Beetles are an incredibly diverse group of insects. Belonging to the order Coleoptera, there are over 350,000 distinct species of beetle the world over. There are nearly 30,000 unique beetle species in the U.S. alone. While many larger species exist throughout the Earth’s warm tropics, the largest beetle in North America resides in the U.S. and ranks among the largest in the world. In this article, we’ll take a look at some of the largest species of beetle in the U.S. Read on to discover how big they get, where they live, and what makes each one unique.
5. Horned Passalus
The horned passalus feeds on decaying hardwood trees such as oak and elm.
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The horned passalus (Odontotaenius disjunctus) goes by many names. Known colloquially as the bess beetle, betsy beetle, peg beetle, strong boy, or horn beetle, it is the most frequently occurring member of its family on the continent. This beetle can be found throughout most of the eastern United States, ranging from Florida to Massachusetts and extending west to Nebraska. Its range also includes the Midwest, the Great Lakes region, and the mid-South. They feed on fallen, decaying hardwood trees such as oak and elm.
The horned passalus is a dark, glossy black and can reach lengths of around 1.6 inches. This species has a pronotum, which is the exoskeletal plate covering the first segment of the thorax, with a single, deep, central groove. Their elytra, or hardened forewings, are deeply grooved in their entirety. They also have golden-yellow hairs that cover their middle pair of legs, pronotum, and antennae. Between the eyes of both sexes is a small, curved horn, earning this species its common name.
4. Giant Carrion Beetle
Giant carrion beetles are listed as critically endangered by the IUCN.
The giant carrion beetle (Nicrophorus americanus), also known as the American burying beetle, is a beautiful insect that derives both of its common names from its behavior. They bury themselves under soil or vegetation during the day, then in the evening, they fly out in search of carrion. While their range once spanned the vast majority of the temperate, eastern portion of the continent, they are currently believed to be extirpated from all but nine U.S. states. They are currently listed as Critically Endangered on the IUCN’s Red List.
These are the largest carrion beetles in North America, reaching up to 1.8 inches in length. They are a shiny black with reddish-orange markings. These beetles also have a large reddish-orange marking on their raised pronotum. They can inhabit a wide range of environments, as long as there are birds, small mammals, reptiles, and other sources of carrion that both adults and larvae need for food.
3. Giant Stag Beetle
Male giant stag beetles are distinguishable by their giant, antler-like mandibles.
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The giant stag beetle (Lucanus elaphus) easily ranks on the list of the largest beetles in the United States. This species appears across the east coast of the United States, ranging from Florida to the Northeast and westward to Nebraska. They favor deciduous forests and can often be found on rotting logs. They primarily feed on plant juices, tree sap, and rotting fruit.
These beetles are reddish-brown to black, and males can grow to nearly 2.5 inches including their mandibles, or mouthparts. Male stag beetles are instantly recognizable by these elaborate mandibles for which the species earned its scientific name elaphus — derived from the Greek word for deer. These robust mandibles extend from the beetle’s head like a rack of antlers on a buck. Like a buck, the male beetle uses its mandibles for mating displays and territorial defense. Females also have mandibles, but they are much smaller and are used for digging.
2. Eastern Hercules Beetle
The Eastern Hercules beetle has a wide distribution across the eastern half of the U.S.
The Eastern Hercules beetle (Dynastes tityus) appears throughout the eastern half of the United States. Their range extends from New York to Florida and west to Texas. They prefer forested areas with hardwood trees and are often seen around fallen trees and rotting logs. They have been observed consuming tree bark, leaves, rotting fruit, and tree sap.
These massive beetles can reach up to 2.5 inches long, including the horns. They are normally tan, green, or grey with dark spots. Eastern Hercules beetles are sexually dimorphic. Only the males have a pair of long, robust horns used to assert dominance and fight over potential mates. All species belonging to this beetle’s taxonomic subfamily, Dynastinae, possess horns and share the common name “rhinoceros beetle.”
1. The Western Hercules Beetle
Western Hercules beetles are the largest beetles in North America.
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The Western Hercules beetle (Dynastes grantii) is the largest beetle crawling around the U.S. In fact, it is the largest beetle in North America. These rhinoceros beetles can be found in the southwest, including Arizona, New Mexico, and Utah. They prefer mixed highland forests of pine and oak, where they feed on tree sap and other juices. Hercules beetles are not pests, and their larvae are important decomposers in their ecosystems.
Although they are very similar to their Eastern cousins, the Western Hercules beetle has longer horns. The female beetles lack horns. They can reach up to 3 inches in length, including their horns, and some individuals may grow even larger. The Western Hercules beetle can also be distinguished by its widely bifurcated horns, while the Eastern Hercules beetle has only a slight bifurcation or none at all. Western Hercules beetles are always pale grey with dark spots. Despite their impressive size, both Western and Eastern Hercules beetles can also fly, making them some of the largest flying insects on Earth.
