Prionoxystus robiniae

Peck, 1818

Carpenterworm Moth, Locust Borer

Prionoxystus robiniae is a in the Cossidae, 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 larvae are wood-borers that tunnel into hardwood trees, causing economic damage to timber. Females release to attract males, which fly upwind to locate them; mating occurs at dusk and early night, with copulation lasting 1–2 hours.

Prionoxystus robiniae by James Solomon, USDA Forest Service, United States. Used under a CC BY 3.0 license.

Prionoxystus robiniae 06-06-15 (18458157559) by Smithsonian Environmental Research Center. Used under a CC BY 2.0 license.

Prionoxystus robiniae P1190086a by
xpda. Used under a CC BY-SA 4.0 license.

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 Cossidae by its association with hardwood and its specific adult period. Larvae create extensive tunnels in wood, which may be detected by at holes.

Images

Habitat

Associated with hardwood forests and urban areas where trees grow. Larvae 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 wing from May to July, with timing varying by location.

Diet

Larvae feed on the wood of locust (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

Larvae tunnel into hardwood, creating galleries that reduce timber value. Development occurs within wood; emerge to mate. Specific details of -laying, larval instars, and are not documented in available sources.

Behavior

Females adopt a calling posture with elevated and wings folded to expose between the 7th and 8th abdominal segments. Males detect with their and fly 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.

Prionoxystus macmurtreicongeneric in same , may share wood-boring habits and require association for distinction
Megacyllene robiniaeshares 'locust borer' but is a cerambycid beetle, not a ; active in fall rather than summer, and found on goldenrod flowers

Misconceptions

The 'locust borer' is also applied to the Megacyllene robiniae, a cerambycid that is unrelated and active in a different season.