Fig. 1. Giant stag beetle, Lucanus elaphus (male). Photography Credit: Natasha Wright, Cook's Pest Control, Bugwood.org.
Most recently reviewed by: Pat Porter (2018)
Common Name(s): Stag Beetle
Description
Stag beetles are very large, robust beetles. Depending on species, these beetles can be a variety of colors, but are typically dark brown to black. Like many beetles, they have clubbed antennae but the segments appear separated, rather than compact like scarab beetles. The most distinctive morphological character of stag beetles is the elongated and sometimes elaborate mandibles possessed by males. In fact, they owe their common name to these structures which not only resemble deer (or stag) horns, and are used by male stag beetles to fight with rival males for preferred territory. Females have a much more reduced mandible structure. Stag beetle size is species dependent and ranges from 2 – 4.5 inches in length. Larvae are similar in shape to white grubs of Scarabeidae, but are often larger during the latter stages of development. The giant stag beetle (Fig. 1 (male) and Fig. 2 (female)), Lucanus elaphus Fabricius, occurs in Texas. Males of this species have elaborate mandibles.
Larvae develop in damp, decaying wood. Adults are sometimes attracted to lights. Adults can also be found near stumps or rotting logs. Adults may feed on leaves but Texas species are seldom common enough to be considered pests. They may bite if handled.
Origin and Distribution
Lucanus elaphus are native to North America.
Life Cycle
Fig. 2. Giant stag beetle, Lucanus elaphus (female). Photography Credit: Natasha Wright, Cook’s Pest Control, Bugwood.org.
Females seek out suitable dead trees and lay eggs. After egg hatch, grub-like larval stag beetles feed on the wood provided by the decaying tree. Developmental times vary by species, but many stag beetles require multiple years (1-3) to complete their larval development. Pupation can last 7-9 months and adult emergence typically occurs during spring. Adults are relatively short-lived (3-6 weeks).
Management
If you live in the State of Texas, contact your local county agent or entomologist for management information. If you live outside of Texas, contact your local extension for management options.These insects are not considered pests and management is not necessary.
