Did you know that carved scarab beetles were some of the most popular amulets in ancient Egypt because they were a symbol of the sun god Ra? Today, they are familiar to most people as the June bugs that are attracted to porch lights, but if you’re lucky, you might see dung beetles rolling and burying balls of dung. Many people have also seen impressive stag beetles with large mandibles or shiny, bright chafers that feeds on flowers.  

Jewellery of a beetle with a red disc at the top.
Ancient Egyptians used the symbol of the sacred scarab extensively, and likened dung beetles rolling balls of dung to the sun god Ra rolling the sun across the sky each day. Here, Ra as a scarab is pushing a red solar disc. Image: Wikimedia Commons 

Scarab beetles include a diverse range of families that feed on everything from plants and decaying wood to dung, dried carcases, fungus, and soil detritus. There are approximately 32,000 described species in the world, and experts estimate that this number is closer to 50,000 when you include all the undescribed species. This far exceeds the combined number of species of mammals, birds, reptiles, and amphibians. Scarabs have their greatest diversity in tropical regions (there are thousands of species in Central America alone) but occur in most terrestrial habitats worldwide. In Canada, 290 species have been recorded, with a few occurring as far north as the Subarctic Realm above treeline. 

A beetle with huge jaws twice the length of its body.
Male specimen of Grant’s Stag Beetle (Chiasognathus grantii) showing the greatly enlarged mandibles. This species occurs in southern Chile and neighbouring areas of Argentina. Image: Andrew Smith © Canadian Museum of Nature

Scarabs play several key ecological roles. Some recycle nutrients in the dung of herd mammals. Many scarabs are also nectar feeders that pollinate a wide range of plant species, while others play a role in seed burial and germination though soil tunnelling and in ecosystem services such as facilitating the decomposition of dead wood and animals. Because scarabs are everywhere and can be very numerous, they are a major food source for many predators such as other insects, birds, mammals, and reptiles. 

A small percentage of scarab beetles are considered pests due to the damage they inflict on agriculture and native ecosystems. Examples include the Japanese beetle, which can skeletonize many garden plants, and the European chafer, whose grubs (larvae) can destroy lawns. Other invasive species of scarabs have been known to overwhelm and outcompete native species, which has been documented with invasive dung beetles that originated from Africa. 

An orange and green beetle on a plant.
The Japanese beetle is a notorious pest in many parts of North America and can be highly destructive to both garden and native plants. This invasive species is well established in Canada from southern Ontario to the Maritime provinces, and has started showing up in significant numbers in Vancouver, British Columbia. Image: Wikimedia Commons
Green and metallic coloured beetles lined up in a shallow drawer
A drawer of metallic leaf chafers (genus Chrysina) from the museum’s Entomology Collection. This genus occurs from the southwestern United States to Ecuador. Image: Andrew Smith © Canadian Museum of Nature

Our museum has a world-class scarab beetle collection that ranks among the top five in the number of specimens and species represented. Our collection includes some of the largest holdings in the world for many countries in Central and South America and the West Indies such as Argentina, Chile, Cuba, Panama, and Costa Rica. Scientists describe roughly 200 new scarab species annually. We have estimated that there are currently at least 1,000 undescribed species of scarabs housed in the Entomology Collection of the Canadian Museum of Nature.