common drone fly

not listed

NNA - Not applicable

not listed

Common drone fly is a large, exotic, migratory, cosmopolitan, drone fly. It is native to Europe and Asia. It has been widely introduced and now occurs worldwide on every continent except Antarctica. It has been recorded in the United States in every state except Mississippi and Louisiana but including Alaska and Hawaii, and in every Canadian province except Nunavut. It is common in Minnesota.

The adult is ½″ to ⅝″ (11.7 to 15.8 mm) in length. It is similar in shape, appearance, and behavior (Batesian mimicry) to the western honey bee (Apis melifera). The body is robust and hairy.

The head is wider than high and is as broad or slightly broader than the thorax. There are two large compound eyes on the sides of the head and three small simple eyes (ocelli) in a triangle on top of the head. The compound eyes are uniformly dark brown, without colored bands or spots. They are densely covered with short erect hairs and have two broad vertical bands of long erect hairs that are more dense than the short hairs. On the male the compound eyes meet at the top of the head. On the female they do not. The forehead (frons) is black in the middle with a broad pale yellow stripe on each side. The face is slightly projected diagonally forward and downward. It is pale yellow except for a black stripe in the middle that extends all the way to the lower margin. The protruding mouthpart (proboscis) is short and fleshy. The antennae are short, have three segments, and are inserted near the middle of the head. The third antennal segment is long on the upper side, short and rounded on the underside. It has a long, stiff, forward-pointing bristle (arista) above. The arista is feather-like (plumose) at the base. There is no line-like groove (suture) extending downward from the base of each antenna.

The thorax is black, short, and somewhat convex when viewed from the side. It is moderately or densely covered with long, more or less erect, brownish-yellow hairs. The hairs are not dense enough to obscure the ground color, so that when viewed from directly above, the thorax appears black. On each side of the thorax, in the shoulder (humeral) area just behind the head, there is a small plate (postpronotum). The postpronotum is hairy. The small rear part of the thorax (scutellum) is more or less translucent with a variable amount of yellow tinting. It does not have a fringe of hairs.

The abdomen is black with variable orange or yellowish-orange markings. The first segment is very short and is covered with long hairs. The remaining segments are moderately covered with hairs. The second segment has a pair of large spots that narrow toward but do not meet in the middle, and a narrow band on the rear margin. The third segment is shiny and has a variable amount of orange. Generally, it has a narrow orange band on the front and rear margins, and a pair of stripes on each side that sometimes merge together but do not reach the opposite pair in the middle. Sometimes these markings are very faint and the third segment appears entirely black. The fourth segment may have a pair of large spots or be entirely black.

The wings are usually clear. There is sometimes a diffuse brown cloud near the middle, but it is never a well-defined, squarish spot. There is a false (spurious) vein between the radius (R) and media (M) veins and parallel to them. It is not a true vein but rather a streak of discoloration. The radial sector (Rs) vein has two branches. The R₄₊₅ vein is deeply bent (sinuous), appearing “bumped” downward in the middle. The anal cell is long and is closed near the wing margin. Cell R₂₊₃ is closed before the wing margin. The marginal, R₁, and M₂ cells are also closed.

The legs are black and yellow. The third segment (femur) on the hind leg is moderately thickened and has no spurs, spines, or teeth. The fourth segment (tibia) on all legs is straight or moderately curved. On the hind legs the tibia is entirely dark brown or black.

½″ to ⅝″ (11.7 to 15.8 mm)

Early July through early November in Minnesota, year round in the south.

Larvae have a long, tail-like extension of the body (siphon). As they swim through the water searching for food the tip of the siphon remains at the water surface, allowing them to breathe air.

Groups of females have been observed hibernating in crevices and holes in the sandstone caves near St. Paul.

After migrating, individual males disperse, establish a territory, and fiercely defend it.

Females hibernate in protected areas, but males do not survive the winter. Masses of eggs are laid in small ponds, ditches, drains, and manure lagoons, near the surface of water with high levels of organic matter. Adults emerge in Minnesota beginning in early July. A new generation migrates north in the summer.

Flower nectar

Sources

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

Telford, Horace S.. (1939). The Syrphidae of Minnesota. University of Minnesota. Minnesota Agricultural Experiment Station.

Very common and very widespread

Eristalis tenax (common drone fly)

Location: Woodbury, MN