geometer moth

Xanthotype is a genus of medium-sized geometer moths. There are five species of Xanthotype, all occurring only in North America. Two species occur in Minnesota. They are found in mixed and deciduous forests. Larvae feed on many trees, shrubs, and forbs, including poison ivy. Adults are active during the day but will also come to lights at night.

Adults are pale yellow or bright yellow with numerous pinkish- or purplish-brown spots. The background color and density of spotting is variable. Some individuals have just a few large dark spots on a pale yellow background, others are heavily spotted on a dark yellow background. Unfortunately, this does not help to identify the species.

A study (Rindge, 1978) of 1,886 specimens concluded that there is no reliable way to distinguish species within this genus except by genital dissection, a procedure not ordinarily performed in the field. “The adults of all species in this genus are, for practical purposes, externally indistinguishable from one another, as they are almost identical in color, maculation, and size.”

Sources

4, 21, 24, 27, 29, 30, 71, 75, 82.

The genus Xanthotype was assigned to the tribe Angeronini in 1983. Four analyses published between 2015 and 2019 suggest that Angeronini should be considered a junior synonym of Gnophini. This recommendation has not been widely followed. One source that does follow it is iNaturalist.

Location: La Crescent, MN

Location: south Central Ottertail County Minnesota. Inspiration Peak area.