Eurytides marcellus

Eurytides marcellus (Zebra Swallowtail) is one of North America's most stunning butterflies. This species belongs to a group of butterflies that is otherwise tropical in distribution, but for whatever evolutionary reason, this species has managed to carve a niche for itself in the more temperate regions of North America while its relatives have not. It is found in the eastern half of the USA, and very rarely reaches extreme southern Ontario, Canada. Some sources will place this butterfly in the subgenus Neographium, but most sources still use the genus Eurytides.

The larvae of this species feed only on plants from the family Annonaceae, and in North America, the predominant food plant is Asimina triloba (common pawpaw). There are other species of Asimina found in North America, and some of these can also serve as host plants occasionally. For example, in Florida, the larvae of the Zebra Swallowtail will happily feed on Asimina angustifolia (slimleaf pawpaw), Asimina reticulata (netted pawpaw), or Asimina pygmea (dwarf pawpaw). This genus is closely related to the genus Annona, which contains species that produce some commercially important fruit such as the cherimoya and custard apple. However, I am uncertain if the butterfly can also feed on plants from the Annona genus.

Both the food plant and butterfly species are rare where I live, but a few years ago, I lived in Washington DC for a period of time, and was able to locate this species and raised 3 caterpillars on common pawpaw. I also saw this species when I visited Florida recently, but did not raise any from that trip as I didn't have the food plant available to me at that time of year.

The picture above is of a 5th instar caterpillar on common pawpaw. It pupated a couple of days later as I recall.

The pupa is compact and angular, and mimics leaves. The larvae will often pupate on the host plant itself, where as many butterfly species tend to wander away to find shelter. There are two color morphs, green and brown. As with many other swallowtail species that hibernate as pupae, the summer generations tend to form green pupae that develop directly into butterflies, where as brown pupae tend to hibernate, and produce the spring generation the following year. The top photo is a green pupa, and after about 9 days, the butterfly has nearly finished development and can be seen through the pupal casing.

This butterfly emerged the following day, and was a male (top picture). The bottom picture is of the same butterfly, now set as a specimen.

As fortune would have it, I recently located some common pawpaw fruit, and will try to grow some plants from seed. Once they are large enough, I may try my hand at raising this species again and take additional photographs.

The common pawpaw is actually the largest native fruit in North America, but is not well known and is not usually available in grocery stores. They do not ship well, and spoil in a short period of time. There are some places that sell them, and some research is currently being done to try to commercialize the fruit and improve its shelf life. A lot of this work is being done at Kentucky State University, and if I recall correctly, Ohio also has an annual pawpaw festival. The fruit are tropical looking and mature in September/October. When mature, the skin turns from green to yellow, similar to a banana. In fact, pawpaw is sometimes also known as the prairie banana, though it neither grows in prairies nor is it related to bananas. Inside, the pulp is soft and yellow. It's hard to describe the flavor to someone who has not eaten pawpaw, but some say it's a combination of mango and banana. I think it's closer to mango, but the pulp is really soft and not stringy at all.

Inside each pawpaw fruit are usually two rows of brown flat seeds, each about the width of a quarter. I have a bunch of these now, and will try to germinate them next spring. In order for them to germinate optimally, they require several months of cold moist stratification, which basically means you have to keep them cold and moist for a while (can be done in a fridge). The cold treatment breaks the dormancy of the seeds.

The mature tree is pyramidal shaped with large drooping leaves, as shown above.

Papilio troilus troilus

Papilio troilus (Spicebush Swallowtail) is found throughout the eastern half of the US and also ranges into southern Ontario in Canada, reaching as far north as Toronto. Occasionally, this species is seen east of Toronto along the north shore of Lake Ontario. There are two subspecies. Subspecies troilus is found throughout most of its range, and subspecies fakahatcheensis is restricted to the southern tip of Florida. This is likely a relic population from the last ice age, and was only recently described by the late Ron Gatrelle in 2000.

The larvae of this species feed on plants in the Laurel family, mainly spicebush (Lindera benzoin), sassafras (Sassafras albidum), and in the southern parts of its range, red bay (Persea borbonia) along with its close relative, Papilio palamedes (Palamedes Swallowtail). The caterpillars of these two species are very similar and can be difficult to distinguish for the novice. In my area, the dominant food plant is sassafras, and that is where I find most of the ova and larvae. I occasionally find pupa on or near the food plant.

Eggs are cream white and laid singly on the underside of leaves. After several days, a black dot will develop centrally within the egg, which is the head of the small caterpillar inside.

These are 1st instar larvae. Right from the start, these caterpillars build shelters for themselves to hide from predators. They will lay silk strands across the edge of a leaf and use that to pull the leaf upon itself and form a furl. They will rest inside this furl most of the time, and only come out to feed. Recognizing these furls is one of the best ways to find larvae in the wild. Occasionally, caterpillars of other species or even spiders will build similar furls, but after a while, you start to recognize the furls that are characteristic of Papilio troilus.

There are two 2nd instar larvae in this picture. When the caterpillars are small, they are a mottled black and white pattern to mimic bird droppings. This is another way in which they try to fool predators.

This is a 3rd instar larva. In this picture, I have unfurled the furl it was hiding in, and you can see the shimmering silk strands the larva is resting upon. You can also see the beginnings of eye spots, which become more noticeable as the larva grows.

These are newly moulted 4th instar larvae. Again, I have unfolded the furls they were hiding in, and again one can see the silk strands across the leaf. The eye spots can be seen a bit better in these pictures.

This is the 5th instar, or final larval stage before pupation. As with many other swallowtail species, the last instar heralds a dramatic color change. The larvae are now a bright green, and no longer mimics bird droppings. They have two huge fake eye spots to scare away predators. At this stage, the furls made from the edge of a leaf is no longer big enough to conceal them, and often they will fold an entire leaf on itself to form its shelter.

Prior to pupation, it will stop eating and start to change color from green to an a burnt orange. I'm not sure why this happens, as it does make them quite conspicuous. They will also leave their shelter, wander off and usually away from their food plant, and try to find a good spot to pupate. In this above picture, the larva is just starting to turn a bit yellow.

This is what the larva looks like when it has completely changed color. They are quite noticeable crawling on the ground, and this is when most people come across these larvae.

There may be anywhere from two to several generations per year, depending on latitude. The pupae come in two color forms, green and brown, like many other swallowtail species. In most swallowtail butterflies, the green pupae are most common for the summer generations that develop directly into butterflies, while the brown form pupae tend to overwinter and emerge the following spring.

The top two pictures are of the same individual - a female raised this year from a larva. The bottom picture is a wild female nectaring on burdock. The adults are medium to large butterflies that are predominantly black with varying amounts of green-blue on the hind wings. They are thought to mimic the unpalatable Pipevine Swallowtail.

From top to bottom, the above pictures are of males dorsal and ventral, and females dorsal and ventral. The males have more green-blue on the hind wings, where as the females have less extensive but bluer coloring.

Battus philenor philenor

Battus philenor (Pipevine Swallowtail) is a really unique looking butterfly in North America, which is hard to mistake for anything else. This butterfly belongs to the genus Battus (no relation to bats) which is mostly found in Central and South America. In North America north of Mexico, there are only two representatives of this genus, the other being Battus polydamas (coming soon!). All butterflies in this genus feed on plants in the pipevine family (hence the name), which is scientifically known as the family Aristolochiaceae.

This family of plants contains distasteful toxins, and most other bugs avoid eating pipevine. However, the butterflies in this genus have evolved to take advantage of this plant family. Instead of avoiding it, it eats the plants and then stores the toxins in its own body, and then gains protection from vertebrate predators as a results. The female butterfly also lays eggs which contains these toxins, and so even the eggs get some protection. Additionally, many other butterfly species in North America, which share a similar distribution range, have evolved to look similar to this butterfly, attempting to gain some protection as well.

This butterfly can be found all over the southern half of the USA, with occasional migratory incursions into southern Ontario in Canada. Every once in a while, one will see reports of this butterfly in other parts of Canada, but these are very rare strays, and even in southern Ontario, this butterfly is not expected to be seen in great numbers in most years. There are two subspecies distributed in the USA and Canada. In California, subspecies hirsuta is present, feeding primarily on Aristolochia californica. Everywhere else in its range, we find subspecies Battus philenor philenor. This butterfly can feed on many plants in the pipevine family, depending on what's available in a certain location. Some common host plants include A. macrophylla, A. tomentosa, A. serpentaria, A. reticulata. Three additional subspecies are found from Mexico through to Guatamala and Costa Rica (acauda, orsua, and insularis).

Eggs are a rust red and laid in clusters. The young larvae prefer to eat young tender leaves, and the eggs are therefore usually laid on young shoots or tendrils.

These caterpillars are very coordinated, and hatch and eat and moult in near unison. I'm not sure how this happens, and I'm not sure anyone knows yet, but they are all probably synchronized by chemical means. When they first hatch, they are tiny, and you can't see much detail. They are brown with little bumps. At higher magnification, you can see little hairs sticking out from these bumps.

These larvae eat a large amount for their size and also grow quite fast. The egg clusters are usually about 10-20 in size, so that doesn't help either, because if you're going to try to raise this species, you can't just raise one. You pretty much have to raise the whole lot. So if you're going to try this, make sure you have enough pipevine plants around. This above picture shows a cluster of second instar larvae. You can see a bit more detail now, and the caterpillars have slightly larger bumps which are tipped with orange.

Unlike some other swallowtail larvae which show dramatic color changes as they mature, this species does not. As they grow, the bumps and filaments get larger, but the general color scheme stays the same. The larvae are uniformily brown, and have a multitude of filaments and tubercles, with most of the ones in the mid body being tipped with orange. This third instar larva is about to moult. Notice the translucent bump behind the black head capsule. That`s where the new head capsule is developing.

These are fourth instar larvae. Starting at about this stage, they start to disperse a bit. They no longer feed in huge groups, but form smaller congregations or start to feed in solitude. This behavior likely reduces competition for food amongst the larvae.

When fully grown, this caterpillar will be nearly 5 cm in length.

The larva empties its guts and then wanders around for about half a day. After it has settled on a good spot to pupate, it will make a raised silk pad on which to attach its anal prolegs. The picture above shows the caterpillar in the process of building this silk pad, which is that blob of white stuff near its mouth.

After a bit of rest, it will then proceed to construct its silk girdle, which will support it across its mid section when the larva transforms into a pupa. This process takes about 30-45 minutes. Like many other swallowtails which have adapted to survive winters, the pupae of this species may take on two color forms.

The green form is a bright beautiful green, designed to blend in with leaves. Usually, pupae of this color tend to develop into adult butterflies right away, and do not hibernate.

Pupae can also be of the brown form, though to tell you the truth, it`s not really brown. It`s more a purple pastel color. This form usually blends in with twigs and dead leaves, and will usually hibernate (aka diapause) through winter, only to emerge the next spring.

As the butterfly develops within, you will slowly notice that the pupa turns from it`s normal color to black, which is the predominant color of the wings of this species. As it gets closer to emerging from the pupa, you will actually be able to recognize the wing patterns of the future butterfly through the pupal shell. The above picture was taken just as a newly emerging butterfly is pushing its way out of the pupa.

The newly emerged butterfly will find a place where it can hang, so that the wings can expand and straighten with the aid of gravity. The wings take about 10-15 to expand, as the butterfly pumps the veins of the wings with body fluid. It will then take about 2 hours for the wings to become hard enough to sustain flight.

From top to bottom are male (dorsal and ventral) and female (dorsal and ventral) specimens. I kept a few of the butterflies I raised, but let most of them go. I`m not sure how many, if any, survived in the wild. The ones I released as nearly full grown caterpillars were often not relocated when I checked on their food plant later. Either they were really good at hiding (though I`m pretty good at spotting them), or they were eaten. Despite the protection they should gain by the toxins stored in their bodies, the defense isn`t perfect, and the vast vast majority of butterfly larvae die in the wild at the hands of a myriad of predators. Besides, if that were not the case, we`d be overrun with Pipevine Swallowtails.

Papilio polyxenes asterius

Papilio polyxenes asterius (Eastern Black Swallowtail) is a very common and widespread butterfly in North America. In part, this is probably because this butterfly feeds primarily on plants in the family Apiaceae, which includes parsley, dill, carrot, celery...etc. Many of these plants are found in urban gardens, and wild carrot is a common weed (at least, it's a common weed where I live). So, there's basically no shortage of food plants for the larvae of this species. This butterfly can be found in central and eastern USA, as well as in southern portions of Canada, primarily in Manitoba, Ontario, Quebec, and some of the southern maritime provinces.

For me, this has always been one of the easiest butterflies to raise, not only because they can be attracted to most home gardens, but I find the females aren't shy about laying eggs. Some butterflies, like Papilio glaucus (Eastern Tiger Swallowtail) need certain conditions to induce oviposition (egg laying), including a certain amount of sunlight, temperature, and enough space in which to fly around and find the host plant. While Papilio polyxenes asterius may not be hurt by those optimal conditions, I've found that it often doesn't need that perfect combination either. I recall fondly once when I was still in university, where I caught (by hand!) a female specimen on campus. I bought some parsley from the grocery store, and just put the butterfly on the parsley bunch and that was all it took for it to lay eggs. Over two days, it laid about 120 eggs, and I raised all of them! She probably could've laid more, but I didn't think I could handle any more after seeing what she did after just two days of egg laying, so I released her into the wild.

The eggs are spherical, about 1 mm wide, and is shown in the center of the above photo. Depending on temperature, the egg will turn dark over the course of several days, and a caterpillar will hatch. This species has five larval instars.

It's dark, with a white saddle in the middle, mimicking a small amount of bird poo. This, as you will find out, is a common theme amongst swallowtail butterfly larvae.

After about 2 days of eating, it moults into a second instar larva. It's still black with a white saddle, but you can also see tiny bumps on the larva which are surrounded by an orange/red base.

The third instar is a bit bigger, but not much changed in terms of color.

This is the fourth instar larva. It's now a nice green with black stripes that are interrupted by yellow dots. Many swallowtail larva undergo such a color change for its fourth or fifth instar, whereby they no longer mimic bird droppings, but become various patterns of green to blend in with the foliage. It still has some small black bumps all along its body.

This is a fully grown larva, the fifth and final instar. It's now totally smooth, with no bumps anywhere. When fully grown, it will be about 4.5 cm long. It gets to be a pretty decent size, but it doesn't seem to eat as much food as some other caterpillars that reach a similar size, in my experience. This guy isn't starved or malnourished at all - look at those chubby prolegs! The stripes and dots pattern help break up its outline and helps it camouflage - it's similar to the spots on a cheetah.

When it's done feeding, it will evacuate its guts with a semi-solid greenish stool, and then find a place to pupate. Like other swallowtail caterpillars, it attaches its bum to a pad of silk, and then builds a silk girdle to support its mid section.

Pupae can be either green or brown. Green pupae tend to happen in the summer, and is for blending in with green foliage. Brown pupae tend to results from larvae which develop toward the end of a growing season, and are likely to hibernate. Having said that, both color forms occur in any population and at any time, so this isn't a hard and fast rule. Certainly, brown pupae can produce adults without going into hibernation first. This pupa eventually produced a female butterfly which was released.

Going from top to bottom are two males, dorsal and ventral, and two females, dorsal and ventral. Females tend to have less yellow overall on both the upper and under surfaces, and females also have more blue coloring on the upper side of the hind wings. There are many butterflies that look similar, and it is theorized that they are all mimics of Battus philenor philenor (Pipevine Swallowtail), which is distasteful to birds. By looking similar, they may gain some protection, as birds will avoid both Battus philenor philenor and these mimics.

If you'd like to try your hand at this, just plant some parsley, and sooner or later, these butterflies will show up (if you live in an area in which they naturally occur - this information is easily obtained via the internet). If you happen to be less than successful at attracting them to your garden, at least you can enjoy fresh parsley from your garden.