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Larder Beetles
DESCRIPTION
Order: Coleoptera (‘sheath wings’)
Characteristics:
Forewings hard and leathery, meeting along mid-line of dorsal surface;
hind-wings membranous, sometimes lacking; biting mouthparts; well-developed
thorax; complete metamorphosis with egg, larval, pupal and adult stages.
Family: Dermestidae (skin feeders)
Species characteristics:
Larder Beetle (Bacon Beetle)
(Dermestes lardarius)
Adults, 7-9mm long, body, oval-shaped and densely covered with round scale-like
hairs; broad light band crosses elytra, with three black spots on each
side.
Hide Beetle (Leather Beetle)
(Dermestes maculatus)
Adults, 5.5-10mm long; elytra: uniformly coloured brown/black; body, oval-shaped
and densely covered with round scale-like hairs; inner apex of each elytron
produced backwards into a fine point.
DISTRIBUTION
The Dermestes beetles are common where animal products are handled, for
example hide, skin, bone, dried meat, fish meal and dog biscuit manufacturing
premises. Where infestations occur in domestic premises, they are often
encountered in larders, hence their common name. Alternatively they may
be found feeding on dead rodents or birds, in attics or under-floor spaces.
SIGNIFICANCE
Dermestes literally means ‘skin-eaters’, and this is precisely what the
beetles do. They play only a very minor role in disease transmission,
although they may act as mechanical vectors of anthrax. They will breed
on any animal protein and can be a serious pest in hide warehouses, tanneries,
milk-processing plants and other premises where animal products are processed.
Damage is caused by the larvae which bore holes in materials, either as
they feed or in order to pupate. The soft sapwood of wooden structures
are preferred pupation sites. They will also excavate plaster, lead and
tin, but not zinc or aluminum. Similar damage to stored commodities may
also be caused by the adult beetles.
General Life-Cycle of Dermestes species
The females lay up to 200 eggs on materials such as hides and skins which
are suitable for larval development. They are white, 2mm in length and
often laid in the crevices of commodities. The larvae, which hatch out
in about a week, are dark brown, hairy and feed on almost any dry or decomposing
animal material. They will occasionally feed on vegetable matter. They
are very active, and will avoid light, frequently boring into commodities
to do so. If disturbed they will curl up and feign death. There are usually
5 or 6 moults and the full grown larva is 10-15mm in length. When mature
the larvae often leave the foodstuff, and will excavate holes in hard,
inedible material in order to pupate. The burrows created for this purpose
may be up to 300mm long.
Alternatively, pupation takes place deep inside the infested commodity,
or if the larvae are forced to pupate in the open they do so inside the
last larval skin. The speed of larval development depends upon conditions
and may extend beyond a year. Generally the pupal stage is completed in
2-4 weeks and the full cycle in 2-12 months.
CONTROL
Assessment of infestations
The first step in control is to trace the source of infestation. This
is usually obvious although in domestic premises it may be obscure and
found to be a dead animal that has passed unnoticed or an old bird’s nest.
a) Hygiene/management
All sources of infestation should be removed and burnt if possible. Routine
surveillance and regular cleaning are also important.
b) Insecticidal control
Thorough surface spray treatments with residual activity are vital where
infestations are extensive.
Glossary of terms
Elytra: Hardened forewings of the beetle.
ADVICE
Valent BioSciences has an extensive range of products specifically formulated
for the control of flying and crawling insect pests.
Further information on all Valent BioSciences' household insecticide products
is available from:
Valent BioSciences Corporation
870 Technology Way
Suite 100
Libertyville, IL 60048
The greatest care has been taken to ensure the accuracy of the information
contained in this Fact Sheet. Under no circumstance, however, will Valent
BioSciences Corporation be liable in respect of any error or omission.
© Copyright Valent BioSciences Corporation 2001
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