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!

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

Bodacious Borers

Cottonwood Borer

As spring turns into summer in Central Texas, the heat brings out some of our most interesting creatures, most notably the native wood-boring beetles.  This group encompasses many species and families of beetles, all of whom eat wood either in their larval or adult form.  Most often they are found in or around dead or dying trees, as they are vital players in enabling the turnover of weak trees with strong ones, and acting as primary decomposers of wood which allows for the recycling of nutrients back into the soil.

One large family of beetles in the wood-boring group is the longhorn beetles, or Cerambycidae, typically characterized by their extremely long antennae which are often as long or longer than the beetle’s body.  Their family scientific name comes from the mythological Greek shepherd Cerambus, who was turned into a large beetle with horns after an argument with nymphs.  Three of the more noticeable wood-boring longhorn beetles in our area include the Banded Hickory Borer (Knulliana cincta), Cottonwood Borer (Plectrodera scalator), and Texas Bumelia Borer (Plinthocoelium suaveolens plicatum).

Banded Hickory Borer

With a body length of up to 1.4 inches, the Banded Hickory Borer is a fairly slender, typically gray to reddish-brown beetle with a pair of pale marks near the base of the elytra or wing covers that are sometimes absent, and tiny spines at the ends of the elytra.  Eggs are laid by the adults in bark crevices or directly into hardwoods such as oak, pecan, walnut, willow, and hackberry, upon which their larva feed.  In their first season, the larva feed just beneath the bark, then head deeper into the wood as they develop, a cycle which takes two to three years to complete.

Cottonwood Borer

The Cottonwood Borer is an elongate, unmistakably robust beetle with black and white markings that are formed by contrasting areas of white pubescence or fine short hairs on black body parts.  At a body length of up to 1.6 inches, the summer-active adults lay eggs in August and September on cottonwood and willow, where larva bore into the base and overwinter.  After two or three years to reach maturity, they pupate in chambers beneath the bark and emerge as adults in late spring, and are often found feeding on new shoots, leaf petioles (stems), and the bark of their host trees.

Texas Bumelia Borer

One can hardly miss the bright iridescence of the metallic green Texas Bumelia Borer, with its contrasting reddish-orange and black legs. The larva of this species feed on gum bumelia and mulberry, developing in the roots and trunks of these host plants.  With a body length of 1.5 inches, the adults are diurnal and often found on the trunks of their host plants, although they typically feed on flower nectar and are attracted to lights.

Despite their large size, most native wood-boring beetles are not pests.  Instead, they take advantage of dead and dying trees and aid in the natural decomposition process. As you venture out and about this summer, see if you can find some of these bodacious borers!