Parnassius smintheus

Rocky Mountain parnassian
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Insecta
Order:	Lepidoptera
Family:	Papilionidae
Genus:	Parnassius
Species:	P. smintheus
Binomial name
Parnassius smintheus Doubleday, [1847]

Parnassius smintheus, the Rocky Mountain parnassian

Although the species is not yet

endangered, the climate change and human activity over the last few decades have reduced its viable habitats, and this process is continuing.^[6]

Range and habitat

The range of the butterfly is based primarily in the Rocky Mountains, which spans Canada and the United States.^[4] This includes the mountainous areas of Yukon, Alaska, and British Columbia in Canada, and as far south as New Mexico in the United States.^[1]

P. smintheus can often be found in alpine and subalpine meadows. It was found that males of this species preferred meadows with a greater abundance of nectar flowers and a higher quantity of the host plant Sedum lanceolatum. They also preferred meadows with a greater number of females of their species. Males may sample two or more meadows to gain information on their relative quality. It has been suggested that this preference in males for meadows with more food resources may be due to their increased energy requirements, as they spend much more time flying than females. In contrast, the female butterflies showed no preference for meadows with more nectar flowers or host plants, or for greater numbers of males.^[4]

Food resources

The primary larval

cyanoglycoside

, sarmentosin, so there is little risk that larvae will be accidentally preyed upon as a result of the foodplant being ingested.

The larvae also sequester sarmentosin from the plant in their bodies for their own defense. However, it has been found that if the S. lanceolatum plant becomes physically damaged by mechanical means, the larvae feeding on it have reduced growth rates, possibly due to an induced defense by the plant itself. While damage by insects does not cause plant defense,

toxic to the larvae, but for the rest of the year, the larvae feed and develop normally. If the snow melts before March, the eggs hatch while the larval foodplant is still toxic, and the larvae perish.^[3]

Reproduction and life cycle

Reproduction

Mate searching behavior

Males of this species often have poor visual discrimination, so they investigate all flying or sitting objects of the approximate size and color of the females of their species. They primarily identify females by their light color, so they are as likely to chase small

fritillaries.^[3] The males emerge from their pupae before females do in order to patrol for newly emerged females over a large area.^[5] They patrol by flying over large areas then investigating any resting or flying females after spotting them. Males fly long distances continuously in search of females, stopping only to bask or feed.^[3]

Mate choice

Males mate with young females, preferring females that have not yet expanded their wings. The females only mate once, lay eggs only once, and mature their eggs throughout their life, so the youngest females have the greatest potential

population densities, and greater success at higher population densities. However, other studies have suggested that female mating success decreases as density increases, possibly due to male-male competition for mating.^[9]

Mating behavior

The species has no courtship. Rather, males simply dive on a female upon finding her and force her down to the ground if she is not already there, and forcibly attempt to mate. This is successful if she has not already mated, but usually unsuccessful if she has already mated, due to a mating plug, a small waxy plug deposited onto a female's abdomen by a male to prevent future copulation. Unsuccessful matings may last an hour or more before the female escapes. If a female is unreceptive to mating, she may close up her wings tightly when a male approaches in an attempt to avoid being seen.^[3]

Nuptial gifts

After

fertilize the female's eggs. Occasionally, the mating plug is not properly deposited, which means a mated female may sometimes present with no plug, or a mated male may present with a plug retained in his claspers.^[3]

However, no difference has been shown in the number of eggs laid by females with and females without a mating plug, indicating that male-donated nutrients play a negligible role in female fecundity. This suggests that in this species, the plug's primary role is to prevent the female butterfly from mating multiple times.^[11]

Oviposition

Oviposition, or the laying of eggs occurs around the host plant Sedum lanceolatum, but not on the host plant itself. Females tend to search for good-quality meadows that have S. lanceolatum, though high host plant density is not required. They will retain their eggs and travel greater distances to find suitable meadows before oviposition. It is likely that there is some chemical or physical cue from the larval host plant that stimulates the females to oviposit near them. It is not as well understood why oviposition occurs off of the host plant, but researchers have suggested that it may be to avoid exposure of eggs to predators associated with the host plant.^[12]

Life cycle

Egg

The eggs are white and round, but flattened at the top and bottom. They exhibit a pebbled surface, while the

predators, parasitoids, and adverse environmental conditions.^[13] Around 75 eggs are produced per female.^[9] However, the eggshells are not consumed upon hatching, despite its high nutrient content.^[14] The eggs are generally laid on the underside of flower heads, leaves, sticks, stones, moss, clumps of dirt, and sometimes on the larval foodplant. The female may or may not oviposit on the foodplant itself, and may often lay her eggs over a meter away from the plant. The embryo develops into first instar larva within a month of oviposition but the egg does not hatch until the snow melts the next spring.^[3]

Larva

The larva completes five instars before pupating, developing over a period of around 10 to 12 weeks.

basking location on open ground up to a few meters away for thermoregulation.^[3] If disturbed, the larvae twitch violently, then drop to the ground to seek cover, and may discharge a bad-smelling brown chemical.^[14]

Pupa

The

pupae are dark yellow brown to red brown and are formed in the leaf litter, gravel, or rocks lying near the soil surface.^[3] The larvae do not spin a cocoon but rather gather some silk around them simply to attach themselves to the surroundings.^[12] When ready to emerge, newly developed butterflies have two tiny hooks to assist in emerging from where they were pupating.^[10]

Adult

Adults are generally translucent yellowish white with black, grey, and red markings, though they vary greatly in color.

Immigration and emigration into different meadows increases when there is greater connectivity of the meadows. There is greater immigration to larger populations in general, while emigration from large populations tends to be low. This trend is probably related to mating opportunity, as the males search vigorously for young females.^[7] The species tends to avoid forest edges and shows lower migration rates into different meadows in a forest habitat. They also tend to fly less often and at lower rates in forests than in meadows, due to lower light levels.^[6] The total distance moved by both flying and crawling is significantly greater in meadows than in forests, though the distances moved by crawling were generally limited to less than 2 meters. Since the butterflies avoid forest edges, meadows surrounded by forest will experience lower immigration and emigration rates.^[16]

Predators

The species faces

Parnassius smintheus is vulnerable to changes in temperature as a result of climate change. In particular, warm Novembers as well as short-term cold and warm temperatures extremes in November are associated with the greatest declines in population. Short term warm weather in November could cause premature hatching of the eggs, the larvae of which would then die as normal winter temperatures resume.^[18]

Subspecies

P. smintheus has the following subspecies:^[19]

• P. s. magnus Wright, 1905: Washington state
• P. s. olympiannus Burdick, 1941: Olympic Mountains, Vancouver Island
• P. s. pseudorotgeri Eisner, 1966: Colorado (San Juan Mountains)
• P. s. sayii Edwards, 1863
• P. s. smintheus Doubleday, 1847
• P. s. sternitzkyi McDunnough, 1936: North California (named for Robert F. Sternitzky)
• P. s. xanthus Ehrmann, 1918: Washington State
• P. s. yukonensis Eisner, 1969: South Yukon, British Columbia

Similar species

P. smintheus is often misidentified as Parnassius phoebus, which is a closely related Holarctic species. Some researchers also tend to split the North American population of the butterfly into two or three species. Usually, the northernmost populations will be regarded as being part of P. phoebus, while the rest is considered to be P. smintheus. These regional species can be best distinguished by the location of where they are found.^[20]

• P. phoebus (Phoebus apollo)
• P. clodius (Clodius parnassia])
• P. eversmanni (Eversmann's parnassian)

References

External links

Wikimedia Commons has media related to Parnassius smintheus.

Wikispecies has information related to Parnassius smintheus.

• Funet Taxonomy, distribution, images
• Butterflies of America images including types and habitats
• P. smintheus images at Consortium for the Barcode of Life