Hello,

As known, many species of Lepidoptera have various wing spots that confuse and scary off predators, avoiding this way to be eaten, and only get some -not lethal- wing damage. Some of the most striking examples are the S. American nymphalid genera Morpho and Caligo, which show large patterns like eyes on the undersides of their wings. Especially Caligo show 2 very large eyespots on the underside of their hindwings, which, together with the general pattern of the wings, make it look superficially like an owl's face. In such species, it is often that, even in fresh specimens, large pieces of wings are missing only in the areas of the eyespots, as a result of predator attacks.

Now, specifically in your cases, the male of Polyura athamas looks that it was not an old, end-life specimen at the time of its death, judging from its not so faded colours. And from the shape of wing damage, I think it is clear that it came from predator attack, possibly a lizard.

On the other hand, the pictured Euthalia amanda looks to be an old, worn specimen, with quite faded colours (an end-life specimen at the time it was collected), and the type/shape of the damage suggests more mechanical destruction as the reason (flight wear cause of various hits of the butterfly's wings between tree branches, cause of rain and wind in bad weather conditions in its habitat, etc).

Regards,

Athanasios

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Based on wing lesions it would not be easy to identify the predator type as evident from the Polyura specimen attached with the question. The V marks looks like attack marks by toothed predator not beak mark or collision mark. Similar marks are present on both wing in a pattern. It can be hypothesised that it was attacked in resting position, thus, from the mark pattern (by overlaying both wing in resting position) you may try to get the number of teeth marks, shape and size of the tip of jaw. If you can get the teeth count-jaw size ratio and shape of jaws of predators in the study area then the obtained ratio the lesion will give you the type of predator or maybe even its genus. You may also try to use the angle of the lesion as a detector of the attack direction.

However, the marks on Euthelia (aged specimen evident from faded colouration and descaling) indicates mechanical or collision damage from flight or vegetation or traps or something such. genetic material recovery from the lesions maybe would help with at least identification of the damage type.

If you get any significant result from this please let me know, even if you differ. :)

Thank you Athanasios, María and Kamalika for your response! I would like to add another image of the Polyura here which shows that adjacent lesions differ markedly in size and shape. Interestingly the tip of each lesion exactly meets a wing vein. Furthermore the lesions usually does not exceed the adjacent intervenosa at both sides. It seems that the lesions are not the result of a single attack or even the same predator species.

Any interpretation of wing damage of particular specimen is highly speculative. See the experiments by Wourms and Wasserman where birds attacked butterflies in aviaries: handling by birds could lead to no damage and various types of damage. Also Robbins did an experiment keeping butterflies in cages with some plants and then looking at the wing damage patterns.

That most of the triangles are exactly at the veins indicates that veins broke and then tore a triangular piece of wing with it as a matter of wear. This might happen during combat between butterflies over food (these Charaxes can fight fiercely) or other instance when wings are pressed against a surface and multiple veins brake near the wing margin (speculating! Could easily be tested with some life specimen). It is extremely unlikely that predators would exactly aim at the veins multiple times, even though they would probably get a better grip on veins than between veins. If birds can aim, they should aim for the head and thorax. Eyespots are between veins, attracting attacks to the tissue between veins. It would be wrong to classify these triangles in the specimen as bird beak marks. The ‘teeth idea’ is not serious to me. Symmetrical damage is an indication of predator attacks on resting butterflies. Since left and right wing have the same physical structure they tend to brake in the same places and can this can also result in symmetrical damage. I do not see very convincing evidence of such attacks in these 2 specimen, even if you would have to score it as symmetrical damage. At the end of the day, we can only speculate about individuals. It becomes more interesting if we can 1) experiment or 2) collect data on many specimen and compare groups statistically. There is a lot of scope to record details of wing damage where you can spend 15 min per specimen taking all the data. On the other extreme you can just score ‘damaged or not’.

Thank you Freerk for your exhaustive comment!

I am happy to hear that you reject the 'teeth idea' with respect to the shown lesion patterns. This was also my conclusion based on the properties of the lesions. I documented these 'triangle lesions' for many specimens of and species in particular of the family Nymphalidae including Satyrinae.

I appreciate your help, Peter

Dear Freerk, I have read your article ''lizards as predators of butterflies'', where there is a pictured hindwing of Melanitis leda from your experiment with geckos' attacks in cages, which shows 2 large triangular chips between the eyespots, with their tips meeting veins, like above. Although most of the wing damages from lizard attacks are rounded from bites (as shown also in your experiment), I think that, when a butterfly is resting and feeding on the ground, and a lizard jumps powerfully on its hindwings from behind, then, especially a Charaxinae with strong muscles and rapid flight, will fly at the same time wildly (even before lizard's bite), and this can result to broken veins and triangular chips.

Looking at the angles and measurement provided in the last photograph I totally agree with Freerk.. The "teeth idea" do not stand up right, it has to be a post damage tear-off as mentioned by Freerk.

Lovely discussion,

Thanks all,

Kamalika

Thank you Albert for your detailed analysis of the damage patterns. Now, we have differing opinions on their origin and I have no final conclusion. I will gather more data and try to find a convincing answer.

Best wishes, Peter

Peter, according to the typ of lesions on your Euthalia specimen, definitely present damage to the right hind wing from a beak mark, you can see the straight horizontal cut, which I point to with the arrow. This is a characteristic damage done by insectivorous birds in butterflies. The damage in your Polyura is mecanical destruction inside an entomological net due to excessive flapping especially in fast and strong flying butterflies.

This is another example of a bird attack on a butterfly in the family Lycaenidae. The arrows indicate the beak marks. In the lesion of the upper right wing the mark of the bird's beak is clearly visible

Beak marks like impressions found in aposematic species with tough wings can be used to identify bird species or at least families like jacamars and tyrant flycatchers. Marks involving tears are found mostly in palatable butterflies with soft wings and rarely allow predator identification.

I would like to thank

Luis Miguel Constantino and Carlos Eduardo Guimarães Pinheiro for their answers. I will consider their suggestions in further studies!

Peter