Description
The ‘Silverfish’ and the ‘Firebrat’ are closely related insects,
both belonging to the group of insects known as bristletails. They
are elongated wingless insects with a pair of long, fine antennae
and three narrow, tail-like appendages which are frequently broken.
Silverfish may grow to about 12mm in length but the Firebrat tends
to be larger with much longer antennae. The body of both is covered
with scales but the Silverfish as its name implies, is silvery and
glistening, while the Firebrat is greyish with dark, irregular
markings.
Life History
The female Silverfish is believed to lay about one hundred eggs,
either singly or in groups, usually in crevices and cracks and not
glued to the surface. They are small and white when first laid but
soon turn brownish and are difficult to find. The time taken to
hatch varies from two to eight weeks, depending on the temperature
and humidity. Newly hatched insects are about 2mm long and resemble
the adults in appearance. Development to maturity takes from a few
months under favourable conditions to over a year if it is cool and
dry.
The life cycle of the Firebrat is similar to that of the
Silverfish but the female lays more eggs.
Habitat
The Silverfish is found where conditions are fairly damp, such
as in kitchens, larders and particularly in bathrooms and
basements. It may occur amongst books and papers, in slightly damp
cupboards and behind skirting and loose wallpaper. It is a general
scavenger in warehouses and granaries.
The Firebrat requires much higher temperatures, ideally between
32 and 41° C and can stand drier conditions. It is found in
consistently hot places, such as bakeries, mainly living near ovens
and hot pipes and is not uncommon in similar situations on
ships.
Both the Silverfish and Firebrat are nocturnal in habit, hiding
during the day and coming out in search of food at night. They move
very rapidly when disturbed; turning on a light generally causes
them to seek cover.
Food
Both species feed on carbohydrates with a small amount of
protein. The Silverfish feeds mainly on small food particles and
starchy paste on the back of old wallpaper which has become
detached. It attacks the sizes, gums and glues of book bindings and
some types of paper and may thus cause serious damage in libraries.
It feeds also on fragments of dead insects and may damage textiles
of vegetable origin such as cotton, linen and rayon which have been
treated with special dressings. The Firebrat feeds mainly on food
debris.
Control
These insects may be controlled by sprays or dusts suitable for
the control of crawling insects. The insecticide should be blown or
brushed into crevices, e.g. behind skirtings, cupboards, etc.
Aerosol sprays for the control of crawling insects are suitable for
small infestations.
