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Saturday, June 29, 2019

Some Like It Hot

Eastern Ringtails, a type of Clubtail, obelisking.
The dog days of summer are upon us, and a long stretch of sultry weather lies ahead.  It can be a challenging time for people and for wildlife, but for some, it is their chance to put on a show. 

Bouquets of Mountain Pinks
Mountain Pink close up
Mountain Pink (Zeltnera beyrichii), also called Meadow Pink, Catchfly, or Quinineweed, is an annual herb less than a foot tall and best described as a neat bouquet of small, pink flowers.  Blooming May through July, Mountain Pink sprouts up like an inverted cone 8 to 12 inches high, on hot, rocky hillsides, limestone outcrops, and along gravelly roadways.  Its leaves are threadlike and are held below the multiple 0.5 to 1.0 inch wide showy pink five-petaled blooms that provide nectar for moths, butterflies, bees, and other insects.

Woolly Ironweed
Woolly Ironweed (Vernonia lindheimeri) is a 10 to 30 inch high clumping perennial, with woolly gray stems and long, narrow leaves.  Its bright purple flowers lack true petals, but the disk flowers are arranged in showy, terminal clusters.  A well-behaved species that should be used more often in gardens and landscapes, Woolly Ironweed blooms from June to September, and prefers open hillsides, roadsides, and fields offering full sun.  It is a good nectar source for many species of butterflies during the heat of summer, and is highly deer-resistant.

Blue Dasher, a type of Skimmer, obelisking
To prevent overheating on hot, summer days, some dragonflies and damselflies assume a handstand-like position called ‘obelisking.’  They raise their abdomens until the tip points up toward the sun, which helps to minimize the surface area of their body that is exposed to solar radiation.  Both males and females of these species will raise their abdomens when the temperature is high, and lower them again if shaded. Laboratory experiments have shown that this behavior is effective in stopping or slowing the rise in their body temperature.  This method of thermoregulation is practiced by about 30 different species in the Skimmer, Clubtail, and Broadwing Damsel families.  All are considered ‘perchers’ or sit-and-wait predators that spend a considerable amount of time stationary.

A sure sign that we are in the midst of a hot summer is the sound of cicadas buzzing in the air.  For their size, cicadas make as much noise as a large animal, and can be heard up to a quarter of a mile away.  In fact, the word ‘cicada’ is a direct derivation from the Latin meaning ‘buzzer.’  Many common species of cicadas in North America are in the genus Megatibicen  and are generally called the annual or ‘dog-day’ cicadas because they emerge every year in July and August, the dog days of summer.

Resh Cicada, Megatibicen resh
Male cicadas have structures called ‘timbals’ on the sides of their abdomens, and it is with these structures that they create their buzzy songs.  Unlike grasshoppers or crickets that rub their wings or legs together to produce sound, cicadas vibrate these timbals against their hollow abdomens, which amplifies the resonance of the sounds. They can even modulate the sounds by wiggling their abdomens toward or away from the tree trunk on which they are perched.  Each species has its own distinctive sound, and they use different mating songs to attract the appropriate mate.

Even in the heat of a long Texas summer, nature is busy going about its mysterious ways, offering sights and sounds that can recalibrate our senses, and allow us to continue to appreciate all that it has to offer.

Monday, June 3, 2019

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!”

Sunday, May 19, 2019

Poisonous or Venomous?

Poison Ivy
Often used interchangeably when describing some plants and animals, in reality poisonous and venomous mean two different things.  Poisonous describes plants or animals that are harmful when consumed or touched.  Venomous refers to animals that inject venom into their prey, by means of a bite or sting, when hunting or for self-defense.  To add to the confusion, all venoms are a poison but not all poisons are venoms!

Poisonous species typically produce a toxin that can range from irritant to fatal. Plants such as Poison Ivy (Toxicodendron radicans) and some members of the Spurge family are considered irritants when they come in contact with skin, but this effect is produced through different mechanisms.  Nearly all parts of the Poison Ivy plant contain urushiol, which is a substance that gives us contact dermatitis, or a severely itchy and painful inflammation of the skin.  

Texas Bull Nettle
Spurges such as Texas Bull Nettle (Cnidoscolus texanus) and Betonyleaf Noseburn (Tragia betonicifolia) have raised structures called trichomes that are capable of ’stinging' animals and humans that brush against them.  These plants have trichomes on their leaves and stems that have bulbous tips that break off and reveal needle-like tubes that pierce the skin. They can cause an itching, burning rash by emitting onto the skin a mix of acetylcholine, formic acid, histamine, and serotonin.  

Jimsonweed or Sacred Datura
One local native plant, Jimsonweed or Sacred Datura (Datura wrightii) goes well beyond irritant to hallucinogenic and even fatal if ingested.  All parts of this plant contain toxic alkaloids, and the narcotic properties of this plant have been known by humans since before recorded history.  They once figured prominently in important religious ceremonies of various southwestern Native American tribes.

Gulf Coast Toad
Animals that are poisonous include most amphibians (frogs, toads, salamanders, and newts), that have some amount of toxins on their skin and within other tissues. Special skin glands produce useful proteins, some for use in respiration, others for fighting bacterial or fungal infections, and at least one in each species that is used for defense.  For example, many toad species will release their toxins when they feel threatened, such as when they are caught by a dog or cat, and can trigger drooling, vomiting, and respiratory or cardiac problems.

Western Diamondback Rattlesnake
While some snakes are the most commonly known venomous animals, all spiders, some lizards, and many bees, ants and wasps are venomous as well.  The venoms they inject through a bite or sting contain various classes of toxins designed to perform specific biological effects such necrosis or death in multiple cells (necrotoxins) or individual cells (cytotoxins), disruption of the nervous system (neurotoxins), or damage to muscle tissue (myotoxins).   The venom of our Western Diamondback Rattlesnake (Crotalus atrox) carries both necrotoxins and myotoxins, Black Widow spiders (Latrodectus macrons) carry both neurotoxins and cytotoxins, and Striped Bark Scorpions (Centruroides vittatus) and Texas Redheaded Centipedes (Scolopendra heros) carry neurotoxins.

Striped Bark Scorpion
Texas Redheaded Centipede
While the vast majority of snake toxins are transferred by bite, one exception includes garter snakes (Thamnophis sp.), which are small and harmless in terms of their bite but are toxic to eat because their bodies absorb and store the toxins of their amphibious prey.  In our area, these snakes include the Black-necked Garter Snake (T. cyrtopsis) and the Western Ribbon Snake (T. proximus).

Western Ribbon Snake
It is important to keep in mind that many plants and animals that are poisonous or venomous are not necessarily a guaranteed threat to humans, as much depends on how the plant or animal is encountered, its toxicity level, and the amount of toxin absorbed.  Regardless, respecting these species and giving them their space is the cardinal rule.  Interestingly, the medicinal use of venoms for therapeutic benefit in treating diseases dates back to 380 B.C. in ancient Greece.  Today, the venoms produced by different organisms, which contain hundreds of different bioactive elements, are isolated, purified, and screened, then studied to identify components that may have desirable therapeutic properties.  This research is often the starting point for developing a therapeutic drug, and those types of drugs on the market today are used to lower high blood pressure, relieve severe pain, act as blood thinners, treat Type 2 diabetes, and stop bleeding during surgical procedures.

Sunday, April 7, 2019

Royal Ruse

As spring unfolds in Central Texas, butterflies begin to appear ever present in our gardens and landscapes.  A subfamily of the Brushfoot butterflies, milkweed butterflies are a group of butterflies whose larva feed only on various milkweed species, and these plants provide the adults with certain chemicals that make them naturally distasteful to most predators.  This subfamily is composed of ‘the royals’, better known as the Monarch (Danaus plexippus), Queen (Danaus gilippus), and Soldier (Danaus eresimus).

Monarch ventral, or underside.
The well-known Monarch is probably the most famous butterfly in North America, but it often confused with the Queen and Soldier.  Monarchs have rich cinnamon-orange wings with distinctive bold black veins and white dots on the black wing borders and on the black body, and look remarkably similar on the underside.  Its larva are striped with yellow, black, and white, and they have two sets of black tentacles rising from their bodies.  

Queens mating, showing their undersides
While the underside of the Queen butterfly can look a lot like a Monarch, it is its upperside that allows for a definitive identification.  Queens can appear almost solid orange compared to stained glass pattern of the Monarch, having rich dark orange wings that lack the black veining and white spots toward the dark wing tips and along their black edges. While adult Queens seek out ageratum, eupatorium, and heliotrope as preferred nectar flowers, adult Monarchs are much broader generalists in terms of their use of many types of nectar plants.

Queen dorsal or upperside, showing white spots along forewing

Soldier dorsal or upperside, showing absence of white spots along forewing
and more obvious wing veining
Soldiers typically occur where Queens are common and are often overlooked due to their very similar appearance.  They can be properly identified by fewer white spots and more obvious dark wing veining on the forewings than on the Queen, but less defined veining than on the Monarch.  Another clue is that Soldiers generally fly in our area in late summer and fall.  Both Soldier and Queen larva are Monarch look-alikes, sporting yellow, black, and white stripes, but with three sets of black tentacles instead of two.

Viceroy dorsal or upperside, showing black band across middle of the hindwing
In an action intended to deceive, the Viceroy (Limenitis archippus) is a milkweed butterfly mimic, using its similar patterning and color to trick predators into thinking it is just as distasteful.  Viceroys are smaller than Monarchs or Queens and usually have a black band across the middle of each hindwing.  This band can be faint or missing, but it can also be identified by its flying style of quick flaps and flat-winged glides, rather than flying strongly with wings in a shallow V-shape like the Monarch and Queen.  One more way that you can uncover this butterfly’s royal ruse is by knowing that its host plant is willows and not milkweeds, and its larva resemble a horned bird-dropping.

Take a closer look the next time you see an orange butterfly on the wing.  It might just be a Monarch heading north, or a Queen or Soldier nectaring on mistflower, or maybe even a Viceroy trying to pull off a royal ruse!

Thursday, March 28, 2019

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!

Monday, March 11, 2019

Plant Natives!

Non-native, invasive, Nandina - Please avoid planting this and consider removing it from
your landscape.  It is a pest in our parks and preserves.
Spring is the ideal time to think about planting, and how you manage your garden or landscape can have an effect on the overall health of the soil, air, water and habitat for native wildlife as well as our human community. Help conserve and improve the quality of these resources by using sustainable gardening practices such as mulching and composting, reducing or eliminating lawn areas, xeriscaping (planting native, drought-tolerant plants), installing rain barrels, and removing non-native invasive plants and restoring native ones.

The U.S. government defines an invasive plant species as one “that is not native to the ecosystem under consideration and whose introduction is likely to cause economic or environmental harm or harm to human health.” These species grow outside desired boundaries, out-competing native species, and spread by seeds, berries, spores, runners, rhizomes, and stems. Some can be easily transported long distances, and every year millions of our tax dollars and thousands of volunteer hours are spent trying to eradicate them.

Many of these plants have already invaded our preserves and greenbelts in Austin, originating in our landscapes, escaping cultivation and spreading into the wild. Invasive species may grow faster, taller, or wider and shade out native species. Many stay green later into the season or leaf out earlier, giving them an advantage over natives. They can change the vertical and horizontal structure of ecosystems, alter hydrology, and disrupt nutrient cycles, all of which can have devastating effects on native plants and animals.

Although invasive exotics may offer birds fruit, squirrels nuts, and hummingbirds and butterflies nectar, they do not provide the entire range of seasonal habitat benefits that an appropriate locally native species will provide. If we want not only to satisfy our desires to attract wildlife, but also to restore the critical, often unseen, small pieces in our ecosystems, we need to bring back our locally native plants. These plants are not only attractive to humans, they also meet the food and cover needs of all wildlife species: bees, wasps, butterflies, grasshoppers, bugs, beetles, spiders, and thousands of others that sustain and support food webs which songbirds, salamanders, bats, toads, and box turtles more visibly demonstrate.

Escarpment Black Cherry is a beautiful native tree that makes a great replacement for the

highly invasive privets or ligustrums.
Aside from attracting a diversity of wildlife, the use of native plants minimizes the impact our landscapes have on the natural environment around us. They reduce water consumption, eliminate the need for chemical fertilizers and pesticides, and limit the competition from invasive exotics. This results in a much healthier habitat—water, soil, and air—for humans and animals alike, and is less costly, too. Invite wildlife to put on a show in your backyard by replacing the invasives in your landscape, and encourage your neighbors to do the same.

Non-Native/Invasive Plant(s)
Some Native & Adapted Alternative(s)
Wax Myrtle (Morella cerifera)
Yaupon Holly (Ilex vomitoria)
Bamboo Muhly (Muhlenbergia dumosa)
Chinquapin Oak (Quercus muehlenbergii)
Texas Red Oak (Quercus buckleyi)
Chinese Tallow Tree 
Bigtooth Maple (Acer grandidentatum)
Lacey Oak (Quercus laceyi)
Elephant Ear
Arrowhead (Sagittaria latifolia )
Crinum Lily (Crinum americanum)
Pigeonberry (Rivina humilis)
Frogfuit (Phyla nodiflora)
Horseherb (Calyptocarpus vialis)
Giant Cane
Roughleaf Dogwood (Cornus drummondii)
Yaupon Holly (Ilex vomitoria)
Japanese Honeysuckle
Coral Honeysuckle (Lonicera sempervirens)
Passion Vine (Passiflora foetida or incarnate or lutea or tenuiloba)
Rock Rose (Pavonia lasiopetala)
Holly Fern
River Fern (Thelypteris kunthii)
Kudzu, English Ivy, Vinca
Virginia Creeper (Parthenocissus quinquefolia)
Trumpet Vine (Campsis radicans)
Coral Vine (Antigonon leptopus)
Ligustrum (all species) or Common Privet
Evergreen Sumac (Rhus virens)
Barbados Cherry (Malpighia glabra)
Yaupon Holly (Ilex vomitoria)
Possumhaw Holly (Ilex decidua)
Texas Sage (Leucophyllum frutescens)
Cherry Laurel (Prunus caroliniana)
Black Cherry (Prunus serotina)
Desert Willow (Chilopsis linearis)
Texas Redbud (Cercis canadensis var. texensis  )
Elbowbush (Forestiera pubescens )
Nandina or Heavenly Bamboo
Texas Lantana (Lantana urticoides)
Bush Germander (Teucrium fruticans)
Texas Sage (Leucophyllum frutescens)
Paper or White Mulberry
Red Mulberry (Morus rubra)
Texas Persimmon (Diospyros texana)
Possumhaw Holly (Ilex decidua)
Cherry Laurel (Prunus caroliniana)
Yaupon Holly (Ilex vomitoria)
Possumhaw Holly (Ilex decidua)
Evergreen Sumac (Rhus virens)
Red-tipped or Chinese Photinia
Evergreen Sumac (Rhus virens)
Carolina Buckthorn (Frangula caroliniana)
Yaupon Holly (Ilex vomitoria)
Russian Olive
Texas Persimmon (Diospyros texana)
St. Augustine Grass
Buffalo Grass (Bouteloua dactyloides)
Tamarisk or Salt Cedar
Bald Cypress (Taxodium distichum)
Arizona Cypress (Cupressus arizonica)
Tree of Heaven
Chinquapin Oak (Quercus muehlenbergii)
Lacey Oak (Quercus laceyi)
Vitex or Chastetree
Texas Pistachio (Pistacia mexicana)
Mexican Buckeye (Ungnadia speciosa)
Passion Vine (Passiflora foetida or incarnata or lutea or tenuiloba)
Trumpet Vine (Campsis radicans)

Tuesday, February 12, 2019

Early Spring Heralds

Windflower, typical white form
February is a time of change in Central Texas, with temperatures often ranging from the 30s to the 70s, and it is precisely these large swings in temperature that create challenges for local wildlife. Finding food is essential, and the little things like insects that emerge in early spring rely heavily on the early bloomers in our native landscape.

Elbowbush (Forestiera pubescens), also commonly called Stretchberry or Spring Herald, is a multi-branched deciduous shrub with smooth gray bark, long arched branches, and light green leaves.  It is most conspicuous, though, in late January and early February, when small, yellow-green, petal-less flowers begin to burst in small clusters on the bare twigs. Common in open woodlands, brushy areas, and near streams, its early flowering period provides nectar for native bees and spring butterflies, namely Gray, Juniper, and Great Purple Hairstreaks.  Elbowbush gets its common name from branches that typically form in right angles to one another, reminiscent of a bent elbow.  It produces a quarter-inch, fleshy, dark blue fruit often devoured by wildlife in the summer, and its leaves turn a unique chartreuse color in the fall.  Additionally, Elbowbush is one of the larval food plants for the Incense Cedar Sphinx (Sphinx libocedrus). 

Two-flowered Anemone, exhibiting side stem
Poking their colorful blooms above the drab winter landscape are two species in the Buttercup Family,  Two-flowered Anemone (Anemone edwardsiana) and Windflower (Anemone berlandieri). While both of these plants bloom from February to April, Two-flowered Anemone is an uncommon plant that is also called the Edwards Plateau Thimbleweed, since it grows only in this region of Central Texas.  Windflower is common and has a more widespread range, and is often called Southern Anemone or Tenpetal Anemone (even though it can have 10 to 20 petal-like sepals).

Two-flowered Anemone, deep blue form
Two-flowered Anemone grows 6 to 12 inches tall, and is most often found on the moist banks of shaded canyons.  Midway or further up the stem are three bracts, with side stems growing from those bracts, and each side stem can produce 1 to 3 flowers, with only 1 flower on the main stem. In reality, most plants carry only 2 or 3 flowers in total, each 0.5 to 1.25 inches wide and typically white, but can exhibit pink, lavender, light blue, or deep blue. In comparison, Windflower grows 6 to 15 inches tall, with low-lying leaves that are divided into three segments and are often reddish-purple on the underside.  Its single stem carries only 1 flower, 0.75 to 1.5 inches wide, and it can exhibit the same range of colors as the Two-flowered Anemone. 

Windflower, pink form
Windflower, light blue form
Found on the moist soils in shaded canyons in the southern half of the Hill Country, Golden Groundsel (Packera obovate) is a rosette-forming perennial that blooms from February to April. Slender flowering stems rise up to 18 inches above the basal rosette of oval leaves, topped with yellow flower clusters few to many-headed, with each flower 0.5 to 0.75 inches wide.  Once established, this plant colonizes quickly, and can create an early-blooming, evergreen ground cover in shady, woodland areas.

Golden Groundsel
Why not plant some these early bloomers in your landscape, as they not only provide early nectar for bees and butterflies, but they are also heralds of our coming spring!