The Mormo Complex in Southern California

The taxonomy of the fascinating mormo complex of butterflies is, well, complex. In southern California, there are many distinctive populations of this group adapted to various species of wild buckwheats (Eriogonum), from the beaches to the deserts and high into the mountains. Some of these fly only in the fall; others only in spring; and some have two or more broods per year. Some are nearly all black on the dorsal side with relatively bold white macules, while others are golden yellow, or somewhere in between. Despite the variety in appearance, host plants and life-cycle timing, these were all thought of as a single species for most of the twentieth century. But now there is evidence of at least four species involved, with perhaps a dozen subspecies in southern California alone.

Our knowledge of these butterflies has increased significantly thanks to careful rearing and genetic studies, as well as the discovery of places where two or more members of the complex co-exist without blending. This page is intended to give a general overview of this interesting group in southern California. These sometimes superficially-similar butterflies reward close attention, as the differences between populations are real and they hint at a long evolutionary story that continues to unfold right here in our backyard.

Three pictures of Apodemia mormo butterflies showing distinguishing characteristics

From left: golden-orange A. mormo cythera, which flies in the autumn at Big Rock Creek; spring-flying A. virgulti pratti from the Holcomb Valley near Big Bear, where it uses E. kennedyi as host; and the dark, E. wrighti-feeding "near mormo" fall-flying entity from along Wildhorse Meadows Road below Sugarloaf Peak south of Big Bear. As distinctive as some of these are, looks alone aren't enough to identify all the various members of this complex. Life cycle timing, location, and plant associations are important.

The mormo-complex in and around the Mojave desert in southern California was described in terms of three "biotypes" in a landmark 1991 paper by Gordon Pratt and Greg Ballmer ("Three Biotypes of Apodemia Mormo (Riodinidae) in the Mojave Desert," Journal of the Lepidopterists' Society 45(1), 1991, 46-57). The three biotypes are multiple-brooded (type 1); single-brooded with a small egg and flying in the spring (type 2); and single-brooded with a large egg and flying in the late summer or fall (type 3). "To determine whether these different biotypes are due to seasonal or host-related factors or to genetic differences, we reared a number of populations under similar laboratory conditions" (p. 48). They found that the three types maintained different development times under identical conditions. For instance, type 2 spring-brooded butterflies are characterized by long larval development times, perhaps 8 or more months of the year (including winter). These go through the egg and pupal stages relatively quickly. Type 3 fall-brooded mormo, in contrast, have a much shorter larval stage and pass much of the year (including winter) as eggs (first instar within the eggs to be precise), then develop as larvae through the summer, pupating and emerging as adults in late summer or early autumn when they mate and the females oviposit, completing the year-long cycle. The eggs of these butterflies - home to tiny larvae for months - are also larger than those of type 2. The timing of diapause and larval feeding corresponds to the patterns of dormancy and growth of the buckwheat host. For instance, the spring-flying desert subspecies mojavelimbus has a long larval development time, and the host, E. fasciculatum, usually goes dormant during the summer along the desert edge. When the plant resumes growing (after sufficient rainfall), the larvae may resume eating. In type 1 (multiple-brooded) populations, eggs hatched relatively quickly, and larvae developed and pupated without long periods of diapause. These butterflies could go through the life cycle two or three times per year, thanks to the availability of edible plant material for the larvae most of the year. Under identical laboratory conditions, a multiple-brooded deserti could complete the life cycle three times per year, but the type 2 and 3 butterflies, even with fresh plants offered to them, persisted in completing the cycle once per year, just as in nature.

The biotype concept was helpful for roughly grouping these populations of butterflies that had been considered a single species. In an excellent article called "Buckwheat Metalmarks" in American Butterflies magazine (Vol.19, Nos.2/3/4, Summer/Fall/Winter 2001), Gordon Pratt, John F. Emmel and Gary Bernard used the word "group" for the various populations. For example, the "mormo group" was characterized as "single-brooded, late flying (mainly August through September) populations with large eggs." That group included mormo, autumnalis, pueblo, langei, tuolumnensis, cythera, parva, and an unnamed population. Other groups are mejicanus, duryi, multiple-brooded virgulti, and single-brooded virgulti (which fly in the spring). It would be good to have a different name for the spring flyers, and for a brief time dialeuca was floated (I used it here for awhile), but true dialeuca is double-brooded, so that name isn't appropriate.

So for now here's one way of organizing these southern California populations:

One spring brood - virgulti group

Butterfly Host buckwheat Comments
Pratt's Metalmark
Eriogonum kennedyi There is a colony in the Holcomb Valley, just north of Big Bear Lake. Flies early May to mid-June. Prominent white macules. Described in Systematics pp. 795-6. My photos are from May 29th, 2009.
Peninsular Metalmark
Eriogonum wrightii ssp membranaceum San Jacintos to Palomar Mountain and Laguna Meadows. Flies from mid-May to late June but emerges earlier some years. I found a couple of peninsularis freshly emerged in a large patch of wrightii in the Laguna Mountains near the TL on April 17, 2008, so they can emerge earlier than once thought. Because these use wrightii even where fasciculatum also grows, and they apparently overlap nominate virgulti in some places without interbreeding, they are a good candidate for species status. Described in Systematics, pp. 805-6.
Davenport's Metalmark
Eriogonum fasciculatum Flies April - May. The Type Locality is Walker Pass at 5300'; it is also in the Tehachapis, the Piutes, and above Jawbone Canyon and is usually found between 4000' and 6000' elev. Named after the estimable lepidopterist Ken Davenport. Blends with the subspecies below. Described in Systematics, pp. 801-2.
Ord Mountains Metalmark
Eriogonum fasciculatum Found early April to mid-May at the southern edge of the Mojave desert, the TL being the Ord Mountains near Hesperia. On the northern slope of the San Bernardinos to the east into Joshua Tree, these have a dark phenotype; populations north of the San Gabriels, as at Valyermo, are a blend zone with davenporti, so you see a lot of variety there. Described in Systematics, pp. 803-4.
Whitish Metalmark
Eriogomun wrightii ssp. subscaposum Late May to early July from Sugarloaf Mtn to Onyx Peak, south of Big Bear in the San Bernardinos. Described in Systematics, pp. 804-5. Many have searched for this metalmark in recent years without seeing it; may be extirpated.

One fall brood - mormo group

Butterfly Host buckwheat Comments
nr mormo
Mormon Metalmark (S. Bern.)
Eriogomun wrightii ssp. subscaposum Wildhorse Canyon and up to Onyx Peak, using same host as dialeucoides above, in some of the same places, but later in the year. Very dark; some have no orange at all. Gordon Pratt (pers. comm.) says these are an undescribed subspecies.
nr mormo
Mormon Metalmark (Temblors, such as Cottonwood Pass)
Eriogonum nudum var indictum July to early October; discussed in Ken Davenport's book on Kern and Tulare Counties and in his Emmel update. Variable but many strikingly similar to langei. I have it on this website because it is such a distinctive population.
Autumn Metalmark
Several late-flowering Eriogonum species Late August to early October. Range includes southeastern California, as well as parts of Arizona, Nevada, New Mexico, and Utah. Described by the late George Austin in Systematics, pp. 561-2. This subspecies name may or may not cover the Mojave Preserve.
Cythera Metalmark
Eriogonum fasciculatum Populations characterized by a striking overall light yellow-orange aspect extend from the northwestern San Gabriels into the desert at Mojave River Forks at least, and up north to Inyo County. Whether it covers western populations is controversial; see next entry.
Tuolumne Metalmark
Eriogonum fasciculatum, wrightii, microthecum and poss. kennedyi The Mt Piños/Frazier Park area colonies flying beginning in the late summer have been called tuolumnensis by Ken Davenport. A single-brooded mormo that flies late August through late September where pratti flies in the Holcolm Valley - and to the west as far as Santa Barbara Co. - looks similar to tuolumnensis: see Systematics p. 796. John Emmel called it "near tuolumnensis", and said there was a blend zone with nr. mormo to the southeast. I've come to think cythera is a better choice. We'll see. For now, I've lumped these under cythera.

Multiple broods - mejicanus group

Butterfly Host buckwheat Comments
Desert Metalmark
Usually Eriogonum inflatum Desert flyer with gray hindwind background and large white macules. Larvae may burrow into stalks of host desert trumpet if they need to wait out a dry spell. Flies with other mormo without blending. Where these overlap with others in this complex, they tend to fly earlier or later. Very clearly a different species from those above and below.

Multiple broods - second virgulti group

Butterfly Host buckwheat Comments
Behr's Metalmark
Usually Eriogonum fasciculatum Fairly widespread and common, from the coast into the foothills, as well as desert transition and the mountains where the host does well most of the year. This is what one will see on California buckwheat in the Santa Monica Mountains or foothills around the Los Angeles basin, for example.
Sand Dunes Metalmark
Eriogonum cinereum Flies at Playa del Rey near LAX property with El Segundo blues. Described in Systematics, pp. 806-7. DNA studies suggest that phylogenetically, this metalmark branched off surprisingly early and probably deserves full species status; it doesn't cluster with the others. This was particularly surprising because visually it isn't all that distinctive. Looks can be deceiving.
Dark Metalmark
Eriogonum fasciculatum Dense colony at Colton near railroad yard. Darker than nom. virgulti. It also differs in that G. Ballmer found 80 larvae on a single buckwheat plant, whereas one or two is considered normal for virgulti. Described in Systematics, pp. 796-8.

All named mormo-complex members with type localities

Apodemia mormo mormo (C. Felder and R. Felder, 1859) West of Washoe Lake, NV.
Apodemia mormo cythera (W. H. Edwards, 1873)Area of Independence; neotype 9 mi. west of Lone Pine (which is towards Whitney Portal), both Inyo Co., CA.
Apodemia mormo langei J. A. Comstock, 1939Antioch, Contra Costa County, CA.
Apodemia mormo tuolumnensis Opler and Powell, 1962Grand Canyon of the Tuolumne, Yosemite National Park, Tuolumne County, CA.
Apodemia mormo autumnalis Austin, 1998Two road miles N. of Red Cloud Mine, Spring Mountains, Clark Co., NV.
Apodemia mormo parva Austin, 1998West slope of Diamond Mountains, Nevada state route 46, 0.8 miles north of Eureka, Eureka County, NV.
Apodemia virgulti virgulti (Behr, 1865)Verdugo Mountains, Los Angeles Co., CA.
Apodemia virgulti pratti J. Emmel and T. Emmel, 1998Holcomb Valley, San Bernardino Co., CA.
Apodemia virgulti nigrescens J. Emmel and T. Emmel, 1998Pepper Ave. at Slover Ave., Colton, San Bernardino Co., CA.
Apodemia virgulti davenporti J. Emmel, T. Emmel, and Pratt, 1998Walker Pass, 5300' elev., Kern Co., CA.
Apodemia virgulti mojavelimbus J. Emmel, T. Emmel, and Pratt, 1998Ord Mountains, San Bernardino Co., CA.
Apodemia virgulti dialeucoides J. Emmel, T. Emmel, and Pratt, 1998Sugarloaf Mountain, San Bernardino Co., CA.
Apodemia virgulti peninsularis J. Emmel, T. Emmel, and Pratt, 1998NE edge of El Prado Meadow, Laguna Mts., San Diego Co., CA.
Apodemia virgulti arenaria J. Emmel, T. Emmel, and Pratt, 1998Sand dunes west of LAX, Los Angeles Co., CA.
Apodemia mejicanus mejicanus (Behr, 1865)Sinaloa, MX?
Apodemia mejicanus deserti W. Barnes and McDunnough, 1918La Puerta Valley, San Diego Co., CA.
Apodemia mejicanus peublo J. Scott, 1998South of Security, El Paso Co., CO.
Apodemia duryi (W.H. Edwards, 1882)Organ Mts. foothills, 5 mi. W. of Mesilla, Doña Ana Co., NM.


Selected Bibliography

1859: Cajetan and Rudolf Felder, "Lepidopterologische Fragmente," Weiner Entomologische Monatschrift 3, pp.271-2. [This is where the Felders named mormo, illustrated in the next entry.]

1865: C. Felder, in Reise der österreichischen Fregatte Novara um die Erde in den Jahren 1857, 1858, 1859 unter den Befehlen des Commodore B. von Wüllerstorf-Urbair, pp.302-3 and plate 37.

1918: William Barnes, J.H. McDunnough, "Notes and New Species," Contributions to the natural history of the Lepidoptera of North America, p.75. [Deserti described.]

1927: John A. Comstock, Butterflies of California, pp.149-151.

1938: John A. Comstock, "A new Apodemia from California (Lepidopt.)," Bulletin of the Southern California Academy of Sciences, 37:129-132. [Langei described.]

1961: Paul Opler, Jerry Powell, "Taxonomic and Distributional Studies on the Western Components of the Apodemia mormo Complex (Riodinidae)," Journal of the Lepidopterists' Society 15(3), pp.145-171. [Overview, desc. ssp. tuolumnensis and dialeuca.]

1973: Ray Stanford, "Apodemia mormo near dialeuca (Riodinidae) from Montane Southern California: New for U.S.A.," Journal of the Lepidopterists' Society 27(4), pp.304-5.

1973: John F. Emmel, Thomas Emmel, The Butterflies of Southern California, pp.48-9.

1979: Gregory S. Forbes, "Description and Taxonomic Implications of an Unusual Arizona Population of Apodemia mormo (Riodinidae)," Journal of Research on the Lepidoptera 18(3), pp.201-207.

1991: Gordon Pratt, Gregory R. Ballmer, "Three Biotypes of Apodemia mormo (Riodinidae) in the Mojave Desert," Journal of the Lepidopterists' Society 45(1), pp.46-57. [Landmark paper establishing criteria for sorting out populations.]

1998: John F. Emmel, Thomas Emmel, "Two New Geographically Restricted Subspecies of Apodemia mormo (Lepidoptera: Riodinidae) from the Vicinity of San Bernardino, California," Systematics of Western North American Butterflies, ed. Thomas Emmel, pp.795-800. [named pratti, nigrescens.]

1998: John F. Emmel, Thomas Emmel, Gordon Pratt, "Five New Subspecies of Apodemia mormo (Lepidoptera: Riodinidae) from Southern California," Systematics of Western North American Butterflies, ed. Thomas Emmel, pp.801-810. [named davenporti, mojavelimbus, dialeucoides, peninsularis, arenaria.]

2011: Gordon Pratt, John F. Emmel, Gary Bernard, "The Buckwheat Metalmarks," American Butterflies 19, 2/3/4 (2011), pp.4-31. [thorough overview, relatively up-to-date.]

2015: Proshek, B., Dupuis, J.R., Engberg, A. et al., "Genetic evaluation of the evolutionary distinctness of a federally endangered butterfly, Lange’s Metalmark." BMC Evol Biol 15, 73 (2015).

2018: Ken Davenport, Butterflies of southern California in 2018: updating Emmel and Emmel's 1973 Butterflies of southern California, pp.115-124.

2018: Dupuis, Julian R., Jeffrey C. Oliver, Bryan M. T. Brunet, Travis Longcore, Jana J. Johnson, Felix A. H. Sperling, "Genomic data indicate ubiquitous evolutionary distinctiveness among populations of California metalmark butterflies," Conservation Genetics (2018) 19:1097–1108

2022: Gordon F. Pratt, Dennis Walker, Joseph Zarki, and John F. Emmel, The Butterflies and Skippers of Joshua Tree National Park. On pp.130-139, Gordon has a discussion of the mormo-complex, then species accounts for deserti, mojavelimbus, and the fall-flying near mormo, fully illustrated by yours truly.


©Dennis Walker