Prionoxystus robiniae
Peck, 1818
Carpenterworm Moth, Locust Borer
Prionoxystus robiniae is a in the , found across much of North America from southern Canada through most of the United States. are active from May to July, with wingspans ranging from 43–85 mm. The are wood-borers that tunnel into hardwood trees, causing to timber. Females release to attract males, which upwind to locate them; mating occurs at dusk and early night, with copulation lasting 1–2 hours.



Pronunciation
How to pronounce Prionoxystus robiniae: /ˌpraɪ.oʊˈnɒksɪ.stəs ˈroʊ.bɪni.aɪ/
These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.
Identification
have a wingspan of 43–85 mm. The can be distinguished from other by its association with hardwood and its specific adult period. create extensive tunnels in wood, which may be detected by at holes.
Images
Habitat
Associated with hardwood forests and urban areas where trees grow. develop within the wood of living or recently dead hardwood trees.
Distribution
Southern Canada (Alberta, Manitoba, Saskatchewan) and most of the United States, including Vermont.
Seasonality
are on from May to July, with timing varying by location.
Diet
feed on the wood of (Robinia), oak, chestnut, poplar, willow, maple, and ash. do not feed.
Host Associations
- Robinia - larval primary ; implied by epithet
- Quercus - larval oak
- Castanea - larval chestnut
- Populus - larval poplar
- Salix - larval willow
- Acer - larval maple
- Fraxinus - larval ash
Life Cycle
tunnel into hardwood, creating galleries that reduce timber value. Development occurs within wood; emerge to mate. Specific details of -laying, larval , and are not documented in available sources.
Behavior
Females adopt a calling posture with elevated and folded to expose between the 7th and 8th abdominal . Males detect with their and upwind to locate females. Males produce ultrasonic clicks during courtship, possibly for mate recognition or to inhibit rival males. Males may fight for access to calling females. Females typically mate only once, while males may mate multiple times.
Ecological Role
act as wood-borers in hardwood trees, contributing to in dead or dying wood but also causing to living timber.
Human Relevance
Considered a because larval tunnels decrease the value of hardwood lumber.
Similar Taxa
- Prionoxystus macmurtreicongeneric in same , may share wood-boring habits and require association for distinction
- Megacyllene robiniaeshares '' but is a , not a ; active in fall rather than summer, and found on goldenrod flowers
Misconceptions
The '' is also applied to the , a that is unrelated and active in a different season.
Sources and further reading
- BugGuide
- Wikipedia
- GBIF taxonomy match
- iNaturalist taxon
- NCBI Taxonomy
- Catalogue of Life
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- Mating Behavior in the Carpenterworm Moth, Prionoxystus robiniae (Lepidoptera: Cossidae)1