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!

Beat the Heat

 

Flame Acanthus is a hot weather bloomer.

The heat of the Texas summer is enough to make everything wilt, but there are some native plant species that truly thrive in these unrelenting temperatures and drought-stricken conditions.  These plants include Turk’s Cap (Malvaviscus arboreus var. drummondii), Flame Acanthus (Anisacanthus quadrifidus var. wrightii), Violet Ruellia (Ruellia nudiflora), and Western Ironweed (Vernonia baldwinii).

Turk’s Cap, also known as Drummond’s Turk’s Cap, Wax Mallow, Mexican Apple, Manzanita, and Sleeping Hibiscus, is a spreading shrub to 4 feet high, with large green leaves on upright stems.  Bright red flowers atop the stems are twisted into a whorl from which protrude red stamens.  These flowers are a natural source of nectar for hummingbirds and butterflies, and it is a host plant for the Turk’s-cap White-Skipper butterfly.  The resulting fruit is red and marble-sized, and edible for animals and humans alike. Turk’s Cap is the perfect plant to grow under trees that tend to shade out non-native turf grasses, as they form a natural cover and provide much needed color from May all the way to November.

Turk's Cap

Turk's Cap fruit

Turk's-cap White-Skipper

An airy, spreading shrub to 5 feet tall, Flame Acanthus has tender lance-shaped green leaves and tubular red flowers that open to 4 lobes and occur along terminal spikes.  Blooming in full sun from June to October, it attracts both hummingbirds and butterflies, and is also known as Hummingbird Bush, Wright’s Acanthus, and Mexican Flame.  It is the host plant for the Crimson Patch, Elada Checkerspot, and Texan Crescent butterflies. The fruit is a small, hood-shaped capsule with seeds attached to a hooked stalk that helps to eject them from the capsule when it dries and splits open.

Flame Acanthus

Flame Acanthus seed capsule

Crimson Patch

Violet Ruellia is an erect herb that is woody at the base with few branches, growing to 2 feet tall.  The dark green leaves are oval-shaped, and the trumpet-shaped violet flowers at the ends of stalks open at sunrise and fall from the plant in early afternoon, from March all the way through October. Also called Wild Petunia, it does well in sunny areas and is a host plant for the Common Buckeye butterfly.  One of its’ subspecies is a host plant for the Malachite butterfly, a south Texas species rarely seen in central Texas.

Violet Ruellia

Common Buckeye

Often stout and forming colonies 5 feet high, Western Ironweed has hairy unbranched stems, large green leaves with serrated edges, and loose clusters of bright purple blooms at the apex of each stem.  From July to the first frost, these fuzzy blooms provide nectar for various types of pollinating insects and the seeds nourish several species of birds.  Also called Baldwin’s Ironweed, it is the host plant for the Parthenice Tiger Moth.  While this species’ growth can be aggressive, it flourishes if allowed to spread in larger, open, sunny areas.

Western Ironweed

These native species can (and often should) be pruned back in winter as they can get too leggy.  They have low water needs once established, and can tolerate hot temperatures and still continue to bloom.  They are the perfect plants to beat the heat, benefit our local wildlife, and provide much needed color in your own native summer garden!

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!

Quercus with a Purpose

All oaks, like this Post Oak, are members of the genus Quercus.

Texas is home to dozens of native species of oaks, all of which are in the genus Quercus.  These trees provide humans with ample shade in the summer and beautiful color in the fall, and they sustain many mammals and birds with their acorn fruit.  But did you know that they are native host plants for dozens of butterflies and moth species, or the plants the female adults lay their eggs on for their caterpillars to eat?  In turn, the caterpillars of these butterfly and moth species provide a critical food source for almost all of the songbirds raising broods in the spring. Three of the most productive native oak species in central Texas are the Texas Live Oak (Quercus fusiformis), Post Oak (Quercus stellata), and Bur Oak (Quercus macrocarpa).

Texas Live Oak

The Texas Live Oak is also known as Escarpment Live Oak, Hill Country, and Plateau Live Oak.  Considered a semi-evergreen tree, the previous year’s leaves fall from the tree only when pushed out by newly emerging ones in early spring.  It has a stately mature form and unparalleled longevity, reaching to 40 feet in height with large limbs that over time spread an appreciable distance from the main trunk.  Firm textured leaves are oval to elliptical, 1 to 3 inches long, with young leaves having pointed lobes.  Its acorns are spindle-shaped or fusiform, narrowed at the base and ¾ to 1 inch long.  

Juvenal's Duskywing

Grote's Buckmoth

The Texas Live Oak is a host plant for Oak Hairstreak (Northern form), Juvenal’s Duskywing, and Meridian Duskywing butterflies, as well as Grote’s Buckmoth, Eastern Buckmoth, and Delilah Underwing moths.

Post Oak

Also known Iron Oak and Cross Oak, Post Oak is a deciduous oak to 50 feet, coarsely-branched with a dense, oval crown.  Its leaves are typically 3 to 5 inches long, with 4 pairs of lobes on each side, and the upper pair are often larger than the others, resembling a cross.  Acorns are ¾ to 1.25 inches long.  Post Oak is the most common oak throughout Texas, and its hard or iron wood is used for railroad ties as well as construction posts and timbers.  

'Northern' Oak Hairstreak

Polyphemus Moth

It is a host plant for the Oak Hairstreak (Northern form) and White M Hairstreak butterflies, and the Polyphemus, Eastern Buckmoth, Scarlet Underwing, and Little Nymph Underwing moths.

Bur Oak Acorn

Bur Oak is one of our largest oaks, also known as Savanna Oak, Overcup Oak, Prairie Oak, and Mossy-cup Oak.  A deciduous tree that can exceed 100 feet in height, its massive trunk supports heavy, horizontal limbs and lobed leaves up to 9 inches long.  Its acorns are the largest of all native oaks, up to 1.5 inches wide, with much of the acorn enclosed in a coarsely scaled cup with a heavily fringed margin. Sometimes spelled Burr Oak, it is the northern most oak in the New World, extending farther north than any other oak species.  

Banded Hairstreak 

Imperial Moth

Bur Oak is the host plant for the Banded Hairstreak and Juvenal’s Duskywing butterflies, in addition to the Ilia Underwing, Imperial, and Greater Oak Dagger moths.

While Texas is known for its oaks, care must be taken in identifying and maintaining oak trees.  Most all of the species can hybridize, occasionally making exact identification difficult,  and several of them are susceptible to oak wilt disease. However, they are worth the effort from a human and wildlife standpoint, as they are Quercus with a purpose!

Summer Sulphurs

Orange Sulphur, Colias eurytheme, on Indian Blanket

The family of butterflies known as Pieridae includes the whites and sulphurs, our most conspicuous and abundant butterfly species. They easily draw the attention of even the most casual observer as they flit about our gardens, fields, and open habitats in summer.  Sulphurs are usually some shade of yellow, orange, or white, and avidly visit flowers.  Their uppersides often feature black borders or patterns and while they usually perch closed, these patterns can sometimes be seen faintly through the wing or glimpsed in flight. The most widespread sulphurs in our area include the Orange Sulphur (Colias eurytheme), Southern Dogface (Zerene cesonia), Little Yellow (Pyrisitia lisa), and Dainty Sulphur (Nathalis iole).  

Orange Sulphur, Colias eurytheme

White Female Orange Sulphur

Found throughout most of North America, the coloration of the Orange Sulphur can be quite variable, but the typical male has a yellow upperside with orange overlay, yellow veins, a wide black border, and a dark black cell spot.  Females can be yellow or white with an irregular black border surrounding several light spots.  Both sexes have a silver spot surrounded by two concentric dark rings and a spot above it on the underside of the hindwing. With a wingspan of about 1.5 to almost 3 inches, males patrol around for receptive females, who lay eggs singly on the leaf tops of host plants in the pea family, such as alfalfa and clovers.  Orange Sulphurs have 4 to 5 broods from March to November, and overwinter in the chrysalid form.

Southern Dogface, Zerene cesonia

The Southern Dogface is easily identified by both sexes having the shape of a yellow dog’s head surrounded by black on the upperside of their forewings, with the black and white ‘eye’ not touching the black border.  The underside of the hindwing in summer is pale to bright yellow, becoming tinged with pink markings in the fall.  With a wingspan of 2 to 3 inches, the males seek out females who lay eggs on the undersides of terminal leaves of host plants such as alfalfa, clovers, and indigo.  Three broods are produced almost year round, with adults overwintering in reproductive arrest during the coldest months.

Little Yellow, Pyrisitia lisa

As their name suggests, Little Yellow butterflies are on the small side with a wingspan of 1 to 2 inches.  The upperside of the male has a yellow forewing with a wide black tip or apex and a hindwing with a black border. While the female is usually yellow and sometimes white with black borders, both sexes usually have two tiny black dots at the base of the hindwing underside.  Four to five broods occur in the south, and females lay eggs singly on midveins or between leaflets of partridge pea, wild sensitive plants, and sennas.

Dainty Sulphur, Nathalis iole

A mating pair of Dainty Sulphur in winter form

Our smallest sulphur, the Dainty Sulphur, has a wingspan of ¾ to slightly over 1 inch, and is identified by a yellow upperside with black markings that are more extensive on the female.  The underside of the forewing has an orange or yellow patch near the base with a few strong black spots closer to the outer wing edge.  In summer, the hindwing underside is pale yellow, and turns to dusty green in winter.  Both males and females tend to fly low, rest with their wings closed and held perpendicular to sun’s rays to gather warmth, and overwinter in adult form.  Flying year round, the females lay single eggs on sneezeweed, dogweed, and other asters.

Send your nature-related questions to naturewatch@austin.rr.com and we’ll do our best to answer them.  Check out our book, Nature Watch Austin, published by Texas A&M University Press, and our blog at naturewatchaustin.blogspot.com if you enjoy reading these articles!