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Updated: Mar 1



Osmoderma eremicola, commonly known as the Hermit Beetle, is a species of beetle in the family Scarabaeidae, and along with Osmoderma scabra and Osmoderma subplanata, one of the three representatives of the genus Osmoderma in Canada. Reaching a maximum length of 35 mm and living up to 8 months in captivity as an adult beetle, Osmoderma eremicola is a communal, large beginner species of arboreal scarab that can successfully be reared in captivity.

Native to the deciduous old growth forests of Eastern Canada, Osmoderma eremicola can be found from Ontario and Quebec to the Maritimes. In nature, the larvae develop in the decaying heartwood of various species of hardwood trees including Linden, Elm, Maple, Oak, Ash, Birch, Beech, Aspen and Poplar. The Hermit Beetle is nocturnal and can often be found on tree trunks of hollow trees. They produce a characteristic odour reminiscent of leather products.

Females deposit between 25 - 40 eggs within the rotten hollowed out cavities mature trees, often over 100 years old. Larvae are not cannibalistic, and grow communally as they consume the rotten heartwood. The larvae of Osmoderma eremicola undergo three larval instars before constructing vertically oriented, elliptical pupal chambers constructed from a mixture of frass, organic material and adhesive secretions. In nature, this species overwinters as both an L2, and L3 larva with pupation taking place in late Winter - early Spring. Adults will remain in their pupal cells until emerging from late July through August.

Like most adult scarab beetles, Osmoderma eremicola demonstrate sexual dimorphism, with males exhibiting a significantly wider and more sculptured pronotum. Both males and females are known to feed on tree sap in nature. Adults are fully arboreal in the wild, but can be adapted to a terrestrial vivarium in captivity. As such, this species will greatly benefit from a well designed vertically oriented, arboreal vivarium



In captivity, Osmoderma eremicola can be kept individually or in small groups. Although able to be reared communally as larvae, adult male Hermit Beetles are territorial and it is recommended that no more than 1 male be present for every 5 gallons of terrarium space. Humidity should be maintained above 50 % at all times which can be achieved by ensuring a moist but never damp substrate. For hygienic reasons and to extend longevity, we keep our adult Osmoderma eremicola individually on slightly moist aspen shavings. For this method, sphagnum moss can also be used. Alternatively, for a more natural environment, a bioactive substrate mix can be used. Examples of ingredients include fermented hardwood sawdust, black earth, peat moss, and organic potting medium. We seed our Bioactive terrariums with springtails ( Folsomia candida ) and provide an additional layer of dried Oak leaves and bark. Due to their preference for an arboreal environment, we provide our enclosures with a natural bark background in addition to vertically oriented branches.



In captivity, Dorcus parallelus can be offered a wide range of fruit, sugary liquids as well as beetle jelly. Example of fruits include banana, apple, and watermelon, which should be replaced every second day to prevent mold, mites or fungus gnats. Alternatively, beetle jelly can be offered as a lower maintenance option, which need only be replaced as required. Additionally, Dorcus particularly enjoy the occasional treat consisting of a cotton ball soaked in a 1:1 ratio of maple syrup to water.



Breeding Osmoderma eremicola in captivity is a relatively straight forward process requiring little more than the correct substrate and attention to some key details. The ideal substrate will consist of a mixture of either white rotten wood or fermented sawdust, with crushed leaf litter, black soil or peat moss. Larvae grow communally and will not readily cannibalize one another. Humidity should be maintained over 50 % at all times, but attention must be given to avoid over saturating the substrate, as this species is sensitive to excessive moisture. The larvae of Osmoderma eremicola undergo three larval instars before constructing vertically oriented, elliptical pupal chambers constructed from a mixture of frass, organic material and adhesive secretions.





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