How crickets co-exist with hostile ant hosts

(Press-News.org) Researchers at Nagoya University in Japan have discovered sophisticated behavioral strategies that enable parasitic crickets to survive within ant colonies. Led by Ryoya Tanaka, the team documented how these insects successfully navigate life among potentially lethal hosts through precise evasion tactics. Their findings, published in Communications Biology, reveal remarkable adaptations that allow these cricket species to thrive in a hostile environment. 

Animals that live in ant colonies, known as “ant guests”, exploit their hosts’ resources.  However, this behavior carries a significant risk because ants ruthlessly exterminate intruders upon detection.   

Myrmecophilus ant crickets employ specialized escape behaviors to avoid ant attacks. Tanaka and colleagues studied this behavior in Myrmecophilus tetramorii, a "brood parasite" that sustains itself within host colonies by consuming dead insects and ant larvae. The researchers studied the behaviors that allow crickets to escape from their hosts.

They found that most behaviors could be classified into two types: “distancing,” where the crickets move directly away from the ants and “dodging,” where the crickets fled from the ants in a circular movement that positioned them behind the ants to avoid their mandibles. They noticed that when the cricket initiated dodging behavior, it stayed farther from its host and moved at a slower pace than during distancing. 

The researchers concluded that crickets employ dodging behavior to methodically evade perceived threats under low-risk conditions, while they utilize distancing behavior as a rapid defensive response when facing imminent attack.

“While distancing behaviour 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. Ant crickets benefit from a slow and precise reaction to dodging, which reduces the probability of being attacked by ants,” Tanaka explained. “In most cases, the ant cricket used dodging to escape from its host ants. Distancing incidents were comparatively rare.” 

When they observed the behavior of crickets that were already integrated into the host ant colony, the researchers found that the crickets did not move uniformly around the colony but tended to stay close to certain locations, such as those with accumulated debris, areas with wet paper, and corners.  

“Dodging behaviour is advantageous for staying in attractive areas while avoiding ants,” Tanaka explained. “The unique trait of dodging behaviour 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.”  

By staying in advantageous locations and carefully employing the two strategies, crickets can survive in the hostile environment of the host colony. Tanaka hopes that his research will open people’s eyes to the fascinating world of insects. “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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