common tiger fly

Common tiger fly is an exotic, small, predatory fly. It is native to Europe. It was introduced into North America in the early 1800s, and it has spread widely. It is most common in the northeast, the Upper Midwest, and the West Coast, though scattered populations exist throughout the rest of the United States and southern Canada, often concentrated around major metropolitan areas.

Adults are active from May through September. They are found in a wide range of habitats, including at forest edges, in wet meadows, and in waste places. They are commonly found in greenhouses. They live just six to eight weeks. They are predatory on flying insects, mainly on other flies, usually smaller than themselves, but also on grasshoppers. The larvae prey on earthworms.

Adults are stocky and 3⁄16″ to ¼″ (5.75 to 7.0 mm) in length. Females are yellowish gray or buff gray, and males are whitish gray. The thorax and abdomen are covered with black dots, small ones at the base of each hair, larger ones at the base of each bristle.

The antennae are feather-like (plumose). The finger-like sensory mouthparts (palps) are black.

The thorax is large and has three segments. The upper (dorsal) plates, from front to rear, are the prescutum, scutum and scutellum. The number and arrangement of bristles on the thorax are important identifying features. The pre-alar bristle, located in the area just in front of the alar (wing) area on the mesothorax, is missing. There is a distinct, visible line (transverse suture) running across the scutum, and there are two longitudinal rows of bristles (dorsocentral bristles). There is one dorsocentral bristle in front of the suture and three dorsocentral bristles behind the suture. Between the rows of dorsocentral bristles there is no row of bristles along the midline (acrostichal bristles). The space between the dorsocentral rows of bristles is bare. On each side of the thorax there is a plate (sternopleuron) above the middle legs. There are three bristles arranged roughly in a triangle on each sternopleuron.

On the abdomen, there are large dark spots on segments 2 through 4.

The wings are slightly tinted yellowish gray. The cross veins are not bordered with dark shading.

On the hind legs, there is a pair of bristles very close to each other on the middle of the fourth segment (tibia). According to the literature, which is repeated literally word for word by most sources, “the mid and hind femora black with red tips.” Photos on BugGuide and iNaturalist do not bear this out. On these photos, the color is highly variable. All of the legs usually have both dark (gray, black, or both) and pale (reddish brown or brownish yellow) areas, but they may be mostly dark, mostly pale, or sometimes entirely pale.

Total length: 3⁄16″ to ¼″ (5.75 to 7.0 mm)

A wide range of habitats, including forest edges, wet meadows, waste places, and greenhouses

May through September

Earthworms

Flying insects, mainly other flies, also grasshoppers

Sources

4, 29, 30, 82, 83.

Coenosia tigrina
Ophrus

Fliege Coenosia tigrina
Chrigu wälti

Coenosia tigrina
Oliver's Nature

Tiger Fly (Coenosia tigrina)
Bugging You From San Juan Island

Tiger Fly (Coenosia Tigrina) eating a Cereal Fly (Geomyza tripunctata)
Bugging You From San Juan Island

Alfredo Colon
7/6/2024

Location: Albany, NY

Alfredo Colon
8/4/2022

Location: Albany, NY