Scarab beetles include the biggest insects in the world, in terms of sheer mass. Scarabs were revered in ancient Egypt as symbols of resurrection. More than just powerhouses, scarab beetles serve important roles in the habitats where they live. The family Scarabaeidae includes dung beetles, June beetles, rhinoceros beetles, chafers, and flower scarabs.
Most scarab beetles are robust, convex insects with brown or black coloring. Whatever the coloration, size, or shape, scarabs share a key common feature: lamellate antennae that can be closed tightly. The last 3-7 segments of each antenna form plates that can be expanded like a fan or folded together into a club.
Scarab beetle larvae, called grubs, are c-shaped and usually live in the ground, feeding on roots. The grubs have a distinctive head capsule, and easy to identify legs on the thorax.
While most scarab beetles feed on decomposing matter – dung, fungi, or carrion – some visit plants, feeding on pollen or sap. Flower scarabs are important pollinators, for example. Larvae feed on plant roots, carrion, or dung, depending on the type of scarab.
Like all beetles, scarabs undergo complete metamorphosis with four stages of development: egg, larva, pupa, and adult.
Scarab beetles generally lay their eggs in the ground, in dung, or in other decomposing materials including carrion. In many species, the larvae feed on plant roots, though some feed directly on dung or carrion.
In areas with cold winter climates, grubs typically move deeper into the soil to survive freezing temperatures, and emerge as adults in early summer.
Special Adaptations and Defenses:
Some male scarabs, such as rhinoceros or Hercules beetles, bear "horns" on their heads or pronotums, which they use to spar with other males over food or females.
Dung beetles excavate burrows below manure piles, then mold the dung into capsules in which they lay their eggs. The mother cares for her developing young by keeping the dung ball free of mold or fungi.
Range and Distribution:
Some 20,000 species of scarab beetles inhabit terrestrial habitats around the world. Well over 1,500 species of Scarabaeidae live in North America.