lesser bulb fly

(Eumerus spp.)

               
Conservation Status

IUCN Red List

not listed

lesser bulb fly (Eumerus sp.)

 

NatureServe

not ranked in the United States

Minnesota

not listed

Occurrence

Common

Flight/Season

Two generations per year: April to September

Habitat

Dry grasslands and woodland edges near their host species; suburban gardens

Photo by Alfredo Colon
Size

Total Length: 3 16 to ½

 

Identification

This is a small to medium-sized, 3 16 to ½ long hoverfly. It is native to Europe, Asia, North Africa, and the Indian subcontinent, and has been introduced into North and South America. It is found in dry grasslands, woodland edges, suburban gardens, anywhere their host species are found.

The thorax is black tinged with bronze, with a fringe of pale hairs. There are usually two, sometimes three, pale longitudinal stripes, conspicuous toward the front, fading toward the rear. The plate between the abdomen and thorax (scutellum) is large and convex. It is colored like the thorax and has a fringe of long yellow hairs.

The abdomen is black with a pair of gray or silvery-white oblique spots on the second, third, and fourth segments.

The wings are clear and are covered with fine hairs. The second cell on the leading edge of each wing toward the tip (pterostigma) is tinted brown.

The legs do not have spurs. The third leg segment (femur) is thickened.

The face is flat and covered with downward pointing hairs. There are two large compound eyes and three very small simple eyes (ocelli). The compound eyes are covered with hairs. On the male the compound eyes meet at the top of the head, and most of the head is covered with hairs. On the female the compound eyes do not meet and the hairs are parted on the forehead. The antennae are very short.

 
Similar
Species

 


Larval Food

Larvae tunnel into plant bulbs, causing the bulbs to rot. The bulb either dies or produces stunted growth in the following growing season.

 
Adult Food

 

 
Life Cycle

The female lays a single egg or a small mass of 2 to 40 eggs on or near a bulb. The eggs hatch in 5 to 10 days and the maggots attack the top or the base of the bulb. The bulb begins to decay, producing organisms the maggots need to complete their development. The maggots mature in about 30 days, then crawl to the surface and pupate. Adults emerge in one to four weeks. Larvae of the second generation overwinter in the bulb. In the spring, they pupate in the soil at the surface. Adults emerge in April and May.

 
Behavior

 


Distribution Distribution Map  

Sources: 24, 29, 30.


Comments

 


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 (circular-seamed flies)

 

Section:

Aschiza

 

Superfamily:

Syrphoidea

 

Family:

Syrphidae (hover flies)

 

Subfamily:

Eristalinae

 

Tribe:

Eumerini

 
Subordinate Taxa

lesser bulb fly (Eumerus funeralis)

narcissus bulb fly (Eumerus narcissi)

onion bulb fly (Eumerus strigatus)

 
Synonyms

 

 
Common
Names

lesser bulb fly


 

 

 

 

 

 

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.

 

Ocellus

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

 

Pterostigma

In Odonata and Hymenoptera, the dark, blood-filled second cell at the leading edge of each wing toward the tip. It is heaver than adjacent, similar sized areas and is thought to dampen wing vibrations and signal mates. [= stigma. More precise than stigma but less often used, even by entomologists.]

 

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.

 

 

 

 

 

       

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Alfredo Colon


  lesser bulb fly (Eumerus sp.)    

       
       
       

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Alfredo Colon
6/8/2018

Location: Woodbury, MN

lesser bulb fly (Eumerus sp.)


     
     
 

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