The popular image of the scarab beetle as a swarm of aggressive, flesh-eating insects is a dramatic exaggeration rooted more in fiction than in biological fact. While the term “scarab” refers to a massive and diverse group of beetles, their diets are overwhelmingly focused on decomposition and plant matter. The true scarabs, which were highly revered in Ancient Egypt as symbols of rebirth, are primarily detritivores or herbivores. This complexity, coupled with specific cultural and cinematic portrayals, has led to a widespread misunderstanding of their actual role in the ecosystem.
Defining the Scarab Beetle Family
The scarab beetles belong to the family Scarabaeidae, one of the largest and most varied groups within the insect order Coleoptera. This family encompasses over 30,000 described species found across nearly every continent. A scarab is scientifically defined by its robust, often stout body shape and its distinctive antennae. These antennae terminate in a unique structure called a lamellate club, consisting of flattened plates used to detect odors. The family includes well-known insects like the common June bug, the Hercules beetle, and the Japanese beetle.
The Diverse Diets of Scarab Species
The vast majority of Scarabaeidae species are involved in recycling organic material, making them detritivores or herbivores, not predators of living flesh. Their diets fall into three major categories.
Coprophages (Dung Beetles)
This is the most famous subgroup, feeding exclusively on the feces of mammals and other animals. These beetles play a fundamental role in nutrient cycling by burying and consuming manure. This process aerates the soil and removes waste from the surface.
Phytophages (Plant Eaters)
These groups are strictly phytophagous, meaning they consume living plant material. Adult chafers, such as the Japanese beetle, feed on leaves, flowers, and pollen. Their larvae, often called white grubs, live underground and consume plant roots.
Saprophages and Necrophages
Saprophages specialize in breaking down non-living, decaying plant matter, such as rotting wood and leaf litter. While some true scarabs are Necrophages that consume carrion, this behavior is limited to a small number of species. Scarabs predominantly aid in the decomposition of plant-based materials or manure.
Addressing the “Flesh-Eating” Misconception
The public’s association of scarabs with the consumption of flesh stems from confusion with other beetle families and the influence of popular culture. The insects most accurately described as “flesh-eating” are not Scarabaeidae but members of the family Dermestidae, commonly known as skin beetles. Dermestid beetles possess the unique ability to digest keratin, allowing them to consume dried animal remains, hides, and museum specimens. These Dermestids are used by museums to clean bones for skeletal displays, as they strip away dried tissue without damaging the bone structure. They are completely separate from the scarab family, which lacks this specialization.
The misconception is further cemented by Hollywood films, such as the 1999 movie The Mummy, which inaccurately portrayed scarabs as swarming, aggressive creatures that consume living humans. The reverence for the scarab in ancient Egypt also contributes to its dramatic image. Egyptians associated the sacred scarab (Scarabaeus sacer) rolling its ball of dung with the god Khepri, symbolizing creation and the cycle of rebirth. This powerful cultural history, combined with fictionalized horror, has created a lasting myth that outweighs the actual ecological truth.