Jeffrey Belth

Zebra Swallowtail

Zebra Swallowtail (Eurytides marcellus), form "lecontei." June 15, 2016, Monroe County, Indiana.

Last Wednesday I had a few spare hours before a routine eye exam. My plan was to drive down Tower Ridge Road, one of Monroe County’s better gravel roads, to a spot where I have seen hairstreaks in the past. I have found Banded Hairstreaks regularly there, but others have found Striped and Hickory Hairstreaks at times, so I thought I would give it a try. I never got there.

Gravel roads are great for butterflies, especially after a good soaking rain. Male butterflies that “patrol” for mates—flying continually through appropriate habitat, rather than “perching” near larval hosts and waiting for females—often stop at moisture to replenish minerals burned as they patrol. These patrolling butterflies include swallowtails, sulphurs, blues, and satyrs. Wet, muddy, gravel roads can often be a great place to see and photograph these butterflies. Of course you have to watch out for cars, but that is a minor nuisance.

It had rained overnight and in the morning, so in addition to the hairstreak spot, I thought I might find some butterflies in the muddy areas of the road. I turned onto Tower Ridge Road and soon realized there was going to be plenty of mud. About a quarter mile down the road is a horseman’s campground with a gravel loop road. In the campground is an overgrown corral that has a nice population of Common Milkweed. I decided to make a quick detour and check out the campground to see if the milkweed was blooming yet or if any Monarchs were around (a few have been reported in our area recently but I have not seen one yet this year). At the beginning of the loop there was a Tiger Swallowtail in the middle of the road. I thought about spending a few minutes trying to photograph it, but I noticed it had broken tails, and I had many photos of Tigers with intact tails, so I decided to move on. A little further, directly adjacent to the pit toilets, I flushed a beautiful summer form Zebra Swallowtail out of the road. I immediately pulled over and stopped.

Zebra Swallowtails (Eurytides marcellus) appear in three forms, marked by slight differences in size, pattern, and flight time. Form “marcellus” appears in early spring and has short tails and large red spots on the upperside of the hindwings. Form “telamonides” appears in late spring and has slightly longer tails and less red. William Henry Edwards, one of our premier lepidopterists from the mid-1800s and author of the classic The Butterflies of North America (published serially from 1868-1897), reared many Zebra Swallowtails and determined that these two spring forms emerge from hibernating chrysalises. The summer form “lecontei” flies from June through August, and has even longer tails and less red. Edwards found that individuals of form “lecontei” are offspring of the first two forms and that some chrysalises from each generation hibernate until the following spring.

For some reason I’ve had very poor luck getting photos of the summer form. I see fewer of them, and the individuals I do see are sipping nectar from flowers, and their wings are usually beating while they are nectaring, making photography difficult. The only time I have seen the summer form in large numbers was several years ago during a visit to Revis Hill Nature Preserve in Illinois. A few appeared to be recently emerged from chrysalises, and I got several photos of one particularly beautiful individual (see photo below). However, it was cool that morning and I had to leave before the heat of the day, so all of the Zebras had their wings open to allow sun to hit their abdomen and warm their wing muscles. So I have never obtained a good photo of the ventral, or underside, of the wings. Since the temperature was in the mid-80s as I stopped the car in the horseman’s camp, I was hopeful that if this individual landed it would close its wings.

I got my camera gear out of the car. The Zebra continued to fly around, exhibiting the gliding flight punctuated by shallow wing flapping that is somehow distinctive to Zebras. The delicate tails, nearly as long as the hindwings, trailed behind, and appeared to be intact. If only it would land! Finally, after about five minutes, it settled down at a particularly wet spot, with its wings closed tightly over its abdomen. I slowly moved in, and obtained many photos. Zebras sometimes can be a bit flighty, but this one was patient with me, even allowing me to set up my tripod.

By the time I finished with the Zebra it was time to head back into town for my eye appointment, so a visit to the hairstreak spot will have to wait for another day. I was happy though, because one more shot that I didn’t have for my book had been acquired. Despite the Zebra being cooperative, I still had to crawl through some wet spots, decorating my shoes and knees with mud in the process. I didn’t have a change of clothes with me, so I had to explain to my optometrist why I was such a mess. It reminded me of the time I had to explain to him how I smashed one of the lenses of my eyeglasses while photographing butterflies. But that is another tale …

Zebra Swallowtail, form "lecontei," Mason County, Illinois, June 12, 2011.

Zebra Swallowtail, form “lecontei.” June 12, 2011, Mason County, Illinois.



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