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Updated: Mar 1



Lucanus placidus, commonly known as the Smooth Stag Beetle, is a species of stag beetle in the family Lucanidae, and along with Lucanus capreolus and Lucanus elaphus, is one of the three representatives of the genus Lucanus in Canada. Reaching a maximum length of 37 mm, this species has a recorded adult lifespan of over 12 months in captivity. Lucanus placidus is a powerful, large species of sand loving stag beetle that can be successfully reared in captivity.

Native to the sandy soils surrounding the great lakes region, Lucanus placidus larvae develop within the decaying roots of various species of hardwood trees including Oak and Maple. Lucanus placidus is nocturnal and can uncommonly be found from dusk until midnight on warm summer nights.

Females deposit between 30 - 50 eggs which upon hatching will burrow and feed within the rotten roots. Larvae are not cannibalistic, and grow communally as they consume the rotten heartwood. Larvae are known to stridulate, producing a characteristic chirping sound. It is speculated this tactic is used to identify themselves as being of the same species. The larvae of Lucanus placidus undergo three larval instars before constructing horizontally oriented, elliptical pupal chambers constructed in the substrate. 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 May through June.

Like most adult scarab beetles, Lucanus placidus demonstrate sexual dimorphism, with males exhibiting a significantly wider pronotum as well a large imposing mandibles. Females display modified frontal tibia, designed and optimized for burrowing and egg laying.. Both males and females are known to feed on tree sap in nature. Adults are terrestrial in the wild, but will climb if given the opportunity. As such, this species will greatly benefit from a well designed vertically oriented, arboreal vivarium



In captivity, Lucanus placidus can be kept individually or in small groups. Although able to be reared communally as larvae, adult male Lucanus placidus 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 70 % at all times which can be achieved by ensuring a moist but never damp substrate. Substrate should contain a majority % of playsand, mixed with crumbled hardwood / flake soil / top soil. 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 semi arboreal environment, we provide our enclosures with a natural bark background in addition to vertically oriented branches.



In captivity, Lucanus placidus 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 or third 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, Lucanus particularly enjoy the occasional treat consisting of a cotton ball soaked in a 1:1 ratio of maple syrup to water.



Breeding Lucanus placidus in captivity, like other larger Lucanids, is a more challenging but rewarding process. Substrate should contain a large percentage of sand, mixed with an organic substrate. Rotten hardwood logs can be burried to simulate rotten underground logs Larvae grow communally and will not readily cannibalize one another. Humidity should be maintained over 70 % 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 Lucanus placidus undergo three larval instars before constructing horizontally oriented, elliptical pupal chambers.





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