Iced in again

Yep, those are all wrecks

On friday I drove home through some of the gnarliest traffic the metroplex has seen this winter. It was bad enough to make the national news. By the time I was on the roads, most of the wrecks had already happened but had not been cleared. Abandoned cars facing the wrong direction lined the interstates. It looked apocalyptic. The few of us out trying to get somewhere were hitting top speeds of 20 mph. I wouldn't have tried it, but I was heading home from a meeting in Austin so I could pick up my dog from daycare and return a rental car. I knew all these tasks would be much harder the next day.

I tried to get out again on Saturday, and I made it a block before I slipped into a skid on a downhill and came to a gentle stop wedged against the curb. I was totally unharmed and rather lucky to be within an easy walk of my house, but I felt foolish for letting my cabin fever get the better of me. It was so slippery I couldn't even walk-- one of my neighbors came out to offer me a hand leaving the ice patch. I was slowly sliding downhill in my snow boots. He seemed skeptical when I said I was fine and could make it home on my own. I guess I was so fired up to get out because I haven't really gone walking in a couple weeks and it's been wet and cold. I appreciate the snow and ice for recharging the aquifer, but I miss going outside.

View of my backyard

I did get to see a little nature in Austin, however. I went to an amazing nursery called "East Austin Succulents" to peruse their collection of weird plants. I ended up taking two home, a split rock plant and a rattlesnake tail Crassula columella, both native to the South African Karoo. So cool. I'd love to tour the Karoo someday.  I adore botanical oddities.

Two new friends. 

I also saw some diminutive native wildlife. A moth sheltered from the cold under a blade of agave in the outdoor portion of the nursery. Thanks to the "Mothing and Moth Watching" Facebook group, this fluffy little guy was ID'd as a Hyphantria cunea, or Fall Webworm Moth. He looks quite stylish to my eyes-- I admire his fuzzy stole and leopard-spotted wings.

A male fall webworm moth

Fashionable as he may be, the fall webworm moth is a pest to many horticulturalists. They are called "webworms" because their caterpillars graze socially within a silk tent on branches. The netting lessens predation. Their caterpillars tend to prefer broadleaf trees, and in Texas they favor pecans. Like many other pests, their damage is mostly cosmetic. Even complete defoliation by webworms is unlikely to seriously harm a tree. It's just unsightly. Though it was certainly too cold for this moth to fly (many insects are unable to fly at temperatures below 55F), late february is not excessively early for these fellas to emerge.  

Fall webworm moths are native to most of North America, and they have invaded eastern europe and asia. Apparently they were accidentally introduced in Yugoslavia in the 40s, and they expanded from there. I feel a little vindicated, because there are few other non-native insect pests you hear about colonizing in that direction. While they are not a major problem in the States, I'd be interested to hear whether they are harder on the ecosystem outside their native range.  Considering that we live in a world with truly catastrophic invasive pests, I have trouble taking a little aesthetic damage seriously. I hope that's something horticulturalists consider when creating a management plan for this little moth. 

An everyday epiphyte

Mistletoe, Phoradendron spp.

Great Purple Hairstreak

Remember this guy (at left)? Remember how his caterpillars only eat mistletoe? For this and other reasons, our Texas mistletoe (Phoradendron spp.) is worth another look.  Mistletoe is an arboreal hemiparasite, related to sandalwood (another hemiparasite), with fleshy green leaves and stalks. It grows best as a rounded clump in the upper branches of hardwood trees where it has access to abundant sunlight and can practice its nutritional thievery unmolested.

Besides the caterpillars of the lovely great purple hairstreak and some other Lepidoptera, few creatures eat the toxic leaves of this plant. Birds, however, adore its fruit.  The berries are a valuable winter food source. Providing winter nourishment is not an act of philanthropy on the part of the mistletoe. Mistletoe berries are extremely sticky. Birds eat and poop them out, wiping off their little tails, feet, and beaks on the branches of a preferred roost, effectively dispersing the mistletoe progeny. It's ingenious. Humans appreciate and disperse mistletoe berries for their own purposes. Specifically-- stolen kisses in the holiday season.

A few white berries

Despite its bad reputation, mistletoe is unlikely to bring down a tree single-handedly. It may sap the vigor and weigh down individual branches, but it is unlikely to seriously harm an otherwise healthy tree. This is good news, because once established mistletoe is nigh impossible to remove. Cutting off a branch to excise the plant causes more harm to the host tree than leaving it in place. This practice is unlikely to completely remove the mistletoe anyway.

By flowering and fruiting in the winter, mistletoe provides resources when little else is available. It is well past time for blooming, but I saw some mistletoe flowering today anyway. The inconspicuous yellow flowers are a pollen source during this season of scarcity. Male and female flowers occur on different plants, and reproductive development is slow. Mistletoe doesn't typically flower before its third year. The large clusters you see in treetops are decades old.

I like epiphytes and parasitic plants.  I don't really have a good reason-- I guess they have a "tropical" feel. I can understand a homeowner not being thrilled at the arrival of this clever little plant on a favored shade tree, but seeing as there's no stopping it, you may as well take a philosophical perspective.  You can decide to appreciate its genius, and be comforted that it is unlikely to do serious harm for a few more decades.

Male flowers?

Spring heralded on valentine's day at Tandy Hills

A honey bee enjoys her non-traditional flowers on Valentine's day

We had perfect weather for a walk on Valentine's day this year, so I decided to tool around Tandy Hills and see how spring is progressing in this part of the metroplex. More butterflies were out. I saw little yellows and possibly dainty sulphurs, in addition to the occasional question mark canvassing about in the sunshine. I know question marks over winter as adults, but I didn't expect the appearance of the little yellows. Apparently they also overwinter as adults in the southern part of their range.

Blooming vetch?

These butterflies weren't nectaring, but they were actively flying on the ridge top. I didn't notice many green legumes for their caterpillars to eat, so I wonder if what I saw were males patrolling for females. In many butterflies and moths, the males emerge first in the season. They use their head start to stake out females.

I also saw a few honey bees out scouting for food. Other than dandelions, hen bit, and the occasional vetch, there wasn't much available. The honey bees seemed to ignore these flowers in favor of the small yellow elbow bush blossoms (Forestiera pubescens). Elbow bush is one of the first shrubs to bloom in Texas. It's flowers tend to appear in February or March, so it's right on time this year. Other common names for this plant include "spring herald" and "stretch berry".

It is fortunate that these honey bees have a few flowers from which to chose. Flowers like dandelions are deficient in multiple amino acids which honey bees are unable to manufacture. The bees would effectively starve and be unable to rear brood if that was the only pollen available.  By collecting pollen from multiple sources, they ensure that their diet satisfies the colony's nutritional requirements.

Busy loading up her saddle bags with food for the hive

Emergence and old skins

Shed snake skin

I was out looking for the first signs of spring at Fort Worth Nature Center yesterday. Trout lilies and other spring ephemerals emerge about this time of year in Texas, and spring itself will be truly upon us in another month. The birds were chattering and excited. I only realized I had missed them upon hearing them call again.

Question mark butterfly

I jumped the gun a little on wildflowers, however. It's still a bit early for them, despite the taste of perfect weather we've had this week. I did see other signs of the new season. A neatly coiled snakeskin sat on top of crispy brown leaves. Its perfect placement made me think it hadn't been there all winter. I don't know when snakes normally emerge from hibernation in Texas, but February seems premature.

Question mark butterflies were also awake and flying in the sun. These butterflies overwinter as adults. They roost in crevasses in tree bark, but they break dormancy on warm days. I didn't see much for them to feed on, but they seemed compelled to flit about. I don't imagine that butterflies 'play', that's what it looked like they were doing.

I also found an empty silk moth cocoon dangling from a small shrub. I'm on the fence as to whether the cocoon is from this year or last. It is remarkably well preserved, and it is certainly well attached to its little twiglet, but in our region silk moths don't normally begin to emerge until March.

Native silk moths are enormous, fuzzy, and brightly marked. The sea green luna moth is one of the more familiar representatives. Silk moths have an outer silk cocoon protecting their pupa. The silk moth used for commercial silk production is the only fully domesticated lepidopteran. They don't exist in the wild.

Adult silk moths do not have mouths. They do not feed as adults- they live for a week or two and are entirely consumed by the need to breed. In fact, some moth watchers rear female moths in order to use their pheromones as bait to lure in males of the species.

A luna moth- a type of silk moth

Until yesterday I'd never wondered how these mouthless moths fight their way out of their cocoons without mandibles. Apparently they either split their cocoons with a built-in escape hatch that only works from the inside, or they exude silk dissolving chemicals ("cocoon-ase") to ease their emergence.

Snakes and silk moths are both taken as symbols of rebirth and renewal, so it is fitting that I found them while out looking for signs of the changing season. As for spring beauties and trout lilies, I'll just have to keep checking. I don't mind the task.

A closer view of the cocoon

Spicebush, sulcatone, and mosquitoes

Aedes aegypti, wiki [8]

I fell down the google rabbit hole in a big way earlier today. I was digging around, looking for info on the chemical composition of some of my favorite scents from childhood. I wasn't doing this idly- essential oil companies sell these compounds. My though was this: wouldn't it be nice to blend a fragrance that captures where I grew up? 

Sweetgum Range, from wiki [6]

The aromas of a southern childhood that I settled on were forest soil, cedar, tomato leaves, gardenia, maple syrup, wet dog, and the fragrant terpenes from sweet gum (Liquidambar styraciflua) and spicebush (Lindera benzoin). Most of these were pretty easy to find. Oakmoss and vetiver conjure a forest floor, two varieties of cedarwood oil are manufactured in Texas alone, a tomato leaf accord is a popular perfume top note, blended jasmine and honey smells similar to gardenia, immortelle flower smells of maple syrup, costus of wet dog, etc etc. In fact, the resin of sweet gum’s Chinese cousin, also in the family Liquidambar, is a perfume staple. It is sometimes referred to as a variety of ‘styrax’.

Spicebush was the only fragrance without an obvious analog. Its crushed leaves smell of fresh citrus and camphoraceous cloves (like a hot toddy!). This lovely odor is referenced in its species epithet- ‘benzoin’. Derived from the the resin of trees in the genus Styrax, benzoin is another staple in perfumery. It smells of vanilla, warm powder, and musk. Spicebush was used by early American colonists as a substitute for allspice, and native peoples used it as a panacea, marinade, and fragrant tea. The spicebush swallowtail relies on spicebush as its only larval food source. It is also a preferred food of the gorgeous promethea silkmoths, and its bright red berries are a treat for the birds. 

A day-flying hypocala moth

The beautiful Hypocala andremona

As far as lepidoptera go, moths came first.  Butterflies are essentially a type of moth, a moth with brilliant colors that flies in the daytime. Moths show up in the fossil record 190 million years ago.  Butterflies appear as a sub group later, perhaps as late as 130 million years ago.  It could be for this reason that there are ten times as many species of moths as there are butterflies. Some of the most primitive micromoths (Micropopterigidae- mandibulate archaic moths) hardly resemble their larger cousins at all. Their caterpillars are slug-like detritivores, and the adults retain their chewing mandibles. They are closely related to caddis flies.

Sphinx moth

 I find moths fascinating because they surround us, but their nocturnal habits assure that we rarely notice them unless they are knocking against our porch lights. There are exceptions, however. Some moths, like the sphinx moths, fly in the daytime. Others, like the Hypocala andremona pictured above, stay up past their bedtime.

I was delighted to find a hypocala moth in south Texas (November 2014). S/he had obligingly posed on an orange bank of flowers, accentuating the bright underwing coloration. They can be a defoliating pest on persimmon leaves as caterpillars, but I can't begrudge them that. It is rare for a tree to die from periodic defoliation. Hypocala moths themselves are heavily parasitized by beneficial insects, especially the trichogramma wasps. To me, they don't seem like a pest that requires active intervention. Supposedly they are most frequently seen in Texas, and they can be found from Central America up through the southern states.

Distinguishing the very similar underwing moths (catocala) from the hypocala moths is not easy. Both are medium-large moths with drab upper wings and colorful, patterned underwings. I read that catocala means "beautiful below" in latin on bugguide.net, so hypocala must mean "beautiful underneath". Basically the same thing. They are both in the Erebidae family, but the precise taxonomic split varies by source.  I doubt I could have teased apart this taxonomic distinction without help from the "Mothing and Moth Watching" Facebook group. Following this group is addictive. People post pictures from all over the world-- who knew there were so many gorgeous moths in China and Brazil?

If I've piqued your interest, you can read more about moths on this blog here and here, or you can become a member of "Mothing and Moth Watching" on Facebook.

Possibly a day-flying large lace border moth (Scopula limboundata)

A visit to the coastal prairie

Gayfeather on the dunes

I spent the end of last week down in San Marcos giving a "Monarchs 101" talk to agency personnel. My monarch talk was something of an opportunistic afterthought, appended to an existing gathering of the Gulf Coast Prairie Landscape Conservation Cooperative (GCP LCC). This organization was formed as a collaborative effort, driven by the Department of the Interior, to protect the Gulf Coast Prairie from threats including climate change and urbanization. Because Texas' geographic extent encompasses the funnel through which the majority of migratory monarchs pass every spring and fall, and because the Feds have been under a lot of pressure to develop a strategy to save the monarch butterfly migration, the GCP LCC and their partners are tackling this issue. I was brought in to provide an overview of monarch biology. I've discussed monarchs and other milkweed butterflies before in this blog.

It's easy to forget about the coastal prairies up here in the Great Plains. After living in Nebraska, it's a stretch to imagine a tall grass prairie within earshot of the surf, but I've seen it. Last November I stopped off in Corpus Christi to visit Padre Island on my way to the Texas Butterfly Festival. There I found tall grass species commingling with yucca and hardy halophytes.

As the southern-most extension of the tall grass prairie, you recognize seemingly misplaced familiar plants. I noticed little bluestem and gayfeather, among others. You also get coastal species, like sea oats and fleshy succulent forbs. It sure felt tropical-- my leeward arm was entirely coated in mosquitoes. Luckily, I was wearing a thick wool sweater over a flannel shirt. All I could think was "malaria, yellow fever". Prior to eradication efforts, visiting coastal Texas must have been a real gamble. I spent a summer as a research assistant in the salt marshes of coastal Virginia, but I've never seen mosquitoes like that.

A tallgrass dune system

The gulf coast prairies are also unusual because they exist in a land that receives more than enough rain to support forests and other vegetation. You can find these prairies from Lafayette, Louisiana to south Texas. Supposedly, edaphic (soil) characteristics and fire maintained these grasslands' open canopy.  I would guess that salinity in the water table also prevents trees from getting established.

crested caracara

Corpus Christi is far enough south that you get some semi-tropical birds. In fact, Padre Island is renowned for birding. The National Park Service website claims that Corpus Christi won the "birdiest city" award for 10 consecutive years. You get both winter residents and migrants. It is one of the richest areas for birding in North America. Obsessive birders travel from all over to get 'lifers'.

I didn't do much birding, but I saw a pair of crested caracaras gliding and diving in the dunes. These funky raptors are most closely related to falcons, but they live like vultures. They are inefficient hunters, and prefer carrion and thievery to catching their own dinner. They also look like they are wearing poorly fitted toupees. This 'bad wig' effect, combined with their pink faces, make them look rather non-threatening for a bird of prey. Their range barely extends into the US. The crested caracara heartland is Central America and northern South America.

This bird doesn't mind the seaweed

Another distinctive facet of the Gulf Coast Prairies is their exposure to the by-products of petroleum exploitation. When I asked native Texans about the beaches, their responses tended towards "Eh." A friend of mine reminisced about digging tar balls on the beach as a child. Additionally, something about the rotation of the Gulf Coast gyre leads to heavy trash and seaweed accumulation. The Padre Island entry booth had signs posting the tides, the flag warning, and the levels of trash and debris on the beach.  It's a shame, but the birds still come. If you want to add to your life list, or see a unique prairie system, it's still worth a trip.

Pelican and cormorants hanging out in the surf