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SCARAB BEETLES

SCARABAEOIDEA

T

he Scarabaeoidea, or scarab beetles, is the

smallest of the “big six” superfamilies, with

almost 32,000 species spread across 2,258 genera

and 12 families: Pleocomidae, Geotrupidae,

Belohinidae, Passalidae, Trogidae, Glaresidae,

Diphyllostomatidae, Lucanidae, Ochodaeidae,

Hybosoridae, Glaphyridae, and Scarabaeidae,

though as with most beetles, different experts

apply different family concepts. The families vary

dramatically in numbers of species: The family

Scarabaeidae comprises 85 percent of the group

(27,000 species), while Belohinidae are represented

by a single uncommon small, brown beetle from

southern Madagascar, Belohina inexpectata (“the

unexpected one”).

Adult scarabs are characterized by their

lamellate antennae, the terminal segments of which

form a fanlike structure of scent-detecting flaps,

used for “smelling” the air to detect mates or food

resources. The larvae are C-shaped, white or

yellowish, fleshy grubs with clearly visible legs and

a brown head, and develop buried in substrates

SCARABAEOIDEA—Scarab Beetles

superfamily

Scarabaeoidea

known species

32,000

distribution

All continents except Antarctica

habitat

Most terrestrial ecosystems, especially

plains and forests

size

2–190 mm

diet

Larvae usually eat decaying substrates, from

wood to dung, vegetation to carrion. Some

larvae attack roots. Adults may feed on dung,

leaves, pollen and nectar, or not feed at all

notes

Varying in size and ecology, and divided into

several families, adults of Scarabaeoidea are

united and easily recognized by their fanlike

antennae, robust stocky bodies, and fore legs

with teeth often used for digging. Most

species can fly, albeit slowly and noisily

right | Pleocoma dubitabilis

(Pleocomidae) A male

Rain Beetle. These ancient

scarabs are restricted to western

North America. Males fly,

often during rain, in search

of buried flightless females.

opposite below |

Odontotaenius disjunctus

(Passalidae) The Bess Beetle

or Patent Leather Beetle is

the commonest passalid across

much of North America.

They can squeak loudly

when handled.