Hydraecia medialis Smith

Crabo, Lars G., Davis, Melanie, Hammond, Paul, Tomas Mustelin, & Jon Shepard,, 2013, Five new species and three new subspecies of Erebidae and Noctuidae (Insecta, Lepidoptera) from Northwestern North America, with notes on Chytolita Grote (Erebidae) and Hydraecia Guenee (Noctuidae), ZooKeys 264, pp. 85-123 : 106-109

Hydraecia medialis Smith Figs 24-26

Hydroecia medialis Smith 1892: 251. Type locality: [USA], Colorado.

Hydroecia pallescens Smith 1899: 25. Type locality: [Canada], Alberta, Calgary. syn. n.

Remarks.

Hydraecia medialis is the widespread and variable species that occurs east of the range of Hydraecia obliqua . It is similar to it in size and pattern but is duller gray brown in the PNW, ranging from very pale (Fig. 24) to darker gray brown (Figs 25-26). The forewing postmedial line tends to be more angled relative to the posterior margin than in Hydraecia obliqua and usually lacks a slight bend in or near the fold that is found commonly in that species. The hindwing ground color is variable, most commonly off-white, but lacks a yellow tint. Gray scaling on the hindwing varies from absent to covering the entire wing. When present on the distal portion, it often forms a band to the outer margin, whereas in Hydraecia obliqua gray shading usually leaves the outer edge of the wing pale. Specimens of Hydraecia medialis from forests tend to be darker than those from open sage steppe habitats, especially in southern British Columbia and western Montana. Its northern limit in the PNW is at 100 Mile House in south-central British Columbia.

Specimens of Hydraecia medialis from the Great Plains are similar to those in the PNW but tend to be more uniform with dull gray-tan color, smooth lines, and less contrast between the antemedial and medial areas on the inner third of the forewing. Populations from the southern Rocky Mountains have a similar pattern to those from the Great Plains but are more colorful and variable, with gray or red-brown individuals and paler gray-white subterminal areas. Those from Utah and Arizona are red brown, darkest in Arizona.

As mentioned under Hydraecia obliqua , the barcodes of Hydraecia obliqua and Hydraecia medialis differ by 2%.A third barcode haplotype differing from both of these by slightly more than 2% exists for a single specimen of Hydraecia medialis from Wyoming (BOLDSYSTEMS Sample ID: CNCNoctuoidea6703). This specimen is superficially indistinguishable from two other Wyoming specimens with barcodes that match those of other Hydraecia medialis and this haplotype is therefore interpreted as a DNA polymorphism rather than evidence of a cryptic species.

A discussion of Hydraecia intermedia -known only from the holotype–is warranted in this section because its type locality of Fort Calgary suggests that it should be sympatric with Hydraecia medialis near present-day Calgary in southwestern Alberta. Its forewing is warm yellow brown unlike those of Hydraecia medialis , with markings that are more like those of Hydraecia obliqua than Hydraecia medialis . Structurally, its digitus is shorter and more bluntly rounded than those of all other populations in the Hydraecia obliqua species-group (n=45). The following discussion regarding its type locality is contributed by B. C. Schmidt:

" Hydraecia intermedia is an enigmatic taxon that has not been recorded near the stated type locality, nor anywhere else in Alberta (Pohl et al. 2010), since the collection of the type specimen about a century ago. In Barnes and McDunnough’s (1924) original description, the type specimen data is given as "Ft. Calgary, N. W. Brit. Columbia" and "VIII, 16" without a mention of year or collector. Virtually all of the moth specimens originating from the Calgary area in the early 1900's were collected by the well-known pioneer lepidopterist Frederic Hova Wolley Dod who resided in the foothills just west of Calgary ( Bird et al. 1995), and who was the source of many moths named by J. B. Smith ( Todd 1982). However, Dod’s specimens were never labelled as "Ft. Calgary" nor "N. W. Brit. Columbia" - this convention appears to have been used solely by J. Gamble Geddes, who made extensive Lepidoptera collections in south-western Alberta during his visits in 1883 and 1884 ( Geddes 1889). It is not clear why Geddes referred to the region as North West British Columbia, as the modern bound aries of British Columbia were already established at that time, while southern Alberta was known as the district of Alberta and was part of the North West Territories. A subsequent note on his collecting again shows that he referred to the region as British Columbia ( Geddes 1889), possibly because he considered the mountains and passes he visited to be part of B.C. (the passes indeed straddling the Alberta - B.C. boundary). Several butterflies ( Lycaena dorcas florus W. H. Edwards, Colias elis Strecker) and moths collected by Geddes during these trips were named as new species. Geddes’ handwritten catalogue of butterflies in the CNC Entomology Library indicates that Geddes collected butterflies in the Crowsnest Pass area in August of 1883, and was collecting in the Crowsnest Pass proper on August 16th, corresponding to the "VIII 16" of the intermedia holotype. As there was no direct rail line between the Crowsnest Pass and Calgary, some 350 km distant, it is very unlikely that the intermedia type could have been collected on the same day in Calgary, and it appears that Geddes simply recorded the nearest major settlement before distributing the specimens and associated label data. A week earlier, Geddes collected the type specimens of Lycaena dorcas florus (W. H. Edwards) at “Garnett’s Ranche" near Lundbreck at the mouth of the Crowsnest Pass ( Bird and Ferris 1979). As Geddes visited and likely also stayed at Garnett’s Ranch, which served as a base for geology field parties ( Inglis 1978), Geddes undoubtedly also collected moths at the ranch. The type locality of Gortyna intermedia Barnes & Benjamin is therefore restricted to Lundbreck, Municipality of Crowsnest Pass, Alberta. The diverse montane fauna of southwestern Alberta continues to yield previously undocumented moth species ( Schmidt 2007), and the persistence of an undiscovered population of Hydraecia intermedia is certainly possible."

The holotype of Hydraecia intermedia resembles the single specimen of Hydraecia obliqua in the CNC from Terrace in west-central British Columbia. This locality is far north of the continuous distribution of Hydraecia obliqua , which ends near Vancouver, British Columbia. This specimen is structurally similar to other Hydraecia obliqua populations, not Hydraecia intermedia . All British Columbia Hydraecia obliqua species-group specimens from east of the Cascade Mountains and British Columbia Coast Ranges are typical Hydraecia medialis , including from Cranbrook which is the closest locality to the Crowsnest Pass locality of Hydraecia intermedia . Nonetheless, it is interesting to speculate that Hydraecia intermedia could be an eastern population of Hydraecia obliqua . We retain Hydraecia intermedia as a species because of the structural differences between it and Hydraecia obliqua , and because there are no records of similar specimens in central British Columbia between Terrace and Crowsnest Pass.

Although the present reduction of this species-group to three species– Hydraecia intermedia , Hydraecia medialis , and Hydraecia obliqua -is best supported by the available data there are two remaining issues that cannot be solved with the information at hand. A large series of specimens from the east slope of the Cascades at Camp Sherman, Jefferson County, Oregon at OSAC show possible intergradation between Hydraecia obliqua and Hydraecia medialis , with some specimens that are difficult to assign to either species. This raises the possibility that the original hypothesis that Hydraecia obliqua and Hydraecia medialis are the same species could be correct despite the different barcodes in coastal and interior populations. Barcode or other DNA data from this population might help to elucidate its significance but is not available.

Similarly in the Southwest, at the other end of the rasenkranz, more DNA samples from Colorado, Utah, and Arizona would be helpful to exclude the presence of an undiscovered species amongst the colorful populations that occur there. Of these, a dusky red-brown population from east-central Arizona is the most distinctive.