the usual menu of dead tissue, instead targeting living frogs, salamanders and other amphibians. This species, named Batrachochytrium dendrobatidis, has since turned out to be terrifyingly successful as a parasite, and is thought to be responsible for the collapse or extinction of at least 200 species of amphibians from around the world. Ecologists are now racing to protect the surviving animals, with one of the most promising ideas involving a potentially inoculating bath in bacteria.

Not-so-secret weapon

The bacteria, called Janthinobacterium lividum aka J-liv, is actually incredibly common. The benign microbe can be found on just about every continent, riding on the bodies of everything from birds to, yes, amphibians. It hasn’t been the subject of extensive research up to this point, largely because it didn’t seem to do much. No animal was clearly doing better or worse in its presence, and so it seemed like just another species of bacteria simply along for the ride.

The key factor that has pulled J-liv into this microbial battle is that an ingredient in the bacteria’s metabolism can slow or block fungal growth. Combined with its natural prevalence around the world, it seems that J-liv may be a good way to stop the spread of chytrids. It’s been successful in laboratory settings, but now scientists are trying to use it in the field, hopefully preventing more frogs and toads from their likely extinction.

Bacterial baths

A current project in Colorado is focusing on young boreal toads (Bufo boreas boreas). The toads are most vulnerable when transitioning from tadpoles to adult frogs, as the process requires enormous amounts of energy, leaving their metabolisms without a lot of strength to fight infections. So researchers are looking for these young toads and basting them in a J-liv-rich solution. While some ponds seem to have a natural supply of J-liv, other bodies of water mysteriously lack the bacteria, and so they’re getting extra attention to head off fungal infections.

If spreading J-liv proves successful, humans might not want to pat ourselves on the back too much. Nothing is conclusive at this point, but there’s evidence to suggest that water quality plays a big role in why some ponds are J-liv deficient, putting amphibians at risk. That shift in quality is most pronounced near human development, meaning we may need to look at more than microbes to really figure out how we can help the world’s frogs and toads survive.

Source: Soaking A Bunch Of Toads In Their Own Bacteria Could Save Their Lives by Krista Langlois, FiveThirtyEight

On July 15th, 2015 we learned about

Predatory fungus turns prey into fluffy feasts

Beauveria bassiana is the kind of thing that’s fun to learn about only after you’ve confirmed it doesn’t attack humans. The fungus only targets small arthropods like arachnids or insects, but is so thorough in their destruction that you can’t help but cringe on their behalf. Especially considering the whole “exploding the corpse” part.

Eating bugs from the outside in…

The process starts with B. bassiana boring its way through the bug’s with a mix of enzymes, basically digesting its way into the softer innards. From there, the fungus eats the bug’s blood (or rather, hymolymph) until the bug dies. To make sure it doesn’t have to share the dying feast, B. bassiana leaves a wake of antimicrobial agents, killing off any other microbes that might also enjoy eating the body.

…then back out again

 

Once the nutrition has been exhausted, the fungus eats its way back out of the body so that it can move on to another host. It emerges through seams in the corpse’s exoskeleton, covering it in a layer of white fuzz. The fuzz is made of a mix of thin fibers and new fungal spores, which then facilitate transfer to any neighboring arachnids or insects, like pollen sticks to a bee’s legs. Once contact has been made, the process can repeat itself.

Controlling the spored scourge

B. Bassiana was brought to human attention in 1835 when it was found killing silkworms in Italy. To the chagrin of humans, it doesn’t show much preference for one arthropod over another and our attempts focus its hunger on unwanted species like bedbugs or mosquitoes haven’t proven fruitful so far. The one species that does stand out is a grain-eating beetle, which seems to have the only antifungal compound in its body that can actually overpower the predatory fungus. Perhaps this arms race will swing back in the other direction and other insects arthropods will develop stronger antifungal properties, but for now the fungus seems to have the upper hand on over 700 species of animal worldwide.

Source: A downy killer wages chemical warfare by Beth Mole, Science News

On March 23rd, 2015 we learned about

Why fungi nightlights are glowing in the rain forest

On a dark enough night in the Brazilian rain forest, aside from the dancing lights of fireflies, your journey can be softly illuminated by the green glow of Neonothopanus gardneri. The fact that this mushroom glows at the base of babassu palms each night isn’t really in question. The question has been why they’ve evolved to go from beige in daylight to monster-movie green at night.

A first step towards understanding this was the realization that they’re not glowing all the time. Since a possible explanation had once been that the glowing was just a coincidental byproduct of the mushroom’s metabolism, the discovery of an internal clock that synced their glowing to nighttime hours provided evidence that this was a more sophisticated, beneficial system. If the mushrooms bothering to turn the lights out during the day, there must be some advantage to turning them on at night.

Who’s interested in glowing mushrooms?

A recent test demonstrated that the allure of the night may be the audience available at that time, such as small insects. Researchers put fake mushrooms in the forest, some with matching green lights, some without, and all with a sticky outer layer. The next day, they went to look for evidence of who or what may have come into contact with the mushrooms overnight, and if there was any difference between the lit and unlit mushrooms.

As predicted, the glowing faux-fungi had significantly more bugs stuck to their surface, indicating that the insects are drawn to the light. The hypothesis then goes that the mushrooms’ light attracts the insects, who visit and then spread spores across the forest. It’s sort of a night-club version of being a colorful flower that wants bees to visit and spread pollen. The one missing piece there is if the mushroom provides an equivalent to nectar to its visitors, or if the dazzling lights are enough to draw in spore-carriers.

Source: Why Some Mushrooms Glow In The Dark by Nell Greenfieldboyce, Weekend Edition Saturday