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Tetraopes tetrophthalmus

What do they look like?

Red milkweed beetles are 8-15 millimeters long. They are narrow, thin beetles. They are reddish in color with matching black spots. Their antennae are smooth. Larvae are pale in color, elongated, and ridged. The food that they eat impacts how big they grow. (Coin, et al., 2019)

  • Sexual Dimorphism
  • sexes alike
  • Range length
    8 to 15 mm
    0.31 to 0.59 in

Where do they live?

Tetraopes tetrophthalmus, commonly known as red milkweed beetles, are native to the Nearctic. They are found in the northeastern part of North America. (Coin, et al., 2019)

Tetraopes tetrophthalmus, commonly known as red milkweed beetles, are found in the northeastern part of North America. (Coin, et al., 2019)

What kind of habitat do they need?

Red milkweed beetles are most commonly found near their host plant, common milkweeds. (Coin, et al., 2019)

  • These animals are found in the following types of habitat
  • temperate

How do they grow?

Red milkweed beetles go through different stages of development. Larvae go through a few stages before becoming pupae. They undergo metamorphosis in order to become adults.

How do they reproduce?

Red milkweed beetles use internal fertilization and sexual reproduction. Females lay eggs on their host plants. Females select larger males for mating over the smaller males. (Mason, 1983)

Red milkweed beetles do not take care of their young.

  • Parental Investment
  • no parental involvement

How long do they live?

The lifespan of red milkweed beetles has not been determined.

How do they behave?

Adult red milkweed beetles move around to eat during June and July. They spend their time alone. As fliers, red milkweed beetles are able to easily move around. (Mason, 1983)

How do they communicate with each other?

Red milkweed beetles mostly communicate through pheromones. They use visual, tactile, and chemical senses of perception.

What do they eat?

Red milkweed beetles eat the leaves, stems, and flowers of their host plant, common milkweeds. They have also been observed feeding on horsetail milkweeds. Those that eat horsetail milkweeds are smaller than those that eat on common milkweeds. Adults eat the leaves and stems. Larvae eat the roots. (Coin, et al., 2019; Mason, 1983)

  • Plant Foods
  • leaves
  • wood, bark, or stems
  • flowers

What roles do they have in the ecosystem?

Red milkweed beetles impact the species of plants from which they feed.

Do they cause problems?

They can be household pests.

  • Ways that these animals might be a problem for humans
  • household pest

Are they endangered?

Red milkweed beetles are not currently undergoing any conservation efforts.


Deena Hauze (author), Animal Diversity Web Staff.


Coin, P., B. Moisset, R. McLeod, M. Quinn. 2019. "Species Tetraopes tetrophthalmus - Red Milkweed Beetle" (On-line). Bug Guide. Accessed October 23, 2020 at

Erwin, A., T. Züst, J. Ali, A. Agrawal. 2014. Above-ground herbivory by red milkweed beetles facilitates above- and below-ground conspecific insects and reduces fruit production in common milkweed. Journal of Ecology, 102(4): 1038-1047. Accessed October 26, 2020 at

Mason, L. 1983. Secondary Sexual Characteristics and Sexual Selection in Tetraopes. The American Midland Naturalist, 110(2): 235-239.

Matter, S. 2009. Abundance of an Herbivorous Beetle: Factors Affecting Dispersal and Local Reproduction. The American Midland Naturalist, 162(1): 19-28. Accessed October 26, 2020 at

Price, P., M. Willson. 1976. Some Consequences for a Parasitic Herbivore, the Milkweed Longhorn Beetle, Tetraopes tetrophthalmus, of a Host-Plant Shift from Asdepias syriaca to A. verticillata. Oecologia, 24(4): 331-340. Accessed October 26, 2020 at

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Hauze, D. 2021. "Tetraopes tetrophthalmus" (On-line), Animal Diversity Web. Accessed April 22, 2024 at

BioKIDS is sponsored in part by the Interagency Education Research Initiative. It is a partnership of the University of Michigan School of Education, University of Michigan Museum of Zoology, and the Detroit Public Schools. This material is based upon work supported by the National Science Foundation under Grant DRL-0628151.
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