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| 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).
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| 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.
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| 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.
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| 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!
