Tawny Emperor: a widespread butterfly of "spotty" occurrence

[trehopr1]

The Tawny Emperor butterfly (Asterocampa clyton) is one of only 2 species of Apaturinae occurring in my state of Illinois. It is a widespread species here across the state; and yet it is only "locally encountered" by enthusiasts or collectors alike. In short, it is a species of the most un-common occurrence. If you happen to sight one at all it will likely be a lone male aggressively defending his territory whilst all the while on the lookout for a mate ! These fellows tend to perch very high in the branches of a host tree. Their stout bodies and triangular-shaped forewings afford them a powerful fast flight with an amazingly abrupt turning radius...

The closely related and far more common Hackberry butterfly (Asterocampa celtis) is found in the same environs: woodland edges, muddy places, and anywhere carrion, sap, rotting fruit, or fresh dung may be present. However, it is a grayish species and has an eyespot on its forewing. The size and build for the two species is pretty much the same --- as well as their habits; and yet the Tawny Emperor is strangely absent most of the time.

Below, I offer up a comparison of the 2 species.




Hackberry butterfly (center/left) vs. Tawny Emperor (center/right)

There are however, subtle differences between the two species egg laying habits and this may attribute to one species being widely encountered and downright common (with two generations) in Illinois; whilst the other is "locally encountered/rarely seen (only having one generation) in Illinois. To give credit where credit is due my "Butterflies of Illinois" book (2014) states that: the female Hackberry butterfly lays her eggs either singly or in small clusters, on young hackberry foliage throughout the tree. Opposed, to the female of the Tawny Emperor which lays her eggs in large clusters (up to 500 eggs) on hackberry foliage.

Despite the large quantity of eggs produced (by the Tawny Emperor), few caterpillars seem to survive to adulthood. It is thought that once a predator finds a cluster of eggs or young caterpillars, all are consumed. The book does say that both species feed on Hackberry (Celtis) species. But, nothing more about that is forwarded so the possibility exists here that perhaps the Tawny is just a little more specific about what kind of Celtis (species) it prefers or even relies upon...

Below, I offer up a seldom seen glimpse of a pair of this most uncommon species here.



Males are occasionally seen (one or two examples) in some private collections. Females however, are a very rare occurrence and you are either an "extremely lucky" collector to have encountered her or you got her by way of a bait trap !

This pair belongs to me and the male is the only one which I have ever personally encountered in my field excursions over all these years. The female was something I had to trade another collector "stiffly" for -- to have pride of ownership. It was the only female he ever encountered despite picking up 3 other males over the years...

Now, of coarse because this species is very "un-butterfly" like in its non-preference of flowers one would expect the best manner to get it is via bait traps such as those sleeved types used for Catocala. And to this end, I will say that I have indeed read of one collector on the other forum who has encountered this species with a measure of success. But, the caveat is that he extensively sets many bait traps out at any one time (throughout the summer) and has the TIME to devote to  inspecting his traps regularly; so that his catches are not quickly trashed.

In closing, on this article I will quote one other brief paragraph from my "Butterflies of Illinois" book regarding the STATUS of the Tawny Emperor:

"The Tawny Emperor is found throughout Illinois, and usually occurs in association with the Hackberry butterfly. For every 100 Hackberry butterflies encountered, one will be a Tawny Emperor".

[mothman27]

Wonderful post. I have considered trying to raise this species if I get a fertile female. They do not seem plentiful but I have seen several each year including a handful of females. It is simply neglect on my part that I have so few in my collection. If I had fresh bait in a bait trap more often I would probably have more by now. Also, there are Hackberry trees in the vicinity which I am sure contributes to their presence. I have also found them occasionally not in bait traps but, as you mentioned, not nearly as often as Asterocampa celtis.

[jhyatt]

Both species (celtis and clyton) come freely to fermenting bait here in the southern Appalachians. I typically find
about 10 celtis for every clyton, but clyton is by no means a rarity. Some of the females get really quite large.
I get both species, at about the same ratio, at bait in coastal Georgia also. But it's a rare day indeed when I see clyton
freely flying. Bait trapping is the answer!

Good hunting,

jh

[mothman27]

Mar 16, 2020 14:26:21 GMT jhyatt said:

Both species (celtis and clyton) come freely to fermenting bait here in the southern Appalachians. I typically find
about 10 celtis for every clyton, but clyton is by no means a rarity. Some of the females get really quite large.
I get both species, at about the same ratio, at bait in coastal Georgia also. But it's a rare day indeed when I see clyton
freely flying. Bait trapping is the answer!

Good hunting,

jh

Would that be Asterocamps clyton flora?

[jshuey]

So, what many collectors don't realize, is that both of these species can be quite common in small-town urban environments. The host plant, hackberry, is an adventive tree that is common in older small town American back yards. Its seeds go everywhere and it quickly establishes along fences and foundations.

I live in a a typical "historic" neighborhood in central Indiana - the ages of the homes are between 80-120 years. Over the decades, especially in the era when lawn care was not so intense, the seeds rain in and establish (I have to hand pull them from our flowerbeds). So I have three mature hackberry trees in my yard alone - a small fraction of the total on my block. And I get to see both species perch most of the summer in my back yard. They land on you as you walk down the sidewalks here! And indeed, clyton is less common than is celtis in this setting as well (but more like 10 to 1).

john

[jhyatt]

Yes, I assign the coastal GA clyton to A. c. flora.
jh

[jhyatt]

The greatest concentration of A. celtis I ever found was around an Interstate highway rest
stop in the middle of South Carolina... They were everywhere! Didn't see a clyton among that outbreak, though.

[jshuey]

Mar 17, 2020 13:24:22 GMT jhyatt said:

The greatest concentration of A. celtis I ever found was around an Interstate highway rest
stop in the middle of South Carolina... They were everywhere! Didn't see a clyton among that outbreak, though.

In my back yard, you never see both species on the same day.  Celtis has two generations in Indiana, and clyton flies between them.

j

[jhyatt]

John, I'm pretty sure I've on occasion pulled both species out of a bait trap down here (TN or GA), but very likely one was very worn and
the other very fresh. I haven't kept many specimens, or records in that much detail, so I can't say with 100% certainty.

JH

[louisianacurmudgeon]

Both Asterocampa celtis and Asterocampa clyton are extremely abundant species wherever the host tree occurs. They can be captured by the hundreds daily in UV light traps and using fermenting fruit bait. I am in SE Louisiana, USA.  I have many drawers of spread adults taken over the decades.


imgur.com/a/d4ddYSf