The brain-encysting lancet liver fluke Dicrocoelium dendriticum induces Formica polyctena ants to climb and chunk to vegetation by the mandibles in a state of non permanent tetany, making it extra more likely to be eaten by grazers equivalent to cattle and deer. In accordance with new analysis, Dicrocoelium dendriticum may even get the ants to crawl again down the blade of grass when it will get too scorching.
The contaminated Formica polyctena ant climbs up and clamps its highly effective jaws onto the highest of a blade of grass, making it extra more likely to be eaten by grazers equivalent to cattle and deer. Picture credit score: College of Copenhagen.
As soon as Dicrocoelium dendriticum infects a Formica polyctena ant, a number of hundred parasites invade the ant’s physique.
However just one makes its technique to the mind, the place it may well affect the ant’s habits. The remainder of the liver flukes conceal themselves within the ant’s stomach.
“There could be tons of of liver flukes ready for the ant to get them into their subsequent host,” mentioned Dr. Brian Lund Fredensborg, a researcher on the College of Copenhagen.
“They’re wrapped in a capsule which protects them from the resultant host’s abdomen acid, whereas the liver fluke that took management of the ant, dies. You may say that it sacrifices itself for the others.”
“Animals contaminated with many liver flukes can endure liver injury because the parasite strikes across the host’s liver and bile ducts.”
Over 13 non-consecutive days throughout one yr within the Bidstrup Forests close to Roskilde, Denmark, Dr. Fredensborg and his colleague, Wageningen College Ph.D. scholar Simone Nordstrand Gasque, noticed a complete of 1,264 particular person ants expressing the modified habits. They then individually marked a subset of 172 contaminated ants.
“It took some dexterity to attach colours and numbers onto the rear segments of the ants, but it surely allowed us to maintain monitor of them for longer intervals of time,” Dr. Fredensborg defined.
The authors then noticed the contaminated ants’ habits in relation to mild, humidity, time of day and temperature. It was clear that temperature had an impact on ant habits.
When the temperature was low, the ants had been extra more likely to be hooked up to the highest of a blade of grass. When the temperature rose, the ants relinquished the grass and crawled again down.
“Getting the ants excessive up within the grass for when cattle or deer graze in the course of the cool morning and night hours, after which down once more to keep away from the solar’s lethal rays, is sort of sensible,” mentioned Dr. Brian Lund Fredensborg, a researcher on the College of Copenhagen.
“Our discovery reveals a parasite that’s extra subtle than we initially believed it to be.”
There are lots of different examples of parasites that alter animal habits. As such, parasites that hijack their host’s habits have a better hand within the meals chain than many would possibly suppose.
“Our new research sheds mild on a particularly underrated group of creatures,” Dr. Fredensborg mentioned.
“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 type. That is partly as a consequence of the truth that parasites are fairly troublesome to review.”
“Nonetheless, the hidden world of parasites types a major a part of biodiversity, and by altering the host’s habits, they may also help decide who eats what in nature. That’s why they’re vital for us to know.”
The findings had been printed within the journal Behavoral Ecology.
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Simone Nordstrand Gasque & Brian Lund Fredensborg. Expression of trematode-induced zombie-ant habits is strongly related to temperature. Behavioral Ecology, printed on-line August 24, 2023; doi: 10.1093/beheco/arad064
