spotted-wing drosophila (SWD)

(Drosophila suzukii)

Conservation Status
spotted-wing drosophila
Photo by Alfredo Colon
  IUCN Red List

not listed

     
  NatureServe

NNA - Not applicable

     
  Minnesota

not listed

     
           
           
           
 
Description
 
 

Spotted-wing drosophila is a small, invasive, vinegar fly. It is native to southeast Asia but has been rapidly spreading around the world. It was seen in Japan as early as 1916, and by the 1930s it had spread throughout eastern Asia. In North America it was first seen on the west coast in 2008 and on the east coast in 2010. It was first recorded in Minnesota in 2012. It has been much studied, written and talked about, and is commonly referred to by the acronym SWD. It can be found from spring through fall in agricultural fields, orchards, and gardens, and year round in kitchens.

SWD is a serious crop pest of summer fruits, including cherries, blueberries, grapes, nectarines, pears, plums, pluots, peaches, raspberries, and strawberries. Unlike fruit flies, which feed on decaying fruit and vegetation, SWD lays its eggs on healthy fruit.

Adults are yellowish, 564 to 964 (2 to 3.5 mm) in length, and look like fruit flies.

The head is yellowish-brown. There are two large compound eyes on the sides of the head and and three small simple eyes (ocelli) in a triangle on top of the head. A pair of bristles (setae) behind the ocellar triangle (postocellar setae) are well developed. The compound eyes are red. They do not meet at the top of the head on either sex. The upper part of the face has sparsely scattered bristles. On each side, near the margin of the compound eye, there are two bristles. One is bent down at the base (reclinate seta), the other is bent upward at the base (proclinate seta). The proclinate seta is larger and is above and slightly outside of the reclinate seta. There are two stiff, well-deveolped bristles (vibrissae) below the antenna bases. There is a ridge (carina) in the middle of the face. The carina is broad and well developed, including on the lower part of the face. The antennae are very short and have three segments. The second segment does not have a longitudinal groove (suture) on top. The third segment has a long, forward-pointing bristle (arista) on the upper side. The arista is branched (plumose), with several branches above and two or three branches below.

The thorax is yellowish-brown above and on the sides, with no stripes or spots. It has three segments. Each segment has four principal exoskeletal plates, one above, one below, and one on each side. The upper (dorsal) plates, from front to rear, are the prescutum, scutum, and scutellum. The prescutum and scutum have several large black bristles and numerous shorter hair-like bristles. There are eight longitudinal rows of small bristles in the middle of the scutum, and two pairs of large bristles near the rear margin. The lower front plate of the middle segment (katepisternum) has three large bristles.

The abdomen has six visible segments on both the male and female. On the female, segments 2 through 6 are pale yellow with an unbroken, dark band on the rear margin. On the male segments 2 through 4 are similar to the female, segments 5 and 6 are completely dark.

The wings are clear. Their is a vein (costa) on the leading edge (costal margin) of the wing. The costa is broken twice. On the male there is usually a dark cloudy spot at the end of each radial vein R2+3 and R4+5. This is the feature that gives the fly its common name. On the female the wings are clear with no dark spots or white markings.

The legs are yellow. The last part of the leg, corresponding to the foot (tarsus) has five segments. The first segment is longer than the second, and is not swollen. On the front leg of the male there is a black comb on the first and second segments. The comb on the first segment has 4 to 6 teeth, the comb on the second has 2 or 3 teeth.

 
     
 

Size

 
 

Total Length: 564 to 964 (2 to 3.5 mm)

 
     
 

Similar Species

 
     
     
 
Habitat
 
 

Agricultural fields, orchards, gardens, and kitchens

 
     
 
Biology
 
 

Season

 
 

Up to 13 generations per year: Year-round

 
     
 

Behavior

 
 

 

 
     
 

Life Cycle

 
 

 

 
     
 

Larva Food

 
 

 

 
     
 

Adult Food

 
 

 

 
     
 
Distribution
 
 

Distribution Map

 

Sources

22, 24, 29, 30, 82.
 
  2/1/2021      
         
 

Occurrence

 
 

Common and increasing in Minnesota

 
         
 
Taxonomy
 
 

Order

Diptera (gnats, mosquitoes, true flies)  
 

Suborder

Brachycera (circular-seamed flies, mouches muscoïdes, muscoid flies, short-horned flies)  
 

Infraorder

Muscomorpha  
  No Rank Eremoneura  
  No Rank Cyclorrhapha  
  No Rank Schizophora  
  No Rank Acalyptratae  
 

Superfamily

Ephydroidea  
 

Family

Drosophilidae (pomace flies, small fruit flies, and vinegar flies)  
 

Subfamily

Drosophilinae  
 

Tribe

Drosophilini  
  Genus Drosophila (small fruit flies)  
  Subgenus Sophophora  
  Species
group
melanogaster group  
  Species subgroup suzukii subgroup  
       
 

 

   
       
 

Synonyms

 
 

 

 
       
 

Common Names

 
 

cherry vinegar fly

spotted-wing drosophila

SWD

 
       

 

 

 

 

 

Glossary

Arista

A large bristle on the upper side of the third segment of the antenna of a fly.

 

Carina

An elevated ridge of a body wall of an insect, as in the pronotal carina of many grasshoppers.

 

Costa

On ferns: The central axis of a pinna, to which pinnules are attached. On mosses: the central axis (midvein) of a leaf. On insects: The vein on the leading edge of the forewing.

 

Costal margin

The leading edge of the forewing of insects

 

Frons

The upper part of an insect’s face, roughly corresponding to the forehead.

 

Ocellus

Simple eye; an eye with a single lens. Plural: ocelli.

 

Scutellum

The exoskeletal plate covering the rearward (posterior) part of the middle segment of the thorax in some insects. In Coleoptera, Hemiptera, and Homoptera, the dorsal, often triangular plate behind the pronotum and between the bases of the front wings. In Diptera, the exoskeletal plate between the abdomen and the thorax.

 

Scutum

The forward (anterior) portion of the middle segment of the thorax (mesonotum) in insects and some arachnids.

 

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.

 

Tarsus

On insects, the last two to five subdivisions of the leg, attached to the tibia; the foot. On spiders, the last segment of the leg. Plural: tarsi.

 

 

 

 

 

 
 
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Alfredo Colon

 
    spotted-wing drosophila      
           
 
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Other Videos
 
  Drosophila Suzukii and native European parasitoids
agroscopevideo
 
   
 
About

Mar 20, 2019

The invasive Drosophila suzukii and native parasitoids in Central Europe

The invasive Drosophila suzukii (common name: spotted-wing drosophila or cherry-vinegar fly) was introduced into Europe in 2008. Since then, it has established, spread, and caused significant damage in fruit, berry and grapevine production. The females lay their eggs in ripening and ripe fruit and the larvae develop inside the fruit, causing it to rot quickly. Parasitoids could contribute to the control of Drosophila suzukii.

We conducted field studies on parasitoids of spotted-wing drosophila in Switzerland, collecting and breeding eight species. The film gives a detailed account of some of these species and of how they interact with the different developmental stages of Drosophila suzukii. Larval parasitoids lay their eggs in Drosophila suzukii, but cannot develop. By contrast, pupal parasitoids can complete their whole development on Drosophila suzukii.

The film is the result of a collaboration between Agroscope and Entofilm (Kiel D.), and also contains sequences from A-M. Baumann and M. Breuer from the Weinbauinstitut Freiburg in Germany.

https://www.agroscope.admin.ch/agroscope/en/home/topics/plant-production/plant-protection/drosophila-suzukii.html

http://www.entofilm.com/intro_en.php?...

 
  How to Identify and Trap Spotted Wing Drosophila
Utah State University Extension
 
   
 
About

Aug 11, 2011

Learn ways to identify Spotted Wing Drosophila and how to trap them.

 
  How to Identify Spotted Wing Drosophila Damage
The University of Maine
 
   
 
About

Nov 27, 2012

University of Maine Cooperative Extension shows how to identify the damage caused by Spotted Wing Drosophila.

 
       

 

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  Alfredo Colon
8/30/2019

Location: Woodbury, MN

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Created: 2/1/2021

Last Updated:

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