Aweme borer (Papaipema aweme) COSEWIC assessment and status report: chapter 2

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Species Information

The Aweme Borer is a noctuid (cutworm or owlet) moth belonging to a subgroup known as the borers. It was described from two specimens collected in 1905 at Aweme, Manitoba, in or near present-day Spruce Woods Provincial Park. The genus Papaipema, to which the Aweme Borer belongs, occurs only in North America and is one of the largest noctuid genera, with about fifty describedspecies.

Adult Aweme Borers are medium-size (33-37 mm wingspan), yellowish or pinkish-brown moths with darker brown markings on the forewings. They are difficult to identify by non-experts. There are no described subspecies. The early stages (egg, larva and pupa) are unknown.

Distribution

The Aweme Borer is known from only five localities: Aweme, Manitoba; Grand Bend and Manitoulin Island, Ontario; Beaver Island, Michigan; and Rochester, New York. The Manitoba site is in the Prairie Ecological Area and the Ontario sites are within the Great Lakes Plain Ecozone. The area of occupancy (AO) in Canada is estimated at a maximum of about 625 km².

Habitat

The exact locations of the sites where the few specimens were collected in the early 1900s are unknown, and the specific habitat where they occurred is also unknown. Available historical evidence suggests the specimens were associated with sand dune habitats. The only specimen collected in the past 70 years was collected in a remnant oak-prairie fragment. All collection sites are located along former or present shorelines of glacial Lake Agassiz or one of the Great Lakes.

Biology

Almost nothing is known regarding the biology of the Aweme Borer. It is nocturnal and at least weakly attracted to light. There is a single annual generation, with the adults flying in August. The larvae of all members of the genus Papaipema bore into, and live within, the stems, roots or branches of the host plant. The larval host plant of the Aweme Borer is not known.

Population Sizes and Trends

Aweme Borers are known from only seven specimens collected at five sites in North America. Six of these specimens were collected over a period of 31 years ending in 1936. The most recent specimen was captured almost 70 years later in 2005 in Ontario. 

Limiting Factors and Threats

Loss of habitat and particularly loss of colonies of the unknown host plant are the most likely limiting factors for the species. Fire and predation of pupae by small mammals have been identified as particular threats to Papaipema populations in general. A small number of individuals distributed in widely separated and highly fragmented habitat is also known to increase the possibility of extirpation of a species.

Special Significance of the Species

The Aweme Borer is an extremely rarely encountered insect. More than half of the known collection sites and two-thirds of the known specimens are Canadian.

Existing protection

Both historical Canadian collection sites are probably located within Provincial Parks: Spruce Woods Provincial Park, Manitoba and The Pinery Provincial Park, Ontario. The only recent collection was made on private property.