What in the World is THAT!!??

We often receive pictures that look completely and totally alien and WEIRD to most people, but like good little Entomologists, we know exactly what they are! The picture sent in to us most recently from a gentleman in Deer Park is a two-for-one special!

Have you ever seen a very large green caterpillar with strange-looking white ovals protruding from it? Well, it’s not just one insect, it’s two.

The picture clearly shows a large green caterpillar with a horn on it’s rear. It’s a little blurry, but it’s clearly a type of hornworm. Hornworms are the larvae of sphinx moths. Sphinx moth caterpillars are characterized by a horn-like appendage on their last segment, giving rise to the common name. This is more than likely a tomato or tobacco hornworm. These caterpillars can devastate plants in the solanaceae family (tomatoes, tobacco, potatoes, peppers, etc.), so they are considered a major agricultural pest.  Fortunately for farmers these two species are often attacked by a little monster which lies inside those weird white protrusions.


Braconid wasps are tiny parasitic wasps of which there are over 50,000 species. These wasps are our friends. They do not sting, but they parasitize some of our most damaging pests like caterpillars, aphids, and  beetle larvae.  They are mostly internal parasites and they can parasitize most any developmental stage of insects. There are even ones minute enough to lay eggs inside itty bitty eggs of insects, like aphids. Braconid wasps are very species-specific. The species of wasp that commonly attacks tomato and tobacco hornworms is called Cotesia congregatus.

The female lays her eggs just under the skin of  the caterpillar and within days the larvae hatch and start to eat the caterpillar from the inside. After about a week the larvae of the wasp drill a hole in the host’s skin and form a silken white cocoon to pupate in. The cocoons are what you see protruding from the skin. If the caterpillar is still alive at this point, they don’t have much longer. The adult wasps later emerge and fly off to mate and parasitize another caterpillar.

As gruesome as this sounds, it’s all part of the delicate balance of nature. For every organism that exists, many others exist to keep their populations in check. This is the foundation of biological control. Biological control is a method that uses an insect’s natural predators and parasites against them. Way better than chemicals!

So there you have it, another mystery solved! If you have a tricky bug you’d like identified, or even just a question that’s been bugging you, send an e-mail to blogadmin@hmns.org. We’ll take our best crack at it and feature your question or picture in our blog. Until next time, happy bug watching!

Moths: Butterflies’ Mysterious Cousins

right-wing-waving white ermine
Creative Commons License photo credit: e³°°°

Butterflies are probably the most popular insects ever! But what about moths? What’s their story? Why are they less popular than butterflies, considering the fact that there are nearly 250,000 species of them compared to only about 20,000 species of butterflies? This is one fact among a plethora of others that I’m sure you all would like to know about moths!

The question we get asked the most here at the CBC is what is the difference between butterflies and moths? It can be a little tricky to explain. They are two completely different types of insects. However, the characteristics that define them are not always so clear-cut.  For example, butterflies are diurnal, meaning that they fly during the day. Most moths are nocturnal, but some can be crepuscular (meaning they fly at dawn and dusk) and some are even diurnal. Butterflies and moths can both have thin antennae, but only moths have feathery antennae. Butterflies have thinner bodies with less hair while moths are chunky and hairy! Although, I have seen some stalky butterflies, and hairy ones too.  Butterflies tend to be bright and colorful, whereas moths are normally cryptic and drab. But what is thought to be the most beautiful lepidopteran in the world is actually, a moth. So sometimes, you need to take a second or third look to determine which one it is.

As different as they are, they are similar in many fundamental ways. They both have scales covering their wings, they feed on flower nectar with a proboscis, and they have complete metamorphosis that includes a larva, pupa, and adult stage. These life stages are given specific names. The larva of both are known as caterpillars and the pupa is called a chrysalis. Some moths build a silk covering around their chrysalis for protection. This is known as a cocoon, and despite what some people think, butterflies do not make cocoons.

Moths do get some recognition, unfortunately, it’s not all good. Several moths are serious pests in gardens, in forests, on farms, and even on clothes and in stored grains! If you have tomatoes, you may be familiar with the tomato hornworm.

Tobacco Hornworm (Manduca sexta) on Tomato
Tomato Hornworm
Creative Commons License photo credit: NatureFreak07

This is a huge and beautiful caterpillar but it has a very big appetite that most people don’t appreciate! It is a member of the Sphingidae, or sphinx moth family. These moths are often large and impressive, making them one of the most popular families. The caterpillars can be pesky, but can be deterred by planting marigolds around your tomato plants. The Gypsy Moth is another famous caterpillar that has caused a lot of problems. They originated in Europe and Asia but were introduced to the United States in the 1800s. Since their arrival, they have defoliated millions of acres of forest. Although they are better controlled now, they continue to be a major pest of hardwood trees. We all remember the smell of moth balls in our grandma’s closet. We can thank the common clothes moth for that wonderful smell! The caterpillars of these tiny moths are big fans of natural, proteinaceous fibers such as silk and wool. Luckily, they will not eat artificial fibers, so a lot of our clothes are safe now.

So, I know you’re thinking: “why should we like moths?” Look at all the trouble they cause! Well, like all other insects, the pests are a tiny minority and the rest make up for it in so many different ways! So, a couple of them eat silk, but where do you think we get that silk to begin with?? The silkworm (bombyx mori) is the world’s only domesticated insect. It is farmed for its silk and these little guys produce a ton of silk worth millions of dollars every year. They are not the only ones. There are several types of moths in the family Saturniidae (giant silk moths) that are used for their silk as well.

Hummingbird Moth
Creative Commons License photo credit: mk*

What about pollination? Butterflies do well during the day, but there are so many night blooming flowers. Moths have those covered! Hawkmoths (a.k.a sphinx moths or hornworms) are lovely evening pollinators. They are excellent fliers and some, like the hummingbird moth, are able to hover next to flowers to get nectar. They are often mistaken for hummingbirds. They are awesome to watch! You can plant a moon garden in conjunction with your butterfly garden to attract moths like these. They are attracted to flowers with white blooms that open or are most fragrant in the evening.

One last thing to mention is the beauty of moths. Everyone raves about butterflies, but some moths rival and depending on who you ask, surpass the beauty of butterflies. There are several breathtaking species of sphinx moths such as the Oleander Hawk Moth. All sphinx moths are known for their distinctive wing shape, very thick bodies and amazing flight capabilities. The larvae have a horn at the end of their abdomens during their earlier stages – giving rise to the name hornworm.

Luna Moth
Luna Moth
Creative Commons License photo credit: tlindenbaum

Saturniids, or giant silk moths, are perhaps the most well known moths. They are very large with butterfly-like wings that often have eyespots and brilliant colors. Perhaps the most well known is the Luna Moth. They are a beautiful light green color with graceful, flowing tails. Even more amazing is its relative the Madagascan moon moth or Comet Moth. Some other common saturniids that can be found around here include the Cecropia, Polyphemus and Io moths. Unfortunately, these beautiful giants only live for a couple of days as adult moths. They emerge as adults with no mouth parts, so they do not feed. They live off of food stored from their caterpillar stage until they find a mate and then they die. We do display a species of giant silk moth here at the Cockrell Butterfly Center, the Atlas Moth from Southeast Asia. This is actually the largest moth species in the world and it is amazing!

Finally, there is the Uraniidae, the family that includes the world’s most beautiful lepidopteran, according to some. This family contains several beautiful and colorful moths but the most famous is the Madagascan Sunset Moth. They were originally grouped together with swallowtail butterflies until 50 years after its discovery. I’m not sure if it’s the prettiest, but it is certainly a sight to see!

Whether they’re large and colorful or small and cryptic, I think moths are fascinating and beautiful insects that are just as important as any other beneficial insect. Next time you see one resting during the day, take a closer look. You may be surprised to see the intricate shapes and patterns that make up its “drab” camouflage. Until next time, happy bug watching!

100 Years – 100 Objects: Giant sphinx moth

The Houston Museum of Natural Science was founded in 1909 – meaning that the curators of the Houston Museum of Natural Science have been collecting and preserving natural and cultural treasures for a hundred years now. For this yearlong series, our current curators have chosen one hundred exceptional objects from the Museum’s immense storehouse of specimens and artifacts—one for each year of our history. Check back here frequently to learn more about this diverse selection of behind-the-scenes curiosities—we will post the image and description of a new object every few days.

This description is from Nancy, the museum’s director of the Cockrell Butterfly Center and curator of entomology. She’s chosen a selection of objects that represent the rarest and most interesting insects in the Museum’s collections, that we’ll be sharing here – and on hmns.org – throughout the year.

giant-sphinx-moth-4x6This large sphinx moth (Cocytius antaeus)  has an extremely long proboscis (tongue) – here seen fully extended as it would be if the moth were sipping nectar from the bottom of a very long-tubed flower. Important pollinators, some sphinx moths have very specific relationships with the plants they pollinate.  The giant sphinx, for example, is the only known pollinator of the rare and delicate ghost orchid of Florida’s swamps. 

Ranging from our southern states southward into the Amazon basin, this moth is the New World equivalent of the famous Darwin’s sphinx moth, Xanthopan morganii. As the story goes, when Darwin encountered the very long-spurred Angraecum sesquipedale orchid in Madagascar, he predicted that one day, someone would discover a sphinx moth with a proboscis of the same length as the 12-14 inch nectar spur. He was proven right 40 years after his death when X. morganii with its 13-inch proboscis was discovered.

If you find the sphinx moth really cool, come down to the Cockrell Butterfly Center and see a special art exhibit that the students of Stephen F. Austin State University created.

Learn more about butterflies and their relatives in a visit to the new Brown Hall of Entomology, a part of the Cockrell Butterfly Center– a living, walk-through rainforest at the Houston Museum of Natural Science.

You can see more images of this fascinating artifact – as well as the others we’ve posted so far this year – in the photo gallery on hmns.org.

The Sphinx Moth: A Work of Art

Today we have a special guest blog from Chad Erpelding, Assistant Professor of Art at Stephen F. Austin State University in Nacogdoches, Texas.  He teaches 2D Design and Painting there.  This fall the Cockrell Butterfly Center is hosting an exhibit of some of his students’ paintings that were inspired by sphinx moths.  Here is what he has to say about the project.

The overlap between art and science is a subject rich with potential and currently being investigated by many artists.  Damien Hirst suspends animal specimens in large tanks of formaldehyde.  Olafur Eliasson, who is currently having a major survey of his work at the Dallas Museum of Art, explores weather systems and natural phenomena.  Mel Chin worked closely with a scientist in realizing his piece Revival Field, which uses plants to remove toxic metals from a polluted site.  So when Dr. William Godwin, entomologist at Stephen F. Austin State University and adjunct curator at HMNS, brought up the idea of a joint project between the Biology Department and the School of Art at SFA, I jumped at the opportunity.

We decided to organize a competition for the art students centered on sphinx moths (family Sphingidae), several members of which are found locally in Nacogdoches and throughout east Texas (see Nancy’s recent blog on these fascinating moths.)  Dr. Godwin gave a lecture on the characteristics and life cycle of sphinx moths, giving the students the base of knowledge needed to understand their subject.  From here, I stressed to the students the importance of finding the balance between accuracy towards the moths and the inventiveness that happens in the studio.  The restrictions we put on the entries were only on size and weight of the pieces themselves.  We wanted the students to have the freedom to explore their own interpretations and realize their creative impulses. 

I was thrilled with some of the pieces the students created. Carolyn Norton, a graduate student from Lufkin, won first place for her piece “Sonic Defense,” an ink drawing that follows the paths of a bat and moth in battle, including an explosion of scales – a trick that moths do to fool their predators mid-air. 

Margaret Pledger, a senior from Brenham, received second place for her “Pupa Ring,” a copper ring based loosely on the shapes of sphinx moth pupae.  Chad Hines, a graduate student from Temple, received third place for his “Sphingidae,” a drawing that simultaneously explores the patterns of the moths and the joys of making marks on paper. 

The truly fascinating part of this project for me was to see the many different directions that the artists took.  You never know from where inspiration will come.  While some of the students looked at the patterns and shapes of the moths, others were interested in their habits or specific characteristics.  A few explored broader cultural connections, using the moths as a metaphor for the human experience.  Whatever the source, I think this was a great opportunity for both the science and art communities to see how our fields can interact.  It encourages us to continue to see the world in new and awe-inspiring ways.

Please be sure to stop and take a look at these interesting works of art on your next visit to the Butterfly Center.  They are in the lower level (just around the corner from the mosquito display) and will remain on display until March, 2009.

Sphinx Moth art, on display in the lower level
of the Cockrell Butterfly Center.