Ceroxys latiusculus
(Loew, 1873)
narrow-banded picture-winged fly, picture-winged fly
Ceroxys latiusculus, commonly known as the narrow-banded , is a of ulidiid to western North America. measure 9–12 mm and are recognized by their grayish- bodies, black with gray , and distinctively patterned . The species is frequently encountered as a nuisance pest when adults enter buildings in autumn to seek winter shelter. develop within the seed of Senecio plants.
Pronunciation
How to pronounce Ceroxys latiusculus: //sɛˈrɔksis lætiˈʊskʊlʊs//
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Identification
Distinguished from other by the pattern: the dark bars are less complete than the "tiger-striped" pattern of Pseudotephretina . Larger than Delphinia picta (7–8 mm) and smaller than Idana marginata (10–12 mm). Often mistaken for the walnut husk . The combination of size, gray-banded black , and characteristic wing markings separates it from other .
Images
Appearance
are 9–12 mm in length, comparable in size to a but with slower movement. The body is grayish- overall. The is black with gray . The bear dark patterned markings that are the ' most notable visual feature. The and other body regions lack strong metallic coloration.
Habitat
Found in diverse outdoor environments across western North America. utilize tree trunks, fence rails, and logs as basking and display sites. Frequently enters human structures including homes, sheds, and vehicles during autumn. Observed on nectarine blossoms and other flowering plants.
Distribution
Common throughout western North America. Documented in Colorado, California, Arizona, and Hawaii. Ranges into southern California, New Mexico, Texas, and Utah. Presence confirmed in Birds Landing and Vacaville, California.
Seasonality
Most active in spring and fall. commonly found indoors from early fall through spring, often concentrated around windows. Observed on nectarine blossoms in late February.
Diet
feed on Senecio (groundsels, ragworts), developing within the seed . feeding habits are not documented.
Host Associations
- Senecio - larval develop in seed
Life Cycle
Larval stage develops within seed of Senecio plants. Specific details of -laying, , and longevity are not documented.
Behavior
exhibit slow, deliberate movement compared to . Males have been observed performing involving movements. Adults invade buildings in autumn, seeking winter shelter, and aggregate around windows. One individual was observed crawling on nectarine blossoms, possibly mimicking .
Ecological Role
Larval development in Senecio seed suggests a role in reproductive , though specific impacts are not quantified. may contribute to through flower visitation.
Human Relevance
Considered a nuisance pest due to autumn invasion of homes, sheds, and vehicles. Frequently mistaken for the walnut husk . No documented agricultural or . Occasionally observed on ornamental nectarine trees.
Similar Taxa
- Pseudotephretina spp.Similar size and appearance, but bars are more complete and "tiger-striped"
- Delphinia pictaSmaller (7–8 mm), eastern U.S. distribution, breeds in decaying matter
- Idana marginataLarger (10–12 mm), northeastern U.S., associated with bird droppings and fermenting sap
- walnut husk flyFrequently confused with C. latiusculus; distinct with different biology
Misconceptions
Often mistaken for the walnut husk , though the two have different and economic significance.
More Details
Historical taxonomy
was formerly known as ; older references use this name.