Simply in time for spooky season, scientists have realized extra about how a tiny parasitic flatworm referred to as the lancet liver fluke infects and controls the brains of ants. With their advanced four-step cycle, the flukes might be cunningly adjusting to every day modifications in air temperatures to contaminate extra hosts. The findings have been recently published in the journal Behavioral Ecology.
[Related: Mind-controlling ‘zombie’ parasites are real.]
Step 1: The Zombie Ant
The parasite hijacks an ant’s mind after an ant eats a ball of snail mucus infested with fluke larvae. The larvae then mature contained in the mind, the place the parasite could make the ant climb up a blade of grass and clamp down on the blade. This strategic top makes it simpler for the parasite’s subsequent potential host—a cow, sheep, deer, or different grazer—to eat the flukes and provide it one other place to dwell and breed. This new research discovered that the liver fluke may even get the ant to crawl back down the blade of grass when it gets too hot.
“Getting the ants excessive up within the grass for when cattle or deer graze throughout the cool morning and night hours, after which down once more to keep away from the solar’s lethal rays, is sort of good. Our discovery reveals a parasite that’s extra refined than we initially believed it to be,” College of Copenhagen biologist and research co-author Brian Lund Fredensborg said in a statement. Fredensborg carried out the analysis along with his former graduate scholar Simone Nordstrand Gasque, now a PhD scholar at Wageningen College within the Netherlands.
Of their study, the crew tagged a number of hundred contaminated ants within the Bidstrup Forests close to Roskilde, Denmark. “It took some dexterity to attach colours and numbers onto the rear segments of the ants, however it allowed us to maintain monitor of them for longer intervals of time,” mentioned Fredensborg.
The crew noticed how the infected ants behaved to humidity, light, time of day, and temperature and it was clear that temperature has an impact on their conduct. Throughout cooler temperatures, the ants have been extra more likely to be connected to the highest of a blade of grass. When the temperature rose, the ants let go of the grass and crawled again down.
“We discovered a transparent correlation between temperature and ant conduct,” mentioned Fredensborg. “We joked about having discovered the ants’ zombie change,’”
Step 2: The Grazer
As soon as the liver fluke infects the ant, a number of hundred parasites invade the insect’s physique. Solely one in all these parasites will make it to the mind the place it then influences the ant’s conduct. The remaining liver flukes conceal themselves within the ant’s stomach inside of its intestine. There, the liver flukes discover their manner by the bile ducts and into the liver, the place they suck blood and turn into grownup flukes that start to put eggs.
[Related: ‘Brainwashing’ parasites inherit a strange genetic gap.]
“Right here, there might be a whole bunch of liver flukes ready for the ant to get them into their subsequent host. They’re wrapped in a capsule which protects them from the ensuing host’s abdomen acid, whereas the liver fluke that took management of the ant, dies. You could possibly say that it sacrifices itself for the others,” mentioned Fredensborg.
The eggs are then excreted within the host animal’s feces.
Step 3: The Snail
As soon as the fluke eggs have been excreted, they continue to be on the bottom ready for a snail to crawl by and eat the feces. When the eggs are contained in the snail, the eggs turn into larval flukes that reproduce asexually and may multiply into a number of thousand.
“Traditionally, parasites have by no means actually been targeted on that a lot, regardless of there being scientific sources which say that parasitism is essentially the most widespread life kind,” mentioned Fredensborg. “That is partly as a result of the truth that parasites are fairly tough to check.”
Step 4: The Slime Ball
To exit the snail and transfer on to their subsequent host, the larval flukes make the snail cough. The flukes are then expelled from the snail in a lump of mucus. The ants are drawn to this moist ball, eat it, and unwittingly ingest extra fluke larvae and the cycle begins another time.
The tiny liver fluke is widespread in Denmark and different temperate areas world wide and researchers are nonetheless making an attempt to grasp extra of the mechanisms behind how they take over a bunch’s mind.
“We now know that temperature determines when the parasite will take over an ant’s mind. However we nonetheless want to determine which cocktail of chemical substances the parasite makes use of to show ants into zombies,” Fredensborg mentioned. “Nonetheless, the hidden world of parasites varieties a major a part of biodiversity, and by altering the host’s conduct, they will help decide who eats what in nature. That’s why they’re essential for us to grasp.”
