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!

Neither Hummingbird nor Bumblebee

 

Hummingbird or bumblebee?  Neither!

Take a closer look when you see what you think is a small hummingbird hovering about and nectaring on the tubular flowers in your garden.  It just might be a Snowberry Clearwing (Hemaris diffinis), one of our more common hummingbird moths.  

Moths in the genus Hemaris are often generically called hummingbird moths, due to their ability to fly and move just like hummingbirds. They are rather plump moths, and the tip of their abdomen opens a bit like a fan. Many are brown or black with some yellow, so they are also good bumblebee mimics. Several species have clear wings, as they lack as many wing scales as other lepidopterans, and they actually lose the ones they do have shortly after they emerge due to their highly active flight tendencies.  

This adult Snowberry Clearwing just emerged from a winter spent in leaf litter,
still with all the scales on its wings.

The Snowberry Clearwing is about 1.25 to 2 inches in length, with a yellowish thorax above, a black abdomen with a yellowish band near the tip often split in two, and the namesake clear wings. Like other hummingbird moths, they generally fly during the day, but may continue into the evening if they have found a particularly good nectar source. Their proboscis or sucking mouthpart is quite long, so they prefer to sip from tube-shaped flowers. 

An adult Snowberry Clearwing showing its yellow thorax, black abdomen with a
yellow stripe, and signature clear wings.

The adults start flying in March after emerging from the leaf litter beneath their host plant where they spend the winter as a pupa protected by loose silken cocoon.  Females attract males by broadcasting a pheromone from the glands at the tip of the abdomen, and after mating, they lay individual, tiny, round green eggs on the underside of the leaves of the host plant.  In the south, they typically produce more than one generation each summer, flying well into November.

The common name for the Snowberry Clearwing comes from the fact that it was first described in 1836 in the northeast, where it uses Common Snowberry (Symphoricarpos albus) as a host plant, a native plant in the Honeysuckle family that grows in the northern half of North America. In the southern US, the preferred native host plant for this moth is Coral Honeysuckle (Lonicera sempervirens), which can be purchased at most native plant nurseries.  It is a high-climbing, twining vine to 20 feet long, with smooth, paired semi-evergreen leaves and clusters of red, tubular flowers.  In the wild, they also use our native White Bush Honeysuckle (L. albiflora), which is more shrub-like with twining branches that have smooth, paired deciduous leaves and clusters of creamy white tubular flowers.

Coral Honeysuckle

White Bush Honeysuckle

The larva or caterpillars of the Snowberry Clearwing are commonly called hornworms, due to the horn-like projection on their posterior end.  They are up to 2 inches long, blue-green above and yellow-green along the sides, with black spots and a black horn.  Uncommonly, they can also take a brown form with the same black spots and horn.  They match the foliage of their host plants so well that they are often very difficult to find. 

Snowberry Clearwing larva, green form.

Snowberry Clearing larva, brown form.

Why Insects Matter

 

Insects are terrific pollinators!

As the growing human population transforms our planet, the global insect population is declining at an unprecedented rate of 2% a year. The world has lost 5% to 10% of all insect species just in the last 150 years, so in 40 more years we could lose one third of all insect species. In a study just published in the journal Science, a working group called the ‘Status of Butterflies in the U.S.’ found that the total abundance of butterflies in the U.S. declined by 22% from 2000 to 2020.  Said another way, one in five butterflies have vanished.

Many butterfly species, including the Monarch, are declining in abundance.

What is driving this precipitous drop in insect populations and why does it matter? Insect populations are struggling due to several factors, including deforestation/habitat loss (due to development), non-native invasive species, pesticide use, artificial light pollution, and climate change.  As a result, the populations of other animals, crops, and flowers that rely on insects to survive also struggle.

Non-native, invasive plants, like Ligustrum species, often overtake native habitats.

Scientists say that it is impossible to have an insect-free life on this planet. They perform many essential services that are vital for humans’ quality of life. Pollinators such as bees, butterflies, moths, and many other types of insects are necessary to produce diversity and abundance in our food supply, including crops such as coffee, chocolate, blueberries, apples, almonds, avocados, and pumpkins, just to name a few. In fact, pollinators help ensure that about 75% of the world’s flowering plants and 35% of the world’s food crops are produced.  Other scientists estimate that one out of every three bites of human food are directly related to the work of pollinators such as bees, butterflies, moths, beetles, and other insects.

Moths and beetles are pollinators, too!

Plant and animal waste would pile up if it weren’t for the services of dung beetles and other insect recyclers. Insects like dragonflies, ladybugs, green lacewings, ground beetles, and parasitic wasps keep what we call the ‘pest’ species at bay – the mosquitos, ticks, fleas, lice, and flies that can carry disease as well as crop pests such as armyworms, cutworms, and wireworms.  

Dung Beetles hard at work.

Roseate Skimmer dragonfly eating a mosquito.

Most humans like birds, but most are also unaware of the fact that 96% of birds would not be here without insects. It takes 6,000 to 9,000 caterpillars and other insects to feed a clutch of four to six Carolina Chickadee offspring. Multiply that by the fact that most all avian nestlings and fledglings eat some form of insects, and you very quickly realize how important they are to the food web. Insects are also the main food for all of the fish, so they are the glue that binds together every terrestrial and freshwater ecosystem on the planet.

Many bird species, like the endangered Golden-cheeked Warbler,
feed insects to their young.

What can be done to reduce this downward trend?  The good news is that the things we do in our own backyards can actually make a difference when it comes to insect conservation. First and foremost, reduce or (better yet) replace your non-native lawn with native plants.  Lawns make up about 50% of Austin’s green space, so turning them back into native plantings would provide significant benefit to insects. 

Replace your lawn with native plants -
extra bonus for providing water!

Eliminate all pesticide use, including mosquito spraying. The spray contains pyrethroids which are advertised as “safe as chrysanthemum flowers”, but they are a much stronger synthetic version that is chemically designed to be more toxic with longer breakdown times.  This increased potency compromises the human body’s ability to detoxify the pesticide in addition to killing all insects, not just mosquitos.

Mosquito spraying kills all insects,
not just mosquitos.

Light pollution contributes to insect decline.

And last, but not least, turn your exterior lights off at night so as not to affect the behavior of night-flying insects (this also benefits birds during spring and fall migration). Artificial lighting can disorient moths and confuse their sense of direction, causing one third of those that swirl around a light at night to die from exhaustion or predation. Excess light also disrupts the mating flashes of fireflies and confuses insects like mayflies by bouncing light off of asphalt and causing them to lay their eggs in the street instead of in a lake or stream.

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!

Phenomenal Phenology

 

The color-changing and dropping of leaves is a seasonal process.

Defined as the study of cyclic and seasonal natural phenomena, phenology is critically important in relation to climate and both plant and animal life.  The timing of biological events can be shifted earlier or later by climate variations in temperature, precipitation, and sunlight. Events such as migration, egg laying, flowering, and hibernation are all influenced by these climatic factors.  

Early blooming plants support early spring-emerging insects.

While ecosystems are resilient enough for normal phenological variations, major shifts may indicate a change in normal climate patterns.  These shifts can give rise to larger problems, since all life is interconnected.  In many areas of the world spring events are occurring earlier and fall events are occurring later than they have in the past. But since not all species are changing at the same rate or direction, mismatches are bound to occur.  

Nectar-producing flowers need to bloom in time for migrating hummingbirds.

Flowers that bloom too early leave fewer nectar sources for migrating hummingbirds.  Early flowering also leads to earlier fruiting, which typically yields lower quality fruit for fruit-eating migrating birds.  Many bird species time their nesting and egg-laying efforts so their eggs hatch when insects are available.  The emergence of insects depends on leaf out of their host plants.  One seemingly subtle shift in plant phenology can change entire food webs.  

Nesting and egg-laying are timed to coincide with insect emergence.

Some examples of phenology studies that are easy to perform include the date of emergence of flowers and leaves, the first appearance of migrating birds, the first flight of butterflies, the dates of egg-laying of birds and amphibians, and the date of leaf color changes and dropping in deciduous trees.  Studies can be formal or informal, and while many citizen scientists note these kinds of changes over the years, imagine if hundreds of thousands of them standardize their recording techniques and enter their data into a database that anyone can access.  This describes Nature’s Notebook, a web-based monitoring program of the USA National Phenology Network (www.usanpn.org). 

Anyone can contribute to the USA National Phenology Network's database.

Nature’s Notebook’s vision is to “provide data and information on the timing of seasonal events in plants and animals to ensure the well-being of humans, ecosystems, and natural resources.”  Its mission is to “collect, organize, and share phenological data and information to aid decision-making, scientific discovery, and a broader understanding of phenology from a diversity of perspectives.” Scientists use phenological data for critical applications such as understanding the timing of ecosystem processes like carbon cycling, assessment of vulnerable species and ecological communities, and invasive species and forest pest management.  Phenological data are immensely useful indicators of change, so considering joining the movement to document the changes you see in nature’s calendar, and watch what happens!

A Lady by Many Names

 

Lady Beetle Aggregation

Lady beetles, also known as ladybugs or ladybirds, are familiar insects that are part of the Coccinellidae family, which comes from the Latin coccineus meaning ‘scarlet’ and refers to their bright color.  The origin of their common names traces back to a European legend when farmers were said to pray to the Virgin Mary to prevent their crops from being destroyed by agricultural pests.  Commonly red or orange with black spots on their elytra or wing covers, their coloring serves as a warning to predators that they are not good to eat.

Lady beetles have a lifecycle that begins as an egg and hatches into a larva after 4 to 10 days.  The larvae are quite small, generally dark and alligator-like with three pairs of prominent legs.  They typically spend 20 to 30 days eating and growing until they pupate and then emerge as adults. Most lady beetles are active spring and fall, but can be encountered at any time of year.  During the winter, they gather in large groups called aggregations, to mate and protect each other from the cold during their hibernation period, as some can live as adults for more than a year. 

Lady Beetle Larva

There are more than 5,000 species of lady beetles worldwide, with many species imported from other countries.  This practice started in the late 1800s when an Australian species was imported to California for a pest control experiment which helped to triple the orange crop, so efforts were soon put in place to breed them.  Lady beetles typically eat several types of small, soft-bodied insects that are usually described as garden pests, such as aphids, whiteflies, scale insects, mealybugs, and spider mites. In Central Texas, the lady beetle species most commonly encountered are the Seven-spotted (Coccinella septempunctata), Spotless (Cycloneda sanguinea), Convergent (Hippodamia convergens), Ashy Gray (Olla v-nigrum), and Asian (Harmonia axyridis) Lady Beetles. 

Seven-spotted Lady Beetle

With a total of seven black spots on the red elytra and a black head with two white spots, the Seven-spotted is native to Asia and Europe, and was introduced specifically to control aphids.  Having no spots on bright red to orange elytra, and also called the Blood-Red Ladybird Beetle, the Spotless can often be found on milkweed species searching for aphids.  The Convergent has up to six small black spots on its red to orange-red elytra, white lines that converge behind the head, and are often found in aggregations.  The Ashy Gray comes in two color forms; the light form with ashy yellowish-gray elytra and few to numerous black spots, and the dark form with black elytra and two large red to yellow spots.  It feeds on aphids and jumping plant lice.  

Convergent Lady Beetle

Spotless Lady Beetle

The Asian Lady Beetle is highly variable in color and pattern, but typically has a marking that looks like a W or an M behind its head.  This lady beetle is sometimes called the Halloween Beetle, as it often invades homes to overwinter when the weather starts to cool in October.  Native to Asia, it is the most common and widespread lady beetle in North America, and is universally sold in the nursery trade for aphid control.

Asian Lady Beetle

Introduced Invaders

 

Closeup of a Bastard Cabbage bloom

Spring brings new growth to all types of plants, including those species known as non-native invasives.  Non-native plants, also called exotics, are defined as plants ‘growing in a place that is not the region where they naturally grow’, and invasive plants are defined as plants that are ‘both non-native and able to establish on many sites by growing quickly and spreading to the point of disrupting native a plant community or ecosystem’.  

While plants that are non-native or invasive can be problematic, when a plant is both non-native and invasive, it can quickly outcompete native plants.  These invaders can produce copious amounts of seed easily transmitted by wind, water, or birds, thrive on poor or disturbed soils through aggressive root systems, have an early growth season or produce growth-inhibiting chemicals, and ultimately disrupt natural nutrient cycles of wildlife.  

In Central Texas, the species that cause the most harm to the local environment include Ligustrum (Ligustrum sp.), Nandina (Nadina domestica), Chinaberry (Melia azedarach), Chinese Tallow (Triadica sebifera), Bastard Cabbage (Rapistrum rugosum), and Japanese Honeysuckle (Lonicera japonica).  Most of these species have been introduced to the United States via the nursery trade as ornamentals, and unfortunately many are still sold today.

Ligustrum or Glossy Privet

Ligustrum or Glossy Privet, native to China, Japan, and Korea, is an invader of roadsides, thickets, open woodlands, and disturbed areas.  This evergreen tree to 40 feet has simple green, glossy pointed leaves.  It is widely cultivated and frequently escapes to invade and dominate the woodland understory, as its abundant purple-blue fruits are easily spread by birds and other animals.

Nandina or Heavenly Bamboo

Nandina or Heavenly Bamboo, native to China and Japan, is an invader of landscapes, roadsides, and other cultivated areas.  This erect, multi-stemmed shrub to 8 feet has compound green leaves to 12 inches long that are tinged with red in winter.  It spreads by escaping cultivation through underground root sprouts and animal-dispersed seeds, and quickly forms a colony.  Additionally, its shiny red fruits are toxic to small children, pets, and some grazing animals.

Chinaberry

Chinaberry, native to parts of Asia, is an invader of roadsides, thickets, open woodlands, and disturbed areas.  This deciduous tree grows up to 50 feet and has compound green leaves to 24 inches long.  Lavender blooms distinguish it from the similar but native Western Soapberry (Sapindus drummondii), which has white blooms.  It spreads on site via fast-growing root sprouts and over longer distances via bird-dispersed seeds from its golden-yellow fruits.

Chinese Tallow

Chinese Tallow, native to China and Japan, is an invader of cultivated landscapes and other moist areas.  A deciduous tree that grows to 60 feet, it has diamond-shaped leaves with elongated tips that turn orange-red in fall.  It reaches reproductive age in as little as three years, producing prolific amounts of seed that is readily transported by birds and water.  It is difficult to eradicate once established, and can effectively transform a native habitat into a monoculture.

Bastard Cabbage

Bastard Cabbage, also called Common Giant Mustard and Turnipweed, and native to southern Europe, northern Africa, and western Asia, is an invader of meadows, fields, roadsides, and other disturbed areas.  This many-branched herb grows to 5 feet, with clustered of small lemon-colored flowers at the tips of branches.  Its seeds germinate early in spring, quickly covering the ground with a dense blanket of leafy rosettes that block sunlight from reaching seedlings of native plants.  It reseeds rapidly and forms large monocultures.

Japanese Honeysuckle

Japanese Honeysuckle, native to Japan, is an invader of thickets on disturbed floodplains, creeks, and river banks.  This climbing, sprawling vine grows to 80 feet, with simple oval leaves and tubular white flowers that turn butter-yellow as they age.  Choking out other species by girdling or by blocking out sunlight through overgrowth, its plentiful seeds are easily dispersed by birds and other wildlife.  It is not to be confused with the native, much less aggressive White Bush Honeysuckle (L. albiflora). 

Replacing these non-native invasive plants with native plants help restore natural habitat, preserve and produce much-needed soil, protect fragile waterways from erosion, and as a result, keep vital nutrient cycles intact for all forms of wildlife.  Natives are already adapted to our soils and climate so they require little to get established, are naturally hardy and disease-free, and they provide food, shelter, and places to raise young for local insects (especially pollinators), birds, and other wildlife.  Natives are also a beautiful reminder of the unique natural heritage of Texas, so please consider to replacing your non-native invasive plants with natives today.  Once established, you’ll be amazed at how they bring your landscape to life!

INVADER                                NATIVE REPLACEMENT(S) - some ideas...

Ligustrum species                    Escarpment Black Cherry, Mexican Plum

Nandina                                    Yaupon, Possumhaw, Rusty Blackhaw Viburnum, Sumacs

Chinaberry                                Western Soapberry, Oaks, Redbud, Mexican Buckeye

Chinese Tallow                          American Sycamore, Black Willow, Texas Ash

Bastard Cabbage                      Mistflowers, Salvias, Sages

Japanese Honeysuckle            White Bush Honeysuckle, Coral Honeysuckle

Madrone Mysteries

 

Texas Madrone

A striking small tree, to 30 feet, the Texas Madrone (Arbutus xalapensis) occurs in protected canyons and mountain slopes of Big Bend, but its range extends eastward to the Edwards Plateau in Travis County.  It is a rare native tree, but can be locally common in the right habitat, preferring grasslands and open oak-juniper woodlands on rocky limestone slopes. Its simple, pointed oval, leathery leaves, 2 to 5 inches long, are evergreen and medium green on top and lighter beneath.  In spring, clusters of small, fragrant, bell-shaped white flowers appear above the leaves, developing into bright red-orange fruits in late fall.  These fruits are relished by many species of birds and mammals and are reported to be edible by humans.

Texas Madrone flower cluster

One of the first mysteries of the Texas Madrone is its bark.  Bone-white and smooth when young, with age it becomes scaly and turns to shades of pink, red, and brown. This older bark peels away in patches and strips, revealing a smooth reddish bark underneath, and gives the tree some of its more colorful, old colloquial names such as Lady’s Leg and Naked Indian. But why does the bark exfoliate?  The most commonly accepted theory is that it is an evolutionary development to rid the tree of lichens and parasites such as wood boring insects, preventing their buildup and reducing the chance of disease.

Peeling Texas Madrone bark

Ashe Juniper nurse tree
protecting a young Texas Madrone

While it is one of the most interesting and beautiful native trees of Texas, another mystery of the Texas Madrone is that it is extremely temperamental to grow.  Its propagation requirements are complex, and it is very difficult to successfully transplant from the wild.  Madrones have a fine root system that is easily damaged, and even slight root damage is usually fatal to the tree.  Additionally, new seedlings require the protection of a ‘nurse tree’ to become established.  A nurse tree is a larger, faster-growing tree that safeguards the seedling while it gets established by providing shade, shelter from the wind, and protection from grazing animals.  For the Texas Madrone, its nurse tree is most often the native Ashe Juniper (Juniperus asheii). Adding to its temperamental nature, this tree is slow-growing, taking more than a century to attain a fully mature height.

Texas Madrone fruit

Texas Madrone trees flower from late February to early March, while their fruits don’t mature until late November to late February.  Like several species in the genus Arbutus, the fruits begin to form in mid-spring but fruit development is delayed for several months so that the next spring’s new flowers begin to appear while the previous year’s fruits are ripening.  This timing delay results in a short period of time when both fruit and flower can be simultaneously present on a tree, yet another intriguing characteristic of the mysterious Texas Madrone!

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!