r/MacroPorn • u/leifcollectsbugs • 1d ago
The red-femured milkweed beetle (Tetraopes femoratus) Shot on my phone 🤳
The red-femured milkweed beetle (Tetraopes femoratus) is a longhorn beetle species recognized by its reddish legs, white-ringed antennae, and specialized diet on milkweed plants.
This insect is distinguished from similar species by its unique physical traits. It features partially red or reddish-orange femurs, whereas the closely related common milkweed beetle has completely black legs. Its black antennae are broken up by bright white or gray rings.
Like other members of its genus, its compound eyes are completely divided by the antennal base, giving it a distinct "four-eyed" appearance. The rest of its body is a striking red-orange color accented by tiny black spots, typically measuring between 8 and 19 mm in length.Native to western North America and parts of the Midwest, these beetles spend their entire life cycles intricately tied to host plants like the showy milkweed (Asclepias speciosa).
While adult beetles openly consume the plant's leaves, stems, and flowers, their larvae burrow underground to feed exclusively on the root systems.
By consuming the milkweed, they absorb cardiac glycosides from the plant's sap, making them highly toxic to predators. Their bright coloration serves as an aposematic warning to birds and other animals that they are poisonous.