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Friday, June 20, 2014

Dancing Damselflies

Desert Firetail, Telebasis salva

Often overlooked but in the same Order (Odonata) as dragonflies, damselflies are a group of insects that differ from dragonflies by wing shape, wing position, and eye separation.  Damselflies have similarly shaped fore and hind wings, typically hold their wings together over their abdomen when perched, and their eyes are widely separated but never touching.  In comparison, the hind wings of dragonflies are broader basally than their fore wings, they hold their wings spread out and away from their body, and their eyes are much larger and usually touch at least at a single point. 

Amethyst Dancer, Argia pallens

While damselflies are less robust fliers than dragonflies, they are still quite agile in flight.  They can move each of their four wings independently, and can not only beat them up and down, but also rotate them on their own axes.  Most damselflies fly by alternating the two pairs of wings, and while one is moving down to propel them forward, the other is moving up.  In spite of their fast wing beats, damselflies have relatively short, narrow wings that don’t allow them fast flight, and they move at an average speed of about 2 meters per second.  

Rambur's Forktail, Ischnura ramburii


Over 75 species of damselflies occur in Texas, more than half of the known species in North America.  These species represent members of all families of damselflies, which include broad-winged damsels (jewelwings and rubyspots), spreadwings, threadtails, and pond damsels (dancers, bluets, yellowfaces, wedgetails, damsels, forktails, swampdamsels, sprites, and firetails).  Like most dragonflies, the males are usually the most colorful and the easiest to identify.


American Rubyspot, Hetaerina americana

Springwater Dancer, Argia plana

Usually inhabiting small seepages and springs, the Springwater Dancer (Argia plana) is one of the most common pond damsels in our area, and has a blue head, face, and eyes, and a blue thorax with a black dorsal (top) and shoulder stripe.  Its abdomen is also predominately blue, with black rings on most middle segments.  It can often be found along roadsides, away from water.  The Great Spreadwing (Archilestes grandis) is the largest damselfly in Texas and the US, and is recognized by its blue eyes, the metallic green stripes on the top of its thorax, and bright yellow stripes on its sides.  Its wings are clear to slightly smoky, often with darker tips.  Found around bodies of standing water, it perches in a distinct manner on vertical stems with its body hanging downward and its wings partly spread.  Common around open streams and rivers, the American Rubyspot (Hetaerina americana) is a broad-winged damsel that has a metallic red thorax, a metallic green abdomen, and a vivid red patch at the base of its wings that grows larger with age.    

Great Spreadwing, Archilestes grandis

Observed throughout the summer at almost any body of freshwater, damselflies are slender and delicate.  They seem to dance around and about the water, marked with colors of the rainbow, delighting all those who take the time to get to know and admire them!

Monday, June 9, 2014

Wild Woodland Orchids

Spiked Crested Coralroot, Hexalectris spicata var. spicata

A colorful group of native orchids called Hexalectris or coralroots are found mainly in the mountains of northern Mexico and West Texas, but we are fortunate enough to have at least two species that grow in our area.  The name Hexalectris literally means ‘six cock’s combs,’ referring to the six prominent ridges that were thought to run down the length of the flower’s lower lip.  Despite this name, most flowers have only five or seven ridges.  

These orchids are micro-heterotrophic, which describes a plant that gets some or all of its food from parasitism on fungi rather than from photosynthesis.  Most Hexalectris orchids have only been discovered and studied in the last fifty years.  They depend heavily on an extremely delicate balance of environmental factors, which means they are not always observed every year, and it makes them impossible to transplant from the wild.

In our area, April through August is the best time to spot the Spiked Crested Coralroot (Hexalectris spicata var. spicata).  An uncommon orchid, it is most often found in the leaf litter on the wooded limestone hillsides and canyon slopes in oak-juniper habitats of the Edwards Plateau.  Also called cock’s comb or brunetta, the blooms of the Spiked Crested Coralroot grow on a tall, leafless, fleshy-pink stalk.  Each bloom has creamy yellow petals and sepals striped with brownish-purple, and the central white lip is adorned with five to seven wavy crests of deep, royal purple. 

Giant Crested Coralroot, Hexalectris grandiflora

Recently, the first record of the Giant or Largeflower Crested Coralroot (Hexalectris grandiflora) was discovered in the Balcones Canyonlands Preserve in Travis County.  Previously thought only to grow in the Davis and Chisos Mountains of West Texas, the bright pink, leafless stalk of this species grows from 10 to 24 inches tall.  Along the stalk, vivid pink flowers bloom with a white mark in the center of an elaborately shaped, three-lobed lip.  This coralroot also flourishes in our oak-juniper woodlands, and is thought to bloom from June to September.  Other common names for this beautiful wild orchid include Greenman’s hexalectris or Greenman’s cock’s comb.

These unique wild woodland orchids are uncommon to rare in our area, and together they help define the true nature of the Texas Hill Country.  Monitoring and preserving them is not only good for the sake of maintaining biological diversity and understanding changing environmental conditions, but for the future beauty of our ecoregion as well.