Study of Canadian azures confirms that just one azure species occurs in the Maritimes

The azures have been a challenging for the Maritimes Butterfly Atlas (MBA) because there is (or at least was) uncertainty about just which species occur here. The most widely accepted classification was that three species occur here – Northern Spring Azure (Celastrina lucia), Cherry Gall Azure (Celastrina serotina), and Summer Azure (Celastrina neglecta). These three species are extremely similar in appearance, and the best way to distinguish them is by their flight time. The three species appear in sequence – Northern Spring Azure in May, Cherry Gall Azure in June, and Summer Azure in July. This was the classification presented in The Butterflies in Canada, a book published in 1998 that has become a major reference for butterfly classification in Canada.

However, for the purposes of the MBA all the azures were treated as a single species – Northern Spring Azure. The decision to do this was based on the research and observations of Dr. Reggie Webster, an insect researcher and a member of the MBA steering committee.


Northern Spring Azure – Celastrina lucia –¬†a common species that flies from late April until August throughout the Maritimes

A paper published today (see corroborates Reggie’s classification system. Chris Schmidt and Ross Layberry have been able to demonstrate that all Celastrina in the Maritimes, and much of eastern Canada, are Northern Spring Azure (in their paper they refer to the species as Northern Azure). Their research showed that Summer Azure does occur in Canada, but only in southern Ontario, Manitoba, Saskatchewan and easternmost Alberta, and that Cherry Gall Azure does not occur in Canada at all. Summer records from the Maritimes that had previously been attributed to Cherry Gall Azure and Summer Azure are actually a second, summer-flying generation of Northern Spring Azure.

This paper demonstrates that specimens are of great scientific importance even for really common species. The specimens collected for the MBA will be housed at the New Brunswick Museum and Nova Scotia Museum where they will be available to researchers for generations.

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