THE ANIMAL FILES

Hercules beetle

Dynastes hercules

The horns lift rivals; the larvae spend their time in rotting wood.

The Hercules beetle has a dramatic difference between the sexes: males bear opposing head and thoracic horns, while females lack that long horn pair. Adults and larvae also use different foods and places.[1]

Follow the evidence ↓
Hercules beetle
Image: Didier Descouens · Commons · CC BY-SA 4.0
Male structure
Opposing head and thoracic horns[1]
Larval food
Decaying wood[1]
Adult food
Fruit and tree sap[1]

Horns as lifting tools

In contests, a male can grip a rival between the head and thoracic horns, lifting or throwing it. Horn length varies substantially among individuals, so a large horn is not a fixed proportion of every male body.[1]

A hidden wood-eating youth

Larvae live in and consume decaying wood. They pass through several growing stages before pupation and transformation into an adult. This resource differs from the fruit and sap used by adult beetles.[1]

Night activity and changing wing covers

Adults forage at night and shelter in litter by day. Male wing covers can appear olive or yellowish in drier conditions and darken with greater humidity. Colour can therefore change without the animal becoming a different species.[1]

A COMMON MIX-UP

Do females carry the same long horn pair?

No. The conspicuous head-and-thorax horn arrangement is a male feature.[1]

TRY A LITTLE REASONING

Why record humidity when comparing wing-cover colour?

Reveal the explanation

The covers change optical appearance with moisture conditions, so colour differences need not reflect permanent individual types.[1]

Sources & editorial notes

Adapted and translated from the cited Wikipedia revisions, with source-linked reasoning. Image credit and licence are listed separately above.

Adapted and translated from Wikipedia contributors; exact revisions are linked below. CC BY-SA 4.0

  1. Wikipedia contributors — Hercules beetle (fixed revision; adapted and translated)
  2. NCBI Taxonomy — Dynastes hercules (identity and classification)

Last fact check:

One discovery leads to another

CockchaferA few spring weeks above ground follow years below it.Melolontha melolontha ↗Sacred scarabA rolled dung ball can become both a meal and a nursery.Scarabaeus sacer ↗European stag beetleThe “antlers” are jaws, and the long childhood is spent in decaying wood.Lucanus cervus ↗