Crickets are parasites—for some ant colonies. The species of ant crickets from the Myrmecophilus genus can infiltrate ant colonies, despite the potentially lethal defences that ants have developed to fight back. Now, a team at Nagoya University in Japan has figured out two of the primary ways that these sneaky crickets manage to survive in such a hostile environment. The findings are detailed in a study recently published in the journal Communications Biology.
Interloper animals that live in ant colonies are known as ant guests. These include some species of crickets, butterflies, and silverfish. Ant guests will exploit the food resources in the ant colony, but at a great risk to themselves. Ants are known to kill intruders when they are detected to protect the colony. To avoid attacks, ant crickets use various behaviors that scientists are still figuring out.
In this new study, the team looked at a cricket ant species Myrmecophilus tetramorii. This brood parasite survives in an ant colony by eating dead insects and ant larvae. The team found that most of the behaviors can be classified two ways–distancing and dodging.
In distancing, the crickets simply moved away from the ants. They used distancing as a rapid defense response when faced with an imminent ant attack.
With dodging, cricket fled in a circular movement that put the crickets behind the ants to avoid their deadly mandibles. When a cricket initiated the dodging behavior, it stayed farther away from the host and also moved more slowly than when they distanced. The team believes that crickets use dodging to evade perceived threats in a more low-risk environment.
Parasitic Myrmecophilus tetramorii living in ant colonies use distancing and dodging to stay alive. CREDIT: Tanaka et al. Communications Biology (2024)
“While distancing behavior can quickly get crickets away from the approaching ant, such quick movements may alert surrounding potential enemies to the crickets’ presence, triggering an aggressive chase by another ant,” study co-author and biologist Ryoya Tanaka said in a statement. “Ant crickets benefit from a slow and precise reaction to dodging, which reduces the probability of being attacked by ants. In most cases, the ant cricket used dodging to escape from its host ants. Distancing incidents were comparatively rare.”
The team also looked at cricket behavior after they were integrated into the host ant colony. In these situations, the crickets didn’t move uniformly around the colony. Instead, they remained close to certain locations, including corners, areas with wet paper, and those with debris.
“Dodging behavior is advantageous for staying in attractive areas while avoiding ants,” Tanaka said. “The unique trait of dodging behavior might be a way of effectively staying in a safe location while avoiding a succession of incoming ants, allowing them to reduce the risk of being attacked.”
[ Related: Even ants may hold grudges. ]
Remaining in advantageous locations and being judicious about which strategy to deploy, the crickets showed that they could survive in the hostile environment of the host colony. Tanaka hopes that this kind of research will open up the world of parasitic crickets to the public.
“I often stroll around the Nagoya University campus to see insects. I still remember when I saw an ant cricket skillfully evading ants despite being surrounded by them,” he said. “From that moment on, I was utterly enthralled by this behavior.”
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