Home / Longhorn Beetles (Cerambycidae) / Locust Borer Beetle (Megacyllene robiniae)

Locust Borer Beetle (Megacyllene robiniae)

The locust borer beetle is a member of the family of longhorn beetles. As its name suggests, it is a pest of the black locust tree, having a sympatric relationship with them, as both remain in the same geographical location. They bear a strong resemblance to wasps and bees, mostly in appearance.

Locust Borer Beetle

Scientific Classification

  • Family: Cerambycidae
  • Genus: Megacyllene
  • Scientific name: Megacyllene robiniae

Physical Description and Identification

Adult

Size: 11 to 28 mm (0.43 to 1.10 in)

Color: These beetles are striped yellow and black, similar to a wasp, with reddish-brown legs.

Other Characteristic Features: There is a distinct yellow “W” shape on their elytra. Sexual dimorphism in the species is seen in the size of their antennae. While both of them have dark brown to black antennae, the male’s antennae are 2/3rd its total body length, while those of the females are ½.

Megacyllene robiniae

Larva

Larvae are white, lack legs, and are around 25 mm (0.98 in) in length.

Locust Borer Beetle Larva

Pupa

Once they are fully mature, the larvae begin to pupate after burrowing into the tree trunk of their host plant.

Locust Borer Beetle Pupa

Egg

After mating, females can be seen searching for a gap in the stem of the preferred plant, and lay their eggs in the crevices and close to wounds of their host plant.

Quick facts

Lifespan3 months
DistributionNorth America
HabitatUncultivated fields and meadows
Seasons activeAugust-October
Host plantsPrimarily black locust; also, goldenrod
Diet of adultsPollen of goldenrod
Locust Borer Beetle Damage

Identifying the damage caused by them

The larvae tend to make deep tunnels into their host plants, around 10 cm (3.9 in) in length and 7 mm (0.28 in) in width. These sites later become ground zero for infections of fungi like the cracked cap polyphore.

This will lead to the tree suffering wind damage, in the long run, hampering their growth.

Did you know

  • In 1900, these beetles nearly wiped out the entire population of black locust trees, making the US lose a valuable source of timber.
Locust Borer Beetle Picture

Image Source: objects.liquidweb.services, insectsofbandyfield.files.wordpress.com, images.squarespace-cdn.com, forestpests.org, bugwoodcloud.org, colorado.edu

The locust borer beetle is a member of the family of longhorn beetles. As its name suggests, it is a pest of the black locust tree, having a sympatric relationship with them, as both remain in the same geographical location. They bear a strong resemblance to wasps and bees, mostly in appearance.

Locust Borer Beetle

Physical Description and Identification

Adult

Size: 11 to 28 mm (0.43 to 1.10 in)

Color: These beetles are striped yellow and black, similar to a wasp, with reddish-brown legs.

Other Characteristic Features: There is a distinct yellow “W” shape on their elytra. Sexual dimorphism in the species is seen in the size of their antennae. While both of them have dark brown to black antennae, the male’s antennae are 2/3rd its total body length, while those of the females are ½.

Megacyllene robiniae

Larva

Larvae are white, lack legs, and are around 25 mm (0.98 in) in length.

Locust Borer Beetle Larva

Pupa

Once they are fully mature, the larvae begin to pupate after burrowing into the tree trunk of their host plant.

Locust Borer Beetle Pupa

Egg

After mating, females can be seen searching for a gap in the stem of the preferred plant, and lay their eggs in the crevices and close to wounds of their host plant.

Quick facts

Lifespan3 months
DistributionNorth America
HabitatUncultivated fields and meadows
Seasons activeAugust-October
Host plantsPrimarily black locust; also, goldenrod
Diet of adultsPollen of goldenrod
Locust Borer Beetle Damage

Identifying the damage caused by them

The larvae tend to make deep tunnels into their host plants, around 10 cm (3.9 in) in length and 7 mm (0.28 in) in width. These sites later become ground zero for infections of fungi like the cracked cap polyphore.

This will lead to the tree suffering wind damage, in the long run, hampering their growth.

Did you know

  • In 1900, these beetles nearly wiped out the entire population of black locust trees, making the US lose a valuable source of timber.
Locust Borer Beetle Picture

Image Source: objects.liquidweb.services, insectsofbandyfield.files.wordpress.com, images.squarespace-cdn.com, forestpests.org, bugwoodcloud.org, colorado.edu

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