The American snout or common snout butterfly (''Libytheana carinenta'') is a member of the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

Libytheinae The Libytheinae are a nymphalid subfamily known as snout butterflies, containing two valid genera and about ten species: six in '' Libythea'' and four in ''Libytheana''. The common name refers to the thick labial palps (pedipalps) that look like ...

in the brush-footed butterfly

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

Nymphalidae The Nymphalidae are the largest family of butterflies, with more than 6,000 species distributed throughout most of the world. Belonging to the superfamily Papilionoidea, they are usually medium-sized to large butterflies. Most species have a red ...

. This

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

is found in both North and South America. The larval host plants are ''

Celtis ''Celtis'' is a genus of about 60–70 species of deciduous trees, commonly known as hackberries or nettle trees, widespread in warm temperate regions of the Northern Hemisphere. The genus is part of the extended hemp family (Cannabaceae). De ...

'' species on which the eggs are laid singly. Massive migrations of this species often attract attention in the Texas and Mexican newspapers.

Description

Snout butterflies have prominent elongated mouthparts (labial palpi) which, in concert with the antennae, give the appearance of the petiole (stem) of a dead leaf. Snouts often take advantage of this superb

camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the ...

by hanging upside down under a twig, making them nearly invisible. Wings are patterned black-brown with white and orange markings. The forewings have a distinctive squared off, hook-like (falcate) tip. American snout butterfly

The

caterpillars Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder Symph ...

appear humpbacked, having a small head, swollen first and second abdominal segments, and a last abdominal segment which is tapered and rounded. They are dark green with yellow stripes along the top and sides of the body, and have two black tubercles on the top of the

thorax The thorax or chest is a part of the anatomy of humans, mammals, and other tetrapod animals located between the neck and the abdomen. In insects, crustaceans, and the extinct trilobites, the thorax is one of the three main divisions of the cre ...

. Their food is the common hackberry (''

Celtis occidentalis ''Celtis occidentalis'', commonly known as the common hackberry, is a large deciduous tree native to North America. It is also known as the nettletree, sugarberry, beaverwood, northern hackberry, and American hackberry. It is a moderately long-l ...

'') tree.

Migrations

This species is known to be migratory, and some years the migrations are so huge as to darken the sky in places. Migrations from

South Texas South Texas is a region of the U.S. state of Texas that lies roughly south of—and includes—San Antonio. The southern and western boundary is the Rio Grande, and to the east it is the Gulf of Mexico. The population of this region is about 4.96 ...

northward occur at irregular intervals when southern populations explode, often affecting

San Antonio ("Cradle of Freedom") , image_map = , mapsize = 220px , map_caption = Interactive map of San Antonio , subdivision_type = Country , subdivision_name = United States , subdivision_type1= U.S. state, State , subdivision_name1 = Texas , s ...

, the

Texas Hill Country The Texas Hill Country is a geographic region of Central and South Texas, forming the southeast part of the Edwards Plateau. Given its location, climate, terrain, and vegetation, the Hill Country can be considered the border between the Ameri ...

, and

Austin Austin is the capital city of the U.S. state of Texas, as well as the seat and largest city of Travis County, with portions extending into Hays and Williamson counties. Incorporated on December 27, 1839, it is the 11th-most-populous city ...

. Other migrations have been observed in

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

Kansas Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the ...

, and the

Lake Erie Islands The Lake Erie Islands are a chain of archipelagic islands in Lake Erie. They include Kelleys Island, Erie Island, Pelee Island, the Bass Islands, and several others. The majority of these islands are under the sovereignty of the State of Ohio in t ...

. Migrations occur from June through October, and are thought to be triggered by droughts followed by heavy summer rains: the droughts reduce a

parasitoid In evolutionary ecology, a parasitoid is an organism that lives in close association with its host (biology), host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionarily stable str ...

that would otherwise limit butterfly populations, whereas the rains induce the spiny hackberry to grow new leaves which provide food for caterpillars. Furthermore, whereas the droughts send the butterflies into a sort of hibernation, the rains bring them out of it all at once to lay eggs, causing a population explosion. In Texas, years in which migrations were observed include 1921, 1978, 1996, 2018, 2020, and 2022.

References

External links

Tree of Life Libytheinae

Cirrus Digital Imaging

on the UF / IFAS Featured Creatures website Butterflies of North America Butterflies of the Caribbean Libytheana Butterflies described in 1777 Nymphalidae of South America Taxa named by Pieter Cramer {{nymphalidae-stub