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Species Megacyllene robiniae - Locust Borer

Locust Borers gone wild - Megacyllene robiniae - male - female Locust Borer - Megacyllene robiniae - male - female Locust Borer - Megacyllene robiniae Locust Borer? - Megacyllene robiniae beetle on goldenrod - Megacyllene robiniae Megacyllane robiniae? - Megacyllene robiniae Locust Borer? - Megacyllene robiniae - male - female golden rod bug - Megacyllene robiniae
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Coleoptera (Beetles)
Suborder Polyphaga (Water, Rove, Scarab, Long-horned, Leaf and Snout Beetles)
Superfamily Chrysomeloidea (Long-horned and Leaf Beetles)
Family Cerambycidae (Long-horned Beetles)
Subfamily Cerambycinae
Tribe Clytini
Genus Megacyllene
Species robiniae (Locust Borer)
Synonyms and other taxonomic changes
Megacyllene robiniae (Forster)
Orig. Comb: Leptura robiniae J.R. Forster 1771
Explanation of Names
Latin for "of Robinia". Robinia is the genus of trees which includes the Black Locust.
adult about 20 mm
larva to 25 mm
Adult beetles are black with yellow transverse bands. The third band on the elytra is W-shaped.
Anywhere Black Locust trees are present: most of the US and southern Canada (see tree distribution map).
Adults are frequently found in fields containing goldenrod in late summer and fall.
Larvae live inside Black Locust trees.
Adults most noticeable in August and September when goldenrod is blooming.
Larvae feed on Black Locust (Robinia pseudoacacia and its cultivars and hybrids). Honey Locust (Gleditsia triacanthos) is not affected.
Adults feed on pollen, particularly goldenrod (Solidago sp.).
Life Cycle
Eggs are laid in Black Locust trees in the fall. Newly emerged larvae spend several months in tree trunks, first hibernating through the winter under the bark, then tunneling into trees in spring, eventually making tunnels about 4" long and .25" inch wide. They pupate late July/early August. Adult beetles emerge late August to September (click on the Data tab for a graphic confirmation of that fact).
Considered a serious pest of Black Locust trees; previously weakened or damaged trees are often killed by an infestation of the larvae. Previously confined to the native range of Black Locust in the northeast, it has spread with the trees throughout the US and parts of Canada. Unfortunately Black Locust is used for reclamation and similar projects where trees are likely to be stressed and thus more vulnerable to insect damage.
See Also
Megacyllene caryae, Hickory Borer is active as an adult in the spring, rather than in the fall as this species is. Larvae feed on hickory and pecan.
Megacyllene decora
Internet References
comprehensive and illustrated species account (Jimmy R. Galford, US Forest Service)