Identification of arthropods from fragmentary remains

Hello, ENO!

As I have already written to you, I have experience in analyzing animal feces. This experience is not very great, but still.
Unfortunately, I must immediately state the fact that I have not seen any methodological works on the study of insect nutrition in the scientific literature. I've seen a lot of different things: food for birds (a lot of publications), fish (a lot of publications), mammals, reptiles, amphibians, large marine crustaceans (lobsters, crabs, crayfish, shrimp), but not insects. I may not have been very interested, although I try to download everything on trophological studies in order to know more about how the authors of these works statistically process data, what coefficients they calculate and what models they build.

Maybe I'll look at some publications on this subject in scientific libraries at my leisure.

As for the analysis of feces to determine nutrition... This method, as you know, does not apply to universal methods of studying nutrition, it is not widely used for obvious reasons: all the soft parts of the victims ' bodies are digested, only the hard integuments remain. That is, it is hardly worth counting on determining the entire breadth of the nutrition spectrum using this method. Plus, many parts of even strong invertebrate integuments can be severely crushed, which will make it impossible to determine food objects.

My modest experience of analyzing the feces of birds shows that in their feces from parts of the body of insects, you can find, in principle, all the same body parts: heads, legs, parts of prsp. etc.Everything that is not strongly rubbed in the stomach. In the feces of species that do not use gastroliths, you can even find insect eggs, which are preserved due to their powerful integuments. But these are birds, as you understand, completely different objects of research, different specifics.

To what extent this method is applicable to the study of insect nutrition, I do not know. It may not be applicable at all. At the very least, you should immediately make a calculation that you will not be able to determine everything that the insect eats.

I can say for sure that the creation of micro-preparations of chitinous integuments is a tedious and thankless job, since there are hardly any specialists who can determine an invertebrate from the photo of their integuments on the micro-preparation. I doubt that such specialists exist anywhere at all. Who will take responsibility for such a definition? Do you have any idea what the probability of an error is? It's like pointing your finger at the sky. At least personally, it took me years to do that. to find narrow specialists in their groups of insects who were willing to help me identify them. And then. this is usually the definition of either integers. or partially digested objects with prominent diagnostic features. If I have, for example, badly broken chitin without diagnostic signs, then I don't even go to a specialist for help: it's pointless.

According to your photos of the covers, I would say that the covers of the limbs are similar to those of a spider, but where is the guarantee that it is a spider? And you never know what kind of thread a mosquito is. They also have a lot of hair on their legs. And the covers below me are more like those of some larvae.

I'm afraid of incurring your wrath. Only very carefully do I dare to suggest that the best method of studying the nutrition of wasps is observation. The usual observation of a wasp, who it attacks, who it kills, who it eats. Probably so.

This post was edited by KorvinBF08-04.08.2022 23: 03

Not so important is the nutrition of whom, more important is the nutrition of whom. In this regard, sources devoted to the feeding of birds with insects, if they contain recommendations for determining fragmentary remains of insects, may be quite applicable to the problem of insect nutrition.

I have no doubt that it is fundamentally possible to determine all of the above at least up to the squad. Because the structures are quite specific. For example, if these were the remains of Apocrita larvae, I would definitely identify them at least up to somewhere, because I have a lot of literature on their morphology, even there are determinants of rider larvae based on exuvia alone. But these are not Apocrita larvae and even butterfly caterpillars.

Once I was assured that experts who can determine a beetle to a species by a piece of elytra from a Stone Age pot exist in nature. Also, if you believe the movie about criminologists, they are able to determine not only the type, but also the age of the larvae of various necrophages in order to accurately determine the time of death of a person. I am sure that there are specialists who can determine what is captured in my photos at least before the squad, too. I wish I could find them...

It is fashionable, of course, to offer an alternative way-an extensive one: catch everything that moves, grind it in a mortar and make 100500 reference preparations. But I don't have enough strength, time, or material resources for such a feat.

PS No, definitely not a mosquito, there are not only hairy legs, but also some papillae with long tubular bristles. I think that if a specialist in this systematic group had wandered here, he would certainly have recognized this sign. And the last one is definitely a larva, but not a caterpillar.

Then your main task is to find the appropriate specialists. Yes, you are an expert yourself, you can determine something yourself.

Another way to determine this is genome sequencing. If possible. Take something that might contain DNA and sequence it. And then compare it with existing databases. But this is also, as I understand it, finance.

You see, in my case, when studying the nutrition of birds, it simply does not reach this level of cover. Or it gets there, but rarely. In any case, there may be some head, leg, mandible, chelicerae, faceted eye, etc. Although I have examples when you look at a part of the body of an invertebrate and think "figs go, what is it". This is the reason I've been stuck on this topic for so long (12 years). And I must disappoint you. I don't have much material on bird nutrition. I often post photos of insects on the forum from old materials that I wasn't ready to identify 5-6 years ago, but I'm ready to try it now, when I've gained new experience, found the appropriate qualifiers, etc.

I am a narrow specialist in some groups of hymenoptera only, but here we rather need a certain generalist morphologist. Molecular insects-this is definitely not about the DPR.

It seems that I have determined that the larva is either a leaf beetle or a ladybug (as for me, these two families should be combined, they are very close in everything up to the smell, and the morphology of larvae differs more within them than between them).