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MARSH BEETLES AND ALLIES

SCIRTOIDEA

W

ith just over a thousand species worldwide,

Scirtoidea is one of the smallest

superfamilies of Polyphaga, and is traditionally

divided into four families: Decliniidae, Eucinetidae,

Clambidae, and Scirtidae. Some recent studies

suggest that these divisions may need to change.

Eighty percent of Scirtoidea are in the family

Scirtidae, or marsh beetles. Short-lived as adults,

they are found on vegetation, and have a soft,

fragile exoskeleton. They spend most of their life as

woodlouse-shaped aquatic larvae with distinctive,

exceptionally long, multi-segmented antennae.

Most larvae live in ponds, pools, and marshes, in

submerged leaf litter, or hide between leaves of

reeds or rushes. Some live in forests, in water that

accumulates in holes in trees, or in between the

leaves of bromeliads or orchids in the rainforest

canopy. In Europe the uncommon genus

Prionocyphon is found as larvae in water-filled rot

holes in beech trees, and larvae are easier to find

than the short-lived adults, which are evident only

for a few weeks or even days in summer.

The Clambidae is a family of fewer than 200

round, black or brown beetles that live in decaying

vegetation. Although probably quite common, and

distributed worldwide, they are tiny and rarely seen,

and easily mistaken for mites. Adults can roll into

SCIRTOIDEA—Marsh Beetles and Allies

superfamily

Scirtoidea

known species

1,025

distribution

Worldwide, but almost equally abundant

in tropical and temperate environments

habitat

Associated with wetlands. Many species use

water trapped in plants in the forest canopy,

particularly in wet tropical forests

size

1–10 mm

diet

Adults and larvae graze on algae, moss,

fungi, and decaying vegetation. Eucinetidae

are associated with fungus-like slime molds

notes

Recent DNA studies indicate that Scirtoidea

are among the most ancient groups of

Polyphaga. However, because they are small

and fragile as larvae and adults, they do not

below | Scirtidae A typical

woodlouse-like larva grazing

on moss and algae in still water.