Natures wonders: a beetle fools ants to give it food (Introduction)

by David Turell , Monday, August 21, 2017, 15:34 (2649 days ago) @ David Turell

By exuding a chemical the ant is fooled by the beetle. Other animals do the same thing. Ants communicate by odorous chemicals, which others imitate:

https://phys.org/news/2017-08-dangerous-game-highwayman-beetle.html

"This is the dangerous game played by the nitidulid beetle. It disguises itself as an ant, lurks along their foraging trails and tricks them into giving it food. The beetle is so good at deception that it gets more food from ants than ants get from their fellows.
But if the ants find out, reprisal can be brutal.

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"Insects disguise themselves as ants or mimic ant behavior to successfully live hidden in plain sight amongst ants

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"Creatures that live with ants are called myrmecophiles. Christina Kwapich, a postdoctoral researcher who co-authored the paper with Holldobler, studies them. She explained how nitidulid beetles buffalo the ants.

"We refer to them as highwaymen beetles, because they're robbing the traffic lines of the ants," Kwapich said.

"Ants go out on massive foraging trails to collect honeydew from little insects like aphids. They fill a social stomach, which is an enlargement of their esophagus, with their crop. In that crop they have this sugary liquid that they can share with their own nestmates through mouth-to-mouth regurgitation (a process called trophallaxis).

"It's that behavior that this parasitic beetle has sort of capitalized on," Kwapich said. "It's broken the code of communication between the ants in order to steal that sugary liquid that's meant for other nestmates. What the beetle does, what Bert discovered, is it sits along the sides of these foraging trails and populates the nest entrance area and waits for returning foragers with their crops laden with sugary liquid."

"The beetle is able to steal quite a bit of liquid. They actually get more of the food than the other ants do: 1.8 times as much food. They're true parasites.

"We like to think of what the sensory world of the ant is, and it's mostly tactile and chemical," Kwapich said. "It's those features that the beetle has used to break the code of feeding."

"The food transfer is a one-way street. The ants are feeding the beetles, but the beetles are not giving it back.

"Also, the beetles aren't giving it to each other," she added.

"All the beetle had to do to evolve is to break a simple communication code the ants use to solicit food from nestmates, Holldobler said.

"Employing radioactively labeled honey water, we were able to measure how successful the beetle is soliciting food from the ants," he said. "It turned out that his food-begging behavior is good enough to receive food from workers that carry honeydew in a full 'social crop,' but not good enough to receive food from workers inside the nest."

"The beetles also have a kind of Mata Hari seduction trick scientists have observed but not yet cracked. They have glands in their head and around their mouths which secrete some sort of appeasement compound.

"'At the beginning of the interaction, where the food stealing is happening, the ant is transfixed by the secretion the beetle makes," Kwapich said. "We don't know what that substance is."

"The beetles aren't always successful, but, if discovered, they have some adaptations they can deploy to save themselves. The ants will try to flip the beetle over. If they can accomplish this, they will tear off the beetle's antennae and legs.

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"Most myrmecophiles mimic the smell of the nest they live in. Ants are covered in a waxy hydrocarbon substance, which is how they identify each other and their nest. Crickets and other myrmecophiles don't have this substance. They will comb ants with special tools like brushy mouth parts or leg bristles and anoint themselves with it. Crickets will walk under ants, rise up and rub themselves against the ants.

"'This is all to maintain the chemical mimicry that's allowing the ants to be blind to them in the nest," Kwapich said.

"Myrmecophile spiders can live undetected amongst the ants they prey on.

"'If you switch them to another nest they will actually molt their cuticle," she said. "They'll get rid of that old smell as rapidly as possible."

"Other beetles live inside ant nests. They have adoption glands that encourage ants to pick them up and bring them inside."

Comment: I cannot imagine how this beetle evolved. It had to have mutations to create the chemicals it uses to confuse ants. Ant scent is chemically specific. It is much easier to understand insects which simply cover themselves with ant scent.