The 14 spiders caught near the U.S. Iwakuni base in Yamaguchi Prefecture on Saturday are not venomous black widows, but merely an indigenous species that resembles them, the prefectural government said Sunday.
The Yamaguchi environmental health department said the spiders, measuring 1-2 cm in length, were identified as a local species that is also found in warm climates in other countries.
Thirteen of them were caught in a search called following the discovery Friday of about 60 arachnids believed to be black widows near hangars on the military base. A woman living in Iwakuni had reported to the prefectural health and welfare center that she had found a similar spider in her living room.
Although the female black widow is venomous, its bite is rarely deadly, especially to adults, because of the small amount of venom it injects.
Black widows live in many warm parts of the world, including North America and Southeast Asia. Infants or elderly people bitten by females may suffer shock symptoms such as convulsions, but seldom die.
The prefecture will conduct inspections from Monday at harbor facilities to determine whether black widows have been brought into Japan from overseas via cargo shipments.