The milkweed leaf beetle, or swamp milkweed leaf beetle (''Labidomera clivicollis'') is a species of leaf beetle from the family

Chrysomelidae The beetle family Chrysomelidae, commonly known as leaf beetles, includes over 37,000 (and probably at least 50,000) species in more than 2,500 genera, making it one of the largest and most commonly encountered of all beetle families. Numerous s ...

. It is found in eastern Northern America. These leaf beetles are round bodied, 8–11 mm in length, with a black head and

pronotum The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites (exoskeletal plates) are the pronotum (dorsal), the prosternum (ventral), and the propleuron (lateral) on e ...

and bright orange to yellow

elytra An elytron (; ; : elytra, ) is a modified, hardened forewing of beetles (Coleoptera), though a few of the true bugs (Hemiptera) such as the family Schizopteridae are extremely similar; in true bugs, the forewings are called hemelytra (sometime ...

with variable mottled black patches. ''L. clivicollis'' somewhat resembles a large ladybird beetle, and though it is not in the ladybird

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

(

Coccinellidae Coccinellidae () is a widespread family (biology), family of small beetles. They are commonly known as ladybugs in North America and ladybirds in the United Kingdom; "lady" refers to Mary, mother of Jesus, mother Mary. Entomologists use the ...

), it is closely related (

infraorder Order () is one of the eight major hierarchical taxonomic ranks in Linnaean taxonomy. It is classified between Family_(biology), family and Class_(biology), class. In biological classification, the order is a taxonomic rank used in the classific ...

Cucujiformia Cucujiformia is an infraorder of polyphagan beetles, representing most plant-eating beetles. The infraorder contains the seven superfamilies: * Chrysomeloidea (~7 families including longhorn beetles and leaf beetles) * Cleroidea (checkered be ...

).The

larvae A larva (; : larvae ) is a distinct juvenile form many animals undergo before metamorphosis into their next life stage. Animals with indirect developmental biology, development such as insects, some arachnids, amphibians, or cnidarians typical ...

are light orange, white, or gray with a black

and prominent black spots on the spiracles. They are

grub GNU GRUB (short for GNU GRand Unified Bootloader, commonly referred to as GRUB) is a boot loader package from the GNU Project. GRUB is the reference implementation of the Free Software Foundation's Multiboot Specification, which provides a use ...

-like and can be found feeding on

milkweeds ''Asclepias'' is a genus of herbaceous, perennial, flowering plants known as milkweeds, named for their latex, a milky substance containing cardiac glycosides termed cardenolides, exuded where cells are damaged. Most species are toxic to huma ...

, especially

swamp milkweed ''Asclepias incarnata'', the swamp milkweed, rose milkweed, rose milkflower, swamp silkweed, or white Indian hemp, is a herbaceous perennial plant species native to North America. It grows in damp through wet soils and also is cultivated as a gar ...

. Milkweed leaf beetle

can be distinguished from visually similar and closely related species by color, host plant, and number of spots.

Diet

There are a number of ''L. clivicollis'' host plants which are toxic to most herbivores. Many are in the dogbane family (

Apocynaceae Apocynaceae (, from '' Apocynum'', Greek for "dog-away") is a family of flowering plants that includes trees, shrubs, herbs, stem succulents, and vines, commonly known as the dogbane family, because some taxa were used as dog poison. Notable mem ...

) including milkweeds, especially swamp milkweed (''

Asclepias incarnata ''Asclepias incarnata'', the swamp milkweed, rose milkweed, rose milkflower, swamp silkweed, or white Indian hemp, is a herbaceous perennial plant species native to North America. It grows in damp through wet soils and also is cultivated as a gar ...

'') and 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 ...

''); swallow-wort (''

Cynanchum ''Cynanchum'' is a genus of about 300 species including some swallowworts, belonging to the family Apocynaceae. The taxon name comes from Greek ''kynos'' (meaning "dog") and ''anchein'' ("to choke"), hence the common name for several species is ...

''); twinevine (''

Funastrum ''Funastrum'' is a genus of flowering plant now in the family Apocynaceae. The name is derived from the Latin word ''funis'', meaning "rope", and ''astrum'', alluding to the twining stems. Members of the genus are commonly known as twinevines. S ...

'').

Life cycle

The female lays small groups of orange jellybean-like eggs on its host plant. Miniature sized larvae, about the same shape as later instars, hatch in about a week and graze night and day. Labidomera clivicollis eggs

Finally the mature larvae move to the soil to pupate. After a few weeks, adults emerge to start the next generation eating the same host plants as the larvae. An adult may displace a monarch larvae to feed at the same site. As autumn approaches, the adults feed and eventually find places to shelter through the winter.

Acquired protection

The bright coloration of the milkweed leaf beetle is a classic example of Aposematism. Several insects that share some of the same hosts sport similar warning coloration: monarch, milkweed tussock moths, milkweed beetles and milkweed bugs and hence illustrate Műllerian mimicry. These insects have evolved the ability to thrive on these plants despite the presence of noxious poisons the plants have evolved to protect themselves from most herbivores. These toxins help protect these insects from being eaten by visually gifted predators like birds that regularly prey on caterpillars, butterflies, and beetles. The conspicuous orange and black colors serve as a reminder of a potentially nasty gastronomic misadventure to experienced birds and other predators that may have attempted to make a meal of them.

References

{{Taxonbar, from=Q3214341 Chrysomelinae Taxa named by William Kirby (entomologist) Beetles described in 1837