My cultured species
Dermestidae are the family of skin beetles. The genus Dermestes can be devided into subgenera. One being the subgenus Dermestinus, whom I dubbed the “white-bellies”. Another one being the subgenus Dermestes, whom I dubbed the “black-bellies”. It is best to keep the beetles in a similar temperature and humidity as the habitat of their distribution. Within this natural range of conditions, the general rule is: the warmer the temperature and the higher the humidity, the faster the beetles breed and eat. Some species gain the ability to fly at certain temperatures. Food need to be present at all times for the larvae, since they have a high metabolism and will die of starvation quickly. If they are depleted of anything to eat, then they start to cannibalize on order to survive. You can supplement your beetles with moisture by spraying a bit of water on some non-soaky surfaces to recreate dew drops to drink from.
The biology of the species is important to know if you decide to keep dermestid beetles for a certain purpose. The species that eat the remains of larger animals are more fit to beetle-clean skeletons, whereas species that prefer to eat dead insects are better used as a clean-up crew.
Some noteworthy abilities:
- The species of the subgenus Dermestes can also feed on grains. As a result, these species are more able to survive on a diet of dog or cat food.
- Some species make a chirping sound, called stridulation.
Subgenus Dermestinus
(white-bellies)
Dermestes maculatus
Description: The adults are 5.5 to 10 mm long. The elytra are brownish to black and have, in contrary to D. frischii, a little sharp tip at the end. The underside of the adult beetles are mainly white with a black spot on the last segment of the abdomen. The shape of this spot is an identification key for this species. Full-grown larvae are 10 to 14 mm long. The larvae are dark-brown in colour and have a light-brown median stripe across their back.
Biology: text
Dermestes frischii
Description: The adults are 6 to 10 mm long. The elytra are brownish to black and have, in contrary to Dermestes maculatus, rounded tips. The underside of the adult beetles are mainly white with a black spot on the last segment of the abdomen. The shape of this spot is an identification key for this species. Full-grown larvae are 10 to 14 mm long. The larvae are dark-brown in colour and have a light-brown median stripe across their back.
Biology: D. frischii is relatively tolerant of salt. They can survive a salt content of 25%, whereas the mortality of D. maculatus is 100% with a salt content of 9.2%.
Dermestes undulatus
Description: The adults are 5 to 7 mm long. The head and thorax are speckled reddish brown and the elytra are speckled dark grey. The underside of the adult beetles are mainy white with a black spot at the end of the abdomen. The full-grown larvae are 8,5 to 10 mm long and almost entirely black in colour.
Biology:
Dermestes murinus
Description: The adults are 7 to 9 mm long. The head, thorax and elytra are a mottled pattern of bluish grey. The underside of the adult beetles are light in colour, but not the typical white. The colour is best described as a pastel pink hue. The full-grown larvae are 10 to 12,5 mm long and almost entirely black in colour.
Biology:
Subgenus Dermestes
(black-bellies)
Dermestes haemorrhoidalis
Description: Adults are 6 to 9,5 mm long. The elytra are dark brown to black. The underside of the beetle or dark coloured and tend to have a golden shine to them due to a layer of satae (hair-like structure). Full-grown larvae are 10 to 15 mm long. The larvae are brown in color with light-brown bands deviating the different segments of the body.
Biology:
Dermestes lardarius
Description: The adults are 7 to 9,5 mm long. The elytra are black with a very recognizable orange band across them. There are three dark spots per elytron within the band. The underside of the adult beetles are dark coloured. Full-grown larvae are 10 to 15 mm long. The larvae are brown in color with light-brown bands deviating the different segments of the body.
Biology:
Dermestes ater
Description: The adults are 7 to 9 mm long. The elytra are dark brown to black. The underside of the adult beetles are brown and have medial and lateral brown spots on a dark-brown background. Full-grown larvae are 10 to 14 mm in length and almost entirely black in colour, but a median stripe can be present.
Biology:
The life cycle of dermestid beetles
Click on the images to see their caption:
Eggs are laid singly or in batches. The beetles often lay their eggs in small spaces near the food source, for example between the layers of cardboard. In these spaces the eggs are relatively save from turmoil within the colony. The eggs take around 2 days to hatch. Thereafter, the larvae moult a few times to get bigger. A larva is big enough to pupate after a month and you might notice that it starts wandering around in search for a save spot. They prefer to bore themselves into certain materials to pupate, like wood or styrofoam. The pupal period is about 6 days. Once the adults emerge from the pupae, the female beetles will experience a so called ‘preoviposition period’. This means that they will not lay eggs immediately. It takes 5 or 6 days for the females to start laying eggs. Adult beetles can live up to 1,5 to 2,5 months.
These numbers are based on the species D. maculatus in optimum conditions.
Sex determination in adult beetles
It is quite easy to see the difference between male and female adult beetles. The male genetalia of a beetle appears as three small "threads" - the median lobe is in the middle with a paramere on each side. The male inserts only the tip of the median lobe into the female genital opening during mating and the parameres remain outside. The female genetalia may show as a broad extension - this is the genital pocket. Once the female beetle lays eggs, the ovipositor comes out. The ovipositor can be of quite a length to lay the eggs in the depths of a safe space.
The presence or absence of a tuft of fur on the abdomen of the beetles (visible as dots) are also a key feature to determine the sex, altough the number of tufts in males differ per species. In Dermestes maculatus, D. frischii and D. haemorrhoidalis, specimens with a tuft of fur / dot on their second to last segment of the abdomen are male (figure 2). In D. undulatus, D. murinus, D. lardarius and D. ater, males have two tufts of fur / dots: one on their third to last segment and one on their second to last segment (figure 3). The beetles without a tuft of fur on the abdomen are female.
How to care for Dermestid beetles?
The basics of how to care for dermestid beetles are covered in a YouTube video called "How to: Care for dermestid beetles" uploaded by Dermestaria. Click on the red button to get redirected to the video.
x
Bibliography:
-
Bailey, S.W. & Lemon, R.W. (1967). Sound production by the larder beetle, Dermestes lardarius Linnaeus (Coleoptera Dermestidae). Journal of Stored Products Research: 4(3): 271-273 p.
-
Danladi, Y.K. & Attah, D.D. (2010). Aspects of the Reproductive Biology of Female Dermestes Maculatus Degeer (Coleoptera: Dermestidae) Under Controlled Conditions. International Journal of Tropical Agriculture and Food Systems 4(3): 275-277 p.
-
Fontenot, E.A., Arthur, F.H. & Hartzer, K.L. (2014). Oviposition of Dermestes maculatus DeGeer, the hide beetle, as affected by biological and environmental conditions. Journal of Stored Products Research 64(B): 154-159 p.
-
Haines, C.P. & Rees, D.P. (1989). A field guide to the types of insects and mites infesting cured fish. FAO Fisheries Technical Paper. No. 303. FAO, Rome, 1989. 33 p.
-
Herrmann, A. (No date). Pictures of some Dermestid Species. http://www.dermestidae.com/Abbildungen.html
-
Magni, P.A., Voss, S.C., Testi, R., Borrini, M. & Dadour, I.R. (2015). A Biological and Procedural Review of Forensically Significant Dermestes Species (Coleoptera: Dermestidae). Journal of Medical Entomology 52(5): 755-769.
-
Martín-Vega, D., Díaz-Aranda, L.M., Baz, A. & Cifrián, B. (2017). Effect of Temperature on the Survival and Development of Three Forensically Relevant Dermestes Species (Coleoptera: Dermestidae). Journal of Medical Entomology 54(5): 1140-1150 p. DOI:10.1093/jme/tjx110
-
Robinson, W.H. (2005). Urban insects and Arachnids. A Handbook of Urban Entomology. Cambridge University Press, Cambridge, UK, 472 p.
-
Sjöberg, O. (1950). Drei neue Kaefer aus der borealen Region Schwedens. Entomologisk Tidskrift 71: 159-164.
The rights of all photographs on this page are reserved to © Dermestaria, formerly known as @Sarah's Skulls and Skeletons.