Darkling beetle is the common name of the large family of beetles, Tenebrionidae. Tenebrionidae are cosmopolitan, living on every continent with the possible exception of Antartica, though through human transport this bug may have spread there as well.
The number of species in the Tenebrionidae is estimated at more than 20,000.
The name Tenebrionidae was given to these beetles by Linnaeus in his 10th edition of Systema Naturae in1758-59 and means roughly: “those that seek dark places.” Darkling beetles are thus beetles which dwell in the dark.
Most species do inhabit dark places, but there are exceptions. Some species of Tenebrionidae in genera such as Stenocara and Onymacris are active by day and inactive at night. The family Tenebrionidae includes a large number of species in an immensely varied range of forms, thus presenting challenges in making comprehensive classifications. As of 2005, Alleculinae Laporte, 1840; Cossyphodinae Wasmann, 1899; Diaperinae Latreille, 1802; Lagriinae Latreille, 1825 (1820); Nilioninae Lacordaire, 1859; Phrenapatinae Solier, 1834; Pimeliinae Latreille, 1802; Stenochiinae Kirby, 1837; Tenebrioninae Latreille, 1802; and Zolodininae Watt, 1974 were largely accepted as subfamilies for taxanomic purposes.
The Tenebrionidae may be identified by a combination of features, which include 11-segmented antennae that may be filiform, moniliform, or weakly clubbed, its first abdominal sternite entire and not divided by the hind coxae, eyes notched by a frontal ridge, tarsi which have four segments in the hind pair and five in the fore and mid legs, with simple tarsal claws.
Many darkling beetles feed on plant matter, some on fresh and some on decaying vegetation; some are generalist feeders on detritus, whether of animal or plant material.
Species within the Tenebrionidae occupy various ecological niches and accordingly are important resources for ranges of predators and parasitoids in the food chain, including birds, rodents, reptiles, and arthropods such as sun spiders, Hymenoptera and Acari.
Some species live in intensely dry deserts, and have evolved adaptions by which they collect droplets of fog that deposit on their elytra. As the droplets accumulate the water drains down the beetles’ backs to their mouthparts, where they swallow it.
In the Mojave Desert, a species of the genus Eleodes (particularly E. obscurus) are well known as “pinacate beetles” or “desert stink beetles.”

Do you have special knowledge about San Bernardino County’s wildlife? If you want to share what you know with others, you can do so by becoming a Sentinel contributor and writing an occasional county wildlife corner column. Call Mark at (909) 957 9998 to see how you can become a published columnist.