Desert Darklings

Tenebrionidae, Tenebrioninae, Nycteliini,

Praocini, Scotobiini, etc.

The arid coastal areas of Chile and Peru, including the great Atacama, and the dry steppes of southern South America in general are home to an assemblage of endemic darkling beetles specifically adapted to hot, dry places, much like members of their tribal relatives in the deserts of southern Africa and the southwestern United States.

They are small to moderate-sized (BL 15-25 mm) tenebrionids, mostly dull black and hard shelled. They tend to have compact, oval to elongate-oval body forms, though in endless variety of detail; the strange flattened, spider-legged or sickle-jawed types found in other parts of the world are lacking. The immature stages are almost totally unknown in the majority of species, and there is little recorded on adult biology (Peña 1963).

At times, some species are found in great abundance. Their appearance coincides with wet years. At other times, they are scarce or absent altogether. They are active beetles, scurrying over the sand or sparsely vegetated ground in search of mates or food, which consists of ephemeral grasses, herbaceous plants, or almost any organic debris (ibid.).

There are numerous species, most in dominant large genera such as Scotobius (Scotobiini), Proacis (Proacini), and Nyctelia and Gyriosomus (Nycteliini).

Scotobius (fig. 9.2i) are fairly elongate, with longitudinal, smooth or coarsely cornicled ridges, the space between often transversly corrugate, and the edges of the prothorax may be flanged (Kulzer 1955). Members of the genus Proacis (fig. 9.2h) are wide bodied and with both smooth to ridged elytra (Kulzer 1958). Many Nyctelia (fig. 9.2g) are obovate, with deep, transverse corrugations on the elytra (Kulzer 1963). Gyriosomus (fig. 9.2f) typically sport oblique, white, streaked elytral patterns of dense short setae (Kulzer 1959).

References

Kulzer, H. 1955. Monographie der Scotobiini: Zehnter Beitrag zur Kenntnis der Tenebrio-niden. Mus. G. Frey Entomol. Arb. 6: 383-485, Pls. XIX-XXIV. Kulzer, H. 1958. Monographie der Südamerikanischen Tribus Praocini (Col.). 16. Beitrag zur Kenntnis der Tenebrioniden. Mus. G. Frey Entomol. Arb. 9: 1-105. Kulzer, H. 1959. Neue Tenebrioniden aus Südamerika (Col.). 18. Beitrag zur Kenntnis der Tenebrioniden. Mus. G. Frey Entomol. Arb. 10: 523-567, Pls. XI-XII. Kulzer, H. 1963. Revision der Südamerikanischen Gattung Nyctelia Latr. (Col. Tenebr.). 24. Beitrag zur Kenntnis der Tenebrioniden. Mus. G. Frey Entomol. Arb. 14: 1-71, Pls. 1-VI.

Pena, L. E. 1963. Las Nyctelia (Coleoptera: Tenebrionidae). Mus. G. Frey Entomol. Arb. 14: 72-75.

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