Locust Borer vs Riffle Beetle

Side-by-side species comparison

Attribute Locust Borer Riffle Beetle
Scientific Name Megacyllene robiniae Elmis aenea
Order Coleoptera Coleoptera
Family Cerambycidae Elmidae
Size 14-22 mm 1.5-2.5 mm
Habitat Farmland Rivers & Streams
Diet Pollen Feeders Detritivores
Regions Eastern and Central North America Europe
Conservation Least Concern Least Concern

Locust Borer

A striking yellow-and-black wasp mimic that attacks black locust trees in North America. Adults appear in autumn and are commonly found on goldenrod flowers. Larval boring weakens locust trunks and can cause breakage.

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Did You Know?

Adults synchronize their emergence with goldenrod bloom, making autumn fields their primary mating arenas.

Riffle Beetle

A tiny, dark beetle that spends its entire adult life underwater clinging to rocks in riffles. It breathes using a plastron, a permanent thin film of air.

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Did You Know?

Its plastron air film never needs replenishing, allowing it to remain permanently submerged.