Aerial Assassins

Robber Flies are also called Assassin Flies, and for good reason!

What is that powerfully built, fly-like creature that waits in ambush to catch their prey in flight? It’s a robber fly, otherwise known as an assassin fly, which feeds almost exclusively on other insects, including other flies, beetles, butterflies, moths, bees, ants, dragonflies, damselflies, wasps, grasshoppers, and even some spiders.

Robber flies have stout, spiny legs, short antennae, three simple eyes on the top of their head between two large compound eyes, bristly bodies, and a short, stout proboscis that encloses a sharp, sucking mouthpart called a hypopharynx. They also have a dense moustache of bristles on the face called the mystax, which appears to offer some protection from their struggling prey. These flies attack their prey by stabbing it with the proboscis and injecting it with a saliva that contains both a neurotoxin and proteolytic enzymes.  This paralyzes the prey and liquifies the insides, allowing the robber fly to suck the material up through their proboscis.

In spring and summer in our area, some of the more common robber flies include the Bee-like Robber Fly (Laphria macquarti), Prairie Robber Fly (Diogmites angustipennis), and the Maroon-legged Robber Fly (Promachus hinei). 

The Bee-like Robber Fly is large (up to 1.25” long), hairy, mostly black with a yellow thorax, basal abdominal segments, and some yellow on the legs.  It mimics the American Bumblebee, and while it prefers to feed on small beetles, it will take a wide range of prey, often perching on tree stumps in the open.

Bee-like Robber Fly

The Prairie Robber Fly, also called the Slender-winged Hanging Thief, is about 1” long, with greenish-red eyes, tan to reddish-brown body, thorax with darker brown longitudinal stripes, and abdomen with darker lateral stripes.  It is common in both woodland and meadows, hunting bees and other insects, and typically hangs from vegetation by its forelegs while it consumes its prey.

Prairie Robber Fly

Another large robber fly is the Maroon-legged Robber Fly, up to 1.5” in length.  It has dark eyes, light-colored bristles around the face, a brown thorax, a cream-colored abdomen with thick black bands and a black tip, and hairy reddish-brown legs. It prefers hunting bees and wasps, and can be found flying around a variety of habitats, perching on the ground or in vegetation.

Mating Maroon-legged Robber Flies

Female robber flies deposit tiny, whitish eggs on low-lying plants and grasses, or in cervices in wood or bark, or in soil. After hatching, the larvae live in this detritus, feeding on other soft-bodied insects. Robber flies overwinter as larvae, pupate in the soil, and eventually emerge as adults.  This developmental cycle can take one to three years, depending on the species and environmental conditions. Robber flies generally occur in relatively open habitats with scattered vegetation, or in forested margins and woodland edges.  

Robber flies are generally considered beneficial insects due to their predatory nature, as they primarily feed on other insects, many of which are considered pests. These aerial assassins help to naturally regulate insect populations thereby contributing to a more balanced ecosystem!

Migration Isn't Just For The Birds

 

Wandering Glider dragonflies do more than wander...

Most people who are interested in nature know that each spring many species of birds migrate north, and each fall they migrate south.  But birds aren’t the only animals that participate in this amazing natural phenomenon, as even some insects (other than the well-known Monarch butterfly) participate in long-distance migrations as well.  While insects are the most species-rich and abundant group of macroscopic organisms on the planet, understanding many aspects of their annual cycles and behavior drastically trails behind the ability to identify and classify them. 

Migration is defined as the cyclical travel of an animal as it returns to its place of departure.  It can be accomplished in one or multiple generations.  Some animals don’t migrate at all, and others move only short distances south or north.  While the guiding factors for navigation are still being discovered, migration is typically triggered by local climate, food availability, seasonality, or reproduction.

Adult Common Green Darner

Interestingly, about nine dragonfly species are known to migrate, including the Common Green Darner (Anax junius), Wandering Glider (Pantala flavescens), as well as some species in the Skimmer family such as meadowhawks and saddlebags. These dragonflies are known to travel up to 1500 miles over the full cycle of their migration, taking three generations.

Adult Wandering Glider

The secrets of dragonfly migration were discovered and confirmed by biologists measuring the chemical makeup of their wings.  In their immature or nymph stage, dragonflies grow their wings while still developing in local water.  Because the stable hydrogen isotope concentration varies in concentration by latitude, biologists can estimate the geographic region where adult dragonflies developed as nymphs.  

The female Common Green Darner (bottom) is held by
the male (top) after mating, when ovipositing in water.

From February to August the first generation emerges in the south and migrates north.  From June to October the second generation emerges in the north and migrates south.  Both of these generations have the ability to undergo rapid development from egg to adult.  But from November to March the third generation emerges in the south and is non-migratory, focusing mainly on producing another first generation for the cycle to start again.  It is this generation that employs a different strategy, developing slowly in late fall, entering diapause or actively induced dormancy over the winter, and emerging in early spring.

Dragonfly migration was not well understood until very recently.  Research published in 2018 detailed the journeys of Common Green Darners by analyzing 852 wing samples from eight different countries and utilizing 21 years of citizen scientist observations to link each specimen to its place of origin and establish its migration history. However, it is important to note that the timing of migration and the development of nymphs are both highly temperature dependent, so continued climate change could lead to fundamental changes in the migration cycles for dragonflies and other migrating insect species. So as you can see, migration isn’t just for the birds!

Preparing for a Winter Feast

 

Pine Siskin feeding on Thistle

Gardens can be a source of delight even during the winter months, if created with native plants for wildlife in mind. As the weather turns cold and foraging becomes more challenging, home gardens can be a critical resource for many different species.  Planting layers of vegetation, from ground covers to trees, provides the food and shelter necessary to sustain wildlife. 

Since different species utilize different types of food, it is important to consider the fructivores, nut eaters, granivores, and insectivores.   Native berry producing trees and shrubs that persist into winter are numerous and include yaupon, possumhaw, southern wax myrtle, American beautyberry, flameleaf sumac, roughleaf dogwood, Virginia creeper, Texas persimmon, and rusty blackhaw viburnum.  Trees such as the native Texas Red Oak, Live Oak, Post Oak, pecan, and Arizona walnut provide highly desirable nuts.  

Southern Wax Myrtle Berries

Rusty Blackhaw Viburnum Fruit

Post Oak Acorns

Another valuable practice is to create areas that mimic the forest floor by leaving leaves, which allows animals places to forage for overwintering insects.  Raking, mowing, and blowing is detrimental to many species of moths, butterflies, snails, spiders, beetles, and dozens of arthropods (such as millipedes).  Many moths and butterflies overwinter in the egg, caterpillar, or chrysalis/cocoon stage and use leaf litter as winter cover.  If you must keep your non-native lawn free of leaves, carefully rake them into a pile in the corner or spread them underneath trees and shrubs as a natural mulch.

Just as important is the practice of leaving seedheads and not cutting or pruning back perennials until they begin to break dormancy in late February or early March.  Birds can pluck seeds from spent flowerheads, hollow stems can become nests for solitary bees, and overripe fruits can be left to fall to the ground for animals to find.  Several native plant species that should be left standing throughout the winter include purple coneflower, blazing star, fall aster, common sunflower, tall goldenrod, western ironweed, frostweed, Texas thistle, Turk’s cap, blue mistflower, chile pequin, pigeonberry, and white boneset. 

Tall Goldenrod Seedhead

White Boneset Seedhead

Native grasses left to seed are also very beneficial, with clump-like vegetation at the base providing shelter from the cold and seedheads supplying food.  In early spring, the previous year’s leaf blades also provide necessary nesting material for many birds and small mammals.  The grass species to consider include inland sea oats, sideoats grama, switchgrass, big muhly, big bluestem, little bluestem, bushy bluestem, and indian grass.

Inland Sea-Oats Seeds

The colder months of the year are a good time to evaluate how well your garden provides a winter feast and haven for wildlife.  Helping our native animal species during the more barren months of the year by providing naturally occurring food and shelter helps to prepare them for a healthy and productive spring breeding season.

Black and White All Over

 

The white patches on the black body of this Cottonwood Borer
are actually areas of pubescence or short, dense hairs.

Colorful things typically catch our eye, but the patterns formed by black and white can often be the most striking.  In nature, these patterns can be achieved through contrasting chemical pigments or structural elements such as scales or pubescence (or hairs).  While somewhat rare but not uncommon, these distinct black and white combinations are particularly striking in three native beetles, the Cottonwood Borer (Plectrodera scalator), the Texas Click Beetle (Alaus lusciosus), and the Texas Ironclad Beetle (Zopherus nodulosus haldemani).

The Cottonwood Borer is an unmistakeable, robust, elongate beetle with a shiny black body up to 1.6 inches long, and irregular, contrasting markings of white pubescence.  It has long, black antennae and prominent spines on the side of the pronotum, or the plate-like structure that covers all or part of the thorax. As an adult it is most active in summer, feeding on leaf petioles (stalks) of cottonwoods, willows, and sycamores, and is often found near the base of these trees.  Its' larvae bore into the base of the tree, living under the bark, and require 2 to 3 years to reach maturity.

Cottonwood Borer, from above

Present in Central, South, and East Texas, the Texas Click Beetle, up to 2 inches long, has distinctive, large, round black eyespots its pronotum, usually encircled in white.  White markings made of scales on its black body are clumped and patchy rather than evenly dispersed, and can sometimes look faintly yellowish.  Its common name comes from the fact that they possess an unusual clicking mechanism, whereby a spine on the prosternum (the underside of the thorax) can be snapped into a corresponding notch that produces a violent click that bounces the beetle into the air.  It is mainly used to avoid predation but can be useful when it needs to right itself.  Its species name means ‘dim-sighted’, and it can be found under loose tree bark.

Texas Click Beetle

The Texas Ironclad Beetle, a nocturnal beetle up to 1.5 inches long, has a distinctively round pronotum and raised black bumps or knobs on a white body.  It has a phenomenally strong exoskeleton, very thick and hard, in part due to its interlocking elytra or wing covers.  As such, it cannot fly but will play dead for long periods of time if touched or disturbed.  Also called Haldeman’s or Southwestern Ironclad Beetle, the Texas Ironclad Beetle is endemic to East and Central Texas, and it is active as early as March and into late October.  It has been associated with dead or dying pecan, oak, and elm trees, and has been found feeding on lichen.  Each part of its scientific name has relevance; zopher comes from Greek and means ‘dark' or 'dusky’, nodulus comes from Latin and means ‘little knot' or 'knob’, and haldemani refers to Horace Haldeman (1820-1883), one of the first to concentrate on collecting insects in Texas.

Texas Ironclad Beetle

The next time you see a beetle that is black and white all over, take a closer look at these fascinating creatures.  You just might find them to be as interesting as their more colorful cousins!

Breeding Beauties

White-eyed Vireo nest, a sign of spring

As the fickle winds of  spring come in from  the south, they usher in several  species of birds  that spend the warmer months  in Central Texas.  Most of these species overwinter in Mexico, Central America, or South America, and their arrival in  our  area  signals  the start of the  breeding season.  Most notable  are the  Summer Tanager,  White-eyed Vireo,  Western Kingbird, and Scissor-tailed Flycatcher.

Summer Tanagers (Piranga rubra) are medium-sized, chunky songbirds with big bodies, large heads, and thick, pale, blunt-tipped bills.  Mature males are the only birds in North America that are completely red.  The female and immature males are bright yellow-green, which makes them harder to spot in the forest canopy. These birds prefer to stay fairly high in the trees, often in willows, cottonwoods, and mesquite along creeks and streams.  They prefer to sit still then fly out to catch insects in midair.  They are especially fond of bees and wasps, beating them against a branch once they are caught, but they may also forage on berries and fruits near their forest habitat.  Males have a sweet, whistling song, much like an American Robin.

Summer Tanager, male

Like most vireos, White-eyed Vireos (Vireo griseus) are small songbirds with compact bodies and thick, slightly hooked bills.  They have yellow spectacles around their white eyes, yellow-washed sides, gray head, white throat, and two white wingbars.  They prefer areas that are scrubby and thick with vines and other vegetation, staying hidden in the understory where they glean caterpillars and other insects. Their song is distinctive, rapid and harsh, sounding like ‘Spit. And see if I care. Spit.’ While only the males sing on their breeding grounds, both males and females have been found to sing on their wintering grounds.  They bathe by rubbing their bodies against dewy foliage in the early morning, or by quickly dipping their backsides in a pool of water.

White-eyed Vireo

Oddly often found in parking lots with Live Oak trees, Western Kingbirds (Tyrannus verticalis) are fairly large flycatchers with gray heads, broad shoulders, whitish chest, lemon yellow bellies, heavy straight black bills, and medium-length black tails with white outer tail feathers.  They prefer open habitats, often perching on power lines, fences, and in trees, waiting to hawk insects from the air.  In fact, their breeding range has been expanding as an unplanned result of humans planting trees and installing utility poles in open areas.  Their territory defenses include lots of wing-fluttering and a long series of squeaky, bubbling calls.  Paired males and females work together to defend their territory, which shrinks as the breeding season progresses.

Western Kingbird

Few birds are as graceful to watch as Scissor-tailed Flycatchers (Tyrannus fortificatus).  These elegant, slender birds are gray overall with salmon-pink flanks and underbellies, stout black bills, blackish wings, and long, forked tails they use to sharply twist and turn midair to catch insects.  Interestingly, Scissor-tails are known to use many human-made products in their nests, including pieces of cloth, paper, string, and even carpet fuzz and cigarette filters.  These items can account for up to 30% of the weight of the nests.  In late summer and early fall, these flycatchers gather to form large, bickering flocks and migrate together back to their wintering grounds.

Scissor-tailed Flycatcher

Scissor-tailed Flycatcher, showing its' namesake tail

Color Changers

 

Green Anole, Anolis carolinensis

Native to North America and most abundant from the Carolinas south to Florida, along the Gulf Coast, and as far west as the Texas Hill Country, the Green Anole (Anolis carolinensis) is a small to medium sized lizard with a long, pointed head, slender body, long tail, and toes with adhesive pads that facilitate climbing.  Arboreal in nature, it can also be seen on the ground and in areas with shrubs and vines at the edge of our moist forests.

Males are typically 15% larger than females, from 4.9 to 8 inches long, with about 65% of that length being tail. Males have a dewlap or throat fan that is three times the size of the females and is strawberry-red, while the females’ dewlap ranges from white to light pink.  Unlike males, females also have a prominent white stripe that runs along their spine.

Male Green Anole with dewlap extended

Strongly territorial, males will fight other males to defend their territory, and have even been known to fight their own reflection in mirrored glass. When a male sees a rival, he will compress his body, extend his dewlap, inflate a dorsal ridge, and bob his head to chase off the intruder.  If that doesn’t work, they will fight, especially during mating season. A male’s territory typically includes two to three females, and he will court a female by extending his dewlap and bobbing up and down, mimicking a push-up. 

Breeding begins in April and ends in late September, with females laying their first clutch of one or two eggs about a month later.  Females can produce an egg every two weeks during mating season, up to about ten eggs, and they are buried in a shallow depression in soft soil or leaf litter.  Eggs are incubated by the heat of the sun, and hatch in five to seven weeks, with the hatchlings left to fend for themselves.

What is most intriguing about these lizards is their ability to change color from bright lime green to dark brown, and while often called ‘American chameleons’, they are not true chameleons.  Their ability to change color is a result of three layers of pigment cells or chromatophores.  The first is the xanthophores which is responsible for yellow pigmentation, the second is cyanophores responsible for blue pigmentation, and the third is melanophores responsible for brown and black pigmentation.

Male Green Anole, brown color form

If one of the chromatophores is lacking due to genetics, color mutations can form, but are extremely rare in the wild. Blue-phased green anoles lack xanthophores, and yellow-phased green anoles lack cyanophores.  These color exceptions rarely live long, as they don’t provide the camouflage the green color does, which is highly useful in hiding from predators and hunting down prey.

Several factors contribute to the anole changing its color, including its mood, stress level, activity level, and even social signals such as displaying dominance.  Although claimed, evidence does not support color change due to camouflage or a response to background color, and it is even less clear if the color change is in response to temperature.  When stressed, during a fight for example, the skin behind their eyes may turn black and form postocular spots that resemble a small black mask.  

Regardless of the reason, no other lizard species in Texas is capable of such extensive color change.  With populations existing in even the largest of cities, these color changers are a fascinating part of our suburban landscape! 

Coexisting with Coyotes

One surprising fact about coyotes are that they are adept swimmers!

Intelligent, adaptable, and opportunistic, coyotes (Canis latrans) are generally misunderstood and are the one animal most often persecuted by humans.  As clever omnivores that also have a keen sense of hearing, sight, and smell, one can easily see how many myths and untruths have been associated with this species.

Contrary to popular belief, there have been no coyote attacks on humans in the city of Austin’s history.  Coyotes live in smaller family groups than wolves, and most often hunt solo, searching for small prey such as rodents.  They don’t generally breed with domestic dogs, and seeing them out in the daytime does not mean they are rabid or diseased.

Lanky and leaner than most dogs, mature coyotes weigh between 25 to 35 pounds, and have a territory size that can range from 0.25 miles (if rich in resources) to 40 miles (if poor in resources).  They are native animals that traditionally depended on habitat with lots of vegetation and food sources such as squirrels and rabbits.  However, with few predators and the rapid destroying of habitat through urban sprawl, coyotes are adapting, shifting, and as a result are more often seen and heard by humans.

A coyote's territory can range from a quarter mile to 40 miles.

Socially flexible animals, the behavior of coyotes and their activities change with the seasons and their circumstances. While they are typically most active at dawn and dusk, they can also be normally active day or night, and their activity is often timed to their life events.  From January to March they search for mates, from April to June the females give birth to 5 to 7 pups, from July to September they actively feed their growing pups, and from October to December the juveniles leave their dens and disperse in search of their own territory.

While frequently but not always seen, coyotes also leave telltale signs of their presence.  Their tracks often show two front nails, and there is more space between the paw pads, often forming an ‘X’.  Dog tracks, including the native gray fox, may or may not show nails, and exhibit less space between the paw pads, often forming an ‘H’.  The scat or droppings of coyotes is tubular, 0.4 to 1.4 inches in diameter, and 5 to 13 inches long with tapered ends.

The space between paw pads is different on a coyote (left) versus a gray fox (right).

Historically, coyotes have avoided competing with wolves, until wolves were hunted out (extirpated).  Both species were originally confined to the prairies of central North America, and while both wolves and coyotes were aggressively hunted, wolves were extirpated but coyotes thrived.  While the cause for this dynamic is somewhat complicated, the main factor for the success of coyotes is what happens when a family pack is disrupted.  Coyotes overcompensate for a population reduction, and a lone coyote can fill a void in a pack in as little as 2 to 3 weeks.  If alpha males or females are killed, other pairs quickly form, reproduce, and litter size can actually increase up to 16 pups.  In other words, coyotes have developed a biological response to make up for pack losses.

Coyotes have golden eyes and their coats range from dark gray to buff-colored.

Past attempts to control coyote populations have proved useless, and many methods are now illegal in the city of Austin, including traps, snares, and holds, which are inhumane and indiscriminate.  Even relocation of coyotes is illegal, because they can be a vector species for rabies, and relocating places them in unfamiliar territory.  

What we can do to coexist with coyotes is to learn to share space with them, but not time.  Non-lethal management tools that are ecology-based can successfully balance the humane treatment of wildlife with public safety concerns. Our behavior shapes coyote behavior, so doing simple things can minimize our interactions with them.  Coyotes are naturally afraid of people and their presence alone is no cause for concern. Keep your garbage and recycling cans inside and secure until the morning of pickup, close off crawlspaces under porches and decks, feed your pets indoors and keep them inside at night, and simply use noise to scare them away.

Coyotes are lanky and leaner than most dogs.

Remember that coyotes contribute beneficial aspects to our ecosystem by keeping prey species in check, and many scavenger animals, such as foxes and vultures, benefit from coyote predation on these prey species through increased food availability in the form of leftover carcasses.  And finally, like all wild animals, coyotes have a right to inhabit our wild places, including the preserves and open spaces that border our urban and suburban homes.  If you respect their right to exist, you may well be rewarded with a familial chorus of howls on a moonlight night!

Hoppin' Orthoptera

Grasshopper nymphs are often mini versions of the adults

Take a walk through a meadow on a late summer or early fall day, and you’ll no doubt encounter members of the insect order Orthoptera: grasshoppers, crickets, and katydids.  While their Greek name translates to ‘straight wings’, these insects are better known for their jumping ability and powerful hind legs that can propel them to 20 times their body length. 

Abundant, large, colorful, and often noisy, orthopterans are unlike other insects in that they undergo an incomplete or gradual metamorphosis.  Their simple lifecycle consists of an egg, nymph, and adult, where the nymphs look similar to adults, but lack completely developed wings.  Eggs typically hatch in the spring, nymphs develop through the summer, adults mate and reproduce in late summer and fall, with winter passing in the egg stage.  They have three basic body parts: the head, which contains sensory parts such as antennae, eyes, and mouthparts; the thorax, which contains the legs and wings required for movement; and the abdomen, which bears the digestive and reproductive organs.

The use of sound is crucial in courtship, with each species having its own distinct song.  Males attract mates through stridulation, or producing sounds by rubbing the upper and lower wings or the hind leg and wing together creating a vibration that is species-specific.  The auditory organs for orthopterans are not located on their heads, however, but on the abdomen for grasshoppers and the front legs of crickets and katydids.

Differential Grasshopper

Common throughout Texas is the Differential Grasshopper (Melanoplus differentialis), which is brown to olive-green and yellow and up to 1.8 inches long, with black herringbone markings on its legs.  It feeds on both grasses and broadleaf plants, although it prefers the latter, and is often found in areas of lush vegetation. Both nymphs and adults tend to aggregate together, and the adults are found from July to October.

Obscure Bird Grasshopper

Also found thoughout Texas is the Obscure Bird Grasshopper (Schistocerca obscura).  This large grasshopper, to 2.5 inches long, has olive-green forewings and typically a pale yellow-green dorsal stripe from the front of the head to the wing tips. While females can lack this stripe, both sexes have blackish-purple tibia with yellow, black-tipped spines.  This species prefers fields and open woodlands, and can sometimes feed on flowers and shrubs.

Green-striped Grasshopper

The Green-striped Grasshopper (Chortophaga viridifasciata) is found everywhere in Texas except for the southernmost portion of the Trans-Pecos.  Up to 1.5 inches long, it has both a green form (usually females) and a brown form (usually males). Between forms, the main difference is the coloring of the head, thorax, and outer face of the hind femora, with the abdomen always being reddish-brown. This grasshopper prefers wet areas with short grasses on which to feed.    

Narrow-winged Tree Cricket

More often heard than seen, Tree crickets (Oecanthus sp.) are whitish to light green, with long antennae and slender bodies.  In late summer from dusk into the evening hours, the males begin to chirp, with the rate of the chirp correlating to the outside temperature.  If you count how many chirps you hear in 15 seconds and add that to 40, you’ll come surprisingly close to the actual air temperature in degrees Fahrenheit.  

Field Cricket

Field crickets (Gryllus sp.) are dark brown to black, about 1 inch long, live in cool, dark areas, and normally emit high-pitched, continuous calls.  Those that live in caves are dark brown, have well-developed hind legs, and exhibit a hunchbacked appearance.

Fork-tailed Bush Katydid

The antennae of katydids are hair-like and at least as long as the body, superbly represented by the Fork-tailed Bush Katydid (Scudderia furcata).  This all-green katydid is often found in weedy fields, thickets, forest edges, and along roadsides. Up to 2.2 inches long, the first generation matures in late spring and the second in early fall.  Interestingly, the overall size of the adults varies and is directly related to how fast they must mature in order to fully use the growing season to produce the maximum number of generations.

Often, what you can’t identify by sight during the day becomes clear when it sings, calls, buzzes, or chirps at night.  Immerse yourself in the nighttime soundscape, and hear your way to discovery!

A Killer of a Wasp

In late June and July, cicadas begin emerging from the ground,
breaking  through their shells or exuviae,
leaving the empty husks behind.

What are those large, solitary wasps we see flying around our yards from late June to September?  Often referred to as the Cicada Killer or Cicada Wasp (Sphecius speciosus), this native species occurs in the eastern and midwestern U.S. regions, southwards through Texas into Mexico and Central America. Cicada killers are so named since they prey on cicadas and provision their nests with them.  While large and intimidating, they offer a measure of natural control on cicada populations.  They benefit our native plants by pollinating flowers and protecting trees from the numerous cicadas that feed on their roots and foliage.

Cicada Killer or Cicada Wasp nectaring at a flower.

Cicada killers are robust wasps up to 2 inches long, with amber wings and black to reddish-brown abdomens with yellow stripes.  The females are somewhat larger than the males, and both are among the largest wasps in the U.S. These solitary wasps have a very unusual and interesting lifecycle.  Females are commonly seen skimming around areas with sparse vegetation for nesting sites, burrowing a tunnel, 10 to 20 inches deep, in dry or bare soil.  In digging a burrow, she will dislodge the soil with her jaws, and using her hind legs that are equipped with special spines, push the loose soil behind her as she backs out of the burrow. 

Cicadas, like this Megatibicen resh,
are hunted by the female Cicada Killers.

The female cicada killer proceeds to capture cicadas, sometimes even in flight, paralyzing them with her venomous sting.  She places the cicadas beneath her, grasping them with her legs, and either flies or drags her prey, which is twice her weight, into her burrow.  After placing a few cicadas in her nest, she begins to lay her eggs.  Females can predetermine the sex of the egg, and she lays multiple male eggs on a single cicada.  But each female egg is given 2 or 3 cicadas, as females are larger, require more food, and more females are needed to create new generations.  Eggs are always laid under the left or right second leg of the cicada. The female then closes the burrow with dirt, as the eggs hatch in a few days, but the larvae take some time to mature, feeding on cicadas as they overwinter in their burrow, not emerging as adults until the following spring.

Adult male cicada killers emerge in spring before the females, defending the territory around their emergence hole and searching for females.  They typically perch on the ground, flying up to attack any rival males. Once females emerge, mating occurs, and the males die shortly after.  Females live long enough to dig and provision their nests, and die after laying all of their eggs.

Cicada killer wasps are not aggressive toward humans and rarely sting unless provoked by grasping them roughly, accidentally stepping on them, or if caught in clothing.  Only the females have stingers, and while males will actively defend their perching areas against other males near nesting sites, they have no stingers. Both males and females have large jaws, but they are not known to grasp human skin and bite.  If swatted at, they will just fly away rather than attack. They are simply focused on cicadas or other cicada killers!

Evening Chorus

Green Tree Frog

From late winter into early summer, many of the night sounds you hear are not insects at all, but members of a wide-ranging group of cricket, tree, chorus, and chirping  frogs.  This group of frogs and their allies have adaptations that reveal their mostly arboreal lifestyle, such as forward-facing eyes for binocular-like vision, adhesive pads on their fingers and toes, and a fondness for eating insects.  Often not seen due to their diminutive size, these frogs are commonly mistaken for insects, due to their ability to produce loud and varied mating calls.  Known as ‘advertisement calls’, these calls are produced by the males to attract females and warn other rival males during the breeding season.

Blanchard's Cricket Frog

At ½ to 1 ½ inches, Blanchard’s Cricket Frog (Acris crepitans blanchardi) is found throughout most of the state, except for the Panhandle and West Texas.  Gray to green-brown, this frog has a long rounded snout, dark bands behind its limbs, and a distinguishing triangular patch behind the eyes that points down its back. Diurnal and active all year, these frogs prefer shallow but permanent ponds with vegetation and full sun.  Often seen basking during the daytime, they will jump quickly into the water or away when disturbed, and are capable of covering 6 feet in one leap!  Although they are part of the tree frog family, they are much more terrestrial and are excellent swimmers.  When chorusing, especially at night, the male’s call sounds like clicking small rocks or pebbles together.  Mating occurs in late spring, with the female laying one egg at a time on submerged vegetation.

Green Tree Frog

The Green Tree Frog (Hyla cinerea) is a common, 1 to 2 inch frog with a slender, bright green body, cream-colored belly, and white lips that extend into lateral stripes along the sides of its body.  Found in the eastern third of our state, this frog walks rather than jumps when on the ground.  It is nocturnal, and prefers wet areas such as swamps, edges of lakes, and stream sides.  During its breeding season from March to October, the males start calling just before dark, and sound like groups of tiny ducks quacking.   Females, which are slightly larger than the males and lack the wrinkled vocal pouch, lay their fertilized eggs enclosed in a jelly envelope attached to floating vegetation.   Influenced by the weather, breeding often takes place during or after a rain.

Cliff Chirping Frog

At ¾ to 1 ½ inches, the nocturnal Cliff Chirping Frog (Syrrhophus marnockii) is found in the cracks and crevices of limestone cliffs.  Mostly green with brown mottling and dark crossbars on its hind limbs, this frog also has a proportionately large head and big eyes.  It can run, leap, and hop, and its flattened body allows it to slip into cracks in the rocks to avoid predators.  Sounding a bit like a shy cricket, the call of the Cliff Chirping Frog is a series of short, clear chirps and trills.  While calls are made throughout the year, they are sharper and clearer when females are present.  From February to December females may lay eggs as many as three times in moist leaf litter or soil, although peak breeding occurs in April and May.  

When you’re out at night from winter to late spring or early summer and near one of our natural areas, sit quietly and in no time you should be able to identify the unmistakable sounds that make up the evening chorus!