Thysanura: silverfish

Characteristics
These fast running insects have become common inhabitants of manmade dwellings and are often found in dark sheltered areas about the home. Silverfish are usually less than 20 millimetres in length and silvery-grey in colour. They appear similar to bristletails (Archaeognatha) but can be distinguished by the following features:

• Soft, elongate body tapering towards the abdomen and covered with silvery-grey scales

• Small compound eyes, some species are eyeless

• Wingless

• Long antennae

• 3 long abdominal cerci of similar length with the outer 2 pointing away from the body

Acrotelsella devriesiana belongs to the LEPISMATIDAE family of silverfish which contains 5 cosmopolitan species that are household pests. A.devriesiana though, is generally found in the southern and central parts of Australia under bark, rocks and leaf litter.

Life Cycle
Most silverfish reproduce sexually with the male depositing a sperm packet on the substrate, which is picked up by the female. Depending on the species the female may lay eggs only when she moults or she may lay eggs singularly throughout her whole life. The young develop over a series of moults and may take up to 3 months to reach maturity. Silverfish will continue to moult throughout their lives and individuals may live for up to 4 years. The nymphs of silverfish resemble adults but are generally smaller in size.

Feeding
Most native species of silverfish are nocturnal herbivores feeding on a variety of vegetable matter. The best-known domestic species of silverfish that are common in most houses feed predominantly on paper products and fabric found around the home. Some species are omnivorous.

Habitat
Silverfish occur in a wide variety of habitats both natural and manmade. Native species are generally found living under the bark of trees, under rocks, in rotten logs and among leaf litter. Some species have been found to live exclusively in caves while others have been discovered inhabiting the nests of ants and termites. Most species found in homes are introduced and usually dwell in dark, rarely disturbed places such as in cupboards and bookshelves.