scarab beetle
How many species of scarab beetles are there?
Which species of scarab beetle was revered by ancient Egyptians?
scarab beetle, (family Scarabaeidae), any of more than 30,000 species of beetles (insect order Coleoptera), one of the largest and most diverse groups of insects. Scarab beetles are an ecologically important group of animals and are particularly associated with flowering plants. They vary considerably in habits, with many species feeding on manure or on decomposing plant materials, others on growing roots or leaves, and a few on fungi. The family includes several agricultural pests, including June bugs, rose beetles, and the Japanese beetle. The sacred scarab (Scarabaeus sacer) is a dung beetle that was sacred to the ancient Egyptians.
- Kingdom: Animalia
- Phylum: Arthropoda
- Class: Insecta
- Order: Coleoptera
- Family: Scarabaeidae
See also list of beetles.
Physical description
Adult members of the scarab family are compact and heavy-bodied insects with robustly oval outlines. Like all insects, the body is made up of the head, the thorax, and the abdomen, and they have six legs. The outer edges of their front legs are often toothed or scalloped to facilitate digging. They are distinguished from other beetles by their unusual antennae, each of which terminates in three flattened plates that fit together to form a club. Members of the family include a number of species with relatively bizarre forms, such as horns. For example. the male rhinoceros beetles (subfamily Dynastinae) have one or more horns on the head and sometimes on part of the thorax. Many of the true scarabs (subfamily Scarabaeinae) and other dung-feeding groups also have horns, as do some of the goliath beetles (subfamily Cetoniinae).
Scarab beetles vary in length from 5 mm (0.2 inch) for the smaller species to 12 cm (4.7 inches) for the African goliath beetle (Goliathus goliatus), which has one of the heaviest larvae of any known insect. Members of the family are popular with insect collectors because of the large size and beautifully colored, hard, highly polished forewings (elytra) of many species. Wings for flying, which are delicate and often transparent, are tucked under the protective elytra when not in use.
Like other beetles, the insects undergo complete metamorphosis (holometabolous), meaning their life cycle consists of egg, larva, pupa, and adult stages. The grublike larvae are typically soft-bodied, thick, strongly C-shaped, and somewhat flattened beneath and round above. The larvae of the subfamily Cetoniinae are often short, less C-shaped than most scarabs, hairy, active, and capable of locomotion on their backs through movement of body segments.
Major subfamilies, genera, and species
The family Scarabaeidae includes over two dozen subfamilies, and the group has undergone a number of taxonomic revisions. Scarab beetle subfamilies include:
- chafers (subfamily Melolonthinae)
- cockchafer (Melolontha melolontha)
- June bugs (genus Phyllophaga)
- dung beetles (subfamily Scarabaeinae)
- flower chafers (subfamily Cetoniinae)
- African goliath beetle (Goliathus goliatus)
- rhinoceros beetles (subfamily Dynastinae)
- eastern Hercules beetle (Dynastes tityus)
- shining leaf chafers (subfamily Rutelinae)
- Japanese beetle (Popillia japonica)