Hyalophora euryalus

Hyalophora euryalus
(Boisduval, 1855) Saturnia Euryalus


Hyalophora euryalus series, courtesy of Steve Ife.

Generally as one moves further north along the North American Pacific West Coast from southern California to British Columbia, Canada, the H. euryalus become darker. There is a very dark race, possibly a self-sustaining hybrid of H. euryalus x H. columbia gloveri east of the B.C. mountains and into Idaho and Montana. It is sometimes refered to as Hyalophora kasloensis.

In response to my question as to the geography of the specimens, Steve writes, "Yes, all of those specimens are from Boston Bar, Lytton, and Heffley Creek (all in the Thompson-nicola/Okanogan region). My girlfriend just brought one home that a friend of hers found here in Vancouver. It also looks much like the rest of my specimens with quite a bit of dark scaling along the white borders. (I included an image and it is pretty rat bagged, but you get the idea.) This is the first one I've seen locally in 10 years. I have found a female before, and the resulting larvae also had red tubercles.

"Most of those specimens in the case are offspring from a wild female from Boston Bar. There is quite a bit of variation going on in a single brood."

The image from Vancouver has a postmedian band that is lighter than the basal and median areas and generally the orangey-red post median band is devoid of black scales.

I indicated they all fell in the range of Hyalophora euryalus variation, and expressed a special interest in the moth in the middle row, bottom image, which, to me, most closely resembles Hyalophora columbia gloveri.

Steve clarified, "The smallest specimen at the bottom of the center row was wild caught at Spences Bridge, B.C. about 60k north of Lytton. I have yet to see another specimen like it. None of these specimens have faded as I keep the collection sealed at all times."

Steve also sent me a map showing relative locations of Boston Bar, Lytton, and Heffley Creek in relation to Kaslo, where the very dark "form" kasloensis begins to appear.

Map of southern British Columbia, courtesy of Steve Ife.

The Washington Idaho border is in the green, due south of Kaslo (red spray) in southeastern British Columbia. Boston Bar (red star) is about 150-200km to the west of Kaslo, and Lytton and Heffley Creek (red circles) are north of Boston Bar.

As far as I know the form "kasloensis" is limited to east of the B.C. coastal mountains and in the Bitterroot range in Idaho and Montana. There is probably considerable gene flow between and many intergrades of Hyalophora euryalus and Hyalophora columbia gloveri in that area. As one moves further south through Idaho, Nevada, eastern California and western Arizona, there is a natural divide between the gloveri and euryalus populations.

Here on Prince Edward Island in eastern Canada, where there are populations of Hyalphora cecropia and Hyalophora columbia columbia, I frequently encounter natural hybrids and there is probably considerable gene mixing in the local population. Female hybrids are barren, but the male hybrids are sexually viable.

It seems that Hyalophora euryalus and Hyalophora columbia gloveri are sufficiently close, that hybrid females are sexually viable.

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