Attagenus pellio (Linnaeus, 1758) ()


Synonym(s)Dermestes bipunctatus De Geer, 1774 ,Dermestes macellarius Fabricius, 1781,Dermestes cylindricornis Schrank, 1785,Megatoma atra Herbst, 1792 , Megatoma schranki Kugelann, 1792, Dermestes pellio Linnaeus, 1758
Common French
name
Attagène des peaux
Attagène des pelleteries
Dermeste des pelleteries
Common English
name
Two-spotted carpet beetle
Common Spanish
name
Gorgojo dos manchas de las alfombras
Common German
name
Gefleckter Pelzkäfer
Classification
Order   Coleoptera
Family   Dermestidae
Genus   Attagenus
Species   pellio

General features

Species of the Attagenus genus are very close to those of the related genus Dermestes, but they can easily be told from Dermestes thanks to the presence of an ocellus on their front and to their slightly smaller size.
In France, Attagenus are represented by about 15 species. Several of them are likely to be found in houses and heritage premises. However, in France only the 2 species A. pellio and A. unicolor (Brahm) are important from an economic point of view as they can cause important damage. They are also the most frequent species.

Like most domestic Attagenus species, Attagenus pellio adults cause hardly any damage; besides, they feed very little.
They are good fliers, and in natural environments they are frequently found on flowers, especially from Apiaceae (Umbellifera), in summer, where they eat a little pollen and nectar.

Only Attagenus larvae cause damage in various materials and products. They have a polyphagous food diet, with a strong incline for necrophagous habits.
Amongst others, they feed on dessicated bodies, whereby the serious damage they can cause in insect or stuffed animal collections.
Outdoors, they also infest birds’, bees’ or rodents’ nests, where they eat feather, hair, skin or bone fragments.
However, in experimental conditions, they can also live on an all-plant diet.

A sailor’s story says that in 1592, Dermestes caused the loss of a trade ship that carried hundreds of dead penguins. Dermestes larvae were in such high numbers that they ended up boring galleries in the ship’s hold wood and sinking it.
Like the other species of the same genus, Attagenus pellio is strongly attracted by lights.
Indoors it is often found twirling around windows, seeking a way out. That behaviour makes it possible to easily trap it with ultra-violet lamps.

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Identification criteria

Adult

Size
3.5 to 6.5 mm long. As in the case of many stored goods pests, adult and larva sizes can vary; they directly depend on food availability, nutrient richness and larval competition.
Aspect

Elongate oval body, about 2.25-fold more in length than in width, round at the ends.
Small head, slightly protruding from the prothorax, with one median ocellus on its front.

Males and females have 11-articled antennae, the last 3 articles form a quite clearly differentiated club.
Males can be differentiated from females due to their slightly smaller size and their last antennal segment which is much longer than the last-but-one segment.

Colour

Uniform very dark brown to black. Elytra slightly less dark than pronotum. The ventral face is black and covered in downy, short, fine, greyish bristles. Attagenus pellio is easily recognisable and can easily be told from related species thanks to the presence of 3 whitish spots (2 lateral ones and 1 median one) at the base of the pronotum, and 1 in the middle of each elytron.

Larva

Size
Up to 6.5 mm when fully developed
Aspect

Slimmer and slimmer from the front end to the rear end, convex on upper side and flat on underside.
Rather round head, brush of long, red hairs at the end of the abdomen.
The whole body is covered in a thick, silky, rear-pointed pubescence
The rear end of the larvae is characterised by a very long tuft of bristles.

Colour

The upper side is reddish-brown to very dark brown at the end of larval development, with alternate light-coloured and brown stripes; brown stripes are wider.
The underside is yellowish-white. Honey-brown coloured head. Lighter-coloured zones are visible on the sides, at the front and rear borders of each abdominal segment.

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Development cycle

The development cycle generally lasts more than 1 year on an average, but can last up to 3 years in extreme unfavourable conditions.
Similarly to many other house insects, the full cycle length of the two-spotted carpet beetle highly depends on ambient temperature and hygrometry and on the nutrient richness of the food larvae eat.

Mating most often occurs in May and June. Females lay 50 to 150 eggs in small cracks (flooring crevices, woollen material folds, carpets,…), always nearby a food source for the larvae to develop. I
ncubation lasts 5 to 12 days depending on ambient temperature (the higher the temperature, the faster the incubation).

In optimal temperature conditions (around 25°C), larvae undergo 5 to 11 consecutive molts (20 maximum) over a period of about 10 months.
Nymphosis generally occurs at the beginning of the following year and lasts 7 to 10 days. D
epending on ambient conditions, hibernation takes place at the larval stage or at the adult stage.
Adults do not live more than 6 weeks.
Attagenus pellio preferably inhabits dark places.

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Infested materials

List of infested materials :
Spices, plants
Chitin
Collagen
Keratin
Starch
Spices, plants, Chitin, Collagen, Keratin, Starch

Attagenus pellio are particularly dreaded in insect and animal collections where they can cause considerable damage.
As they are necrophagous, they can also develop on rat, mouse and insect bodies, and they feed on tiny feather, hair, skin and faeces fragments.
It is therefore of importance to keep the places where they are likely to develop clean and dusted.

Yet their food diet is also quite varied: spoilt plant materials (various types of flour, wheat, rice), lining fabrics containing wool, cotton, rayon, Hessian, linen; clothes, furs, woollen materials, leather, skins, carpets, curtains, synthetic and natural silk, powder milk,…
Larvae usually bore holes in fabrics, using support points. Thus infestation starts at the level of the seams.   

Damages

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Distribution

The species has reached a worldwide distribution, but it is particularly frequent in temperate regions. 

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Similar species


Commentaires

Attagenus pellio adults are easily recognisable among the other species of that gender found in France (cf. Identification criteria). Larvae are very similar to those of other Attagenus species, more particularly to that of A. unicolor.

The 2 species can only be differentiated thanks to differences in their respective hairs and colours, in old larvae only:

if larvae are a golden yellow to brown colour, with golden yellow hairiness and a scaly pubescence of the same colour on thorax and abdomen segments, ………………… Attagenus pellio

If larvae are brown to dark-coloured, without a scaly pubescence on thorax and abdomen segments, ……………………………………………………………. Attagenus unicolor


Frequency index : 5 / 5


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