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Pimelia

{{Short description|Genus of beetles}}

{{distinguish|text=the plant genus Pimelea}}

{{Automatic Taxobox

| image =Pimelia (Piesterotarsa) obsoleta Solier, 1836 (3518257693).jpg

| image_caption =Pimelia obsoleta

| taxon = Pimelia

| authority = Fabricius, 1775

| display_parents = 2

}}

Pimelia is a genus of darkling beetles in the subfamily Pimeliinae.{{cite journal |last1=Pons |first1=Joan |last2=Petitpierre |first2=Eduard |last3=Juan |first3=Carlos |title=Evolutionary dynamics of satellite DNA family PIM357 in species of the genus Pimelia (Tenebrionidae, Coleoptera) |journal=Molecular Biology and Evolution |date=2002 |volume=19 |issue=8 |pages=1329–1340 |doi=10.1093/oxfordjournals.molbev.a004194 |doi-access=free |pmid=12140245|hdl=10261/99890 |hdl-access=free }}

Species

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[https://www.biolib.cz/en/taxon/id55552/ Biolib]

Reproduction

Pimelia are univoltine, with one generation per year. Species in North Africa emerge in January to begin mating, synchronously with floral bloom. Normally Pimelia are detrivores, but during mating season they may cannibalize other adults, larvae, and eggs. This behavior may be due to need for extra nutrients or simply to eliminate competitors. Following behaviorRamussen, J.L., et al. (1991). The reproductive behavior of six species of Namib Desert tenebrionid beetles (Coleoptera: Tenebrionidae). Journal of Insect Behavior 4(5) 567-82. {{Failed verification|date=February 2021}} and mating take place on the slip face of a sand dune. After mating, the female digs a shallow hole and deposits a single egg, which closely resembles a grain of white rice. 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.Lillig, M. and T. Pavlicek. Die schwarzkafer des Sinai (Coleoptera: Tenebrionidae). Moscow, Russia. Pensoft. 2002.

Desert adaptations

Many Pimelia species are conspicuous as they cross sand dunes. Locomotion in this difficult terrain is facilitated by numerous tarsal setae that allow for rapid tumbling behavior.Rech, N. D. (1997). Comparison of the tumbling movement found in two species of Adesmia Fischer-Waldheim (Coleoptera: Tenebrionidae). Coleopterists Bulletin 51(1) 86-92.

Adaptations to arid climates and desert 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.Ayal, Y. and O. Merkl. (1993). Spatial and temporal distribution of tenebrionid species (Coleoptera) in the Negev Highlands, Israel. Journal of Arid Environments 27 347-61. Environmental factors influencing these adaptations are extremes of temperature and humidity, excessive radiant energy, low and irregular rainfall, long periods of drought, strong winds, unstable sand substrates, and sparse, specialized vegetation.Cloudsley-Thompson, J. L. (1979). Adaptive functions of the colours of desert animals. Journal of Arid Environments 2 95-104.

Several morphological adaptations allow Pimelia to survive in the desert, including the lipid layers of the epicuticle, fused sclerites, 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.Adhearn, G.A. (1970). The control of water loss in desert tenebrionid beetles. Journal of Experimental Biology 53 573-95. The fused sclerites of desert tenebrionids minimize water loss,Cloudsley-Thompson, J. L. (1968). Respiratory function and thermal acclimation in tropical invertebrates. Nature 218 685. but they result in flightlessness.Buxton, P. A. (1923). Heat, moisture, and animal's life in deserts. Proceedings of the Royal Society of London 96 123-31. The main barrier to the outward flow of water through insect integument is the lipid layer of the epicuticle.Cloudsley-Thompson, J. L. (1956). Studies in diurnal rhythms; bioclimatic observation in Tunisia and their significance in relation to the physiology of the fauna, especially woodlice, centipedes, scorpions and beetles. Annals and Magazine of Natural History 12(9) 305-29. In many terrestrial arthropods, the temperature affects the permeability of the cuticle. There is a sudden increase in the rate of transpiration 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.Hadley, N. F. (1972). Desert species and adaptation. American Scientist 60 338-47. 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 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.Cloudsley-Thompson, J. L. (1964). On the function of the sub-elytral cavity in desert Tenebrionidae (Coleoptera). Entomologist's Monthly Magazine 100 148-51. Pimelia have tubercles on the surface of their elytra which scatter and reflect incident energy.

Burrowing is probably the most important behavior modification for heat regulation in Pimelia, because it permits access to a broad range of ambient temperatures.Hamilton, W. J. Coloration and its Thermal Consequences for Diurnal Desert Insects. Stroudsburg, PA: Dowden, Hutchinson & Ross. 1975. 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

References

{{Reflist|refs=

{{GBIF |id=1208967 |taxon=Pimelia Fabricius, 1775 |access-date=11 December 2023}}

{{NCBI taxid| 45446 | Pimelia | accessdate = 11 December 2023 }}

}}

Further reading

  • Watt, J. C. (1974). A revised subfamily classification of Tenebrionidae (Coleoptera). New Zealand Journal of Zoology 1(4). {{doi|10.1080/03014223.1974.9517846}}

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Category:Tenebrionidae genera

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Category:Taxa named by Johan Christian Fabricius