Neither Hummingbird nor Bumblebee

 

Hummingbird or bumblebee?  Neither!

Take a closer look when you see what you think is a small hummingbird hovering about and nectaring on the tubular flowers in your garden.  It just might be a Snowberry Clearwing (Hemaris diffinis), one of our more common hummingbird moths.  

Moths in the genus Hemaris are often generically called hummingbird moths, due to their ability to fly and move just like hummingbirds. They are rather plump moths, and the tip of their abdomen opens a bit like a fan. Many are brown or black with some yellow, so they are also good bumblebee mimics. Several species have clear wings, as they lack as many wing scales as other lepidopterans, and they actually lose the ones they do have shortly after they emerge due to their highly active flight tendencies.  

This adult Snowberry Clearwing just emerged from a winter spent in leaf litter,
still with all the scales on its wings.

The Snowberry Clearwing is about 1.25 to 2 inches in length, with a yellowish thorax above, a black abdomen with a yellowish band near the tip often split in two, and the namesake clear wings. Like other hummingbird moths, they generally fly during the day, but may continue into the evening if they have found a particularly good nectar source. Their proboscis or sucking mouthpart is quite long, so they prefer to sip from tube-shaped flowers. 

An adult Snowberry Clearwing showing its yellow thorax, black abdomen with a
yellow stripe, and signature clear wings.

The adults start flying in March after emerging from the leaf litter beneath their host plant where they spend the winter as a pupa protected by loose silken cocoon.  Females attract males by broadcasting a pheromone from the glands at the tip of the abdomen, and after mating, they lay individual, tiny, round green eggs on the underside of the leaves of the host plant.  In the south, they typically produce more than one generation each summer, flying well into November.

The common name for the Snowberry Clearwing comes from the fact that it was first described in 1836 in the northeast, where it uses Common Snowberry (Symphoricarpos albus) as a host plant, a native plant in the Honeysuckle family that grows in the northern half of North America. In the southern US, the preferred native host plant for this moth is Coral Honeysuckle (Lonicera sempervirens), which can be purchased at most native plant nurseries.  It is a high-climbing, twining vine to 20 feet long, with smooth, paired semi-evergreen leaves and clusters of red, tubular flowers.  In the wild, they also use our native White Bush Honeysuckle (L. albiflora), which is more shrub-like with twining branches that have smooth, paired deciduous leaves and clusters of creamy white tubular flowers.

Coral Honeysuckle

White Bush Honeysuckle

The larva or caterpillars of the Snowberry Clearwing are commonly called hornworms, due to the horn-like projection on their posterior end.  They are up to 2 inches long, blue-green above and yellow-green along the sides, with black spots and a black horn.  Uncommonly, they can also take a brown form with the same black spots and horn.  They match the foliage of their host plants so well that they are often very difficult to find. 

Snowberry Clearwing larva, green form.

Snowberry Clearing larva, brown form.

Fall Fliers

 

Fall-blooming Blue Mistflower and White Boneset attract late season butterflies.

Butterflies are frequently thought of as insects that fly primarily in the spring and summer seasons.  This is because the emergence of many butterfly species is unimodal, which means that their numbers increase as environmental resources increase.  These resources are defined as their host plants and nectar plants, which also become available during these warmer seasons.  

However, there are some species that have bimodal emergences, or increases in numbers in both the spring/summer and fall seasons.  It is thought that the division of offspring between two different emergence times may have evolved to avoid producing all offspring at one time.  This approach would reduce the risk of species mortality in case of potential fluctuations in habitat quality. 

Whether they be unimodal or bimodal, butterfly species typically exhibit a tightly synchronized adult emergence in order to help them locate mates. Further still, some species are present in low numbers during most of the year, but their numbers increase during the fall.  In central Texas these species include the Tailed Orange (Pyrisitia proterpia), Julia (Dryas iulia), Common Mestra (Mestra amymone), Queen (Danaus gilippus), and White-striped Longtail (Chioides albofasciatus).

In the fall, the Tailed Orange is in its winter form, yellow with brown lines and blotches below and a noticeably pointed hindwing edge.  Its summer form is unmarked yellow below and the hindwing edge is less pointed. It flies late summer through fall, and uses senna species as its host plant.

Tailed Orange, winter form

The fast-flying Julia is mostly orange above and orange to brown below, with the female being a duller orange than the male and having a dark forewing band.  Its longwing shape is quite distinctive and it prefers woodland edges and gardens where it uses passionvine species as its host plant.

Julia, male

A slower, flat-winged flyer, the Common Mestra is pearly white above with a pale orange border on its hindwing, and mostly pale orange below with a thin, white spotband.  It is most often seen from June to November, and it uses noseburn species as its host plant.

Common Mestra

The Queen butterfly is often confused with monarchs, as it also uses milkweed species as its host plant.  Rich dark brown to deep orange above with white spots in the black wing margins, it lacks the strong black veining on the wings like monarchs, and can be found in any open habitat usually visiting flowers.

Queen

Straying into our area from south Texas, the White-striped Longtail is a dark brown butterfly with very long tails, and a prominent white stripe on the underside of its hindwing.  It usually perches with its wings closed, and uses various legume species as host plants.

White-striped Longtail

One way to increase your chances of seeing these fall fliers in your yard is to provide native plant species that bloom in late summer and well into fall. These plants include Frostweed, Gregg’s Mistflower, Blue Mistflower, White Boneset, Lindheimer’s Senna, Plateau Goldeneye, and Texas Lantana.  And remember, fall is the perfect time to plant!

Undervalued Vines

  The uncommon Plateau Milkvine is often mistaken
for the more common Pearl Milkvine (above).

Every species of native plant has its purpose, and while many are valued by humans for their fragrant flowers and foliage, those that are valued for their role in keeping the earth’s nutrient cycles intact should be regarded as having the highest value.  Those nutrient cycles need to be protected through plant preservation or restoration, as they are what provides nourishment for the lifecycles of our native wildlife and protects the health of our ecosystems.

Even among those folks who are familiar with many native plants that perform this role, there are some little-known species that are often overlooked and under appreciated.  In Central Texas, there are a few species of vines in the Milkweed family that many fail to notice, including Star Milkvine (Matelea biflora), Plateau Milkvine (Matelea edwardsensis), and Bearded Swallow-wort (Cynanchum barbigerum).  

Star Milkvine, also called Purple Milkweed Vine, is a relatively common vine that grows in pastures, prairies, and other open ground, usually in chalky soil throughout Central and North Texas.  This small, trailing vine to 2 feet has five-petaled, star-shaped, deep purplish-brown flowers that are 0.5 inches wide.  Blooming from March to June, the flowers occur in pairs along the trailing stems that radiate from a central rootstock, and arise from the axils of the opposite, triangular leaves.  The flowers, leaves, and stems are all quite hairy, as is true of many members of the Milkweed family.  Its habit is to grow low among grasses, often in areas that are mowed, so it is frequently passed over by humans, but is a useful host plant for Queen and Soldier butterflies and a nectar plant for several species of bees.

Star Milkvine has low-growing stems that radiate out
from a central rootstock.

The unusual flowers of Star Milkvine occur in pairs.

Soldier

Sometimes mistaken for the more common Pearl Milkvine, Plateau Milkvine is a vine to 3 feet that is endemic only to the Edwards Plateau of Central Texas.  This uncommon vine shares the same twining habit of Pearl Milkvine, but its leaves, while similar, generally have a somewhat wavy edge, and its flowers are bell-shaped instead of flat. Additionally, its 0.7 inch wide greenish-white flowers do not have a pearl center, and its petals are not solely reticulate-patterned, having parallel veins in their lower halves and centers, and reticulate or networked veins only on the edges or margins.  Blooming in April and May, this vine can be found on gravelly soils in open woodlands, often climbing on other plants, and is a native host plant for Queen butterflies.  Due to indiscriminate land clearing, this plant is listed as ‘vulnerable’ in terms of its conservation status in Texas.

Plateau Milkvine is a rare cousin to Pearl Milkvine.

The flowers of Plateau Milkvine distinguish it
from Pearl Milkvine.

Queen

Growing up to 8 feet long, Bearded Swallow-wort, also called Thicket Threadvine and Aphid Vine, is a delicate vine that climbs on shrubs and small trees in open woodlands, in thickets, and along roadsides and fencerows in the Edwards Plateau and South Texas. It has small glossy lance-shaped, opposite leaves to 2 inches long, and from March to August, tiny creamy-white flowers appear in loose clusters from the leaf axils.  These flowers are 0.25 inches wide, bell-shaped, and have five distinctively hairy or ‘bearded’ recurved petals.  Five similar species in this genus are present in Texas, but this is the only one with ‘bearded’ flower petals.  Aphids are often found on this plant, giving rise to one of its other common names, and it is the host plant for the Obscure Sphinx Moth (Erinnyis obscura).

Bearded Swallow-wort is a rather delicate climbing vine.

The fringed or 'bearded' flowers
of Bearded Swallow-wort.

Obscure Sphinx

Whether it is due to their scarcity or diminutive stature, it is easy to miss these vines.  While they might be undervalued by humans, they are quite valuable to our native wildlife!

Beautiful Hindwings

Can you find the underwing moth?

Commonly known as underwings, the genus Catocala is a large group of moths where most species are somberly clad with brown or gray-shaded forewings, often in variable, cryptic patterns of wavy lines closely resembling tree bark.  It is their hindwings, kept hidden at rest, that are typically a vivid orange, red, or yellow, and marked with black bands or stripes. 

The genus Catocala comes from the Greek kato meaning ‘rear or lower one’ and kalos meaning ‘beautiful’, together translating to ‘beautiful hindwings.’ Of the more than 100 underwing species found in the United States, 15 or so are known in Travis County, including the Ilia Underwing (Catocala ilia), Little Nymph Underwing (Catocala micronympha), and Ultronia Underwing (Catocala ultronia).

Ilia Underwing

The Ilia Underwing, also known as the Beloved Underwing or Wife Underwing, is one of our most common large underwings.  It has a total length to 1.8 inches, and gray to brownish forewings with a bold black line above a white or white-outlined spot. The reddish-orange hindwings have two black bands, and a pale orange, checkered fringe.  It utilizes oaks for its host plants, especially red oaks such as Shumard’s Oak and Southern Red Oak.  Its common and scientific name Ilia likely refers to the mythical mother of the twins Romulus and Remus, who were the mythological founders of the city of Rome.

Little Nymph Underwing

One of our smaller underwings with a total length of up to 1 inch, the Little Nymph Underwing has brown to grayish forewings typically marked with a dark, curving, shadow-like crescent.  The golden orange hindwings have two black bands, sometimes broken, and a pale, checked fringe.  It prefers white oaks as host plants, specifically Post Oak, Bur Oak, and Coastal Live Oak.  Its species name comes from the Greek and means ‘little bride or mistress.’

Ultronia Underwing

The Ultronia Underwing is medium-sized underwing to 1.3 inches in length, and is identified by its grayish-brown forewings marked with a darker brown shading on the inner edge.  The reddish hindwings have two black bands and a mostly gray fringe. Escarpment Black Cherry and Coastal Live Oak are its preferred host plants, and its common and scientific names are said to have come from the name of a Greek island.

It is believed that the bright colors of these moths’ hindwings, which usually form roughly concentric patterns, resemble the eyes of a predatory animal when suddenly flashed toward danger. Underwings are also said to possess fairly well-developed hearing organs, allowing them to evade nocturnal predators such as bats.  Their cryptic forewings keep them hidden during the day as they roost on tree bark and in crevices, and even in their larval form their coloring and patterns often mimic gray bark or green lichen.  While most active shortly after nightfall, several species have a second activity period for a few hours around noon, when these beautiful hindwings can sometimes be found on the wing in broad daylight!

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!”

Day Fliers

Eight-spotted Forester nectaring on Mexican Plum

As part of the larger groups of moths known as the Noctuidae and Thyrididae, Forester and Window-Winged moths are day fliers that commonly have white-spotted black forewings and either similar or bright orange hindwings, and are often found in open woodlands and flowery meadows.  This time of year, you can frequently spot them nectaring on early blooming trees and shrubs, including Mexican Plum, Escarpment Black Cherry, Texas Redbud, and Mexican Buckeye.

A newly emerged adult Eight-spotted Forester

In our area, the Eight-spotted Forester (Alypia octomaculata), Grapevine Epimenis (Psychomorpha epimenis), and Mournful Thyris (Pseudothyris sepulchralis) are the more typical species to be found.  The Eight-spotted Forester has velvety black wings with two large cream-colored spots on each forewing and two large white spots on each hindwing, alluding to its ‘eight-spotted’ common name.  It has a wingspan of about one and a half inches, and its legs are adorned with showy orange tufts where they attach to its body.  Flying from March to June with a second brood in August, the larva of this moth have broader orange bands with black dots, alternating with fine black and white stripes, and an orange head and hind end.  They feed mainly on Virginia Creeper and other various grapevines.

Eight-spotted Forester caterpillar

Grapevine Epimenis nectaring on Mexican Plum

Grapevine Epimenis is another Forester moth that also has velvety black wings, but each forewing has one bold white patch near the outer edge, and each hindwing has a broad orange-red band.  With a wingspan of about one inch, it flies from February to April, and sometimes has a second brood in October.  Its larva feed on various grapevines, most notably Mustang Grape in Central Texas, and are mainly black and white striped with an orange head and hind end.

Mournful Thyris nectaring on Mexican Buckeye

Mournful Thyris is a Window-Winged moth, a chunky-bodied small moth with just under a one inch wingspan, that habitually spreads its wings when alighting on flowers or on wet sandy soils along forest trails.  Its wings are black patterned with multiple various sized white spots, and translucent median patches that form ‘windows.’  It flies from February to April, and its larva also feed on grapevines, most commonly Mustang Grape in our area.

Contrary to popular belief, a surprising number of moth species are day fliers, and many are as beautifully patterned as, and often mistaken for, butterflies.  If you’d like to attract these splendid little moths to your yard, simply plant the native trees, shrubs, and vines listed above, and they will grace you with their presence each spring!

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.