By Scott Teakell
Geographic Range
The giant stag beetle, also known as the elephant stag beetle, can be found in the woodlands of North America ranging from Virginia and North Carolina to the northeastern United States. (Arnett, Jr., and Ph. D., 1985; Milne and Milne, 1980)
Habitat
These beetles live and reproduce in damp, rotting wood. (Arnett, Jr., and Ph. D., 1985; Drees et al., 1998; Milne and Milne, 1980)
These animals are found in the following types of habitat:
temperate
.
Terrestrial Biomes:
forest
.
Physical Description
(1.18 to 2.36 in)
Adult males are 45-60 mm long; females are smaller, around 30-35 mm. This species has a slender, elongated form, with a somewhat flattened back. Adults are reddish-brown, shiny, and have black antennae and legs. Males have a crest above their eyes and a wide head. They are distinguished by their giant antlerlike jaws that may be as long as the head and thorax combined. These jaws have small forked teeth along the inner edge. The females have a narrower head than thorax and much smaller jaws than males. Female elytra are lightly punctate. Giant stag beetles have the segments of their antennae separated rather than compacted like scarab beetles do.
Larvae are white and grub-like, and are characterized by the absence of a 6th segment in the leg. (Arnett, Jr., and Ph. D., 1985; Arnold and Drew, 1987; Drees et al., 1998; Klots and Klots, No Publishing Year; Milne and Milne, 1980; O'Toole, 1986)
Some key physical features:
ectothermic
; heterothermic
; bilateral symmetry
.
Sexual dimorphism:
male larger, ornamentation
.
Development
Giant stag beetle larvae hatch from eggs laid by females on suitable dead trees. They then eat and grow for several years in dead tree stumps. When fully-grown, the larvae pupate for seven to nine months, emerging the following June. After their emergence they live for about three to five weeks more. (Grzimek, 1972; Milne and Milne, 1980; Tweedie, 1973)
Special features of growth:
metamorphosis
; diapause
.
Reproduction
In temperate climates, stag beetles breed in the summer months.
Males use their giant jaws to fight for access to females. Individual males try to control a dead tree or stump suitable for egg-laying, preventing other males from mating with the females arriving on the tree. Consequently one male usually mates with multiple females. (Milne and Milne, 1980)
Mating systems:
polygynous
.
Female stag beetles lay their eggs on dead trees or stumps that will provide suitable food and protection for their offspring. In temperate climates, adults only live for a single breeding season.
Key reproductive features:
semelparous
; seasonal breeding
; gonochoric/gonochoristic/dioecious (sexes separate); sexual
; fertilization
(internal
); oviparous
.
Eggs laid by female stag beetles are supplied with a small amount of nourishing yolk, but the beetle larvae hatch quickly, and receive no additional care. Male stag beetles do not care for their offspring.
Parental investment:
pre-fertilization (provisioning, protecting: female).
Behavior
Males use thier impressive manibles in defense, as well as to compete with other males. Males compete with each other for access to females. Lucanus elaphus is attracted to lights at night. They can also sometimes be seen flying around dusk.
When males are challenged or forced to defend themselves they rear up using their forelegs and spread their jaws. This stance is mainly a bluff though, as their jaws can only pinch rather than inflict a painful bite.
Both males and females have difficulty getting upright if overturned because of their top-heavy heads and flattened backs.
Adults and larvae can be found in large colonies in burrows and rotted out logs. Adults can make noise by rubbing wing-covers or their legs together. (Burton et al., 1968; Cottam et al., 1956; Milne and Milne, 1980)
Key behaviors:
flies; crepuscular
; motile
; territorial
; colonial
.
Food Habits
Adult elephant stag beetles, like most stag beetles, feed on sugary liquid foods, mainly sap leaking from wounded trees, aphid "honeydew" secretions, and ripe fruit. They cannot chew food. The larvae feed on wet, decaying wood, probably getting nutrition from the wood and the fungi and microbes that are decomposing it. (Milne and Milne, 1980; O'Toole, 1986)
Primary Diet:
herbivore
(lignivore, eats sap or other plant foods).
Plant Foods:
wood, bark, or stems; fruit; sap or other plant fluids.
Other Foods:
fungus; microbes.
Economic Importance for Humans: Negative
Though startling if found unexpectedly, these big beetles have no significant adverse effects on humans. They can pinch hard if handled carelessly, but only bite in self-defense. (Drees et al., 1998)
Ways that these animals might be a problem for humans:
injures humans (bites or stings).
Economic Importance for Humans: Positive
These large beetles are collected and raised by hobbyists. In the wild they can be important agents of wood decomposition.
Conservation Status
IUCN Red List: [link]:
Not Evaluated.
US Federal List: [link]:
No special status.
CITES: [link]:
No special status.
This species is uncommon, but not believed to be in need of special conservation efforts.
Contributors
Sara Diamond (editor), Animal Diversity Web Staff.
Scott Teakell (author), Southwestern University.
Stephanie Fabritius (editor), Southwestern University.

