Dunnage is material used to protect and support cargo in a ship's hold. Dunnage could easily be knocked overboard during the unloading of cargo, or adult beetles could emerge from the wood and fly to the nearby shore where trees in the cedar family are sometimes plentiful. We have learned much since the small Japanese cedar longhorn was discovered in Fairfield and New Haven Counties in 1998. We know that the adults, which live about 20 days, are active between late March and early June. The male is mostly iridescent bluish black with red at the corners of the wing covers, and the female is mostly reddish brown.
Adults mate on their host plants, and then females lay eggs under bark, apparently without feeding.
After hatching, the larvae bore under the bark to feed on the cambium and phloem. The channels bored by the larvae may be seen on the branches and trunks. Once the larvae have stopped their feeding, they bore into the sapwood and carve an elongate pupal cell. Here they pupate, and then emerge as adults in about 2 weeks. The adults, however, are destined to stay in their pupal cell until the following spring.