White Spring Moth

Welcome back to Ask a Naturalist, your own personal Google for information on all things natural on PEI! I was thrilled to get this photo from Melanie Sigsworth, along with a request for information about the animal in it. This is a White Spring Moth (Lomographa vestaliata).

Phote: A White Spring Moth on PEI. Photo by Melanie Sigsworth, used with permission.

I appreciate a well-named plant or animal. If you don’t share my admiration for the perfectly logical ‘White Spring Moth’, you may prefer its other, more imaginative title: Spring Faerie. These tiny moths – less than 2.5 cm (1 inch) wide – have been everywhere this year, but my attempts to photograph one for a post had been unsuccessful.

White Spring Moths are in the family Geometridae, which means Earth-measurers. They start out as inchworm caterpillars, familiar to many from both their distinctive gait and the famous song (my favourite version is by Danny Kaye and the Muppets). We have many members of this family on the Island, but White Spring Moth caterpillars are light green, about 16mm (5/8 of an inch) long, with stripes running the length of their tiny bodies.

The adult White Spring Moths we’re seeing around now do not feed, and live only long enough to mate and lay eggs. Those eggs are deposited on host plants that the caterpillars (larvae) will use for food, usually members of the Rose Family (Apple, Cherry, Hawthorn, Mountain Ash, Ninebark, Pear), as well as Maples, Oaks, and Viburnums.

Over the course of a few weeks, White Spring Moth caterpillars feed on the soft, tasty parts of their host plants’ leaves, leaving behind the tough leaf veins as a lacy skeleton. They then drop to the soil, and each forms a cocoon in which it will pupate into an adult moth. Sometimes, White Spring Moths squeeze two generations into a single year, repeating this cycle and producing another whisper of adults later in the summer. They overwinter as pupae, allowing them to get a nice, early start in spring.

We often think of moths as night-flying creatures, but White Spring Moths are also active during the day, making them more noticeable. You can find them in spring and early summer around open areas where the larval host plants are nearby; their all-white appearance with fringed edges to the wings gives them an ethereal appearance. Perhaps Spring Faerie is an appropriate name after all!

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