Mariposa de la Muerte

Commonly known as owlet moths, cutworms, or armyworms, moths in the Noctuidae family make up one of the largest families of Lepidoptera.  The word Noctuidae is derived from the Latin word noctua meaning ‘little owl’ and the largest moth in this family in the continental United States is the Black Witch (Ascalapha odorata).

The Black Witch moth has been known as mariposa de la muerte or ‘butterfly of death’ since the time of the Aztecs, when it was believed that they were harbingers of death.  With a wingspan of up to 6 inches, its upperside is mottled dark brown to grayish-brown with hints of iridescent purple and pink, and females, which are slightly larger and lighter in color than males, have a pale almost lavender-pink median band through both fore and hind wings.  

A Black Witch (male) attracted to our mercury vapor light

Common to abundant in the New World topics as far south as Brazil, the Black Witch flies year-round in south Florida and the Rio Grande Valley of Texas.  In June and July, summer monsoons in Mexico trigger this fabulous creature to migrate north through Texas, where it is often found roosting in garages, under eaves, or under bridges.  It has the ability to migrate great distances over bodies of open water, such as the Gulf of Mexico, and one specimen was recorded in 1903 in Leadville, Colorado, caught in a snowstorm on the Fourth of July!

Primarily nocturnal, the adult Black Witch is attracted to light and fermenting fruit.  Its larvae feed at night on a variety of cassias, acacias, ebony, mesquite, and other woody legumes, and rest during the day hidden under bark and branches.  Up to 3 inches long, its caterpillar is dark gray tinged with brown, with a pale stripe down the back and dark stripes down the sides, and it relies on this natural camouflage to make it difficult to spot.  Pupation occurs on the ground in scattered leaf litter within a fragile cocoon.  Black Witches breed year round in overlapping generations, and their adult stage is thought to last only three or four weeks.

A Black Witch (female) perched above our front door!

At first glance, this very large moth is often mistaken for a small bat hovering around a porch light, but it will eventually land and linger for several hours if undisturbed.  If this happens to you, you can only hope that the South Texas legend of the Black Witch is true, as it states, “If a Black Witch lands above your door and stays there for a while, you could win the lottery!”

It's a Sphinx, Methinks!

A White-lined Sphinx hovers while feeding at a thistle

A family of moths called the Sphingidae are more commonly known as hawk moths, hummingbird moths, and sphinx moths.  This family has over 1,450 species worldwide, and 73 of them are known to be present in Texas.  Generally speaking, these moths are named not just for their streamlined bullet-shaped bodies that have long narrow forewings and short hindwings, but also for their distinct behavior which comes in the form of swift, hovering flight.  Many species in this family hover in mid-air or swing from side to side when feeding on flowers, an ability that has evolved in only three other groups: hummingbirds, certain bats, and hoverflies.  In addition to nectaring on flowers, these moths often pollinate them at the same time.  

The leaf-feeding caterpillars or larva of these moths typically have a smooth body with a characteristic horn near their posterior end, hence the common name hornworm.  They pupate in an earthen cell or loose cocoon at or near the soil surface.  The word sphinx was first associated with the larva in 1736, when Rene Reaumur, a French scientist and entomologist, noted that they often assumed a pose reminiscent of the mysterious Egyptian Sphinx of antiquity.  They accomplish this pose by holding their anterior legs off their substrate and tucking their heads underneath when resting, which appears to form an upright praying position.  

Vine Sphinx

White-lined Sphinx

In our area, some of the more interesting sphinx moths include the Vine Sphinx (Eumorpha vitis), Tersa Sphinx (Xylophanes tersa), Waved Sphinx (Ceratomia undulosa), and Rustic Sphinx (Manduca rustica).  The Vine Sphinx appears similar to the well-known White-lined Sphinx, but is dark greenish-brown with a more complex pattern of sharp whitish streaks and bands on its forewings (instead of an even, pale tan stripe from base to tip intersecting uniform white lines) and a small pinkish patch on its hindwings (instead of a broad pink band).  The wingspan of this moth is 3.5 to 4 inches, it flies from April to May and July to October, and the larva feed on grapevines.  

Tersa Sphinx

The Tersa Sphinx is easily identified by its long pointed abdomen, brownish-tan forewings that look like woodgrain, and hindwings with jagged black and white markings.  This sleek, fighter jet-like moth has a wingspan of 2.5 to 3 inches, flies June to October, and its larva feed on catalpa and smooth false buttonweed.

Waved Sphinx

The Waved Sphinx has brownish-gray forewings with contrasting black streaks and zigzag lines and a small, kidney-shaped white spot outlined in black, while the hindwings are gray with darker gray shading.  Its wingspan is 3 to 4.5 inches, it flies from May to October, and its larva feed on ashes and oaks.  

Rustic Sphinx

The Rustic Sphinx has an abdomen with three pairs of yellow spots along the sides, and yellowish to chocolate-brown forewings with black zigzag lines. It has a wingspan of 3.5 to 6 inches, flies from July to October, and its larva feed on crossvine and trumpet vine. 

Certain species of sphinx moths have been widely used in scientific research aimed at better understanding animal flight and insect physiology.  Some have played a key role in advancing knowledge of hormones produced by nerve cells, while others have contributed to the development of small flying robots by shedding light on how these insects stay airborne while hovering.  Those are some pretty important roles for a sphinx, methinks!   

Discovering Blacklighting

A large Polyphemus Silkmoth, Antheraea polyphemus, is always a 

welcome visitor.

Lepidoptera is the order of insects that includes both butterflies and moths.  While over 180,000 species of these insects have been identified worldwide, recent estimates suggest that this order may have more species than previously thought, and is among the four most speciose orders, along with Hymenoptera (sawflies, wasps, bees, & ants), Diptera (true flies, mosquitoes, gnats, & midges), and Coleoptera (beetles).  Of the approximately 180,000 known Lepidoptera species, some 160,000 are moths, with nearly 11,000 of them found in the United States, and many are yet to be described.

The Imperial Moth, Eacles imperialis, is another silkmoth that may 

come to a blacklight in Central Texas.

Carolina Sphinx, 

Manduca sexta

Small Heterocampa Moth, 

Heterocampa subrotata

With such huge numbers and such a diversity of species, how does one go about studying moths? A good place to start is while knowing that most moths are creatures of the night, they are also attracted to light.  The reason for this behavior is unknown, although one theory is that moths use a form of celestial navigation called transverse orientation.  They attempt to maintain a constant angular relationship to a bright celestial light, like the moon.  But since the moon is so far away, and the angle change is negligible, the moth appears to travel in a straight line.  This theory is tested when moths fly near much closer sources of light, such as a porch light or a campfire.  The angle to the light source changes constantly as the moth flies by, so the moth instinctively attempts to correct it by turning toward the light, thereby producing its erratic flight.

Cellar Melipotis, 

Melipotis cellaris

Giant Leopard Moth, 
Hypercompe scribonia

White Palpita Moth, 

Stemorrhages costata

Cisthene unifasc

Melonworm Moth, 

Diaphania hyalinat

Paler Diacme Moth, 

Diacme elealis

Eggplant Leafroller Moth, 

Lineodes integra

Ragweed Plume Moth, 

Adaina ambrosiae

Swag-lined Wave, 
Scopula umbilicata

Southern Emerald Moth, 
Synchlora frondaria

One way for the moth to keep a constant angle to a stationary light source is by becoming stationary itself, effectively being ‘trapped’ by the light rather than ‘attracted’ to it.  Those interested in studying moths have taken advantage of this fact, and have developed a method called blacklighting to attract and photograph moths.  The first step is to set up a light source, and either an ultraviolet light (also known as a blacklight) or a mercury vapor  light can be used. Mercury vapor is now the preferred source, as it provides a different spectrum of light than a blacklight, although a blacklight emits a greater spectrum of light.  Moths can see waves of light that humans cannot, so providing them with different spectrums will generally produce the greatest response. The light is carefully hung or positioned in front a vertical white sheet, which the light bounces off to produce a big, concentrated, glowing mass, while also providing a safe surface for the moths to land.

The blacklighting setup is positioned out of the wind and typically near a boundary between wooded and open areas.  The light is turned on at dusk and left on all night, as different species of moths are most active at different times.  After taking the desired photographs with a digital SLR with a macro lens and flash, the light is turned off and the sheet is given a vigorous shake to scatter the remaining moths.  After all that was done to ‘capture’ them with light for observation and photography, it would be a shame for them to become easy  quarry for insect-eating birds or other predators!   

Another opportunistic predator at a blacklight is this Mediterranean Gecko, which 
has captured an Underwing moth.