Good looks in adulthood hide the destructive nature of the tree-burrowing Poplar Borer Beetle larvae.
Many adult Poplar Borer Beetles have white bodies that are covered in tiny black dots or freckles. Orange-yellow marks cover the elytra (wing coverings) and also line the 'neck collar' and face. Some individuals are mostly orange with the black dots allover. All have long antennae, which is typical for members of the beetle family, Cerambycidae. Antennae tend to be the same color as the majority of the insect (white or orange).
Larvae of the Poplar Borer Beetle are a tremendous pest in North America. Females lay eggs on tree trunks. Once hatched, the larvae dig into the trunk and tunnel their way through sapwood, disrupting the flow of water and nutrients throughout the tree by girdling (cutting all the way around) branches and the trunk. Girdling strangles a tree branch or trunk.
One sign that Poplar Borer larvae are inside the tree is the presence of wet areas on the trunk that also have sawdust on or near them. The wetness comes from the leaking xylem and phloem tissues, and the sawdust is actually called frass. Frass is a mixture of tree shavings and feces. Frass may also be found piling up at the base of the tree. Another indication of persistent infiltration is a dark stain, almost like black varnish, just below areas of penetration. A single larva may need 1-2 years of growth (and tunneling) before leaving the tree as an adult.
Though it may take years, injury to the tree compounds and eventually causes the tree to die. It is unlikely that poplar trees in the Northeast, and poplars as well as cottonwood and aspen trees in the West, will ever grow to a ripe old age. The activity of the tunneling larvae is expansive and difficult to stop. Natural predators of the Poplar Borer do exist and can help reduce the impact this species has on tree mortality. Birds and insects like parasitic wasps feed on adults and larvae. In areas where such predators are common, trees like poplar, aspen, and cottonwood have a chance to grow a little taller and live a little longer.
Scientific Name: Saperda calcarata
Size (Adult; Length): 18mm to 33mm (0.70in to 1.29in)
Colors: white, yellow, orange, black
Descriptors: speckled, freckled, long antennae, harmful, flying
Note: An insect's reach is not limited by lines drawn on a map and therefore species may appear in areas, regions and/or states beyond those listed above as they are driven by environmental factors (such as climate change), available food supplies and mating patterns. Grayed-out selections indicate that the subject in question has not been reported in that particular territory. U.S. states and Canadian provinces / territories are clickable to their respective bug listings.
Antennae: Beetles have a pair of antennae on the head used as sensors.
Head: The head is home to the insect's eyes, antennae, and mandibles (jaws).
Thorax: Holds the three pairs of legs as well as vital internal organs.
Elytron: One of two wing cases on a Beetle that protects its wings (plural: elytra).
Wings: Appendages used for flying and kept under the elytra until needed.
Abdomen: Houses organs related to circulation, reproduction, and excretion.
Legs: Beetles have three pairs of legs located at the thorax, numbering six legs in all.