WDEL Blog: Eclectic Hobbies with Allan Loudell

Banner year for Eastern Tiger Swallowtails (The Delaware state butterfly)

By all accounts, Eastern Tiger Swallowtails are appearing in large numbers in our region.

These large butterflies, which are mainly black and yellow - except for the 10% or so which are black-form females - seem to be everywhere. I see them flying in neighborhoods, over major roads, and even over parking lots.

A visit to Elk Neck State Park in Cecil County, Maryland, easily yielded 200+ Zebra Swallowtails. Smaller than the Eastern Tigers, these nonetheless magnificent butterflies have the longest tails of any butterflies north of the Rio Grande. Elk Neck is one of the East's epicenters for this species, which seldom stray far from the larval food plant, Paw paw. They are relatively uncommon here in New Castle County.

Conversely, Monarchs seem to be delayed this year; I have yet to see one although others have. Usually, late July is the period during which many see Monarchs AND the major Swallowtails.

Another brood of the big, spectacular silk moths has emerged, including Luna and Imperial, which I keep seeing around Northeast, Maryland.

Take a look at the "Recent Sightings" list from NABA: The North American Butterfly Association...


As noted above, Monarchs are scarce. Some observers fear a population crash.

Listen to my interview with perhaps the world's top Monarch migration expert, Dr. Lincoln Brower, Research Professor of Biology at Sweet Briar College in Virginia, who has long been pessimistic about Monarchs...

Audio Here

Driving north a couple of weeks ago -- through Pennsylvania and New York state to Quebec City, and returning via Vermont and New Hampshire - I saw two rather rare, but intricately patterned moths: The Lettered Habrosyne and the Glorious Habrosyne.

Here's an image of the Lettered Habrosyne from Bug Guide...


Posted at 6:29am on July 29, 2013 by Allan Loudell

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Comments on this post:

Mon, Jul 29, 2013 2:42pm
I haven't seen one Monarch yet this year. It is August.(almost). Wondering if our sector was wiped out last winter, (something I mentioned earlier)?


I never knew the paw paw was the zebra's favorite. Does the tiger have such a known favorite?

Allan Loudell
Mon, Jul 29, 2013 7:43pm
First the easy question: Caterpillars of the Eastern Tiger Swallowtail feed on such plants/trees as black cherry, the tuliptree, sweet bay magnolia, etc.

Monarchs represent a more difficult - even existential - question.

Will we be seeing them in good numbers later this fall?

As I said, I've personally not seen a single one this year. The recent Delaware Nature Society butterfly count found some in far northern Delaware and absolutely none in the surveyed areas around Christiana and Newark.

Has the Monarch population crashed, only to recover in a year or two? (Certain other butterfly species are subject to wide fluctuations in numbers. A couple of years ago, Red Admirals were all over the place; so far this year, very few!)

You gave me an idea, kavips. Listen Tuesday at about 12:18 p.m., when I've scheduled an interview with perhaps the world's top Monarch migration expert, Dr. Lincoln Brower at Sweet Briar College in Virginia.

I've read about him in many books, but I had never talked to him -- until tonight -- when I scheduled the interview.

There's no doubt many Monarch enthusiasts fear a sustained population crash. The Monarchs' overwintering area in Mexico keeps shrinking, and extreme temperatures combined with extreme rainy and dry periods; habitat depletion; and the scarcity of milkweed (or contaminated milkweed next to farms) - in the U.S. - may have all conspired against Monarchs. Add to that the agricultural industry's increasing reliance on herbicides.

Monarch Watch at the University of Kansas suggests drought and record-high temperatures in North America in 2012 led to an earlier-than-usual, Monarch migration which disrupted Monarchs' breeding cycle by drying out their eggs prematurely.

I don't think anyone is forecasting extinction, but the Monarch could become a much less common butterfly.

One spectacular butterfly about the size of the Monarch - the Regal Fritillary - has virtually disappeared since the 1960's, now confined only to two tiny points in the East.

Allan Loudell

Mike from Delaware
Mon, Jul 29, 2013 8:34pm
I saw one of the large butterflies in my yard yesterday. Also saw two baby praying mantis.

Tue, Jul 30, 2013 2:15am
Possible questions for tomorrow:

Where do Delaware's Monarchs go? Or are our Monarchs only those passing through? Charts show one route veers to Florida, where it splits into two routes across to the Yucatan, then disappears. Do these Monarchs then fly onward to central Mexico? I thought Cancun had a winter ground that was a tourist site, but couldn't find any reference to it. If our locals don't go to Cancun, the charts show them following the Gulf Coast then flying south from Texas. Here is one link: https://en.wikipedia.org/wiki/File:MonarchWanderungKlein.gif

Is Lincoln Brower aware that a popular gene modified corn pollen appears to kill Monarchs in their larvae stage? I know with fears over gene modification, that may be of interest to your listeners.

The non-conclusive Cornell Study:


Perhaps it might be interesting to ask how citizen naturalists can participate in a census. If we see a monarch, is their something we should do? http://www.learner.org/jnorth/maps/Gallery.html

Are western monarchs experiencing the same decline as Eastern ones?

Is there a chance our cold spring delayed our milkweed growth several weeks, yet warmer than average global warming temperatures started the migration off early, so no milkweed was available when the Monarchs arrived?

I heard talk of a missing generation this year because of the cold spring, and late arrival of the Monarch. Being an expert, following this for decades, has there ever been a third generation (instead of fourth) southward push of which he is aware? In other words. when the cold weather begins, does he predict the third generation will assume the characteristics usually associated with the super generation, and make the 3000 mile flight then live till next March, or does he think these monarchs are genetically bound, and the third generation will die up north, and there will be no fourth generation to return south to Mexico?

I hope that last one was clear. I'm trying to find out if all butterflies carry the genes for all generations and like a plant can, switch functions with environmental changes (as in stems become roots when the touch the ground). or is their programming very specific, and each generation is genetically specified to follow its course no matter what environmental anomalies it encounters?

Which brings up my last question. Has any genetic study been done on the Monarch genome, and if so, what were the results...

I will be listening, but I certainly hope this very important conversation, a once-in-a-lifetime opportunity gets pod-casted for future researchers.

Allan Loudell
Tue, Jul 30, 2013 6:13am

I'm afraid we won't have time to get to all those questions within the time frame, but I'll try with some of the more interesting ones.

I can partially answer some of your questions.

Lincoln Brower has written extensively about the apparent effects of genetically modified, herbicide resistant crops, and the resulting losses of milkweed.

Many of the Monarchs passing through Delaware earlier in the year may deposit eggs on milkweed and proceed further northwards. In turn the Monarchs produced from those eggs will go through their larval and pupal stages; and head further north as adults.

(It takes 3---4 Monarch generations to make the entire trip!)

In past years, I've seen caterpillars on milkweed in such places as White Clay Creek State Park & Preserve.

East Coast and West Coast Monarchs follow different routes. The fall brood of East Coast Monarchs heads south. Peninsulas - such as Cape May County, New Jersey and Point Pelee, Ontario, Canada - tend to concentrate the migrating Monarchs. Final destination: The Oyamel fir forests in a relatively small mountainous area of the central Mexican states of Mexico and Michoacan. Temperatures and humidity are critical. Extreme weather can cause catastrophic mortality.

West Coast Monarchs are thought to overwinter in eucalyptus trees in southern California. (Some have proposed the West Coast population is NOT truly migratory the way the East Coast population is.)

The Delaware Nature Society conducts an annual butterfly census - in late June or in July - counting ALL butterfly/skipper species and individuals, including Monarchs. Groups in Cape May, New Jersey, capture and tag Monarchs in an effort to track migratory trends.

Allan Loudell

Tue, Jul 30, 2013 12:54pm
Thanks for today's interview with Lincoln Brower. It awakened at least my scope of the damage our genetically engineered crops are creating in un-thought of ways. One could make the analogy that tampering with nature is like tampering with one's computer system. Despite your computer's screen warning, if you remove one file you insist is a spybot, it could cause a whole key element of your system to go nuts.

I hope other listeners also got exposed for the first time, exactly how genetically engineered products may impact us in our future. The Monarch may be a rallying cry for tighter regulation upon this industry. I'm thinking of the parallel of how one can first tsk tsk gun violence, but after losing a close acquaintance to it, one gets converted into a fighting force against it. The Monarchs just might have that appeal to become a prime motivator.

Allan Loudell
Tue, Jul 30, 2013 3:16pm
Interview with Professor Lincoln Brower now posted as podcast (above).

Thanks for your interest.

Allan Loudell

Sun, Aug 4, 2013 5:47pm
Don't know Allan if you will pick up on this, not sure how your feed works, but an interesting association came up in a recent conversation regarding the absence of Monarchs.

That was when a hummingbird enthusiast said none returned to Delaware this year.. Both species winter in Mexico and fly back in spring... I couldn't find anything out on the web; the hummingbird enthusiasts are not as organized as the monarch ones, but wondered if you have heard of, or seen a hummingbird this season?

Allan Loudell
Mon, Aug 5, 2013 5:55am
I have not seen any hummingbirds this year, but I haven't visited ideal habitat where I've seen them in the past.

No doubt drought and hot temperatures in the South may have altered migratory patterns for many creatures.

Mon, Aug 5, 2013 9:42am
Normal time for them to pass back through is mid to late August, so we shall see if any make it. I did see hummingbirds in the Appalachians this year, so some did make the journey out of Mexico. Siting maps show them sited all the way into the Maritime Provinces, but the internet has a lot of people questioning why they didn't show up at their house this year. Whereas Monarchs can lay millions of eggs and bounce back quickly if conditions are right, hummingbirds will have to grow back slowly. It might allow other species to spread to the East Coast, since one of the major reasons only the Ruby Throat exists here, is the aggressiveness of the Ruby-Throated males. If you have a male monopolizing your feeder, hummingbird enthusiasts recommend you put a second one on the other end of your yard so the male can't monopolize both and others can get food too. Unlike Monarchs, hummingbirds fly to Mexico solo, not in pairs, not in groups.

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