Any Thysania agrippina experts out there?

[Panacanthus]

I have recently spread these three T. agrippinas, and I am wondering if anyone can determine if they are male or female. It would also be very interesting to know if anyone is certain of the larval foodplant(s). Photos of the larvae would also be great to see. I've searched, but seem to find conflicting images and information! These three specimens are nearly identical in size, with a single forewing measurement from joint to tip of 130mm to 132mm. Therefore, their true maximum wingspan would be 272mm to 276mm, with thorax (approx. 12mm) included.

Thysania IN recto.jpg (778.31 KiB) Viewed 4557 times

Thysania IN verso.jpg (789.75 KiB) Viewed 4557 times

[Chuck]

Those are spectacular; look at the shades! I have two, one dating to the 1960s and one I caught in 1998.

Last I knew, the food plant is unverified- rather amazing for a moth so well known for so long.

[Panacanthus]

Those are spectacular; look at the shades! I have two, one dating to the 1960s and one I caught in 1998.

Last I knew, the food plant is unverified- rather amazing for a moth so well known for so long.

Thank you Chuck. I totally agree - so little known about such a common moth!

The #3 specimen is indeed especially dark. What surprised me is that the specimen with the (by far) darkest recto, has by far the lightest verso, with the largest white/cream markings. I’m wondering if this is simple variation or an indication of male or female. Abdomens are very similar in size and one would expect a female’s to be larger, but I don’t know if this is the case in this species.

That is very special to own one that you caught yourself!

[boghaunter1]

Hi Panacanthus,

Beautiful specimens nicely spread. I have for years, sexed a lot of moths, in questionable cases, by examining the frenulum; moths usually (not always) have a frenulum, which is a wing-coupling device that joins together the forewing and hindwing. Look at the base of the wings on the underside... Males have a single, thick, hairlike spine that extends from the base of the hindwing up to a corresponding flap on the top wing. Females have 2-3, or more, much finer hairlike spines. A good magnifying glass (10-20x) or low power scope may be needed. Once you see the difference it becomes quite easy to sex the moths. I just used this very method this morning, in Catocala sp. moths, with success...also works for Geometridae & Sphingidae. Not all moths have a frenulum though (i.e. Ghost moths). You may have to use a fine insect pin to brush away some scaling to easily see. All Noctuid moths I have ever collected have a frenulum. Google more info/images.

John K.

[Trehopr1]

Hello Panacanthus,

I was just about to post my answer to your question about determining the sex of these gigantic noctuid moths. However, it seems John K. (boghaunter1) has already done an excellent job explaining.....

Nonetheless, I was going to mention that in Holland's moth book on page 16 at the bottom he remarks:

"the form of the frenulum is of use in determining the sex of specimens, as in the case of the males it consists of a single curved, hook-like projection, whereas in the case of the females it is split up into a number of bristles".

Like John K, I too have known of this for a long time and it was here in Holland's book that I first read of it in the late 1970s.

Old books can still be very useful !

[Panacanthus]

Thank you VERY much John and Trehopr1! That is excellent information, and like Trehopr1 said, very well presented! I have a microscope which I often use for the insects, so that will be very helpful in this case!

It may be a few days, but I will check them and report back with my findings!

[Chuck]

sexed a lot of moths, in questionable cases, by examining the frenulum; moths usually (not always) have a frenulum, which is a wing-coupling device that joins together the forewing and hindwing. Look at the base of the wings on the underside... Males have a single, thick, hairlike spine that extends from the base of the hindwing up to a corresponding flap on the top wing. Females have 2-3, or more, much finer hairlike spines.

I never knew this!

Of all physical features, why would the frenelum be different? That makes no sense from a natural stand point. I wonder if it developed from some sex-related organ.

[Paul K]

sexed a lot of moths, in questionable cases, by examining the frenulum; moths usually (not always) have a frenulum, which is a wing-coupling device that joins together the forewing and hindwing. Look at the base of the wings on the underside... Males have a single, thick, hairlike spine that extends from the base of the hindwing up to a corresponding flap on the top wing. Females have 2-3, or more, much finer hairlike spines.

I never knew this!

Of all physical features, why would the frenelum be different? That makes no sense from a natural stand point. I wonder if it developed from some sex-related organ.

Me too, thank you for such valuable information.

[mothman55]

The frenulum for sexing catocala is well explained complete with drawing in Sergeant's "Legion of Night". I have found this the only way to sex catocala over the years, actually did not know that it was the same for other species as antennae is generally the quickest for saturnids, sphinx, etc.

[Panacanthus]

I have now checked the specimens and all three are very clearly males. A little bit of a disappointment, as I was hoping for males and females, but I’m thrilled to actually know what they are, and to have learned about this technique! Thank you again to John and Trehopr1 for the wonderful information!

I am now curious as to what the approximate ratio of males to females might be in the specimens we see for sale on the market.

[Panacanthus]

I have no idea if this is correct. I am also not familiar with caterpillars from this group of moths. Any thoughts as to whether or not this may be legitimate?

“This is the caterpillar of the white witch moth (Thysania agrippina), the world's largest moth by wingspan. It is the first ever and only photo of its larva, taken in Brazil by Fernando Carvalho-Filho in 2014.”

IMG_1941.jpeg (114.38 KiB) Viewed 4424 times

[bobw]

The retinaculum should be used in conjunction with the frenulum to check the sex. It's the small patch of hairs on the forewing that holds the frenulum in place. In males, the frenulum is a single long spike which is held in place by the retinaculum on the costal vein. In females, the frenulum is a group of much shorter bristly hairs which are held in place by the retinaculum half way doen the forewing towards the anal margin. Sometimes, in set specimens, the frenulum can be broken off or the hairs of the female frenulum fused together, the position of the retinaculum can then show which sex it is.

[Trehopr1]

It is hard to tell the size of this larvae in the photograph. I don't know how one can claim this to be the larvae of Thysania if it was not reared to an adult. At best, this is merely presumption on the part of the photographer !

I think because Thysania agrippina, and T. zenobia are of the same genus and as well are closely related to the Black Witch moth itself; I would expect it's larvae to bear a very strong resemblance structurally to both of these species --- albeit only much larger in proportion.

I think the mystery of its larvae (in general) and what it feeds on can be answered by looking into the canopy trees that the adults (tend) to favor resting on. Perhaps, it is the odor of a certain type of tree (wood) that indicates to them --- this is "home".

This is just one possibility and only a hypothesis that I have but, one sometimes has to think "out of the box" to get to some of nature's myriad unanswered questions.

[Trehopr1]

One also has to keep in mind that science photographers have tried in the past to show pictures of the larvae purportedly of Titanus giganteus.

Only later were the photographs debunked as being pictures of Megasoma larvae or the larvae of other large Prionid species such as Armillatus etc....

[Panacanthus]

I agree Trehopr1. It is unfortunate that I could not find any explanation as to how the photographer came about his determination, but perhaps that just wasn’t written where I found the photo. Perhaps someone here might know more of the story. It is always possible that they did indeed rear it to the adult stage. I did a little searching for the larvae of T. zenobia and they do look very similar aside from color pattern - assuming the images of those were correct!! That caterpillar does look like it could be very large, but like you say, we can only guess. I was just hoping someone might even know more about the person who took the photo. Sometimes one thing leads to another and we end up learning actual facts!

[Paul K]

I have no idea if this is correct. I am also not familiar with caterpillars from this group of moths. Any thoughts as to whether or not this may be legitimate?

“This is the caterpillar of the white witch moth (Thysania agrippina), the world's largest moth by wingspan. It is the first ever and only photo of its larva, taken in Brazil by Fernando Carvalho-Filho in 2014.”


IMG_1941.jpeg

This isn’t Thysania agrippina larvae.

[Panacanthus]

I have no idea if this is correct. I am also not familiar with caterpillars from this group of moths. Any thoughts as to whether or not this may be legitimate?

“This is the caterpillar of the white witch moth (Thysania agrippina), the world's largest moth by wingspan. It is the first ever and only photo of its larva, taken in Brazil by Fernando Carvalho-Filho in 2014.”


IMG_1941.jpeg

This isn’t Thysania agrippina larvae.

Paul - may I ask how you know? I’m not in any way arguing. Just curious!

[Paul K]

Thysania agrippina has only 2 pairs of prolegs and the larvae on the photo has at least 3 or 4 but the fourth one is not really visible. Unless the larvae add one more pair while grow?
There is a true photo of freshly emerged larvae.
http://www.danske-natur.dk/images121b/bere215539apm.jpg

[Panacanthus]

Thysania agrippina has only 2 pairs of prolegs and the larvae on the photo has at least 3 or 4 but the fourth one is not really visible. Unless the larvae add one more pair while grow?
There is a true photo of freshly emerged larvae.
http://www.danske-natur.dk/images121b/bere215539apm.jpg

I don’t know enough about the prolegs, etc. to comment on if they can add more as they grow (doesn’t seem likely!), but that’s good observation! There is also a video of a freshly emerged larva from a female that had laid a few eggs at a light.

Thank you for the reply and explanation!

[Paul K]

Thysania agrippina has only 2 pairs of prolegs and the larvae on the photo has at least 3 or 4 but the fourth one is not really visible. Unless the larvae add one more pair while grow?
There is a true photo of freshly emerged larvae.
http://www.danske-natur.dk/images121b/bere215539apm.jpg

I don’t know enough about the prolegs, etc. to comment on if they can add more as they grow (doesn’t seem likely!), but that’s good observation! There is also a video of a freshly emerged larva from a female that had laid a few eggs at a light.

Thank you for the reply and explanation!

Yes! That is exactly the same caterpillar that you could watch on Pedromariposa videos! Unfortunately Peter wasn’t able to find a food plant although he tried many.
All the larvae refused to eat and die shortly after.