Kikaichū

Kikaichū (寄壊蟲; English TV "Destruction Bugs"; Literally meaning "Parasitic Bugs") are a species of small, beetle-like insects that are bred and utilized by the Aburame clan for their unique techniques. In the series, it is shown that the Aburame clan live in symbiosis with the Kikaichū, the Aburame clan serve as hosts to the Kikaichū, allowing them to live, breed and even feed off of the chakra of the host's body stores. In return, the host ninja recieves the life-long ability to control and command the bugs, using them as their primary fighting technique.

The Aburame clan practice a technique, called the Destruction Bug Host Technique, that cements the symbiotic relationship between both the Kikaichū and all newborn members of the clan: After birth, the newborn's body is offered to the Kikaichū as a new living nest, giving the insects a new selter to house more of their numbers. As the child grows and develops, they are instructed in the Hiden Jutsu of the clan, and learn how the insects may likewise serve them in combat, allowing the shinobi to perform ninjutsu-like techniques without the use of hand seals.

The Kikaichū are small, beetle-like insects, they are able to fly, typically moving in swarms when on the attack, or in smaller numbers when practicing stealth. A female bug can be left on a target and then they can be tracked by smell, or scout bugs can be sent out and return to tell the host information about the area. Thanks to the Kikaichū, Aburame clan members are experts in communication and espionage, due to their ability to communicate with the insects, stealth because the Kikaichū make no noise or motion during combat, as well as in search-and-seizure missions.

Although not brought up in the manga, it is demonstrated that the Kikaichū ('Parasitic' or 'Destruction' Bugs) are always undergoing evolutionary adaption through mutation and natural selection. While the Kikaichū only have a lifespan of a few hours, their lifecycle ensures that there will always be females with eggs. Any variations that prove useful to the individual bug, (and consequently the bug-user) in combat will be passed on to the next generation, which can then be cultivated for their success against dangerous opponents in combat. This was demonstrated in the anime-only 'Three-Tails Arrival' filler arc.

When Shino and the Konoha recon team lead by Kakashi Hatake first came across the Crystal Release Style, a number of Shino's bugs were exposed. While most died from being crystalized, Shino knew that a number of the Kikaichū had survived and tracked down as many as possible, so as to rapidly breed more of those who were resistant to Crystal Style. Later, after Hinata had escaped being crystalized by exerting her chakra to shield herself, Shino speculated that this may have been how his Kikaichū had resisted the Crystal Style.

Armed with this knowledge, Shino was able to command his bugs to use this new defense mechanism to counter against Guren's Crystal Release, because his Kikaichū could "evolve limitlessly" and become "resistant" to a brand of jutsu like Crystal Release. By exerting their Chakra to protect themselves from being crystalized, they could free themselves from their individual prisons and break through Guren's defenses by using their Chakra to shatter her Crystal Release techniques on contact, (giving justification to their name, 'Destruction Bugs'.) Although intervention on Gozu's part allowed Guren to avoid capture, Shino comments that his Kikaichū had performed their role flawlessly.

The most pratical purpose that the Kikaichū serve in combat is to ambush an opponant and then drain the victim's chakra through physical contact, leaving them with enough chakra to live if the adversary is needed to be taken alive. Other techniques included in the Aburame clan's Hiden Jutsu repertoire include techniques like their Bug Clone Technique; which uses the bugs to create copies of themselves, the bonus of this technique is that the bug clone is able to reform itself after being dispersed, as the bugs are not an inanimate material. Their repertoire also includes the defensive Bug Wall Technique, that uses the insects as protective structures to shield the host. Perhaps their most effective manoeuvre in combat has the bug user commanding a large number of his or her bugs in their Secret Technique: Insect Sphere technique, which completely engulfs the target in bugs making escape seemingly impossible.