The Common or American Snout butterfly (Libytheana carinenta) is most easily recognizable by its pronounced labial palpus, which are both olfactory and gustatory organs of the butterfly mouth, and resemble, as the name suggests, a snout. This unusual butterfly is quite common, particularly in the southern regions of the U.S., as well as northern Mexico, but has also been known to migrate as northward as Canada. The snout is classified within its own sub-family, Lytheandae (containing only approximately eight species) that is part of the Nymphanidae (or Brush-footed category), because the larvae lack the spines and horns of most Nymphalidae, and the pupae lack the dorsal bumps of most Nymphalinae. At different times, and by different entomologists, snouts have been classified into 12 species, three genera and ten species, and divided between the Libythea and Libytheana species in a configuration of either seven and five, or nine and four respectively. Currently, there appear to be several subspecies of L. carinenta (including, bachmanii, larvata, mexicana and motya) ranging from Argentina to Canada, but it remains controversial as to where exactly to classify these inauspicious butterflies. If you would like to learn more about the specific anatomical reasons for these classifications, check out this post at the University of Houston. For a more complete history and taxonomy of butterflies, I recommend this article from Citizendia.
My research into this stunning little creature was frustratingly conflicted when it came to taxonomy and identification of the pair I photographed, but what we do know is that the adult butterflies remain relatively near the host food plant for their young. In the Sonoran desert, that is most commonly the Desert or Spiny Hackberry (another difficult taxonomy because of the subspecies and multiple nicknames). Their wingspan is approximately 1 3/8 – 2 inches (3.5 – 5 cm), and they flutter on those tiny wings around 30 cm from the ground in a characteristic bouncy zigzag pattern as they search for landing spots. They appear to be quite hardy, as their habitat varies between tropical savannas, deserts, swamps, forests, canyons, grasslands, marshy meadows, thorn scrub woodlands, and ponds. The snouts meet, mate and ovideposit on the underside of the leaves of the hackberry shrub, where the larvae will hatch, eat and pupate. Once in their adult phase (which from hatching can take as little as 12 days, although 15 to 17 days is more typical), they are almost exclusively nectar feeders, and have been spotted sipping upon: acanthas, aster, cowbane, chrysanthemum, dogbane, dogwood, globe amaranth, goldenrod, knapweed, lantana, madeira vine, milkweed, sumac, sweet pepperbush, thistle and verbena, among others. (Kawahara & Dirig, 2006) They may also seek out vertebrate perspiration, ground water, juice from fruit, urine and aphid secretions.
A fascinating facet of snout reproduction is not so much that the number of generations per year vary between two and four, depending on climate and host plant availability, but that the generations following the first generation of each year often mature faster from egg to adult. Also, it is generally the full-grown fifth instar larva that pupates, but if a generation is hatched late in the year, or if the food source is uncharacteristically scarce, a fourth or even third instar larva may pupate.
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