Description
Beetle, Cyclommatus metallifer, Metallic Stag Beetle Specimen
You will receive the specimen shown, or one like it. Specimens will vary in color. These specimens are from Indonesia.
The stag beetle Cyclommatus metallifer is one of Indonesia’s most visually extraordinary lucanids, celebrated for its metallic brilliance, elongated form, and dramatically oversized mandibles. Native to tropical forests across parts of Indonesia and nearby Southeast Asia, this species represents an exceptional example of sexual selection and structural coloration working together in evolution.
Males are especially spectacular. Their bodies are long, slender, and highly polished, often displaying shifting metallic tones of bronze, emerald green, copper, violet, or gold depending on lighting and locality. The surface of the exoskeleton reflects light with almost mirror-like intensity, giving the beetle a jewel-like appearance that can seem almost artificial under direct illumination.
Its most defining feature is the pair of elongated mandibles. In major males, these jaws become elegantly curved and highly extended, functioning less as feeding tools and more as weapons used during ritualized combat. Rival males grapple for dominance on tree trunks and sap sites, attempting to lift or dislodge one another using leverage and strength rather than lethal force.
The proportions of Cyclommatus metallifer are unusually refined compared to many heavier-bodied stag beetles. The thorax is relatively narrow, the legs are long and agile, and the entire insect has an almost aerodynamic silhouette. Despite their armored appearance, adults are capable fliers, using hidden membranous wings folded beneath the elytra.
Females are smaller and more compact, with shorter, practical mandibles adapted for feeding and preparing egg-laying sites in decaying wood. Both sexes play a role in forest nutrient cycling, as larvae spend extended periods developing within rotting timber and decomposing plant matter.
In terms of rarity, Cyclommatus metallifer itself is not considered exceptionally rare among Southeast Asian stag beetles. It is well known in the insect hobby and has been bred in captivity for many years. However, specimen size dramatically changes rarity and desirability.
A male reaching 90mm is considered highly impressive and genuinely uncommon. While smaller males are regularly encountered, achieving or exceeding 90mm requires a combination of excellent genetics, ideal larval nutrition, long developmental periods, and stable environmental conditions. Wild specimens of that size are particularly scarce, and even among captive-bred individuals, a true 90mm male represents a top-tier example of the species.
Collectors especially value these giant males because the increase in size disproportionately enhances the mandibles and overall elegance of the beetle. At 90mm, C. metallifer begins to display the exaggerated proportions that make the species legendary among stag beetle enthusiasts—long sweeping jaws, intense metallic luster, and an almost impossibly refined body structure.
Scientifically, these oversized males are excellent examples of allometric growth, where certain body parts—in this case the mandibles—expand disproportionately as body size increases. The result is an insect shaped not only by survival pressures, but also by evolutionary competition and mate selection.
