locust borer

(Megacyllene robiniae)

Conservation Status
locust borer
Photo by Alfredo Colon
  IUCN Red List

not listed

 
  NatureServe

NNR - Unranked

 
  Minnesota

not listed

 
           
           
           
           
 
Description
 
 

Locust borer is a large, colorful, round-necked long-horned beetle. It is native to the Appalachian and Ozark regions of the eastern United States, where its larval host, black locust, is also native. Black locust has been widely cultivated as an ornamental and as a soil improver in restorations. As the tree spread across North America, locust borer went with it. Locust borer is now common in Minnesota. Larvae develop within the stems of their host and are rarely seen. Adults are seen during the day from August to October on goldenrods. It is considered a serious pest of black locust. The wood of infected trees is commercially worthless, and the infected trees may die.

Adults are 716 to 1 (11 to 28 mm) long and are densely covered with short, velvety hairs. They are jet black with numerous bright yellow bands and spots, looking something like a wasp or hornet. This is probably an example of Batesian mimicry, making the beetle appear unpalatable to potential predators. The body is constricted between the thorax and the abdomen, forming a distinct rounded “neck”.

The head is black with three yellow bands. The face is slanted forward, not vertical. The small antennae-like structures (palpi) emerging from the lower jaws (maxillae) are blunt at the tip, not pointed. The antennae are long, at least half as long as the body. The base of each antenna is surrounded by the compound eye.

The exoskeletal plate covering the thorax (pronotum) is black, rounded, and widest near the middle when viewed from above, strongly convex when viewed from the side. It is black with yellow front, rear, and lateral margins, and two narrow yellow bands.

The hardened forewings (elytra) are black with seven narrow yellow bands. The third band is strongly W-shaped. The inner one-third of each elytron is abruptly depressed.

The legs are reddish.

 
     
 

Size

 
 

Total length: 716 to 1 (11 to 28 mm)

 
     
 

Similar Species

 
 

Painted hickory borer (Megacyllene caryae) appears nearly identical but the adult emerges in the spring. It has not been recorded in Minnesota.

 
     
 
Habitat
 
 

Wherever black locust has been planted

 
     
 
Biology
 
 

Season

 
 

August to October

 
     
 

Behavior

 
 

Adults are active during the day

 
     
 

Life Cycle

 
 

 

 
     
 

Larva Food

 
 

Black locust

 
     
 

Adult Food

 
 

Goldenrod flower pollen

 
     
 
Distribution
 
 

Distribution Map

 

Sources

24, 27, 29, 30, 82.

 
  9/*6/2023      
         
 

Occurrence

 
 

Common

 
         
 
Taxonomy
 
 

Order

Coleoptera (beetles)  
 

Suborder

Polyphaga (water, rove, scarab, long-horned, leaf, and snout beetles)  
 

Infraorder

Cucujiformia  
 

Superfamily

Chrysomeloidea (longhorn beetles and allies)  
 

Family

Cerambycidae (longhorn beetles)  
 

Subfamily

Cerambycinae (typical longhorn beetles)  
 

Tribe

Clytini  
 

Genus

Megacyllene  
       
 

Synonyms

 
 

Megacyllene flexuosum

Megacyllene pictus

 
       
 

Common Names

 
 

locust borer

 

 

 

 

 

 

 

Glossary

Elytra

The hardened or leathery forewings of beetles used to protect the fragile hindwings, which are used for flying. Singular: elytron.

 

Maxillae

Paired mouth structures of arthropods located immediately behind the mandible and used for tasting and manipulating food. “Under-jaws”.

 

Palp

Short for pedipalp. A segmented, finger-like process of an arthropod; one is attached to each maxilla and two are attached to the labium. They function as sense organs in spiders and insects, and as weapons in scorpions. Plural: palpi or palps.

 

Pronotum

The exoskeletal plate on the upper side of the first segment of the thorax of an insect.

 

 

 

 

 

 
 
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Alfredo Colon

 
    locust borer   locust borer  
           
    locust borer   locust borer  
           
    locust borer   locust borer  
           
    locust borer   locust borer  
           
    locust borer   locust borer  
           
    locust borer   locust borer  
 

Greg Watson

 
    locust borer   locust borer  
           
 
MinnesotaSeasons.com Photos
 
 

 

 
           

 

Camera

     
 
Slideshows
 
Locust Borer
Andree Reno Sanborn
  Locust Borer  
 
About

Megacyllene robiniae

 

 

slideshow

       
 
Visitor Videos
 
       
 

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Other Videos
 
  Locust borer beetle eating pollen in flowers
GoTrails
 
   
 
About

Oct 6, 2019

Locust borer beetle crawling / walking and eating / feeding on pollen / nectar of bright yellow flowers of goldenrod plants | Bee-like, Wasp-like | Megacyllene robiniae, Robinia borulo, cyllène du robinier | Coleoptera, Käfer, coleópteros, escarabajos, coléoptères, coleotteri | serious pest of the black locust tree | Wildlife, Animal Behavior, Nature, Insect facts | #GoTrails, #beetle, #arthropod, #insect, #insects, #beetles, #animalforkids | HD video, nature sounds

 
  Longhorned Beetle Wasp Mimic - Locust borer
Stoil Ivanov
 
   
 
About

Sep 1, 2019

Locust borer ( Megacyllene robiniae ) Filmed on 8-31-2019 McDonald Woods Forest Preserve ,Lindenhurst Illinois. Good example of Batesian mimicry. Pest of the Black locust tree , but so beautiful.

 
  Locust Borer, Part 1 - August 25, 2013
Don Gagnon
 
   
 
About

Aug 26, 2013

Locust Borer (Megacyllene robiniae), Pottersville Woods, Somerset, Massachusetts, Sunday morning, August 25, 2013, 12:57 PM - Canon PowerShot SX50 HS MVI_43272; 1:11 min.

 

 

Camcorder

 
 
Visitor Sightings
 
           
 

Report a sighting of this insect.

 
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Be sure to include a location.
 
  Alfredo Colon
8/25/2022

Location: Albany, NY

locust borer  
  Alfredo Colon
8/16/2022

Location: Albany, NY

locust borer  
  Alfredo Colon
8/11/2022

Location: Albany, NY

locust borer  
  Greg Watson
9/23/2021

Location: Apple Blossom Overlook, near La Crescent, Winona County MN

locust borer

 
  Alfredo Colon
8/31/2019

Location: Maplewood Nature Center

locust borer

 
           
 
MinnesotaSeasons.com Sightings
 
 

 

 

 

 

Binoculars


Created: 2/12/2020

Last Updated:

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