Catocala unijuga
kah-TOCK-uh-lah mm ewe-nih-JOO-guh
Walker, [1858]

Catocala unijuga August 15, 1983, Ann Arbor, Michigan, © Donald H. Gudehus

This site has been created by Bill Oehlke at oehlkew@islandtelecom.com
Comments, suggestions and/or additional information are welcomed by Bill.

TAXONOMY: Superfamily: Noctuoidea Family: Noctuidae Group: Noctuinina Subfamily: Catocalinae Genus: Catocala, Schrank, 1802

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DISTRIBUTION:

Catocala unijuga, The Once Married Underwing, (wingspan: 70-90mm) flies across Canada (rare in Newfoundland) from British Columbia to Prince Edward Island, south through Connecticut and west to Montana, Minnesota and Colorado.

Dr. Wayne H. Whaley reports C. unijuga flies in Utah in August within the Wasatch Mountains nr. Provo Cyn and northward into Idaho.

Scott Shaw reports unijuga is taken (not common) "on Pole Mountain, in the Medicine Bow Forest, Wyoming, about 10 miles east of Laramie near I-80 in the mountain willow bogs."

There is a melanic form,"agatha", Beutenmuller, whose forewings are a dark, smoky grey.

The aberration "fletcheri", Beutenmuller has hindwings which are entirely black.

Catocala unijuga, Peterborough, Ontario, August 25, 2004, courtesy of Tim Dyson, copyright.

Catocala unijuga has a fairly wide black inner band (almost reaching inner margin) in the hindwing and very distinctive patterning in forewing. Meskei tend to have a narrower band and a dustier (less distinct) looking forewing. Semirelicta tend to have inner bands that terminate well before the inner margins. Also note the "buck teeth" on the face on the thorax, and the very white fringe on both the forewings and hindwings. Image (right), Peterborough, Ontario, August 25, 2004, courtesy of Tim Dyson copyright.

John Acorn confirms C. unijuga from Redcliff, Alberta, Canada.

FLIGHT TIMES AND PREFERRED FOOD PLANTS:

Catocala unijuga are usually on the wing from late June (Indiana) through July, August and September to early October (Quebec).

:

Catocala unijuga, (very fresh) Peterborough, Ontario, July 12, 2005, courtesy of Tim Dyson.

This species probably has one of the longest flight periods of all the Catocala but is still believed to be univoltine (single brooded).

Larvae feed on cottonwoods, poplars and willows.

Adults come to lights and to bait and can sometimes be "caught with a flashlight" while nectaring on joe-pye-weed (pond or stream edges), milkweed (open fields, roadsides) or other nectar sources.

They often rest high on tree trunks with head up.

You won't often see a live unijuga in flight, captured the way Tim Dyson has captured this one. Note the wide black banding on the forewing and the narrow discal lunule in the hindwing cell. These features help to identify unijuga from some similar relatives. Catocala unijuga, Peterborough, Ontario, August 25, 2004, Tim Dyson copyright. The hindwing inner black band also terminates well before the inner margin.

ECLOSION:

Adults eclose from pupae at soil surface.

:

Catocala unijuga, (very fresh) Peterborough, Ontario, July 12, 2005, courtesy of Tim Dyson.

SCENTING AND MATING:

Catocala unijuga females emit an airbourne pheromone and males use their antennae to track the scent plume.

EGGS, CATERPILLARS, COCOONS, AND PUPAE:

Eggs are deposited on tree bark in the fall and hatch the following spring.

Catocala unijuga eggs, courtesy of Tim Dyson. copyright

The dark grey larvae attain lengths of 50 mm. The middorsal stripe is very irregular and pale, and the head has black side stripes broadly connected across the vertex.

Larval Food Plants

Listed below are primary food plant(s) and alternate food plants. It is hoped that this alphabetical listing followed by the common name of the foodplant will prove useful. The list is not exhaustive, although some species seem very host specific. Experimenting with closely related foodplants is worthwhile.

Populus tremuloides..... Populus nigra Salix

Quaking aspen Lombardy Poplar Willow

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