The Butterfly Center beat: Everything you ever wanted to know about raising Atlas moths

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The Atlas moth (Attacus atlas) is a large moth belonging to the Saturniidae family. Saturniids, familiarly called giant silk moths, include some of the largest species of Lepidoptera (moths and butterflies). Two local species that may be familiar to readers are the polyphemus and luna moths.

Atlas moths are considered the largest moths in the world in terms of total wing surface area. Their wingspans are also among the largest, often reaching over 10 inches. They are strikingly beautiful, with tawny wings punctuated with translucent “windows” bordered by black. Their most distinguishing feature (other than their size) is an extension of their forewings that resembles a snake’s head, thought to be a means of scaring off potential predators.

The forewing of an Atlas moth resembles a snake’s head. ©Erikki Makkonen

The forewing of an Atlas moth resembles a snake’s head. ©Erikki Makkonen

These spectacular moths make superb additions to the Cockrell Butterfly Center. During the day, they spend most of their time motionless, clinging to the side of a tree or other surface. Visitors can thus get up close to intimately study these creatures, and can clearly observe their fat, furry bodies, fuzzy antennae, and teddy bear like expressions.

Close-up of the fuzzy face and feathery antennae of a female Atlas moth (males have larger antennae). © John Horstman

Close-up of the fuzzy face and feathery antennae of a female Atlas moth (males have larger antennae). © John Horstman

Once night falls, the male Atlas moths take flight in search of a female. The search has a sense of urgency, as adult Atlas moths typically live only about one week. This is because the adults do not have fully formed mouth parts and therefore cannot eat; they are sustained only by the fat reserves they built up as a caterpillar. The moths will quickly mate, lay eggs, and die soon after.

One day at the Cockrell Butterfly Center, a male and female emerged from their cocoons around the same time. We took the opportunity to breed and raise this species of moth. The newly emerged male and female were placed in a flight cage in the greenhouses on the top level of the museum parking garage. They paired the very first night they were together. During mating, the moths remained coupled for several hours. Then, over the next three days, the female laid approximately 150 crimson eggs, placing them indiscriminately along the walls and edges of the flight cage.

A mating pair of Atlas moths clinging to the sides of a flight cage. The larger of the two is the female.

A mating pair of Atlas moths clinging to the side of a flight cage. The larger of the two is the female.

Atlas moth larvae are generalists, meaning they will feed on a wide variety of host plants (but not all plants). Hoping to determine which of several possibilities would be the best food for our caterpillars, we searched the literature for recorded host plants.

We chose four that we had available, including Camphor Tree (Cinnamomum camphora), Vitex (Vitex trifolia purpurea), Mahogany Tree (Swietenia mahoganii) and Sweet Potato Vine (Ipomoea batatas). Gathering the eggs, we divided them among four plastic containers lined with moist paper towels and ventilated with tiny holes poked in the lid, each containing a different kind of leaves.

The eggs took 10 days to hatch. The hatchling larvae were covered in pale protuberances and had black heads. After eating their eggshell, the tiny caterpillars began eating the provided foliage. Once the caterpillars were feeding reliably, they were moved to netted cages containing potted plants, so the leaves would be constantly fresh.

The caterpillars hatched on a Friday in September. To track their weekly growth and development, we took a photograph of them each Friday thereafter. It quickly became obvious that the caterpillars on Camphor were thriving: they grew bigger and faster than their siblings on the other plants (the pictures shown below are of larvae fed on Camphor). In each photograph, larvae were placed next to a standard sized Popsicle stick, fondly known as “Size Reference Ralph,” to track their relative growth.

The caterpillars took six weeks from hatching to pupation. They ate voraciously, becoming soft and fleshy to the touch, and were a pale blue-green color. Their backs were covered in a Mohawk of tubercles with a thick, waxy, flaky coating. After six weeks, the caterpillars were almost as long as Size Reference Ralph and were quite pudgy.

The sequential pictures show the dramatic changes in the larvae, followed by the start of silk spinning, and finally a complete cocoon. Once they finished their cocoons, the larvae pupated inside. We then gently moved the dried cocoons to the emergence chamber inside the entomology hall of the Butterfly Center.

Egg to cocoon in Atlas Moths. Pictures were taken one week apart next to Size Reference Ralph. ( Pictures courtesy of Lauren Williamson)

Egg to cocoon in Atlas Moths. Pictures were taken one week apart next to Size Reference Ralph. (Pictures courtesy of Lauren Williamson)

Then we waited. Atlas moths may eclose from their cocoon in as little as three weeks, but can sometimes take several months. To escape from their silken enclosures, they must excrete a substance that dissolves a hole in the silk, allowing them to crawl out. They then cling to their cocoons while their wings expand and dry.

The first Atlas moth of our batch of cocoons emerged on Dec. 17, almost 3 months after hatching from the egg. It was a large female, with a wingspan of just over 10 inches. As you can see, Size Reference Ralph was dwarfed by her!

Our first Atlas Moth to emerge on Dec. 17th 2013. (picture courtesy of Lauren Williamson)

Our first Atlas moth to emerge on Dec. 17, 2013 (picture courtesy of Lauren Williamson).

Know a girl who’s interested in math and science? Come to GEMS (Girls Exploring Math & Science) on Sat., Feb. 8 from 9 a.m. to 1 p.m. The Museum will be filled with hands-on science and math for everyone to experience. Local professionals will be at the Museum to answer questions about their careers in the fields of science, technology, engineering and math.

The event is free with paid admission to the Museum. Click here for $7 admission to all permanent exhibit halls on Sat., Feb. 8.

 

 

Giant Atlas Moths fluttering into the Butterfly Center soon

atlas moth secret cloaking device revealed
Creative Commons License photo credit: woodleywonderworks

Well, it’s that time of year again… we have started to get Attacus atlas, aka Atlas moths, YEAH!!!!  This is always an exciting time for me because I get to tell everyone who keeps asking me that they are finally here!  Last week, I received 60 atlas moth cocoons from Malaysia and the Philippines.  Unlike the butterflies we receive on a regular basis that all emerge within a few weeks, the atlas moths should be emerging over a few months, so we should have them for a while. 

The Atlas moth belongs to the family of giant silk moths, Saturniidae. They are considered to be the largest moths in the world in terms of wing surface area.  These impressive moths can only be found naturally in Southeast Asia, where they are very common. Their name comes from either the Titan of Greek mythology or from the striking pattern on their wings, which resembles a map.  If you look at the tips of the forewings they resemble a snakes head, which makes for great predator protection.

The females are significantly larger than the males, especially their abdomen because she has to lay a bunch of eggs, which are already developed and ready to be fertilized.  The males have larger, bushier antennae, in order to detect female pheromones. 

 The females
are larger and have bigger abdomens

 The males are smaller and have longer antennae

 

Each moth starts it’s life as a beautiful, emerald-colored caterpillar. The larvae feed on a wide variety of food plants, and may even wander from one to another.  As it gets bigger it developes a more waxy, light-white-ish green coloration.  It then spins a silken cocoon to protect itself and pupates inside (This is different from butterflies who develop inside a chrysalis, not a cocoon).  The adults, as in other Saturniids, have no mouth parts whatsoever, so they cannot feed. They survive off of fat reserves they build up as caterpillars.

Moth
Polyphemus Moth
Creative Commons License photo credit: Andreanna

Moths fly at night, so you may see these large moths resting on trees in the Butterfly Center during the day, paying no attention to the butterflies fluttering all around them.  I try really hard each time a moth emerges to place it in a very obvious place so people can see them.  Many people think they are fake because they sit so still, but now you know they are not!

Some other moths that belong in the Saturniidae family that you can find around here include the cecropia moth (Hyalophora cecropia), polyphemus moth (Antheraea polyphemus), and the luna moth (Actias luna).  These moths aren’t as big as the atlas moth, but they are big when compared to other moths and butterflies in Texas. 

luna
Luna Moth
Creative Commons License photo credit: Aunt Owwee


I hope you get a chance to stop off and see our wonderful giants and keep a look out for the native moths, they are a wonder to see too!

The Black Swallowtail

I would like to introduce you to my favorite caterpillar, the Black Swallowtail, Papilio polyxenes.

I knew I had not seen a Black Swallowtail butterfly in my garden for a few weeks so, I thought I might not have any caterpillars to take a photo of. 

I was so pleased when I saw a large caterpillar resting on a stem covered in the fresh morning dew – especially when it just happened to be a Black Swallowtail. The caterpillars, when almost mature, are uniformly colored with their soft green skin etched in jet black stripes and speckled with lemon yellow dots.  The caterpillar’s soft creamy foot pads adhered so tightly to the stem swaying in the breeze, it looked as though it would never let go. It was certainly an unexpected pleasure.

The early stages of these larvae look like bird droppings.  This is a method of camouflage that protect them from predators. I ran to get my camera and tried to get a good shot.  Not wanting to disturb the larvae, I sat down in the grass next to the garden bed and took the photo.

The Black Swallowtail butterfly is a graceful flyer swaying from left to right (not in a zigzag, but in a gentle glide swaying from side to side.)  The Black Swallowtail male and female butterflies are dimorphic, meaning that they have a difference in the coloration of their wing patterns.

Blacktail Swallowtail Host Plant

The host plants of the Black Swallowtail are in the parsley family such as carrots, parsley, dill and celery fennel.  I recall one afternoon late in the fall, a museum visitor brought in some Black Swallowtail caterpillars because they had eaten all the parsley in her garden and she was worried that they would not live.

I placed the caterpillars in a plastic shoe box with holes in the lid.  Inside the box I placed a slightly moist paper towel and some fresh organic parsley I purchased at the grocery.  The caterpillars were just fine with this method of alternative feeding.  They all pupated on the lid of the box and remained in good health. Within a few weeks time they were set free atop the 7th floor of the parking garage.  They gently took the breeze on down to the Cockrell Butterfly Center’s Demonstration garden and began their life cycle once again.

Stop by the Demonstration garden the next time you visit the museum and see if you can spot any caterpillars.

Sky High Delivery! News from the greenhouse

Guess what I found on the curled up leave of our potted Camphor Tree last week!

Seven absolutely beautiful Spicebush Swallowtail caterpillars, Papilio Troilus, of various sizes, just hanging out for the day, all curled up in their little hideaway.

Swallowtails are a beautiful sight to the eye as they gracefully sail down into the garden.  Outside the greenhouse area, we quite often have visitors in flight feasting upon our smorgasbord of tasty nectar sources.  Not only do they find the feast of nectar sources available to them, but they also check to see if we have any host plants available to lay their eggs upon while they are visiting us.

spicebush-swallowtail-pupae-resize.jpg

The Caterpillar has formed a chyrsalis
photo credit: Don Johnson

And that is just what this Swallowtail did.  She lighted upon the leaves of our potted Camphor Tree, Cinnamomum camphora, and in doing so she triggered hormones from the pads of her feet that let her know this is the food source for her offspring. 

To our delight, she delivered  to us  her brood of eggs.  During the first few weeks of life, the caterpillar of this specific butterfly takes on the beneficial camoflauge of bird droppings.  After a few weeks, the larvae, or caterpillar, boasts a beautiful green covering with artificial eye spots outlined in black resting within a background coloring of creamy yellow. 

In order to hide out during the day and feast at night, the caterpillar spins silk in a back and forth motion across the midrib of the upper side of the leaf. This silk causes the leaf to curl up around their bodies protecting them from predators during the day. 

spicebush-pupation-yellow-don-j-resize.jpg

The caterpillar turns yellow before pupation.
Photo credit: Don Johnson

Other known Host Plants of the Spicebush Swallowtail Butterfly are the Sassafras Tree, Sassafras albidum, Red Bay, Persea borbonia, and the Sweet Bay, Magnolia virginiana.

Fluttering across the pink

Spciebush Swallowtail Butterfly

Creative Commons License photo credit: Benimoto

It never ceases to amaze me, that these delicate creatures find their way up here to the seventh floor  of the parking garage amidst all the concrete and stone.  They leave their gifts of life to us; another beautiful butterfly family to carry on and inspire us with their sense of wonder.