Utah Butterflies!

Butterflies (as well as moths) belong to that order of insects called lepidoptera or scaled-winged insects. These insect beauties have a world of fascinating attributes. The first, which will be discussed in more detail further on, is their life cycle which is called metamorphosis. Another fascinating attribute of some butterflies is mass migrations. Two of the more popular Utah butterflies involved in mass migrations are the Monarch and the Painted Lady.

Butterflies, in the eyes of some, are the most attractive and aesthetically pleasing of insects. Some associate butterflies with things that are gentle like icons of peace, delicate flower petals, or reverent classical music.

Nevertheless, don't let their beauty and aesthetic appeal deceive you into thinking that butterflies are fragile. They are not. Those who have carefully studied their life histories, which sometimes can be in the most inhospitable of habitats, have learned by respect and experience that they are anything but fragile.

Butterflies are inherently resilient. Because of butterflies' incredibly reproductive capabilities coupled with adaptive self-defense mechanisms such as mimicry, camouflage, population size, extended diapause, symbiosis, aestivation, etc., only the destruction of their habitat should be of concern for their long-term viability and welfare. (Habitat destruction can either be caused by man or by natural means--i.e, an invasive plant choking out a native hostplant for a butterfly.)

Understanding where to find butterflies requires a basic understanding of their differing habitats. At the same time, the first thing to remember is that butterflies are closely tied with their larval hostplants as well as their adult nectar sources. These plants, in turn, are closely associated with their habitat. In the state of Utah, there are nine different physiogeographic regions (some right within the Wasatch Front) where one can find different mixes of butterfly species.

For current Utah Bug Club members in the Salt Lake Valley and Utah Valley, there are eight areas or habitats where one can find differing species of butterflies--including your own yard. For a complete overview of these Utah County habitats, and which butterflies you can find there, please click here. For a complete overview of the entire state's habitats, click here.

The first thing to remember when learning to identify butterflies is the basic differences between butterflies and moths. These basic differences are outlined below:

The next step in identifying Utah butterflies is a matter of understanding the basics of the eight different families with which butterflies belong. These families include Swallowtails, (Papilionidae,) Whites and Sulphurs, (Pieridae,) Gossamer-wing Butterflies, (Lycaenidae,) Metalmarks, (Riodinidae,) Brush-footed Butterflies, (Nymphalidae,) Milkweed Butterflies, (Danaidae,) Wood Nymphs, (Satyridae,) and Skippers, (Hesperiidae.)

For a sampling of some of the common species of butterflies within these eight families, please see the table below. For a complete list of all the butterflies in Utah--including subspecies, click here. For a complete list of all the butterflies in Utah Valley segregated by their unique habitat, click here. (Please note that the matrix below has many images and requires a few minutes to download with a 56K modem. Your patience is appreciated.)

Papilionidae (Swallowtails & Parnassians)	Pieridae (Whites, Sulphurs, & Orange-tips)	Lycaenidae (Blues, Coppers & Hairstreaks)	Riodinidae (Metalmarks)

Nymphalidae (Brush-footed Butterflies)	Danaidae (Milkweed Butterflies)	Satyridae (Wood Nymphs)	Hesperiidae (Skippers)

As stated earlier, butterflies and moths go through a four-phased life cycle called complete metamorphosis or "metamorphosis." (Contrast that to the life cycle of a dragonfly which has three stages and is called incomplete metamorphosis.)

The first stage of complete metamorphosis occurs when an adult female butterfly lays an egg or "ova" on the specific hostplant for that species. After the egg is laid, it takes, on average, five days for the ova to hatch. The newly hatched hungry caterpillar is termed a first instar because it has not yet moulted its skin. When a first instar consumes enough foodplant that its skin is too tight to support further growth, the caterpillar becomes dormant for a day or so, and then sheds its skin revealing a larger head and new skin capable of sustaining further growth. This caterpillar is now a second instar.

Butterfly larvae repeat this pattern of feeding and moulting until the mature fifth instar caterpillar sheds its skin one last time to form a chrysalis or pupa. (Note: The term "cocoon" is a chrysalis or pupa with an outer shell of protection spun by a moth prior to pupation and only applies to moths; not butterflies.) Some butterfly pupae will emerge from their chrysalis after 1-2 weeks. Others wait until the next year to emerge because their larval hostplant cannot sustain another flight during the year in question. When the fully grown butterfly emerges from the chrysalis, the cycle repeats itself.

Adult butterflies no longer "feed" as their caterpillars did. They do not have chewing mouthparts to ingest plants. Instead, in order to sustain themselves, they have a coiled tubular straw or "proboscis" with which they obtain only liquid nutrients from flowers, streams, and sometimes animal dung. Adult butterflies do not grow. They will die the same size they were when they emerged from their chrysalis.

In the state of Utah, the two most popular butterfly species that experience northward migrations in the spring, and southward migrations in the fall are the Monarch (Danaus plexippus,) and the Painted Lady (Vanessa cardui.)

Monarchs migrate to and from Utah for the simple reason that no stage of their life cycle--ova, larva, pupa nor adult--can tolerate our Utah cold winters. For this reason, freshly emerged Utah Monarch adults migrate in the fall; some to Mexico (Bob Pyle) and some back to Monterrey Park, California where their parents and grandparents overwintered and migrated to Utah the winter and spring before. Once these fall migrants reach Mexico and California, they overwinter as their progenitors did and the cycle repeats itself.

The purpose for the Painted Lady's mass migrations are less clear. Although the Painted Lady butterfly migrates north to the Western United States and Canada every spring, from time to time colonies of these Painted Ladies will experience population explosions south of the border resulting in mass migrations northward. These mass migrations can literally result in millions of butterflies taking flight which can be quite conspicuous to those who normally do not pay attention to butterflies and can result in being quite the nuisance for travelers' car grills and windshields.

Whether or not Painted Lady adults or caterpillars can or cannot tolerate Utah winters has not yet been established. The purpose and magnitude of Painted Lady migrations is not as clearly understood or documented as is those of the Monarch butterfly.

One thing to remember about Utah butterfly migrators is that, although Monarchs seem to be more popular with the public at large, the most visible Utah butterfly migrant is truly the Painted Lady.


*The Monarch (Danaus plexippus)* Photo Courtesy Jay Cossey	*The Painted Lady (Vanessa cardui.)* Photo Courtesy Paul Opler

Because butterflies have many natural enemies, they have evolved to protect themselves in several different ways. Three of these self defense mechanisms are mimicry, camouflage, and symbiosis.

Some butterflies have evolved to protect themselves by adapting to larval hostplants which are poisonous to their avian (bird) predators. A classic example of this is the Monarch butterfly. Birds who feed on Monarch larvae or adults quickly learn to leave them alone as toxins found in milkweek plants cause birds to regurgitate.

At the same time, another butterfly, The Viceroy, in a completely different butterfly family feeds on willows and is more palatable to birds. Nevertheless, birds avoid Viceroys, because of their superficial similarity to Monarchs. This is called Batesian Mimicry. Viceroys are protected because their avian preditors' mistaken identity. The truth of the matter is that Viceroys belong to the same genus as Weidemeyer's (or Western) Admirals and are closely allied to them. But, wing coloration of the two similar species is quite dissimilar. (See below.)

In order to protect themselves, many butterfly species have wing coloration--especially on their ventral side--that blends in beautifully with their environment. One such species is the Jutta Arctic (Oeneis jutta.) This butterfly, when flushed out by a potential predator, often will dash for the safety of the lodgepole pine forest where they alight on a fallen log or branch and promptly disappear into the background with its cryptic coloration. Many other species of butterflies and even moths blend in well with the background of their natural habitat.

Other butterflies including the buckeye and owl butterflies have large eye spots that might make them look like scary animals and frighten predators away. Other butterflies mimic living or dead leaves in order to discourage predators.

Not only do butterfly adults camouflage themselves to look like something else; but, their caterpillars do as well. The Two-tailed Swallowtail butterfly young caterpillar looks oddly enough like bird droppings making themselves very unappealing to their avian predators.

In Utah, there are several species of butterflies from the family Lycaenidae (Gossamer-wing butterflies) that have caterpillars that have a unique win-win relationship with ants. Normally, one might think of ants as another predator to butterfly caterpillars.

However, caterpillars of Strymon melinus, Satyrium californica, Satyrium fuliginosum, Euphilotes pallescens, and others, from a gland on the back of the caterpillar, secrete a liquid containing sugars and amino acids (protein building-blocks) that help sustain the ants.

As the ants utilize this secretion, they are benefited and the caterpillars are not harmed in any way. Therefore not only do the ants not harm the caterpillars; but also they aggressively tend the caterpillars protecting them from any would-be predators. (In The Ants (Holldobler and Wilson, 1990) it was reported that "ant-tended larvae during the study were 4 to 12 times more likely to survive to pupation than an otherwise similar group of untended larvae.")


Strymon melinus larva being tended by ant. (Photo courtesy Tom Allen.)	Everes comyntas larva being tended by ant. (Photo courtesy Tom Allen.)	Strymon melinus larva being tended by ant. (Photo courtesy Tom Allen.)

Perhaps one of the most stabilizing mechanisms to insuring that butterfly colonies remain healthy over time is the sheer magnitude of their numbers. Most butterfly females lay around 300 eggs in their short lifetime--some a few more; some a few less.

In order for a butterfly colony to remain stable from one generation to another--all things remaining equal--only 2 of those 300 ova (one male and one female) need survive to provide offspring for the next generation. In other words, if any female suffers a 99 percent mortality rate, as caused by weather, predation, parasitism, genetic defect, crop spraying, or any other cause, there will still be enough offspring to support adults for the next generation.

In fact, if butterflies didn't have natural enemies such as spiders, earwigs, wasps, etc. to keep their population numbers in check, we would certainly have to deal with population explosions that would be difficult to deal with. (Well, it would require that we wash our cars with much more frequency.)

At the same time, those interested enough in butterflies, to collect them in order to document species distribution, subspecific variation, population numbers, etc. are certainly justified in doing so. This activity furthers the science while not harming population numbers. (That is unless a colony is already sensitive due to other factors such as habitat loss. Conservation efforts should certainly apply under that scenario.)

Another defense mechanism that some butterflies that fly in desert regions have adapted is that of extended diapause. Before discussing extended diapause, it is necessary to review the importance of butterflies' four-phased life cycle called metamorphosis. Most all butterflies, except those that fly in tropical or subtropical regions, have a season--usually in the winter--where they hibernate or diapause until the next spring.

As is the case with all of Utah butterflies, this is certainly true in Utah's Mojave Desert in Washington County. The life cycle stage (ova, larva, pupa, or adult) in which desert butterflies hibernate can be any of the four stages and depends upon, with few exceptions, the preference of the butterfly genus. For example, swallowtails (Papilionidae) mostly diapause as pupa; checkerspots (Nymphalidae) mostly diapause as half-grown larvae; tortoiseshells and anglewings (Nymphalidae) diapause as adults; coppers (Lycaenidae) mostly diapause as egg or ova.

It has been written in this paper and is now reinforced that butterflies are tightly associated with their larval hostplants. Another example of this is the fact that the first emergence or flight of all of these butterflies depends strictly upon the healthy generation of their larval hostplant in the spring. However, in the desert region, sometimes a dry winter will pass preventing the germination (annuals) or new growth (perennials) of these butterflies' host plants.

It is in these dry conditions that diapausing desert butterflies will remain in diapause and skip a year in order to prevent what is termed a "suicide flight." Although extremely rare in nature, a suicide flight occurs when butterflies emerge from their pupae, mate; but are unable to lay eggs because of absence of their hostplants. When those butterflies die, there will be no offspring to replenish population numbers.

One of the remarkable butterflies of Utah's Mojave Desert is the Pima orange-tip (Anthocaris cethura pima.) This butterfly diapauses (or overwinters) as a chrysalis. Pupae of the Pima orange-tip are both photoperiod sensitive and moisture sensitive. In other words, if the Mojave Desert does not get sufficient moisture somewhere in the window of time between ~January 1 and ~February 15, none of the three known hostplants of this butterfly will not germinate in sufficient numbers.

These orange-tips, closely allied to their hostplants, respond accordingly and either fly approximately 15-28 days after February 15, or they do not. If a chrysalis of this butterfly does not sense sufficient humidity in this window, it will extend its diapause another year and repeat its cycle of critically analyzing humidity during the same time frame as it did a year before. If there is insufficient moisture during the same timeframe, the pupa will extend its diapause yet another year.

In the lab, pupae of the Pima orange-tip have been known to survive up to 9 years and counting without emerging because these critical parameters were not met.

It is simply amazing how this and many other desert butterflies have adapted to their harsh environment in order in insure survival.


Arctic/Alpine	Wasatch Canyons	Wasatch Hilltop

Basin and Range Province	Canyonlands	Utah's Dixie


Poisonous to birds	The Viceroy--Mimics the Monarch	Western Admiral--close relative to the Viceroy


*The Jutta Arctic (Oeneis jutta) avoids predators by darting for the safety of the lodge pole pine forest where they alight on a fallen log or branch camouflaging themselves.*	The Owl butterfly from Africa mimics the Owl quite remarkably fooling predators into perceiving something more ferocious.	The third instar caterpillar of the Two-tailed Swallowtail butterfly looks oddly enough like bird droppings making themselves very unappealing to their avian predators.


Anthocaris cethura pima (Pima orangetip) adult.	Mature larva.	Anthocaris cethura pima (Pima orange-tip) pupa. Able to sustain drought conditions for at least 9 years.