Apodemia mormo

Adult A. mormo feeding on nectar in California

In general, species of Eriogonum serve as larval host plants for A. mormo. In the Saskatchewan population, Eriogonum niveum, or snow buckwheat, functions as the primary host plant and food resource. In the British Columbia population, the branched umbrella plant Eriogonum pauciflorum solely fulfills this role.[3][6][2] These species flourish with adequate soil disturbances, thus only those on rocky hillsides tend to bloom and attract A. mormo.[2]

Eriogonum pauciflorum doubles as the primary nectar source for adult Mormon Metalmarks; however, rabbitbrush (Ericameria nauseosus) is often used as a secondary nectar source.[6] A. mormo preferentially visit branched umbrella plants, and have only been observed visiting rabbitbrush once Eriogonum pauciflorum flowers are in decay.[2]

Eggs are laid by adult females in clusters ranging from 1-4, depending on the specific population being observed. In Canadian populations, Scott reported the eggs as resembling “flattened spheres”, and described their color as “pink turning purple”.[5][10] In contrast, Wick observed “amber coloured” eggs the size of a “pinhead” in the Saskatchewan population. Egg development is potentially dependent on habitat choice, temperature, and exposure to solar radiation; further studies are needed in regards to A. mormo.[7]

Larvae emerge from eggs during the winter, and are thought to remain at a single host plant during this stage of their lives. Early instar larvae hibernate following their eclosion. From June to July, the late instar larvae feed nocturnally on the leaves of their host plants, which are various species of buckwheat, depending on the population under study. During the day, larvae can be found resting in nests made of leaf debris and silk at the base of the plant.[5][2]

Pupation takes place by between July and August, with “hairy…mottled brown” pupas congregated in leaf litter underneath the host plant.[10][5][2]

Adult emergence occurs spread out over the course of a month, with males preceding females by a few days. These mature butterflies live between nine and twelve days, with females having a slightly longer lifespan than males. During this time, A. mormo prefer to stay near to their host plant, travelling short distances of up to 50 m. Again, there is a slight distinction between sexes, with females tending to fly farther than males. Both males and females forage for nectar.[10][5][2]

Mating occurs approximately three days into the adult lifespan. Females seek out male partners, who wait on food plants for their arrival. It has been postulated that females of the subspecies Langei mate multiply, because of an observed ratio of 2.6 spermatophores per female.[11][10][2]

Trichogramma kaykai, a small parasitic wasp, parasitize Apodemia mormo deserti, primarily located in the Mojave Desert. These wasps lay clutches of 3-5 offspring in each Apodemia mormo deserti egg.[12]

The proper taxonomic classifications for Apodemia mormo are still under debate. Because the species tends to occur in small, isolated populations, the relatedness between populations is frequently questioned. A population genetics study conducted by Proshek revealed that the British Columbia and Saskatchewan populations of A. mormo in Canada are genetically distinct; furthermore, they uncovered higher genetic diversity in eastern vs. western populations, emphasizing low diversity in the British Columbia population.[4] A second genetic study using AFLPs supports low genetic diversity in the British Columbia population, and reports high spatial genetic structure and limited gene flow between populations.[3] Furthermore, they found genetic similarities between the Saskatchewan population and more eastern populations. The combined results of these two studies indicate potentials for current migration activities, as well as high genetic drift.[4][3] In addition to genetic evidence, morphological and behavioral data are required to make firm taxonomic distinctions; however, genetic investigation has begun to reveal some of the challenges of classification.

There are at least twenty named subspecies of A. mormo.[10][2] Below is a partial list of recognized subspecies:

1. A. m. langei[5]
2. A. m. pueblo[13]
3. A. m. mejicanus[10]
4. A. m. nigrescens[14]
5. A. m. arenaria[15]
6. A. m. pratti[16]

Both the Canadian populations and the endangered A. m. langei are univoltine, meaning they have one generation annually. Following emergence, A. mormo adults have a flight period of roughly thirty days, with specific timing ranging from mid-July into September.[6][18][5] They reach their highest concentration two weeks after the first adult emerges, usually during August. Adults do not fly long distances, and display mostly sedentary behaviors. The primary purposes for flight include foraging for nectar on nearby plants, and seeking out mates. Their flight pattern can be characterized as short, linear and fast.[5][2]

Low genetic diversity, small, distinctive populations, semi-isolated geographic distribution, and habitat dependence all predispose A. mormo to risk of extinction and warrant conservation efforts. In particular, Canadian populations are perceived as especially vulnerable to stochastic events, such as natural disasters, climate change, and outbreaks of disease. Conservation efforts have been in effect for the Canadian populations since the early 2000s under COSEWIC,[2] and for A. m. langei since 1976 under the US Federal Endangered Species Act.[5]

A key concern for conservationists is potential habitat loss. Urban development, agricultural expansion, ranching practices, and campground activities may be responsible for disturbing natural habitats and breaking them up into small patches. While efforts to prevent such fragmentation are encouraged, Crawford emphasizes a need to conserve even small habitat zones, which may function as bridges between sub-populations.[3][19] Furthermore, habitat loss might result from invasive, competitive plant species. A. mormo populations would severely suffer if these intruders successfully outcompete local Eriogonum species, given their dependency on the host plant.[19][20] Finally, Eriogonum plants go into senescence after 10–15 years. This poses a significant problem for habitat maintenance, and suggests a need for regular dispersal of new Eriogonum plants as part of conservation efforts.[5]

Recovery strategies are consistently developed and updated as new research emerges. Regarding the Lange population in California, efforts to clear weedy vegetation and recreate mounds of sand and soil were started in 1991. Eriogonum species were seeded through the habitats and the land was completely fenced in, preventing destructive human presence.[5] With respect to the Canadian populations, Crawford suggests the development of strategies which recover habitat patches, regardless of size, and encourage gene flow between isolated populations.[3]