Bug FAQEastern Catkin Fly
Brachypalpus oarus · Order: Diptera · Family: Syrphidae
Adult Eastern Catkin Flies visit flowers to sip nectar and collect pollen for protein. Their larvae are rat-tailed maggots that live under tree bark, feeding on decaying sap. The species is native to northeastern North America, especially the United States and parts of Canada.
Source: Wikipedia
How to recognize it
Adults are commonly called flower flies because they are often seen on blossoms.
Source: Wikipedia
Where it lives
Adults are typically found on flowers where they feed. Larvae develop in decaying sap that pools under tree bark.
Source: Wikipedia
What it eats
Adults obtain energy from flower nectar and protein from pollen. Larvae feed on decaying sap found under bark.
Source: Wikipedia
Where it comes from
It occurs in Canada and the United States. Within North America it is most common in the northeastern region, with a population in southwestern Canada.
Source: Wikipedia
Where it is found in the US
Recorded in 31 of 51 states and DC. Most records: Illinois, Massachusetts, Pennsylvania, New York, Ohio, Virginia, Vermont, New Jersey.
Darker = more records. Counts are museum and citizen-science records, not population size.
Source: GBIF
Status: native in North America; native in Canada; native in United States. Source: iNaturalist
Months it is reported in the US
Source: GBIF
More photos
Questions people ask
What do the larvae eat?
The larvae are rat-tailed maggots that feed on decaying sap under tree bark.
Source: Wikipedia
Where is the Eastern Catkin Fly found?
It is native to Canada and the United States, especially the northeastern part of North America.
Source: Wikipedia
What do adult Eastern Catkin Flies feed on?
Adults visit flowers to drink nectar and collect pollen for protein.
Source: Wikipedia
Same family (Syrphidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Brachypalpus_oarus
Look it up elsewhere: GBIF · iNaturalist · BugGuide · ITIS · Wikipedia
Text written 2026-10-25 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-25.