cluster flies

(Pollenia spp.)

Overview
cluster fly (Pollenia sp.)
Photo by Alfredo Colon
 

Pollenia is a common and widespread genus of flies known as cluster flies. There are at least 102 Pollenia species worldwide, 6 species in North America north of Mexico, and 4 species in Minnesota. It occurs worldwide mostly in the Northern Hemisphere, and to a lesser extent in the Southern Hemisphere. It is common throughout North America and Europe.

The biology of Pollenia is poorly known. Many species are parasitic on earthworms. The female lays her eggs on soil known to be inhabited by earthworms. When the eggs hatch, the larvae burrow into the soil in search of a host. A few species are known to parasitize caterpillars and bees.

 
 

Pollenia are often extremely common in urban and agricultural areas. They can be the most abundant species visiting flowers in gardens. When the weather cools, they seek shelter from the cold, often in the walls and attics of humans’ homes. On warm winter days and in early spring they become active. They are often seen clustered at windows seeking escape. This is the source for the common name of the genus. If a large fly appears in your house in midwinter, it is probably a cluster fly.

 
     
 
Description
 
 

The following description refers only to the species that occur in North America.

Pollenia are small to medium-sized flies. They are similar in appearance to house flies but slightly larger. The body is dull, not metallic.

The thorax is covered with crinkly, golden-yellow hairs (setae), but these may wear away as the fly ages. On most species there are no pale longitudinal stripes on the thorax. Pollenia vagabunda has a single stripe in the middle (middorsal), but this is sometimes indistinct.

The abdomen is hairy and dark gray with black and pale patches.

 
     
 
Distribution
 
 

Distribution Map

 

Sources

24, 27, 29, 30, 82, 83.

 
  4/15/2023      
         
 
Taxonomy
 
 

Order

Diptera (flies)  
 

Suborder

Brachycera  
  Infraorder Cyclorrhapha  
  Zoosection Schizophora  
  Zoosubsection Calyptratae  
 

Superfamily

Oestroidea (bot flies, blow flies, and allies)  
 

Family

Polleniidae  
       
 

Subordinate Taxa

 
 

Until recently, it was thought that the genus Pollenia was represented by a single species, Pollenia rudis, in North America. Following recent revisions of the genus (Rognes, 1991; and Whitworth, 2006) there are now six species recognized in North America.

 
 

cluster fly (Pollenia angustigena)

cluster fly (Pollenia griseotomentosa)

cluster fly (Pollenia pediculata)

cluster fly (Pollenia labiais [=Pollenia intermedia])

cluster fly (Pollenia vagabunda)

common cluster fly (Pollenia rudis)

 
       
 

Synonyms

 
 

 

 
       
 

Common Names

 
 

cluster flies

 

 

 

 

 

 

 

 

 

 

 

Glossary

Seta

A stiff, hair-like process on the outer surface of an organism. In Lepidoptera: A usually rigid bristle- or hair-like outgrowth used to sense touch. In mosses: The stalk supporting a spore-bearing capsule and supplying it with nutrients. Plural: setae. Adjective: setose.

 

 

 

 

 

 
 
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Alfredo Colon

 
    cluster fly (Pollenia sp.)      
           
 
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Other Videos
 
  CLUSTER FLY Pollenia
Rob Curtis
 
   
 
About

Nov 19, 2017

Pollenia GRAY CLUSTER FLY. Willow Springs, IL. 11/1/2016.

 
  Cluster Flies (Calliphoridae: Pollenia) Mating
Carl Barrentine
 
   
 
About

Aug 7, 2011

Photographed in Wisconsin, across the Mississippi River just North of Red Wing, Minnesota (04 August 2011). Thank you to 'v belov' (@Bugguide.net) for identying the genus for these specimens!

 

 

Camcorder

 
 
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  Alfredo Colon
8/16 to 8/18/2019

Location: Slinger, Wisconsin

cluster fly (Pollenia sp.)

 
           
 
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Created: 4/15/2023

Last Updated:

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