Mexican grass-carrying wasp

(Isodontia mexicana)

Conservation Status
Mexican grass-carrying wasp
Photo by Alfredo Colon
  IUCN Red List

not listed

     
  NatureServe

not listed

     
  Minnesota

not listed

     
           
           
           
 
Description
 
 

Mexican grass-carrying wasp is a slender, solitary, thread-waisted wasp. It is common in the northern half of the eastern United States and adjacent Canadian provinces. It has also been found, but is not common, south to Florida and west to California. It is common in Minnesota. It is found from May to October in fields and other grassy open areas.

Adults are to ¾ (16 to 20 mm) in length. Females average (17 mm), slightly larger than males which average (16 mm).

The head, thorax, and abdomen are completely black. The thorax is covered with long, erect, white hairs. The shield on the first segment of the thorax (pronotum) is short. There is a small rounded lobe on each side of the pronotum that does not reach the small plate (tegula) at the base of the wing.

The abdomen is shiny. The first segment is contracted into a thin stalk (petiole), making the body appear “thread-waisted”. There is a small brown spot at the base of the first segment of the abdomen, where the abdomen meets the petiole. This feature is thought to be diagnostic for this species.

The legs are black. On the middle leg there are two spurs at the tip (apex) of the fourth leg segment (tibia). The tibia on the hind leg sometimes has a reddish tint. The end part of the leg, corresponding to the foot, has five segments. The last (terminal) segment on the front legs have no teeth.

There are both apressed silver hairs on the face and head, and erect white and brown hairs on the face. The antennae are black. The first antenna segment is longer than the second.

The wings are clear and tinted smoky brown.

 
     
 

Size

 
 

Total Length: to ¾ (16 to 20 mm)

Male Average Length: (16 mm)

Female Average Length: (17 mm)

 
     
 

Similar Species

 
     
     
 
Habitat
 
 

Fields and other grassy open areas

 
     
 
Biology
 
 

Season

 
 

Two generations per year: May to October

 
     
 

Behavior

 
 

 

 
     
 

Life Cycle

 
 

The female builds a nest in a pre-existing natural cavity, an abandoned nest of another speceis, or a track of a storm window, lining it with dry or drying grass. She then finds and paralyses a tree cricket, katydid, or grasshopper, and carries it back to the nest. She partitions the nest and lays a single egg in each section. When the eggs hatch, the larvae feed on the still living cricket. They pupate after 4 to 6 days and emerge as adults in 2 to 3 weeks.

 
     
 

Larva Food

 
 

 

 
     
 

Adult Food

 
 

 

 
     
 
Distribution
 
 

Distribution Map

 

Sources

24, 27, 29, 30, 82.
 
  1/26/2021      
         
 

Occurrence

 
 

Common

 
         
 
Taxonomy
 
 

Order

Hymenoptera (ants, bees, wasps, and sawflies)  
 

Suborder

Apocrita (wasps, ants and bees)  
 

Infraorder

Aculeata (ants, bees and stinging wasps)  
 

Superfamily

Apoidea (apoid wasps, bees, sphecoid wasps)  
 

Family

Sphecidae (thread-waisted wasps)  
 

Subfamily

Sphecinae  
  Tribe Sphecini  
 

Genus

Isodontia  
       
 

 

 
       
 

Synonyms

 
 

Sphex apicalis

Sphex apicalis mexicana

 
       
 

Common Names

 
 

Mexican grass-carrying wasp

 
       

 

 

 

 

 

Glossary

Pronotum

The saddle-shaped, exoskeletal plate on the upper side of the first segment of the thorax of an insect.

 

Tegula

A small, hardened, plate, scale, or flap-like structure that overlaps the base of the forewing of insects in the orders Lepidoptera, Hymenoptera, Diptera, and Homoptera. Plural: tegulae.

 

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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Alfredo Colon
       
  Mexican grass-carrying wasp    
       
  Mexican grass-carrying wasp   Mexican grass-carrying wasp
       
  Mexican grass-carrying wasp   Mexican grass-carrying wasp
       
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Camera

     
Slideshows
   
  Digger Wasp (Isodontia mexicana)
Andree Reno Sanborn
 
  Digger Wasp (Isodontia mexicana)  
 
About

Summer World page 72:

. . . I thought I saw a light-colored piece of straw about half a foot long "flying" horizontally and then hovering in midair. That caught my attention — I looked closer and saw a black wasp that seemed identical in form to a mud dauber, and it was carrying an object. I jumped up in my excitement, and the wasp was spooked and flew off. The proof eluded me, but it dropped its "prey" onto the porch. I picked it up — definitely a long piece of dry grass!

Expecting the wasp to return, I waited. After about twenty minutes it did return, carrying another piece of grass. This time I was ready with an insect catcher net, and I snagged the wasp along with the grass it carried. The wasp was about 0.6 inch long, and the lbade it was carrying was about 2.4 inches long. The wasp looked superficially almost identical to the mud dauber, but its body was black rather than black-blue and its wings were smoky-colored instead of blue-black like the mud dauber's. It was a different species of wasp, which I later identified as Isodontia mexicana. I also learned later that rather than making clay organ-pipe cavities for its nest and filling them with spiders, this wasp lines preexisting cavities with grass and fills them with paralyzed crickets or katydids.

 
     
  grass-carrying wasp (Isodontia apicalis or mexicana)
Bill Keim
 
  grass-carrying wasp (Isodontia apicalis or mexicana)  

 

slideshow

       
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Other Videos
 
  Isodontia mexicana
69Patchou
 
   
 
About

Published on Aug 28, 2009

   
       
  Guepe solitaire Isodontia mexicana:Ponte
Marc Germain
 
   
 
About

Published on Mar 17, 2013

   
       

 

Camcorder

         
Visitor Sightings
   
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Alfredo Colon
August 2019

Location: Slinger, Wisconsin

Mexican grass-carrying wasp


Christine Gerjets
6/14/2019

Location: Glenwood MN; Pope County

Building nest in window frame


Alfredo Colon
8/16/2018

Location: Woodbury, Minnesota

Mexican grass-carrying wasp


Alfredo Colon
6/8/2018

Location: Woodbury, Minnesota

Mexican grass-carrying wasp


     
     
 
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Created 9/23/2018

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