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Odd beetle, adult, female (15b).jpg
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Coleoptera
Family: Dermestidae
Motschulsky, 1839
Species:T. contractus
Binomial name
Thylodrias contractus
Motschulsky, 1839

Thylodrias is a monotypic genus [1] of beetles in the family Dermestidae containing the single species Thylodrias contractus, known commonly as the odd beetle and tissue paper beetle. It is native to Asia and is a widespread introduced species in North America. [2] It can be a pest at times.

Monotypic taxon taxonomic group which contains only one immediately subordinate taxon (according to the referenced point of view)

In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon.

Beetle order of insects

Beetles are a group of insects that form the order Coleoptera, in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 species, is the largest of all orders, constituting almost 40% of described insects and 25% of all known animal life-forms; new species are discovered frequently. The largest of all families, the Curculionidae (weevils) with some 70,000 member species, belongs to this order. Found in almost every habitat except the sea and the polar regions, they interact with their ecosystems in several ways: beetles often feed on plants and fungi, break down animal and plant debris, and eat other invertebrates. Some species are serious agricultural pests, such as the Colorado potato beetle, while others such as Coccinellidae eat aphids, scale insects, thrips, and other plant-sucking insects that damage crops.

Dermestidae family of insects

Dermestidae are a family of Coleoptera that are commonly referred to as skin beetles. Other common names include larder beetle, hide or leather beetles, carpet beetles, and khapra beetles. There are approximately 500 to 700 species worldwide. They can range in size from 1 to 12 mm. Key characteristics for adults are round oval shaped bodies covered in scales or setae. The (usually) clubbed antennae fit into deep grooves. The hind femora also fit into recesses of the coxa. Larvae are scarabaeiform and also have setae.



T. contractus is an elongate beetle with slender legs. The male can be recognized by its yellowish-brown elytra and covering of silky, white hairs. The abdomen has seven sternal segments and the antennae are filamentous rather than club-shaped, which distinguishes it from all other members of the Dermestidae. [3] [4] The female looks very different from the male. It resembles a larva, and though it is free-living and has legs and antennae, it lacks elytra and hind wings. [3] The larva of the odd beetle resembles that of most other Dermestidae, but it lacks a tuft of hair at the posterior end and any long hairs along the dorsal surface. At the end of each segment of the body is a row of short bristles. [2]

Elytron hardened forewing of certain insect orders, notably beetles

An elytron is a modified, hardened forewing of certain insect orders, notably beetles (Coleoptera) and a few of the true bugs (Hemiptera); in most true bugs, the forewings are instead called hemelytra, as only the basal half is thickened while the apex is membranous. An elytron is sometimes also referred to as a shard.

Larva juvenile form of distinct animals before metamorphosis

A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.

Natural history

Life cycle

Like all beetles, the odd beetle undergoes complete metamorphosis, or a dramatic reorganization of the body plan of the insect and the formation of two distinct life stages, growth and reproduction, which are separated by a pupal phase. Although the female is larviform, she also undergoes metamorphosis from a true larva to a sexually mature adult. Once T. contractus has reached sexual maturity, the female produces a sex pheromone which attracts the male. [5] Once the female has mated she no longer produces this pheromone, which suggests that she mates only once. There is no indication that this is true for the male. [5]

Sex pheromones are pheromones released by an organism to attract an individual of the opposite sex, encourage them to mate with them, or perform some other function closely related with sexual reproduction. Sex pheromones specifically focus on indicating females for breeding, attracting the opposite sex, and conveying information on species, age, sex and genotype. Non-volatile pheromones, or cuticular contact pheromones, are more closely related to social insects as they are usually detected by direct contact with chemoreceptors on the antennae or feet of insects.


The odd beetle was given its other common name, the tissue paper beetle, because it was believed to eat tissue paper. [2] It does not actually consume tissue paper, but it may chew through it to reach objects wrapped in it. It feeds on fabrics such as wool and silk, and dried animal matter such as fur, feathers, and skin. Captive odd beetles are also known to feed on cooked beef liver. [6]

Tissue paper

Tissue paper or simply tissue is a lightweight paper or, light crêpe paper. Tissue can be made from recycled paper pulp.

The beetle is usually found in dark corners of human structures, such as drawers, cupboards, and museum displays. [2]

Museum institution that holds artifacts and other objects of scientific, artistic, cultural, historical, or other importance

A museum is an institution that cares for (conserves) a collection of artifacts and other objects of artistic, cultural, historical, or scientific importance. Many public museums make these items available for public viewing through exhibits that may be permanent or temporary. The largest museums are located in major cities throughout the world, while thousands of local museums exist in smaller cities, towns and rural areas. Museums have varying aims, ranging from serving researchers and specialists to serving the general public. The goal of serving researchers is increasingly shifting to serving the general public.

The odd beetle displays several behaviors as a reaction to stress. When disturbed it may roll into a ball. It may undergo retrogressive molting in stressful conditions; instead of growing larger, it grows smaller with each molt. [6]

Moulting process by which an animal routinely casts off a part of its body

In biology, moulting, or molting, also known as sloughing, shedding, or in many invertebrates, ecdysis, is the manner in which an animal routinely casts off a part of its body, either at specific times of the year, or at specific points in its life cycle.

Related Research Articles

Mealworm species of insect

Mealworms are the larval form of the mealworm beetle, Tenebrio molitor, a species of darkling beetle. Like all holometabolic insects, they go through four life stages: egg, larva, pupa, and adult. Larvae typically measure about 2.5 cm or more, whereas adults are generally between 1.25 and 1.8 cm in length.

Larviform female is biological phenomenon occurring in some species, where the females in the adult stage of metamorphosis resemble the larvae to various degrees. Typically, the female is wingless and generally larger than the male. Larviform females occur in many insect groups, including many beetle species.

Varied carpet beetle species of insect

The varied carpet beetle is a 3 mm-long beetle belonging to the family Dermestidae. They are a common species, often considered a pest of domestic houses and, particularly, natural history museums, where the larvae may damage natural fibers and can damage carpets, furniture, clothing, and insect collections. A. verbasci was also the first insect to be shown to have an annual behavioral rhythm and to date remains a classic example of circannual cycles in animals.

Ten-lined June beetle species of insect

The ten-lined June beetle, also known as the watermelon beetle, is a scarab beetle found in the western United States and Canada. The adults are attracted to light and feed on foliage. They can make a hissing sound when touched or otherwise disturbed, which can resemble the hissing of a bat. This sound is made by their wings pushing down, forcing the air out between their wings and back. They can be an agricultural pest affecting a wide range of crops because their larvae feed on plant roots and can weaken or kill the plants.

Cabbage looper species of insect

The cabbage looper is a moth in the family Noctuidae, a family commonly referred to as owlet moths. Its common name comes from its preferred host plants and distinctive crawling behavior. Cruciferous vegetables, such as cabbage, bok choy, and broccoli, are its main host plant; hence, the reference to cabbage in its common name. The larvae is called a looper because it arches its back into a loop when it crawls.

<i>Goliathus</i> genus of insects

The Goliath beetles are any of the five species in the genus Goliathus. Goliath beetles are among the largest insects on Earth, if measured in terms of size, bulk and weight. They are members of subfamily Cetoniinae, within the family Scarabaeidae. Goliath beetles can be found in many of Africa's tropical forests, where they feed primarily on tree sap and fruit. Little appears to be known of the larval cycle in the wild, but in captivity, Goliathus beetles have been successfully reared from egg to adult using protein-rich foods such as commercial cat and dog food. Goliath beetles measure from 60–110 millimetres (2.4–4.3 in) for males and 50–80 millimetres (2.0–3.1 in) for females, as adults, and can reach weights of up to 80–100 grams (2.8–3.5 oz) in the larval stage, though the adults are only about half this weight. The females range from a dark brown to silky white, but the males are normally brown/white/black or black/white.

<i>Macrodactylus subspinosus</i> species of beetle

Macrodactylus subspinosus is a North American beetle of the family Scarabaeidae. The members of this genus are known as "rose chafers", not to be confused with the European "rose chafer", Cetonia aurata. M. subspinosus occurs from Eastern Canada to Colorado and is considered a pest of many crops and flowers. It is given its common name of rose chafer because it eats the leaves of roses, although it also feeds on many other plants.

<i>Agrotis ipsilon</i> species of insect

Agrotis ipsilon, the dark sword-grass, black cutworm, greasy cutworm, or floodplain cutworm is a small noctuid moth found worldwide. The moth gets its scientific name from black markings on its forewings shaped like a letter "Y" and resembles the Greek letter upsilon. The larvae are known as "cutworms" because they cut plants and other crops. The larvae are serious agricultural pests and feed on nearly all varieties of vegetables and many important grains.

<i>Attagenus pellio</i> species of beetle

Attagenus pellio, the fur beetle or carpet beetle, is an important pest damaging stored products such as furs, skins, textiles and grain.

<i>Oiceoptoma noveboracense</i> species of beetle

Oiceoptoma noveboracense is a member of the family Silphidae, or carrion beetles, which feed on decaying organic matter such as dead animals. Its common name is the margined carrion beetle, from the orange-red margins on the pronotum, which are helpful when identifying this species. The larva is typically light brown to red and also has vertical ridges on its thorax like the adult. This diurnal beetle can be found mainly in the spring into the fall, and it has a strong preference towards a deciduous forest habitat. The primary forensic importance of this beetle is its ability to use the succession of insect fauna to provide confirmation of postmortem intervals.

<i>Rhyzopertha</i> genus of insects

Rhyzopertha is a monotypic genus of beetles in the family Bostrichidae, the false powderpost beetles. The sole species, Rhyzopertha dominica, is known commonly as the lesser grain borer, American wheat weevil, Australian wheat weevil, and stored grain borer. It is a beetle commonly found within store bought products and pest of stored cereal grains located worldwide. It is also a major pest of peanuts. The first documentation of wheat infestation by R. dominica was observed in Australia. R. dominica are usually reddish brown to dark brown in coloration, vary in sizes, elongated and cylindrical when viewing through a cross-section.

<i>Anthrenus scrophulariae</i> species of beetle

Anthrenus (Anthrenus) scrophulariae, also known as the common carpet beetle or buffalo carpet beetle, is a species of beetle originally found in Europe, the Middle East and the Nearctic, which has now spread to most of the world. Adult beetles feed on pollen and nectar, but the larvae feed on animal fibres and can be damaging pests to carpets, fabrics and museum specimens.

<i>Rosalia funebris</i> species of beetle

The banded alder borer, Rosalia funebris, is a member of the very diverse family of longhorn beetles.

<i>Drilus flavescens</i> species of beetle

Drilus flavescens is a species of beetles belonging to the family Drilidae.

<i>Anthrenus flavipes</i> species of beetle

Anthrenus flavipes is a species of beetle in the family Dermestidae known by the common name furniture carpet beetle. It has a cosmopolitan distribution, occurring throughout the world, being most active in warmer climates. It is a pest that damages household materials such as textiles.

<i>Dermestes ater</i> species of insect

Dermestes ater, also occasionally called Dermestes haemorrhoidalis, is a species of beetle in the family Dermestidae, the skin beetles. It is known commonly as the black larder beetle or incinerator beetle. It is native to North America, but today it is found nearly worldwide. Like several other dermestid beetles, this species is familiar as a common pest of stored products.

<i>Ceroctis capensis</i> species of insect

Ceroctis capensis or Spotted blister beetle is diurnal and endemic to Southern Africa occurring in diverse habitats, and belonging to the Meloidae or Blister beetle family. It secretes a toxic liquid from its leg joints when roughly handled, blistering human skin. This species somewhat resembles Mylabris oculata, a member of the same family.

Carpophilus lugubris species of insect

Carpophilus lugubris, commonly known as the dusky sap beetle is a species of beetle in the genus Carpophilus. It is an agricultural pest of corn and tomato.


  1. Thylodrias contractus (Motschulsky, 1839). Pest Insects of our Cultural Heritage. Centre Interdisciplinaire de Conservation et de Restauration du Patrimoine.
  2. 1 2 3 4 Ebeling, W. Chapter 8: Pests of Fabrics and Paper. Urban Entomology. University of California, Riverside. 2003.
  3. 1 2 Arnett, R., et al. American Beetles. CRC Press, New York, NY. 2002.
  4. Dillon, E. and L. Dillon. A Manual of Common Beetles of Eastern North America. Row, Peterson and Company, Elmsford, New York. 1961.
  5. 1 2 Mertins, J. (1982). Sex pheromone communication in the odd beetle, Thylodrias contractus Motschulsky. Journal of Chemical Ecology 8, 653-61.
  6. 1 2 Berenbaum, M. R. Ninety-nine More Maggots, Mites, and Munchers. University of Illinois Press, Chicago, IL. 1993.