Tawny Emperor: a widespread butterfly of "spotty" occurrence
Mar 16, 2020 9:43:32 GMT
deliasfanatic, mothman27, and 1 more like this
Post by trehopr1 on Mar 16, 2020 9:43:32 GMT
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".
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".