Spring Azure (Celastrina ladon)
Male - Warner, ON 2017/04/14
Male - Caistorville, ON 2017/04/16
Member of Family: Lycaenidae
French common name: Azur printanier
The identifications of the butterflies shown above were verified by microscopic examination. The individual on the left is equivalent to the "marginata" form associated with other Celestrina species. I don't have any dorsal photos for this species where the IDs have been similarly verified. It is similar in appearance to the Northern Azure, which is more common through most of Ontario.
This species can be difficult to distinguish from the other closely related Celastrina species based solely on appearance ( especially in photographs ). The males can be reliably identified by examining them under a microscope. In Ontario, C. ladon is only known from the Carolinian Zone, and more research is required to map its range out completely.
There is still uncertainty about the taxonomy of the genus Celastrina in Ontario and the rest of Eastern Canada, and experts are not in agreement on where to draw the boundaries between species. Some more recent research is referenced at this link: Ontario Insects page on Azures
To see where this butterfly has been reported, visit: The Ontario Butterfly Atlas Online