Biodiversity Highlight - Series #1: Lucanidae of the Bull Run Mountains - Part Two

Biodiversity Highlight (Series #1: Part Two): Dorcus parallelus (Antelope Beetle)
Virginia Outdoors Foundation - Bull Run Mountains Natural Area Preserve


Dorcus parallelus (Antelope Beetle) ♀ spotted on The Preserve's north section

© Joe Villari (@jvillari), some rights reserved (CC-BY-NC)


Hello again everyone!

Welcome to the second installment of our four-part dive into the Lucanidae, or stag beetles, of the Bull Run Mountains. This week we will be looking at the antelope beetle, Dorcus parallelus. This stag beetle is one of two species of its genus found in North America, both of which are found throughout the eastern portion of the United States. While very few of these have been observed in The Preserve, they seem to prefer the biodiverse quarters found in our northern section. This species of stag beetle is medium-sized, all black, with striated elytra, and modest to medium-sized mandibles (but we'll come back to that). With all our other species of Lucanidae, this gorgeous, albeit incredibly stereotypical-looking beetle has a strong affinity with hardwood tree species like Quercus sp., or oaks - though a thorough ecological investigation has yet to be published (at least I couldn't track one down).

Similar to their sister species in Europe (Dorcus parallelipipedus - thank goodness our species got the easier name), these beetles are frequently encountered in gardens. At least two female specimens have been observed in a garden here on the preserve! This is likely due to the reproductive cycle of the species, which lays its eggs in soil rich in decaying wood and hardwood tree leaves - which may be a large component of a gardeners homemade compost materials. Burrowing into these materials, the female stag beetle will lay her eggs within the substrate where tiny beetle embryos will develop over the next several weeks. Upon hatching the c-shaped, white grub larvae can spend the next one-to-two years feeding and growing underground. Although similar in appearance, these grubs should not be confused with other, more detrimental garden pest species, as they do not feed on living plant materials like roots.


Dorcus parallelus (Antelope Beetle) ♂ - male specimen observed in Ontario

© Bob Noble (@bob15noble), some rights reserved (CC-BY-NC)


Wow, look at those chompers!

The picture above of an adult male specimen illustrates the most charismatic feature of the Lucanidae - the mandibles. These oversized "teeth" are used for male-on-male battles in competition for females. Just like our last highlighted species, Platycerus quercus, these battles can be fierce, though rarely end with the demise of one of the suiters. These relatively large endowments also don't pose much threat to any human handler. Having been chewed on by much larger Lucanidae, this author can attest that the bite force from one of these beetles is more surprise than pain. Interestingly enough, the real pinch comes from the female, whose small pincers are more suited for chewing into decaying wood. These compact mulchers have a bit more torque, bringing a bit more ouch! to your insect encounter.

Taking a step back, our two species Dorcus are just a couple of many distributed across the world. The genus Dorcus is widespread with 30 or more species and found in eastern North America, Europe, and prolifically across India and eastern Asia. Here in the states, the stag beetle diversity is pretty low (unless you decide take some exceedingly long walks through the western California mountain ranges), but how to do even tell a stag beetle from another family of beetles, let alone species?

There are a few easy ways to pick a stag beetle apart from other local beetle fauna. The family may be the best know for their champion antlers, but the morphology of the antenna is a much better indicator of your Coleopteran family. Although not true for every Lucanidae you may come across here in the United States, the elbowed, or geniculate antenna is a major distinguishing feature of the family. As you can see in the photo above, the antenna of this male D. parallelus possesses an extended initial antennal segment , followed by a series of smaller segments leading into a distal club. This trait can also be observed in our last species and will be a persistent feature as we review additional Lucanidae here at the Preserve. As we continue our exploration of Lucanidae I'll highlight the more subtle morphological features to help with identification.


ABOUT #BullRunMountainsNaturalPreserve
The Bull Run Mountains are the easternmost mountains in Virginia. Virginia Outdoors Foundation - Bull Run Mountains Natural Area Preserve is approximately 2,350 acres that serve as a living laboratory that sits in the backyard of our nation’s capital. The preserve contains 10 different plant community types and a plethora of regionally uncommon and threatened plant and animal species. In 2002, this land was dedicated by the Virginia Department of Conservation and Recreation as a natural area preserve to protect the unique ecosystems found here. As the owner and manager of the preserve, the Virginia Outdoors Foundation is committed to protecting the special ecosystem found here and sharing it with the public through managed access.

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iNaturalist: Preserve Manager Joe Villari (@jvillari)
Instagram: @bullrunmountains
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Meetup Events: Bull Run Mountains Natural Area Preserve Guided Hikes Group

Lähettänyt mjwcarr mjwcarr, 26. heinäkuuta 2022 18:20

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