elm sawfly

(Cimbex americana)

               
Conservation Status

IUCN Red List

not yet assessed

elm sawfly

NatureServe

not listed

Minnesota

not listed

Occurrence

Widespread

Flight/Season

One generation per year: mid-May to mid-August

Habitat

Woodlands

Size

Total Length: 11 16 to 1

Wingspan: 1¾

Larva: 1½ to 2


Identification

This large, colorful sawfly is the largest sawfly in North America.

The body is bluish-black, stout, and almost parallel sided. The base of the abdomen is broadly attached to the thorax, not a slender wasp-like waist.

The thorax is black and hairless, with a large yellowish-white spot on the upper (dorsal) surface. On the male the spot is distinct and conspicuous. On the female it is faint.

The male abdomen may be all black, reddish-brown to black, or mostly reddish brown. The female abdomen is all black and has 3 or 4 yellowish-white spots on the sides of the abdomen. The ovipositor of the female is conspicuous and saw-like, an attribute common to all sawflies.

The head is black and squarish in front. The antennae are orange with 4 to 7 segments and are slightly expanded (clubbed) at the tip.

There are two pairs of transparent, smoky brown wings.

The legs are bi-colored or tri-colored. The third and fourth segments (femur and tibia respectively) may be black, reddish-brown, or a combination of both. The tibia of the front leg has 2 spurs at the tip. The femur of the hind legs are especially robust. The five foot segments (tarsi) are yellow.

The larvae resemble caterpillars but that name is reserved for the larvae of moths and butterflies. The body is cylindrical in shape, pale green or yellow, and warty. The head is smooth, distinctly separated from the thorax, and has no cleavage line. The eyes are black. A black longitudinal stripe extends from the thorax behind the head to the eighth abdominal segment. The thorax has 3 pairs of well-developed true legs. The abdomen has small black spots surrounding the breathing pores (spiracles). There are 7 pairs of false legs (prolegs) attached to the abdomen, unlike true caterpillars, which have only 5 pairs.

 
Similar
Species

 


Larval Food

Leaves of elm, maple, birch, willow, and American basswood.

 
Adult Food

Tree sap of mostly elm and willow, but also other hardwoods including maple, birch, and American basswood.

 
Life Cycle

The female uses her saw-like ovipositor to cut a slit on the underside of leaves and deposit eggs. The eggs hatch in 7 to 10 days and the larvae feed on leaves. In late summer or early fall the larvae drop to the ground and spin cocoons in the leaf litter at the base of the host tree. They overwinter in the cocoons, pupate in the spring, and emerge as adults in May or June. Some larvae spend two winters in the cocoon before pupating.

 
Behavior

Larvae feed with the rear of their abdomen coiled around a twig. They rest in a coiled position. They can cause sporadic defoliation but are not considered forest pests.

Adults use their powerful mandibles to cut horizontal gashes in the bark of twigs and small branchlets in order to feed on sap. They sometimes girdle the limb, causing it to die.


Distribution Distribution Map  

Sources: 7, 24, 29, 30.


Comments

 


Taxonomy

Order:

Hymenoptera (ants, bees, wasps, and sawflies)

 

Suborder:

Symphyta (horntails, sawflies)

 

Superfamily:

Tenthredinoidea (sawflies)

 

Family:

Cimbicidae (cimbicid sawflies)

 
Synonyms

 

 
Common
Names

elm sawfly


 

 

 

 

 

Glossary

femur

On insects and arachnids, the third, largest, most robust segment of the leg, coming immediately before the tibia. On humans, the thigh bone.

 

ovipositor

A long needle-like tube on the abdomens of some female insects, used to inject eggs into soil or plant stems.

 

proleg

A fleshy structure on the abdomen of some insect larvae that functions as a leg, but lacks the five segments of a true insect leg.

 

spiracle

A small opening on the surface of an insect through which the insect breathes.

 

tarsus

The last two to five subdivisions of an insect’s leg, attached to the tibia; the foot. Plural: tarsi.

 

tibia

The fourth segment of an insect leg, after the femur and before the tarsus (foot).

 

 

 

 

 

       

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Courtney Walker


  elm sawfly   elm sawfly

       
       
       

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  elm sawfly   elm sawfly
       
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Other Videos

 
  Elm Sawfly Larva (Cimbicidae: Cimbex americana) Defensive Posture
Carl Barrentine
 
   
 
About

Uploaded on Sep 5, 2011

Photographed at the Turtle River State Park, North Dakota (05 September 2011).

 
     
  Elm Sawfly Larva (Cimbicidae: Cimbex americana) Locomotion
Carl Barrentine
 
   
 
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Uploaded on Sep 11, 2011

Photographed at the Turtle River State Park, North Dakota (11 September 2011).

 
     
  Elm sawfly larvae epic fail (full version)
Inhibera
 
   
 
About

Published on Aug 25, 2015

English - http://thisishowtogetrich.blogspot.se/

Svenska - http://www.blinyrik.se/

 
     
  Elm Sawfly Caterpillar
Fizacoren
 
   
 
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Uploaded on Sep 28, 2010

Fizacoren

 
     
  Elm sawfly catapillar
nisbet819
 
   
 
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Published on Jul 31, 2013

:p

 
     

 

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Courtney Walker
7/16/2017

Location: Houston, MN

elm sawfly


     
     
 

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