Sunday, September 25, 2011

Weekend Wonders: Beautiful Butterflies and Moths of Georgia

Female Monarch Butterfly from Wikipedia

I saw my first Monarch Butterfly (Danaus plexippus) of the year a few days ago, a sure sign that autumn is fast approaching.  We have many species of beautiful Lepidoptera here in Georgia, and this year they have been especially abundant.  While I am by no means an expert and can only identify a few, I thought I would describe some of my favorites today, starting with the majestic Monarch.  This good-sized orange and black butterfly is famous for its annual migration from as far north as Canada to Mexico for the winter.  Females lay their eggs on milkweed plants such as Asclepias tuberosa, which the caterpillars then feed on.  Toxic compounds from the plant make these caterpillars distasteful to predators.  The butterflies that emerge from the beautiful blue-green chrysalises feed on the nectar of flowers from milkweed, red clover, and goldenrod, among others.

Butterfly Milkweed (Asclepias tuberosa) from Wikipedia

The Eastern Tiger Swallowtail Butterfly (Papilio glaucus) is the state butterfly of Georgia.  These butterflies are large and rather lazy, but can also be aggressive to other butterflies.  They are much less nervous than most species -- after seeing me hanging around for a couple of days taking pictures, they pretty much ignored me, or even flew out to investigate when I appeared, making it quite easy to photograph them!  The males (top photo) are always the typical yellow and black color with vertical black stripes at the tops of the wings, but females can either be this color (middle photo) or a dark, almost black morph (bottom photo).

Male Tiger Swallowtail Butterfly
Yellow morph female Tiger Swallowtail Butterfly
Dark morph female Tiger Swallowtail Butterfly

The females lay their eggs singly on host plants mainly in the Magnoliaceae and Rosaceae families (top photo), preferably near nectar sources such as the Butterfly Bush (Buddleja spp.) (bottom photo).  Younger caterpillars mimic bird droppings as a predator deterrent, while older ones develop eyespot markings to resemble snakes as a defense.  Dark morph female Tiger Swallowtails apparently mimic another swallowtail species, the Pipevine Swallowtail (Battus philenor), which is poisonous to predators.

Magnolia grandiflora with berry cluster
Butterfly Bush (Buddleja davidii) flowers

The Black Swallowtail Butterfly (Papilio polyxenes) is a slightly smaller and more active relative of the Tiger Swallowtail.  The wings of this butterfly are mostly black with yellow spots -- the hindwing of the female also has an iridescent blue band.  Eggs are laid on plants of the family Apiaceae, which includes carrots as well as favorite garden herbs such as dill, parsley, and fennel.  Caterpillars have an interesting defense mechanism called the osmeterium, which is a forked orange appendage that everts and releases a foul smell to repel predators.  The black morph of the female Eastern Tiger Swallowtail superficially resembles the Black Swallowtail Butterfly, but is larger and has no yellow spots on the middle of the wings.

Female Black Swallowtail Butterfly from Wikipedia

I make a point of growing dill and parsley every year just for the Black Swallowtails to use as host plants for their eggs.

A luminous dill flower
Voracious Black Swallowtail caterpillars polishing off the dill flower

Some caterpillars do succumb to predation, especially the younger ones.

Hungry Anolis lizards (Anolis carolinensis) attempt to consume Black Swallowtail caterpillars

But some of the caterpillars always manage to survive and grow into the next generation of beautiful butterflies.

Black Swallowtail Butterfly sipping nectar from a petunia flower

The Gulf Fritillary Butterfly (Agraulis vanillae) is slightly smaller than the swallowtails, and has brilliantly colored orange wings with spots that are more obvious on the undersides than the tops of the wings.  Despite the name and resemblance, according to Wikipedia it is not a true fritillary butterfly.  The first part of the common name is derived from the fact that this species often migrates in large numbers over the Gulf of Mexico.

A Gulf Fritillary enjoying the nectar of Lantana flowers

The eggs are laid exclusively on passion flower species such as the Maypop (Passiflora incarnata).

Maypop vines grow wild on our horse pasture fences

The caterpillars feed on the passion flower leaves, which makes them toxic to most predators.  The cultivation of passion flower species in gardens has allowed this butterfly to extend its range from the East Coast all the way to California.

The Luna Moth (Actias luna), a large, pale green moth, has a wingspan of up to 4.5 inches, making it one of the largest moths in North America.  Males have longer and bushier antennae than females.  The sight of one of these beautiful moths in flight at dusk is something that you will never forget -- they are truly impressive!

Luna Moth from Wildlife Collective

The adult moths do not feed or even have mouths, and only live for about a week, dying soon after reproducing.  Here in Georgia they can go through as many as three generations in a year, from March to September.  Females lay eggs on a variety of host plants, including Sweetgum (Liquidambar styraciflua) (top photo), American Persimmon (Diospyros virginiana), White Birch (Betula papyrifera), alder (Alnus spp.), walnut (Juglans spp.), hickory (Carya spp.), and sumac (Rhus spp.) (bottom photo).

Sweetgum in early autumn splendor
Winged Sumac (Rhus copallina) with berry cluster

I had never seen a Rosy Maple Moth (Dryocampa rubicunda) before we moved to Georgia, even though they are apparently quite widespread in the United States.  They seem to be attracted to the night light above my barn door and I will often find one or two on the door on spring mornings.  The color of these moths is strikingly beautiful.  The ones in our area have broad bands of buttery yellow and slightly purplish pink on their wings, with fuzzy yellow bodies.

Rosy Maple Moth from RTNMT

As many as three broods are possible in the South from March to October.  Adults do not feed.  Eggs are laid on maple (Acer spp.) and oak (Quercus spp.) tree leaves.  The caterpillars, called Green-Striped Mapleworms, feed on the leaves of these trees and may become pests, but as far as I am concerned we have more than enough oak trees to support a population of these gorgeous creatures!  Water Oaks (Quercus nigra) are the most abundant on our property, with some Willow Oaks (Q. phellos) and the occasional Turkey Oak (Q. laevis) as well.

Water Oak with acorns
Willow Oak, less abundant on our acreage than Water Oaks

My interest in Lepidoptera is very recent, and I am only able to identify the larger and/or more colorful ones at this point.  I hope to expand my horizons in the future and learn to recognize a great many more species.  An excellent internet source of information about butterflies and moths that will help me out can be found here.  Hopefully my camera skills will develop along with my ability to identify butterflies and moths so I can keep a photographic record of all that I see!

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