Megacyllene

Classification

Phylum: Arthropoda
Subphylum: Hexapoda
Class: Insecta
Order: Coleoptera
Suborder: Polyphaga
Superfamily: Chrysomeloidea
Family: Cerambycidae
Subfamily: Cerambycinae
Tribe: Clytini
Genus: Megacyllene

Pronunciation

How to pronounce Megacyllene: /ˌmɛɡəˈsɪlɪni/

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Summary

Megacyllene robiniae, or the locust borer, is a longhorn beetle that primarily feeds on black locust trees and can significantly damage these trees, affecting their health and commercial value.

Physical Characteristics

The adult beetle can be 11 to 28 mm (0.43 to 1.10 in) long, with a black and yellow striped pattern that may resemble a wasp or bee. It has a W-shaped third stripe on the elytra. The male's antennae are approximately two-thirds its body length, while the female's are one-half. Legs are reddish brown, and the larvae are legless, white, and robust, growing to roughly 25 mm (0.98 in) long.

Identification Tips

M. robiniae can be mistaken for a wasp or bee due to its coloration. It is similar to closely related species such as M. caryae and M. decora.

Habitat

The beetle is found wherever unprotected black locust trees (Robinia pseudoacacia) grow, often in uncultivated fields and meadows where goldenrod (Solidago) is present.

Distribution

Endemic to eastern North America; range has expanded with the increased planting of black locust as an ornamental tree.

Diet

Adults feed on the pollen of goldenrod, while the larvae feed on the inner bark of black locust trees.

Life Cycle

Females lay eggs in crevices and near wounds of the locust tree, and the larvae overwinter in the tree before boring into the trunk to create tunnels in the spring. They pupate in late July and early August, with adults emerging from late August through September.

Reproduction

Females seek out wounds in black locust trees to lay eggs; eggs hatch into larvae that develop within the tree.

Ecosystem Role

Serves as a pest of black locust trees, promoting fungal infections that can damage the host tree.

Economic Impact

Due to its damage to Robinia pseudoacacia, this beetle negatively impacts the commercial value of black locust timber.

Evolution

Separated from Placosternus by the basal antennomere having a spine; restricted to the New World.

Similar Taxa

Misconceptions

Can be mistaken for wasps or bees due to similar coloration; however, it is a beetle.