An Illustrated Guide to Geographic Variation
in the Indra Swallowtail Butterfly
and its Larval Host Plants

by

Wayne H. Whaley, Ph.D.

A composite of two papers presented at

The Annual Meeting of the Lepidopterists' Society
held in Sierra Vista, Arizona, Aug. 6-8, 1999
&
The Annual Meeting of the Pacific
Slope Section of the Lepidopterists' Society
held in Grants Pass, Oregon on June 23-25, 2000

Photographs by Wayne H. Whaley unless stated otherwise.

This site will be periodically updated with new information.
Clicking on any picture will open a larger image of that picture in a new window.

Title slide Prickly pear cactus (Opuntia sp.)


INTRODUCTION:

For about 19 years I have studied the Indra Swallowtail butterfly (Papilio indra) emphasizing its biology and distribution. I live near the center of its range, a logistically ideal situation for long term studies of this nature. A lot of my work has emphasized Utah and neighboring states, but I have covered nearly the entire known range of the species.

I introduce you to the Indra Swallowtail butterfly. This species has no North American (maybe World) rival amongst the papilionids as far as its geographic variation. Some of this variation is illustrated in the following photographs.
P. i. kaibabensis (top) & phyllisae (bottom)

P. i. pergamus (left) &minori (right) 5th instars

Lees Ferry specimen (top) & fordi (bottom)

Two 5th instars: black from west desert,
UT on Lomatium grayi and pink
from St. George, UT on L. scabrum

Cream-colored 5th instar from Grapevine Mts, Nevada.


The habitats of this species include some of the most scenic places in North America.
Kayenta and Wingate Sandstone cliffs
along the Colorado River, UT
San Rafael Swell Desert, UT
Alpine habitat, WY Navajo Sandstone habitat
of southeastern Utah
Granite Mt, CA
(fordi habitat)
Long Cyn. near
Moab Utah
Gold Butte, NV
Mohave Desert
Columbia River Gorge, OR
Soda Mts, CA Granite Formations of eastern Wyoming
and South Dakota
Navajo sandstone outcrop
amongst Permian limestone in NV
Navajo sandstone
common to UT
   
Navajo sandstone habitat nr.
Gunlock Res., St. George, UT


The purpose of this ongoing work is to document Indra Swallowtail geographic variation by delineating the ranges of the races (filling in the gaps) and locating zones of intergradation. Also I have studied the butterfly's biology, especially its Larval Food Plant (LFP) requirements. This is basic before meaningful DNA work should begin. Also the study of introgression patterns in zones of intergradation may shed insight into the genetics of wing pattern polymorphism in this highly plastic species.

Shown here are the 12 subspecies presently recognized within the Indra Swallowtail complex. Each of the subspecies will be indicated later.

Eight described subspecies Four of the described subspecies


The paramount question is, Why is sub-speciation in Indra Swallowtails so tremendous compared to other members of the North American machaon complex with similar ranges, in particular P. zelicaon? That question should be addressed in the near future.

METHODS:

In order to look at phenotypic differences in early stages and adults from different populations one can capture adult females, which is relatively easy at puddles at about mid-mornings. Females are then enticed to lay eggs. For enticing females to lay it is nice to have potted LFPs.

Two Indra Swallowtails puddling Potted LFPs

Environmental chambers are nice also, especially when the sun does not cooperate.

Adult females in an environmental chamber

However, the best way to find the butterfly in order to delineate populations is to find the LFP and then search for early stages. For this I use herbarium records and search for larvae at these sites.

Mr. Haney searching for larvae on Lomatium
graveolens
in the Wasatch Range, UT


Indra females prefer to oviposit on the side of a plant nearest rocks, so looking for LFPs growing amongst rocks is best. Here's a plant growing in a great looking situation in a crevice of Navajo Sandstone.

Indra host plant growing in rock crevice N of Moab.


Frequently if you look closely at a good plant you can see the "tell-tale signs" of Indra Swallowtail presence.

A spiked , or "caterpickled" plant
resulting from feeding by 4th and 5th instars.


And if you search real close at a nicely situated LFP you might find 5th instars hiding. Can you see them in the two photos below?

Two 5th instars hiding in a typical manner Two 5th instars hiding (closer shot)


And sometimes, if you're lucky, you may find a 5th instar feeding near the top of the larval host plant.

P. i. minori 5th instar feeding
in the wild on L. parryi.


If you're real lucky you might find a 5th instar resting right out in the open entirely off the LFP.

5th instar of P. i. minori resting in open.

Another 5th instar resting in open.

While I am out searching for early stages in a known Indra Swallowtail population I will frequently enhance the butterfly's habitat by creating more oviposition sites.

A plant with rocks placed around it.

Rearing:

For rearing of larvae, I use an aquarium method, placing fresh LFP in bottles of water.

Aquariums on table used to rear indra larvae 5th instars on Lomatium parryi in an aquarium
Various instars on Lomatium parryi in an aquarium.
Water is replenished by refilling water bottles with a syringe.
 
Mature 5th instars are placed in lunch bags for pupation, and developing pupae are taped inside a small cardboard box for eclosion. Adults' wings are allowed to harden for 48 hours in a cool, dark environment.
Lunch bags containing pre-pupation wandering larvae and emergence box containing a recently eclosed adult.


In order to get desert populations of Indra to emerge it is useful to artificially raise the humidity.

Pupae in wet sand-filled aquarium
to control humidity level.


I feel that if one wants to know the biology of a butterfly, they need to know the biology of its LFPs-- for example, when and where they grow, their soil requirements and other environmental requirements. To gain insights into the evolutionary history of a lepidopteran one should know the ranges and distributions of its LFPs, because they have likely played a major role in the evolutionary patterns of the species. With 12 Indra subspecies and others pending, I feel this is important. Lets now turn to the LFPs used by Indra Swallowtail butterflies.

RESULTS:

The larval food plants.

Indra Swallowtail butterfly LFPs are restricted to perennials in the family Apiaceae. Of the many apiaceous plants in Western North America, Indra Swallowtails use just a hand full-currently 21 are documented, barring any mistakes in identification. Utah alone has over 70 apiaceous species and just 9 of these are documented LFPs, with only 7 being used on a regular basis

From over 2,000 herbarium records, I have determined the ranges of these 21 LFPs and listed them by state and by Indra subspecies (unpublished manuscript). Of the 21 species, twelve have very limited distributions, several of these being restricted to a single county (or two) within a state. California has the most endemic LFPs (4) used by this butterfly. These are indicated below with an asterisk by the plant's scientific name. California also has the most Indra races (7 of the 12). California and Utah have the most documented Indra LFPs within their borders-8 and 9 respectively.

Shown below are photographs of the LFPs as an aid for identification in the field. Most of these plants contain highly aromatic oils, the majority of which are pleasant. For example, Lomatium parryi smells like a mix of pine needles and citrus and Cymopterus terebinthinus is similar, except with a stronger citrus-like bouquet. Lomatium junceum has an obvious pine scent, while L. grayi var. depauperatum and L. californicum both smell like celery. Cymopterus hendersonii has an anise scent. Familiarization with the aromas of many of these plants will aid in their identification.


Let's now look at the ranges of these plants along with photographs of each species.

Plant Range Map I

The Larval Food Plants:

 
Lomatium brandegei
(Brandegee's Desertparsley)

(dark green on map)
Cascade Range, northern Washington,
1 August 2002.
Lomatium brandegei
Cascade Range, Washington,
26 July 1968.
(Photo by Dave McCorkle)
 
Lomatium brandegei
(Brandegee's Desertparsley)

(dark green on map)
Cascade Range, northern Washington,
1 August 2002.
 
 
Lomatium brandegei
(Brandegee's Desertparsley)

(close-up of a leaf)
Cascade Range, northern Washington,
1 August 2002.
L. parryi
(Parry's Desert- parsley)
(light green) On Navajo Sandstone
 

Lomatium parryi is a widely used plant, and when found there is usually an Indra population associated with it. It appears to be one of the more preferred LFPs. Captive 1st through 5th instars from any population will readily switch to it.

L. parryi (in flower mid-March) L. parryi
It has a sweet pine scent!
L. parryi L. parryi(close-up)
L. junceum (Rush Biscuitroot)(yellow) Endemic to Utah, mostly in the San Rafael Swell and barely into Capital Reef Natl. Park (Wayne Co.). L. junceum with an early 5th instar of P. i. minori
L. junceum and close-up of the same 5th instar of minori L. graveolens (King's Desert-parsley) (pink)


The photo above shows a field of graveolens growing in the tops of the Wasatch Range, UT at over 9,000 feet. It is a high elevation species (7000 to near 11,000 feet). This species also appears to be a good LFP for rearing purposes. First through 5th instars from any Indra population will readily switch to it. L. graveolens is listed as L. nuttallii in Butterflies of North America by Scott.

L. graveolens in full bloom L. graveolens with 2nd instars
L. eastwoodiae (Eastwood's Desert-parsley) (lavender). Endemic to Mesa,Delta and possibly Garfield Cos., CO. L. marginatum* (Butte Desert-parsley)(orange) Endemic to California.
L. howellii (Howell's Biscuitroot)(dark blue) Very limited range at the California - Oregon border. Harbouria trachypleura (Whiskbroom Parsley) (turquoise) Limited to a thin corridor along the Front Range of Colorado & Wyoming.
Cymopterus panamintensis var.acutifolius* (Panamint Spring-parsley) (light blue) A California endemic. Tauschia arguta* (Southern Umbrellawort)(red) With a wonderful aroma which is not easily described. Another California endemic.
T. arguta Amongst granite boulders T. arguta
T. arguta close-up with a 5th instar P. i. pergamus


Plant Range Map II

 

Cymopterus terebinthinus var. albiflorus
(Smoothshore Spring-parsley) (yellow)


This species has the broadest range of any LFP. In southern Utah, C. terebinthinus var. petraeus is frequently found with Lomatium parryi, and where this occurs it is obvious that L. parryi is the preferred LFP. There are several varieties of this plant.

C. terebinthinus var. albiflorus close-up with a 3rd instar C. t. var. californicus (California Wavewing) A large specimen-the plant that is!
C. t. var. californicus C. t. var. californicus Habitat shot from TL of P. i. shastensis (at McCloud Bridge)
C. t. var. terebinthinus (Terpentine Wavewing)(Columbia River Gorge) C. t. var. petraeus (Rockloving Desert-parsley)
C. t. var. petraeus (Rockloving Desert-parsley) C. t. var. petraeus (Rockloving Desert-parsley) Close-up of a leaf
Aletes acaulis (Stemless Indian-parsley)(blue) A. acaulis
A. acaulis A. acaulis Close-up
Lomatium scabrum var.tripinnatum Low elevation (2,500 to 5,000 ft.) variety of scabrum on Navajo Sandstone. L. s. var. tripinnatum On mixed limestone/volcanic deposits in the Arizona Strip District
L. s. var. tripinnatum With 2nd instars near
a rock where females typically like to
oviposit.
L. s. var. tripinnatum With 2nd instars
(close-up)
Tauschia parishii* (Parish's Umbrellawort)(purple) With near mature seed heads. It is a California endemic. Musineon tenuifolium (Slender Wild-parsley)(green) Has one of the milder aromas.
Musineon tenuifolium

Plant Range Map III


Lomatium californicum (California Buiscuitroot) (light pink) It smells like celery. L. grayi var. depauperatum(Gray's Buiscuitroot) (dark pink)

Lomatium grayi's aroma is indistinguishable from celery, much like L. californicum. Larvae from these populations will switch to other food plants, but do not switch other Indra populations to L. grayi var. depauperatum. They usually die.

L. grayi var. depauperatum L. grayi var. depauperatum
L. grayi var. undescribed (Columbia River Gorge) Note the large number of immature seed heads on 20 May 1999. L. latilobum (Canyonland Biscuitroot)(Not on the range map.) Canyon country near Moab and barely into CO near Fruita. Very limited use by Indra Swallowtails.
L. latilobum Close-up of leaves. L. macrocarpum (Bigseed Biscuitroot)(Range not on the map.)

L. macrocarpum was confirmed by W. H. Whaley in June 2000 at Eight Dollar Mt., Oregon growing with two other LFPs, Lomatium howellii (the preferred LFP at this site) and L. triternatum. D. McCorkle originally identified this species as a host plant for Indra Swallowtails.

Cymopterus hendersonii (Mountain Rock-parsley) I have no good photo of it (Dashed line on map). In Colorado it is now called Aletes anisatus. It has a distinct anise aroma.

Cymopterus purpureus This species is listed in The Butterflies of North America by J. Scott. B.Griffin states that it is used in Monument Valley, UT when growing in association with C. terebinthinus var. petraeus. It is not normally used by Indra Swallowtails, but it should be looked at closer.

Lomatium dissectum var. multifidum Scott (page 176, The Butterflies of North America) lists this as another LFP, but I suspect that it is a misidentification. This is likely C. terebinthinus which occurs in the High Sierras of California from whence the dissectum record came.

Lomatium lucidum Also listed by Scott, but I have not observed indra early stages on this LFP in the wild. However two individuals, Wolfe and Raschko, indicate that they have observed indra early stages on this LFP.

A final note about LFPs and Indra Swallowtail size:

From my experience I must agree with the Emmels that small size is genetically programmed in populations which utilize LFPs that dry up in the Spring. They are genetically programmed to get through five instars quickly, and to pupate by as early as the end of April to early June. I have frequently found 5th instars on desiccated plants of Lomatium grayi in June and there was literally nothing left to eat. By as early as late May some plants (e.g., L. grayi and C. panamintensis) are pretty well desiccated. These two plants also support the smallest Indra races.


The Indra Swallowtail butterfly.

Now let's go to the butterfly. Much of this part of my presentation will include what I have discovered in Utah and neighboring states. First of all, lets look at the races and their known distributions.

The map below depicts the currently known range of the Indra Swallowtail.

Range Map - Range of the species

The 12 described races are shown in the following two photographs.

Upper left: pygmaeus,
Upper right: calcicola

Lower left: panamintensis,
Lower right: shastensis
Upper left to right:
fordi, pergamus, phyllisae, kaibabensis
Lower left to right:
minori, nevadensis, indra, martini

The map below shows the distributions of all described races to date, plus an undescribed population in Utah.

Range Map - The distributions
of the 12 races

The following range maps show the separate distributional ranges of the various subspecies, along with the races authors and Type Localities (TL). Photographs of each race are provided. Some photographs will illustrate comparisons between the races.

Range Map - P. i. indra
(Reakirt) 1866, TL: nr. Empire, CO (green)
& fordi (Comstock & Martin) 1955, TL:
Granite Mts., CA (orange)


P. i. indra (male) P. i. indra (female)
P. i. indra 5thinstar (Clear Creek, CO) P. i. fordi adult female (1 15/16 inches across forewing tips)
P. i. fordi
adult variation
P. i. fordi is the smallest of the Indra races. Note the size contrast with the largest race, P. i. kaibabensis.(3 inches across forewing tips)
P. i. fordi 5th instars, note the typical ivory-white bands
Range Map - P. i. pergamus (Edwards) 1874,
TL: Devil Cyn., San Bernardino Mts., CA (gray),
phyllisae (Emmel)1981,
TL: Butterbread Peak, CA (yellow)&
panamintensis (Emmel) 1981,
TL: Thorndike Campground, CA (orange)
P. i. pergamus adult male "Edwards' Indra Swallowtail" pergamus 5th instar

 

P. i, phyllisae adult male P. i. panamintensis adult from Panamint Range. Note the "peppering" of black scales in the postmedian bands.
Four P. i. panamintensis adults. Note that there is considerable variation in this race. Specimens photographed from the Panamint Range were on loan from the Los Angeles Co. Museum of Natural History.
Range Map - P. i. nevadensis (Emmel & Emmel) 1971, TL: Jett Cyn, Toyabe Range, NV (blue)& martini(Emmel & Emmel) 1966, TL: Gilroy Cyn., Providence Mts. CA (green)

 

P. i. nevadensis adult female nevadensis 5th instars (middle one is atypical) Note the ivory-white bands


P. i. martini adult female martini extremes in adult variation

 

Adult from the Newberry Mts. NV (similar to martini yet different) Note the abundance of white outer margin scales. Newberry Mts., adult variation
Range Map - P. i. minori (Cross) 1937,
TL: Black Ridge Breaks, CO (magenta)
&
kaibabensis (Bauer) 1955, TL: Bright Angel
Point, N Rim Grand Cyn., AZ (purple)
P. i. minori adult (full hw bands) P. i. minori adult (broken hw bands)

P. i. kaibabensis adult female


P. i. kaibabensis female from the Kaibab Plateau,
northern AZ. (photo by Steve Merrin and Wayne Whaley)
  4th instar on L. parryi
Note the big red (or orange) spots and prominent saddle
typical of minori or kaibabensis.


minori or kaibabensis 5th instar on Lomatium junceum Note the bright pink color typical of both races. minori or kaibabensis 5th(left) instar compared to a pergamus 5th instar.
Range Map - P. i. shastensis Emmel & Emmel) 1998, TL: McCloud Bridge Campground, CA (red) & pygmaeus (Emmel, Emmel & Griffin) 1998, TL: Dead Mts, CA (blue)

One of the three most recently described races (Systematics of Western North American Butterflies, T.C. Emmel, editor, Mariposa Press, 1998) is P. i. shastensis from northern California.

P. i. shastensis adult male shastensis 5th instar


P. i. shastensis McCloud Branch of Lake Shasta, CA -- the TL

Another of the three recently described races is P. i. pygmaeus. As shown on the range map above, this race has the most restricted range (as currently known) of any Indra subspecies. It is found only in the higher portions of the Dead Mountains near Needles, California.

P. i. pygmaeus adult. Like P. i. fordi, a characteristic of this race is small size. This specimen measures 2 1/16 inches across forewing tips.
P. i. fordi is found just 50 mi. to the SW of pygmaeus, but they are phenotypically very different. However, they are similar in size as illustrated in this photo. pygmaeus (top) & fordi

P. i. fordi phenotypes regularly appear in the P. i. pygmaeus population.

Both pygmaeus and fordi are restricted to the LFP C. panamintensis var. acutifolius.

In the Newberry Mts. of southern Nevada (10 air miles due N of the Dead Mts.) a larger phenotype similar to pygmaeus is found. These are illustrated in the photo to the left. It uses Lomatium parryi instead of C. panamintensis. Shown here for comparison are pygmaeus (top) and a Newberry Mts. specimens.
Range Map - P. i. calcicola (Emmel & Griffin) 1998, TL: Muddy Mts., NV (brown) and an undescribed race from UT (flesh color).

The last of the three recently describe races is P. i. calcicola from southern Nevada. It does not appear to be a well defined race.

P. i. calcicola adults from the Mormon Mtns (top) & Fossil Ridge

Utah and neighboring states:

Now let's narrow in on Utah and neighboring states.

Range Map - The Utah races and zones of intergradation.

We will work counter-clockwise starting with the St. George area in southwestern Utah.

The St. George Area

In the St. George area, populations appear to be a mix of genes from Indra populations from the northwest, the southwest, and the east. This creates a great degree of variation.

Variation in the St. George Indra Swallowtail population. Some individuals are minori-like (lower right), some are nevadensis or fordi-like (upper left), and some even "superficially" look like pergamus (lower left).

P. i. minori/kaibabensis genes from the east and southeast seem to have great influence in St. George populations, especially in 5th instar characteristics, but also in adult characteristics. In fact most of the St. George 5th instars show various degrees of pink in their bands (next two photos). It is recognized that some of this may be a result of independent adaptation to the reddish-colored Navajo sandstone which is predominant in the area. Other 5th instars are white banded like nevadensis and fordi.

Pink St. George 5th instar Pink St. George 5th instar (bottom) and a cream-colored 5th instar from central Nevada


Pink St. George 5th instar (bottom)

The "?" near St. George on the map above represents a 70 mile gap between the nearest know P. i.minori population east of Kanab, Utah and the St. George population. It is suspected that minori populations extend closer to St. George from the east, or in other words to the west of Kanab, but searches in good habitat to the present time have failed to locate them. There is a lack of herbarium records for LFPs in this area.

However, during Spring 2000 I discovered a population in the newly established Grand Canyon-Parashant National Monument (BLM's Arizona Strip Disctict), that is just 60 miles west of a known population of kaibabensis near Kanab Overlook and about the same distance S of St. George populations. With collecting permit I sampled this population. So far I know what the larvae look like (next photo). Eclosion will be Spring 2001. It appears that some of the minori/kaibabensis characteristics in St George may be due to gene flow from points east or southeast.

Gold Butte, NV specimen compared with larvae in Grand Cyn.-Parashant National Monument. Note the pink hue in the specimen to the right compared with the caterpillar from the Gold Butte, NV area.

The Southeastern Area

Next lets look at the kaibabensis (purple) minori (magenta) regions of Utah and Arizona. Papilio i. kaibabensis grades into minori as one leaves the Kaibab Plateau and this occurs relatively rapidly. In fact there is a sharp drop in frequency of kaibabensis morphs as one leaves the Kaibab Plateau. I have attempted to illustrate this change on the range map. However P. i. kaibabensis phenotypes do extend well northward into Utah, but they get quite rare. The following two photographs show specimens from populations just north of the Kaibab Plateau in northern Arizona.

Echo Cliffs minori-like (top) and kaibabensis for comparison
A minori-like specimen from Lees Ferry with a wide hindwing postmedian band.

By Moab (about 220 miles north of the Kaibab Plateau) only about 1 in 20 individuals is indistinguishable from kaibabensis (see next photo), however a good number of intermediate phenotpyes are still present.

Moab kaibabensis-like specimen. Note the broad expanse of blue scales on the hind wings and lack of postmedian bands.

By the north end of the Tavaputs Plateau in Utah, true kaibabensis morphs are gone.

There is an unusual situation at the Coconino Rim on the east flank of the Kaibab Plateau. Here there are minori-like morphs within 15 air miles of kaibabensis populations. I have tried to illustrate this on the range map. Of the 37 Coconino Rim specimens examined none are kaibabensis morphs and most show little or no influence from kaibabensis genes. In fact several specimens from the Coconino Rim have wider postmedian bands than typical minori from near the type locality in Colorado. An example of this is illustrated below.

Coconino Rim wide-banded adult Coconino Rim female (right) and kaibabensis female

This is an interesting situation in that kaibabensis influence appears to spread very far northward into Utah, yet it is insignificant or appears to be nonexistent just 15 miles to the ESE at the edge of the Kaibab Plateau.

As a final note, minori specimens from southeastern Utah are significantly larger than those taken at Black Ridge Breaks (minori's type locality) in Colorado. When studying the LFPs in these two areas the reasons for the size differences become clearer. Lomatium eastwoodiae at Black Ridge Breaks is a very small plant when compared to L. parryi or Cymopterus terebinthinus var. petraeus in southeastern Utah. L. eastwoodiae also tends to dry up by mid Summer while L. parryi and C. terebinthinus var. petraeus are more persistent. These populations are apparently well adapted to their LFPs' morphologies and phenologies.

The Northeastern Area

Now, lets look at northeastern Utah and an intergradation zone which was recently discovered. In this region the postmedian wing bands of P. i. minori continue to become wider in the northern sector of the Tavaputs Plateau. By extreme northeastern Utah, many individuals have quite wide postmedian wing bands closely resembling the nominate subspecies, but many retain their large size, extensive hind wing blue patches, and the long tails typical of minori. Eventually these minori populations grade into P. i. indra-like morphs near the Wyoming border. This entire area appears to be a zone of intergradations between the two subspecies via secondary contact. Some of the specimens from this region are very beautiful (next photo).

A beautiful mix of P. i. minori and P. i. indra characteristics. (This is a large specimen measuring 2 15/16 across forewing tips.)

The degree of variation within this transition region is phenomenal as illustrated in the next two photo. There is a full range of variation between extremes from P. i. minori-like individuals to P. i. indra-like individuals.

Adult phenotypic extremes from the northeastern Utah area.
Six adults grading from minori-like toindra-like in northeastern Utah. These specimens are larger and have longer tails than nominate Indra in Colorado and Wyoming.


Unlike the nominate race of Colorado, bivoltinism is common in this zone of intergradation-a result of adaptation to the LFP (C. terebinthinus) which retains some green vegetation all Summer. Many of the 5th instars in northeastern Utah are pink, which is likely caused by minori genes from the south. Third and 4th instars also resemble minori, and some are unusual looking (see photos below).

3rd or 4th instar from northeastern Utah. Strange looking 4th instar from northeastern Utah.


In conclusion, there appears to be considerable influence from minori genes all the way to the Wyoming/Utah border which is further north than has be previously documented. The nearest known population of pure minori is just 40 miles to the southwest of Vernal, Utah.

Within this zone of intergradation some "rare" individuals look much like nominate Indra, including smaller size, stubby tails and the broad postmedian wing bands as illustrated below.

Comparison of P. i. indra (top) with a P. i. indra-like adult from the northeastern Utah zone of intergradation.

There is some infusion of minori genes even to the Wyoming border as illustrated below. This is a P. i. indra-like adult with some minori characteristics such as narrower wing bands and tails of intermediate length.

Specimen of P. i. indra-like adult with some minori characteristics taken 4 miles from the Wyoming border in northeastern Utah.


I suspect that this intergradation zone is quite wide--as I have illustrated on the range map--possibly extending well across western Colorado to maybe as far as Steamboat Springs.

There is much work to be done in this area of northwestern Colorado, and a lack of herbarium records makes the Indra search difficult. I am interested in correspondence with anyone who has Indra LFP records or Indra Swallowtail population records from the area marked Integradation Zone ? on the map. Please correspond by phone: (801) 863-8607 or email: mailto:whaleywa@uvsc.edu

The Northwestern Area

Range Map - The Utah races

Finally, let's look at the west deserts of Utah and a new subspecies to be described in the literature. Although superficially like the nominate race, this is not the nominate race which is obvious when comparing 5th instars. Fifth instars from Clear Creek, above Denver, Colorado (near the nominate race's TL) are broad banded with little or no tendency toward becoming all black, as illustrated below.

A typical 5th instar from Clear Creek, Colorado

At what will be designated the type locality of this new race, 90 percent or more of the 5th instars are all black as illustrated in the next photos. Others have broken or incomplete bands. The name to be given this population is P. i. bonnevillensis for its location in the range of pleistocene Lake Bonneville.

All black 5th instar from the west deserts of Utah Another all black 5th instar

Adults are small and have on average wider postmedian wing bands than nominate Indra, as illustrated below.

Adult subspecies Nov. (2 2/16 across forewing tips)

On average they are smaller than nominate Indra.

Comparison of P. i. bonnevillensis (left) measuring 2 2/16 in.,
and P. i. indra (2 11/16 in.)

In comparison with Papilio i. nevadensis populations to the west (the nearest known population being near Ely, NV), bonnevillensis individuals are consistently smaller (see next photo). P. i. nevadensis consistently has long tails, while bonnevillensis never has long tails. P. i. nevadensis is one of the larger races and bonnevillensis represents one of the smaller race. However, more conclusively, nevadensis does not have bandless, black larvae.

Comparison of P. i. bonnevillensis (bottom) 2 2/16 inches with P. i. nevadensis

P. i. bonnevillensis is restricted to the LFP, Lomatium grayi var. depauperatum, an unusual variety of Gray's Biscuitroot, with a distinct celery bouquet. Flight period extremes are from late March to mid-May (average = mid- to late-April). Larvae may be present until about mid June after which the LFPs are for the most part seeded out and desiccated.

ACKNOWLEDGMENT

Funding for this project was provided through grants from the Colorado Plateau Field Institute and a grant from the Utah Valley State College Foundation. Thanks to Los Angeles Co. Museum of Natural History for the loan of several specimens for study and photography purposes.

Sunset over Indra
Swallowtail country.


This resource may be freely used, but it is copyrighted by Wayne H. Whaley and Utah Valley University.
Please credit us when using any part of it. If you have questions or comments, send them to wwhaley@uvu.edu