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 in the brush-footed butterfly family, Nymphalidae. This species is found in both North and South America. The larval host plants are '' Celtis'' 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 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 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. 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, 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, Kansas, and the Lake Erie Islands. 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 IFAS may refer: * Institute of Food and Agricultural Sciences * Integrated Fixed-Film Activated Sludge, a sewage treatment process * International French adjectival system In rock climbing, mountaineering, and other climbing disciplines, clim ...

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