somewhat silky mound ant

(Formica subsericea)

               
Conservation Status

IUCN Red List

not listed

somewhat silky mound ant

 

NatureServe

NNR - Unranked

Minnesota

not listed

Occurrence

Very common in eastern United States; uncommon in Minnesota

Flight/Season

Present from spring thaw to first frost of fall. Nuptial flight in July or August.

Habitat

Woodlands, suburbs

Size

Worker: to 5 16 (4 to 8 mm)

Male: 3 16 to ½ (5 to 13 mm)

Queen: 3 16 to ½ (5 to 13 mm)

          Photo by Alfredo Colon

Identification

Somewhat silky mound ant is very common in the United States east of the Great Plains, with only spotty records in the west. According to an entomologist at Missouri Botanical Garden, it is “By a considerable margin the most abundant and widely distributed black Formica east of the Rocky Mountains.” It is uncommon in most of Minnesota, though it is reported as common at Cedar Creek Ecosystem Science Reserve in Anoka County. It is found in woodlands and in suburban areas.

Workers are to 5 16 (4 to 8 mm) long, black, and somewhat shiny. Winged males and queens are about the same size, 3 16 to ½ (5 to 13 mm) long.

The first body segment behind the head (mesosoma) has two distinct elevated areas (bumps). It is covered with three exoskeletal plates, the pronotum and mesonotum covering the thorax, and the propodeum covering the first segment of the abdomen that is fused to the thorax. The pronotum and and mesonotum form one smooth convex bump, the propodeum a second convex bump. The second abdominal segment (petiole) is narrow and waist-like, and has a single raised bump (node). The remainder of the abdomen (gaster) is bulbous. The head, mesosoma, legs, and first three segments of the gaster are covered with silvery appressed hairs. The fourth segment of the gaster is bare or almost bare. There are single rows of erect golden hairs at the end of each segment. On the first segment there are also usually 10 to 25, sometimes just 1 to 3, erect hairs not including the row at the end. Those are each shorter than or equal to the distance between them.

The head is broadly rounded in outline. The rear margin is rounded, not distinctly concave. The eyes are large. The facial plate above the mouth (clypeus) is not notched. The finger-like sensory mouth part (maxillary palp) is long and has six segments. The basal segment of each antennae (scape) is very long, longer than the length of the head.

 
Similar
Species

 


Larval Food

 

 
Adult Food

Aphid honeydew, soft-bodied insects, and seed husks.

 
Life Cycle

Nests are variable in size.

 
Behavior

Somewhat silky mound ants are often found as slaves in colonies of Amazon ants (Polyergus spp.).


Distribution Distribution Map  

Sources: 24, 27, 29, 30, 80.


Comments

 


Taxonomy

Order:

Hymenoptera (ants, bees, wasps, and sawflies)

 

Suborder:

Apocrita (wasps, ants and bees)

 

No Rank:

Aculeata (ants, bees and stinging wasps)

 

Superfamily:

Formicoidea (ants)

 

Family:

Formicidae (ants)

 

Subfamily:

Formicinae

 

Tribe:

Formicini

 

Genus:

Formica

 

No Rank:

Fusca Group

 
Synonyms

 

 
Common
Names

black field ant

silky field ant

somewhat silky mound ant


 

 

 

 

 

 

 

Glossary

Gaster

The bulbous part of the abdomen of ants, bees, and wasps. In ants it usually begins at segment three.

 

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 weapons in scorpions. Plural: palpi.

 

Scape

On plants: An erect, leafless stalk growing from the rootstock and supporting a flower or a flower cluster. On insects: The basal segment of the antenna.

 

 

 

 

 

       

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Alfredo Colon


  somewhat silky mound ant    

       
       
       

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  field ant (Formica subsericea)
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  field ant (Formica subsericea)  

 

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Alfredo Colon
June 2018

Location: Woodbury, Minnesota

somewhat silky mound ant


     
     
 

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