My cultured species

The genus Dermestes can be devided into three three subgenera. The first being the subgenus Dermestinus, whom I dubbed the “white-bellies”. The second being the subgenus Dermestes, whom I dubbed the “black-bellies”. With the third subgenus, Montandonia, I am unfamiliar.
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Species Subgenus Optimum temp. Min. temp. Max. temp. Optimum RH Min. RH Distribution
D. maculatus Dermestinus 30-35°C 20°C 40°C 75% 30% Cosmopolitan
D. frischii Dermestinus 30-35°C 20°C 40°C 75% 30% Nearly cosmopolitan
D. ater Dermestes 27-30°C 20°C 40°C 75% 40% Cosmopolitan
D. haemorrhoidalis Dermestes 27-30°C 20°C 35°C 75% 40% Nearly cosmopolitan
D. lardarius Dermestes 25-27°C 15°C 35°C 80% 40% Cosmopolitan
D. undulatus Dermestinus 20-25°C 15°C 30°C 80% 40% Holarctic Region
D. murinus Dermestinus 20-25°C 15°C 30°C 80% 40% Palaearctic Region


Some noteworthy abilities:

  • 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%.
  • The species of the subgenus Dermestes can also feed on plant materials including grains. As a result, these species are more able to survive on a diet of dog or cat food.
  • The species of the subgenus Dermestes make a chirping sound, called stridulation.

Subgenus Dermestinus

(white-bellies)

Dermestes maculatus:

(Hide beetle, Bacon beetle)

This is the most commonly kept species for cleaning skeletons and that is for a reason. They clean bones very quickly in warm conditions! 

Distribution: Cosmopolitan. In temperate regions it is limited to heated facilities.
Origin: United States, WA. In my care since 2019.

Description: The adults are 5.5 to 10 mm long. The elytra are brownish to black and have, in contrary to Dermestes 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 (see figure 1). 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.

Figure 1:   A comparison between Dermestes maculatus and Dermestes frischii. The two identification keys are emphasized in red: the shape of the black spot on the last segment of the abdomen and the tip of the elytra.

Dermestes frischii:

(Fringed larder beetle)

My longest thriving colony!  They clean bones very quickly in warm conditions. They are on average the biggest species we offer and quite tolerant to salt!

Distribution: Nearly cosmopolitan in warm regions of the world.
Origin: Europe, Belgium. In my care since 2017.

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 (see figure 1). 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.

Skeleton cleaned with D. fischii:

Dermestes undulatus:

This is the smallest species that we offer and a great addition for terrariums. They don't need a lot of food to breed and have a pretty colouration.

Distribution: The entire Holarctic Region of the world.
Origin: Europe, Netherlands. In my care since 2020.

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.

Skeleton cleaned with D. undulatus:

Dermestes murinus:

Subspecies murinus. This is the most rare species of the subgenus that we currently offer.

Distribution: The entire Palaearctic Region of the world.
Origin: Europe, Netherlands. In my care since 2024.

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 with a black spot at the end of the abdomen. The full-grown larvae are 10 to 12,5 mm long and almost entirely black in colour.

Skeleton cleaned with D. murinus:

(No skeleton yet)

Subgenus Dermestes

(black-bellies)

Sound (stridulation) of this species:

Dermestes haemorrhoidalis:

(African larder beetle)

This species is very robust and survive a lot, but be sure to make their eclosure escape-proof. It is the most rare species of the subgenus that we currently offer.

Distribution: Nearly cosmopolitan.
Origin: Europe, Netherlands. In my care since 2021.

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 larva is brown with light-brown bands deviating the different segments of the body.

Skeleton cleaned with D. haemorrhoidalis:

Sound (stridulation) of this species:

Dermestes lardarius:

(Larder beetle, Moisture Bug)

This is the prettiest species of the subgenus to look at and a great addition for terrariums. Their numbers (colony-size wise) tend to stay modest.

Distribution: Cosmopolitan.
Origin: Europe, Netherlands. In my care since 2019.

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 colour of a larva is brown with light-brown bands deviating the different segments of the body.

Skeleton cleaned with D. lardarius:

Sound (stridulation) of this species:

Dermestes ater:

(Black larder beetle)

Adults are keen to fly, even at lower temperatures. However, they are not as keen to escape as D. haemorrhoidalis.

Distribution: Cosmopolitan.
Origin: United States, ID. In my care since 2024.

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.

Skeleton cleaned with D. ater:

(No skeleton yet)

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.

Figure 2:   A comparison between a male and female adult Dermestes frischii.

Figure 3:   A comparison between a male and a female Dermestes lardarius.

Requirements of the enclosure


Temperature
The general rule for all species of Dermestes is: the warmer the temperature, the quicker the eggs hatch, the quicker the larvae develop and the quicker the pupae develop. Keeping the beetle colony at a warm temperature is recommended to increase it's population size quick. Despite this, you do not want to keep your beetle colony in temperatures that are too hot. At certain temperatures the adult beetles gain the ability to fly and the adult females might stop producing eggs. The threshold temperature differs per species. Temperatures below freezing point will kill dermestid beetles, since they do not go dormant like some other beetle species.

Humidity
You might want to keep the relative humidity in your beetle enclosure low, since mites might infest the colony if the RH is high. Dermestid beetles can live in quite arid environments. But, like all living creatures, these beetles still need water to survive. You can additionally spray water on the sides of the enclosure or place a wet paper ball within the reach of the beetles to give them a drink. Good ventilation helps to keep the RH low and to refresh the air within the enclosure. Without ventilation, gasses like ammonia can build up in the enclosure. In these cases, pupae might not develop correctly and adult beetles start to emerge disfigured. However, if you would like to stimulate colony growth, a higher RH can definitely stimulate the female beetles to lay eggs.

Substrate
Wood shavings are most widely used as ground cover. Try to avoid cedar, since that is a natural bug deterrent. Wood chips from pine or aspen are save options and I personally prefer hemp fibers. The enclosure itself can be in all shapes and sizes, as long as it is made of a material that the beetles can not destroy by boring into and a material they can not use to climb out of the enclosure. Examples of enclosures that work well are smooth hard plastic boxes, aquaria or terraria made of glass or even modified freezers.

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.

  • 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

  • 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.

 

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