Bug FAQOrange-striped Stonefly
Perlodes mortoni · Order: Plecoptera · Family: Perlodidae
The orange-striped stonefly lives in rivers across Great Britain and is considered endemic there. Males have very short wings that are only about one and a half times the width of their heads.
Source: Wikipedia
How to recognize it
It looks similar to the European species P. dispar and P. microcephalus.
Source: Wikipedia
Size
Males are brachypterous, with wings 1.4 to 1.8 × the head width.
Source: Wikipedia
Where it lives
Nymphs live among stones in rivers and streams. Adults are usually seen near river banks.
Source: Wikipedia
What it eats
Adults eat plant material and also prey on other aquatic invertebrates.
Source: Wikipedia
Life cycle
The species overwinters as a nymph and the adults fly from March to June, peaking in May.
Source: Wikipedia
When you see it
Adult flight season runs from March through June, with the highest numbers in May.
Source: Wikipedia
Where it comes from
It is found throughout Great Britain and is thought to be endemic there.
Source: Wikipedia
Lookalikes
It may be confused with P. microcephalus, which could be present in Britain but needs confirmation.
Source: Wikipedia
More photos
Questions people ask
When are orange-striped stoneflies active?
Adults are on the wing from March to June, most abundant in May.
Source: Wikipedia
Where can I find orange-striped stoneflies?
Their nymphs live among stones in rivers, and adults are usually seen near river banks.
Source: Wikipedia
What do adult orange-striped stoneflies eat?
They feed on plant matter and also hunt other aquatic invertebrates.
Source: Wikipedia
How can I tell this stonefly apart from similar species?
It resembles the European P. dispar and P. microcephalus, so careful identification is needed.
Source: Wikipedia
Same family (Perlodidae)
Sources
- Wikipedia: https://en.wikipedia.org/wiki/Perlodes_mortoni
Look it up elsewhere: GBIF · iNaturalist · BugGuide · Wikipedia
Text written 2026-10-23 from the sources above and checked sentence by sentence against them. Data fetched 2026-10-23.