The red milkweed beetle (''Tetraopes tetrophthalmus'') is a

beetle Beetles are insects that form the order Coleoptera (), in the superorder Endopterygota. Their front pair of wings are hardened into wing-cases, elytra, distinguishing them from most other insects. The Coleoptera, with about 400,000 describ ...

in the family

Cerambycidae The longhorn beetles (Cerambycidae), also known as long-horned or longicorns, are a large family of beetles, with over 35,000 species described. Most species are characterized by extremely long antennae, which are often as long as or longer than ...

Explanation of names

The binomial genus and species names are both derived from the

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...

for "four eyes." As in many longhorn beetles, the antennae are situated very near the eye–in the red milkweed beetle, this adaptation has been carried to an extreme: the antennal base actually bisects the eye (See Fig. 1).

Host plants

The milkweed beetle, a herbivore, is given this name because it is host-specific to common milkweed (''

Asclepias syriaca ''Asclepias syriaca'', commonly called common milkweed, butterfly flower, silkweed, silky swallow-wort, and Virginia silkweed, is a species of flowering plant. It is native to southern Canada and much of the United States east of the Rocky Moun ...

''). It has been reported on horsetail milkweed (''

Asclepias verticillata ''Asclepias verticillata'', the whorled milkweed, eastern whorled milkweed, or horsetail milkweed, is a species of milkweed native to most of eastern North America and parts of western Canada and the United States. Description This is a perenn ...

'') in a disturbed site in Illinois.

Toxicity

It is thought the beetle, which as an adult feeds on the foliage of the plant, and its early

instar An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ass ...

s, which eat the roots, derive a measure of protection from predators by incorporating

toxin A toxin is a naturally occurring organic poison produced by metabolic activities of living cells or organisms. Toxins occur especially as a protein or conjugated protein. The term toxin was first used by organic chemist Ludwig Brieger (1849– ...

s from the plant into their bodies, thereby becoming distasteful, much as the

monarch butterfly The monarch butterfly or simply monarch (''Danaus plexippus'') is a milkweed butterfly (subfamily Danainae) in the family Nymphalidae. Other common names, depending on region, include milkweed, common tiger, wanderer, and black-veined brown. It ...

and its larvae do.

Behavior

These beetles feed by opening veins in the milkweed plant, decreasing the beetles' exposure to latex-like sap. When startled, the beetles make a shrill noise, while they make a 'purring' noise when interacting with another beetle. The red and black coloring are

aposematic Aposematism is the advertising by an animal to potential predators that it is not worth attacking or eating. This unprofitability may consist of any defences which make the prey difficult to kill and eat, such as toxicity, venom, foul taste or ...

, advertising the beetles' inedibility. Red milkweed beetles lay egg-clutches in mid-summer inside the stem base of the milkweed plant.

References

External links

* {{Taxonbar, from=Q577252 Tetraopini Aposematic species Beetles described in 1771 Taxa named by Johann Reinhold Forster