''Pimelia'' is a genus of

darkling beetle Darkling beetle is the common name for members of the beetle family Tenebrionidae, comprising over 20,000 species in a cosmopolitan distribution. Taxonomy ''Tenebrio'' is the Latin generic name that Carl Linnaeus assigned to some flour beetles ...

s in the subfamily Pimeliinae.

Species

* '' Pimelia aculeata'' Klug, 1830 * '' Pimelia akbesiana'' Fairmaire, 1884 * '' Pimelia angulata'' Fabricius, 1775 * '' Pimelia angusticollis'' Solier, 1836 * '' Pimelia arabica'' Klug, 1830 * '' Pimelia arenacea'' Solier, 1836 * '' Pimelia ascendens'' Wollaston, 1864 * '' Pimelia baetica'' Solier, 1836 * '' Pimelia bajula'' Klug, 1830 * '' Pimelia barmerensis'' Kulzer, 1956 * '' Pimelia bipunctata'' Fabricius, 1781 * '' Pimelia boyeri'' Solier, 1836 * '' Pimelia brevicollis'' Solier, 1836 * '' Pimelia canariensis'' Brullé, 1838 * '' Pimelia capito'' Krynicky, 1832 * '' Pimelia cephalotes'' (Pallas, 1781) * '' Pimelia costata'' Waltl, 1835 * '' Pimelia cribra'' Solier, 1836 * '' Pimelia elevata'' Sénac, 1887 * '' Pimelia estevezi'' Oromí, 1990 * '' Pimelia fairmairei'' Kraatz, 1865 * '' Pimelia fernandezlopezi'' Machado, 1979 * '' Pimelia fornicata'' Herbst, 1799 * '' Pimelia goryi'' Solier, 1836 * '' Pimelia graeca'' Brullé, 1832 * '' Pimelia grandis'' Klug, 1830 * '' Pimelia granulata'' Solier, 1836 * '' Pimelia granulicollis'' Wollaston, 1864 * '' Pimelia grossa'' Fabricius, 1792 * '' Pimelia incerta'' Solier, 1836 * '' Pimelia indica'' Sénac, 1882 * '' Pimelia integra'' Rosenhauer, 1856 * '' Pimelia interjecta'' Solier, 1836 * '' Pimelia laevigata'' Brullé, 1838 * '' Pimelia lutaria'' Brullé, 1838 * '' Pimelia maura'' Solier, 1836 * '' Pimelia minos'' Lucas, 1853 * '' Pimelia modesta'' Herbst, 1799 * '' Pimelia monticola'' Rosenh., 1856 * '' Pimelia nazarena'' Miller, 1861 * '' Pimelia orientalis'' Senac, 1886 * '' Pimelia payraudi'' Latreille, 1829 * '' Pimelia perezi'' Sénac, 1887 * '' Pimelia punctata'' Solier, 1836 * '' Pimelia radula'' Solier, 1836 * '' Pimelia repleta'' Reitter, 1915 * '' Pimelia rotundata'' Solier, 1836 * '' Pimelia rotundipennis'' Kraatz, 1865 * '' Pimelia rugosa'' Fabricius, 1792 * '' Pimelia rugulosa'' Germar, 1824 * '' Pimelia ruida'' Solier, 1836 * '' Pimelia scabrosa'' Solier, 1836 * '' Pimelia sericea'' Olivier, 1795 * '' Pimelia simplex'' Solier, 1836 * '' Pimelia sparsa'' Brullé, 1838 * '' Pimelia subglobosa'' (Pallas, 1781) * '' Pimelia testudo'' Kraatz, 1885 * '' Pimelia undulata'' Solier, 1836 * '' Pimelia variolosa'' Solier, 1836 * '' Pimelia ventricosa'' Falderm., 1837 * '' Pimelia verruculifera'' Soliér, 1836 * '' Pimelia villanovae'' Sénac, 1887

Reproduction

''Pimelia'' are

univoltine Voltinism is a term used in biology to indicate the number of broods or generations of an organism in a year. The term is most often applied to insects, and is particularly in use in sericulture, where silkworm varieties vary in their voltinism. ...

, with one generation per year. Species in

North Africa North Africa (sometimes Northern Africa) is a region encompassing the northern portion of the African continent. There is no singularly accepted scope for the region. However, it is sometimes defined as stretching from the Atlantic shores of t ...

emerge in January to begin mating, synchronously with floral bloom. Normally ''Pimelia'' are detrivores, but during mating season they may

cannibalize Cannibalism is the act of consuming another individual of the same species as food. Cannibalism is a common ecological interaction in the animal kingdom and has been recorded in more than 1,500 species. Human cannibalism is also well document ...

other adults,

larva A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect development such as insects, some arachnids, amphibians, or cnidarians typically have a larval phase ...

e, and eggs. This behavior may be due to need for extra nutrients or simply to eliminate competitors. Following behavior and mating take place on the slip face of a

sand dune A dune is a landform composed of wind- or water-driven sand. It typically takes the form of a mound, ridge, or hill. An area with dunes is called a dune system or a dune complex. A large dune complex is called a dune field, while broad, flat ...

. After mating, the female digs a shallow hole and deposits a single egg, which closely resembles a grain of

white rice White rice is milled rice that has had the husk, bran, and germ removed. This alters the flavor, texture and appearance of the seed; helps prevent spoilage (extends its storage life); and makes it easier to digest. After brown rice is milled ...

. As the temperature rises above 50 °C the adult population dies off. Immature stages remain below the surface until maturity. During the winter the adults emerge.

Desert adaptations

Many ''Pimelia'' species are conspicuous as they cross sand dunes. Locomotion in this difficult terrain is facilitated by numerous tarsal

seta In biology, setae (; seta ; ) are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Depending partly on their form and function, protostome setae may be called macrotrichia, chaetae, ...

e that allow for rapid tumbling behavior.

Adaptation In biology, adaptation has three related meanings. Firstly, it is the dynamic evolutionary process of natural selection that fits organisms to their environment, enhancing their evolutionary fitness. Secondly, it is a state reached by the p ...

s to arid climates and

desert A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the la ...

environments allow ''Pimelia'' to survive and reproduce in the dunes, but the relative importance of abiotic and biotic factors in this respect is not clear. Environmental factors influencing these adaptations are extremes of temperature and humidity, excessive

radiant energy In physics, and in particular as measured by radiometry, radiant energy is the energy of electromagnetic radiation, electromagnetic and gravitational radiation. As energy, its SI unit is the joule (J). The quantity of radiant energy may be calcul ...

, low and irregular rainfall, long periods of drought, strong winds, unstable sand substrates, and sparse, specialized vegetation. Several morphological adaptations allow ''Pimelia'' to survive in the desert, including the

lipid Lipids are a broad group of organic compounds which include fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include storing ...

layers of the

epicuticle Arthropods are covered with a tough, resilient integument, cuticle or exoskeleton of chitin. Generally the exoskeleton will have thickened areas in which the chitin is reinforced or stiffened by materials such as minerals or hardened proteins. T ...

, fused

sclerite A sclerite (Greek language, Greek , ', meaning "hardness, hard") is a hardened body part. In various branches of biology the term is applied to various structures, but not as a rule to vertebrate anatomical features such as bones and teeth. Instea ...

s, the subelytral cavity, and the texture of the body surface. Much of the success of tenebrionid beetles in desert habitats is due to the development of impermeable cuticles. The fused sclerites of desert tenebrionids minimize water loss, but they result in flightlessness. The main barrier to the outward flow of water through insect integument is the lipid layer of the epicuticle. In many terrestrial arthropods, the temperature affects the permeability of the cuticle. There is a sudden increase in the rate of

transpiration Transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems and flowers. It is a passive process that requires no energy expense by the plant. Transpiration also cools plants, c ...

at what is known as the transition temperature. This may coincide with a physical change, perhaps the disorientation of the lipid molecules in the epicuticle. In tenebrionid beetles, the spiracles open into a humid subelytral cavity rather than directly to the atmosphere, thus reducing water loss. Water retention by intact elytral covers is greater at 0%

relative humidity Humidity is the concentration of water vapor present in the air. Water vapor, the gaseous state of water, is generally invisible to the human eye. Humidity indicates the likelihood for precipitation (meteorology), precipitation, dew, or fog t ...

than at 97%. The size of the cavity is not important. Transpiration increases if the elytra are removed, emphasizing the importance of the epicuticle and subelytral cavity. ''Pimelia'' have

tubercles In anatomy, a tubercle (literally 'small tuber', Latin for 'lump') is any round nodule, small eminence, or warty outgrowth found on external or internal organs of a plant or an animal. In plants A tubercle is generally a wart-like projection, b ...

on the surface of their elytra which scatter and reflect incident energy.

Burrow file:Chipmunk-burrow (exits).jpg, An eastern chipmunk at the entrance of its burrow A burrow is a hole or tunnel excavated into the ground by an animal to construct a space suitable for habitation or temporary refuge, or as a byproduct of Animal lo ...

ing is probably the most important behavior modification for heat regulation in ''Pimelia'', because it permits access to a broad range of ambient temperatures. ''Pimelia'' are diurnal, emerging in early morning and late evening but remaining under the sand during the hot hours of the day.Cloudsley-Thompson, J. L. and C. C. Constantinou. (1980). Circadian rhythmicity in ''Adesmia cancellata'' L. (Coleoptera: Tenebrionidae) from Kuwait. ''Journal of Arid Environments'' 3 319-24.

Gallery

File:Pimelia angulata.JPG, '' Pimelia angulata'' File:Pimelia bipunctata.jpg, '' Pimelia bipunctata'' File:Pimelia bipunctata - 2012-10-25.webm, ''Pimelia bipunctata'' on dune near beach File:Escarabajo - Pimelia punctata (8717930430).jpg, ''Pimelia punctata'' File:Pimelia (Piesterotarsa) obsoleta Solier, 1836 (3518257693).jpg, '' Pimelia (Piesterotarsa) obsoleta'' File:Pimelia ascendens Wollaston, 1864 (14341625972).png, '' Pimelia ascendens'' File:Pimelia baluja Klug, 1830 (28489421274).png, '' Pimelia baluja'' File:Pimelia confusa Senac, 1884 (3058854966) (2).jpg, '' Pimelia confusa'' File:Pimelia laevigata Brullé, 1838 (14439393510).png, '' Pimelia laevigata'' File:Pimelia senegalensis Olivier, 1795 (29388949801).jpg, '' Pimelia senegalensis'' File:Pimelia sparsa Brullé, 1838 (14149179257).png, '' Pimelia sparsa'' File:Pimelia subglobosa (Pallas, 1781) (14626021235).png, '' Pimelia subglobosa''

Species

Reproduction

Desert adaptations

Gallery

References

Further reading