Wordless Wednesday

Two Spectacular Tiger Moths: Arctia caja and Arctia parthenos

Arctia caja, great tiger moth, and Arctia parthenos, St. Lawrence tiger moth, are moths in the Family Erebidae, subfamily Arctiinae, which includes these previously discussed moths: Lophocampa maculata, Halysidota tessellaris, Pyrrharctia isabella, Apantesis williamsii, Apantesis virgo, Apantesis phalerata, and Haploa contigua.

Arctia caja and Arctia parthenos are strikingly beautiful moths, as showy as any butterfly, which are just day-flying moths anyway.

Description

Arctia caja is a large moth with a wingspan of 27-32 mm. The forewings are brightly colored in white and brown, forming a mosaic pattern. The underwings are orange-red and marked with large, round to slightly irregular black discal, basal, and submarginal spots containing metallic blue scales. The abdomen is orange-red but darker than the underwings. (Sources: Moths of North Carolina, Pacific Northwest Moths, BugGuide)

Arctia parthenos is also a large moth with a wingspan of 28-33 mm. Its forewings are chocolate brown, marked with numerous pale yellow or cream-colored spots. The underwing is orange with irregular black markings. The abdomen is dark brown to black with orange sides and tip. (Sources: Moths of North Carolina, Pacific Northwest Moths, BugGuide)

Habitat

Arctia caja occurs in northern hardwood forests, conifer forests, wet meadows along creeks and rivers, in disturbed agricultural areas, gardens, and in urban areas. (Sources: Moths of North Carolina, Pacific Northwest Moths, BugGuide)

Arctia parthenos also occurs in northern hardwood forests, conifer forests, boreal mixed woods and parklands, moist shrubby arctic tundra, and mountains in the south. (Sources: Moths of North Carolina, Pacific Northwest Moths, BugGuide)

Host Plants

Arctia caja is polyphagous and feeds on many kinds of herbaceous plants as well as some hardwoods. (Sources: Moths of North Carolina, Pacific Northwest Moths, BugGuide)

Arctia parthenos is also polyphagous but has a preference for hardwoods such as willow, aspen, and alder. (Sources: Moths of North Carolina, Pacific Northwest Moths, BugGuide)

Range

Wordless Wednesday

Leathery Grape Fern

*Sceptridium multifidum* takes on a purplish tint in the cool autumn weather. Descriptions of the species state its fronds remain green overwinter, but obviously, they do not.

Sceptridium multifidum, the leathery grape fern, is similar to Sceptridium rugulosum (St. Lawrence grape fern), which was covered in an earlier post. At one time, Sceptridium rugulosum was considered a variation of Sceptridium multifidum and was named Botrychium multifidum forma dentatum.

**Frond of a young *Sceptridium mulitifidum* plant.**

Description

Segment blades of Sceptridium multifidum are flat, rounded, with entire to shallowly denticulate margins and blunt tips. The texture is leathery. The fronds can be large, measuring 25 by 35 cm.

**A large (almost 25 cm across) *Sceptridium multifidum* frond**.

*Sceptridium multifidum* plant with two photosynthetic fronds, an unusual occurrence.

Habitat

Sceptridium multifidum grows in old fields, the edges of woodlands, and in open forests. Often, there will be dozens of plants growing at a single location. Sceptridium rugulosum and Sceptridium dissectum may also be present.

They live a long time

Like Sceptridium rugulosum, Sceptridium multifidum can live for many decades (Stevenson 1975). The ferns in the photos with the larger fronds were first seen by me around 1994. Even then, the fronds were large. I excavated two medium-sized plants in 1995 and counted the leaf scars on the stems. They had about 25 leaf scars each. If Sceptridium produces one frond per year, then those two plants were 25 years old. So, it is possible that the other larger ferns were also 25 years old or older, making these in the photos at least 55 years old.