Long-winged forms in usually short-winged insects

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PVOzerski, 27.09.2011 23:02

It is known that it is not uncommon for insects to have imagos that can and cannot fly within the same species. In many cases (ants, aphids, female wasps, turtle cockroaches, etc.), the presence of forms that differ in their ability to fly in populations is obligate and clearly adaptive). However, this also happens when the species is represented almost exclusively by short-winged, flightless individuals, and only as an exception are full-winged specimens (f. macroptera). This phenomenon is very common in erect-winged birds and, if I'm not mistaken, is also known in bedbugs.

From time to time, I have come across the explanation of the appearance of such individuals as the adaptation of the species to settlement. At the same time, the phenomenon itself "offhand" looks like an example of atavism almost worthy of entering in a textbook.

In general, I want to share my thoughts on this matter and listen to other people's thoughts . I have encountered the phenomenon of macropteria in locusts and grasshoppers many times. These meetings left a rather strange impression. First, in nature, macropterous individuals behave differently: some use their wings to lengthen jumps, like representatives of normally long-winged species, while others do not seem to know that they have flying organs. Unfortunately, I did not conduct these observations specifically and did not record them, so I did not collect quantitative data. Nevertheless, I will venture to share what I noticed. In my life, for example, I have seen at least several dozen full-winged individuals of Bicolorana roeselii, and only a couple of times did I come across those that opened their wings during jumps. The long-winged Chorthippus parallelus never flew in my presence. But the male Chrysochraon dispar surprised me: it flew better than the males of the common skate and green grasshopper. The most amazing impression on me was made by collecting insects that drowned in the Elton salt Lake, brought by a colleague from the Lower Volga region: there turned out to be a decent number of full-winged Miramiola pusilla and not a single short-winged one (so, apparently, grasshoppers did not fall from the shore into the water, but got there when they failed to fly).

In general, the issue does not seem to be resolved for me. Something may become clear if it turns out that the flight-capable individuals are only a small percentage of the full-winged ones (i.e., "anomalies among anomalies"). What are your observations, colleagues?

This post was edited by PVOzerski - 27.09.2011 23: 27

Comments

28.09.2011 1:51, bryodema

In this regard, I can answer that I also came across Bicolorana roeselii f. macroptera, and in the main case of females, the use of their wings was also not noticed by me. Chorthippus parallelus was also found (mostly males, long-winged females are much less common), so they just used their elongated wings for their intended purpose and were quite active. Regarding Chrysochraon dispar, there was an interesting case: once I managed to "stumble" on a clearing in lipnyak, where at least 80 percent of all my half-hour gatherings were macroptera, and what is remarkable, this ratio was observed for both sexes. At first, I thought that the Chrysochraon population was affected by selection and wing elongation as a result of the high dispersal activity of the species. However, I found it strange that most females of the species also had elongated canines. After all, it is known that during dispersal, selection in a population acts primarily on males (for example, changes in certain morphometric characteristics in male carabuses, such as changes in the width of the pronotum, changes in the distance between the eyes, and an increase in the size of the eyes). I think there must be an explanation for the sudden "outbreak" in the population of a short-winged species of individuals of one or both sexes of the form macroptera. What exactly induces such spontaneous mutations is difficult to say, perhaps the notorious environmental factors, i.e. something from outside. Or it is hidden intra-population mechanisms, the effect of accumulation of mutations in the recessive and then their manifestation in the next generation of individuals of the species. This question is extremely interesting, and species of straight-winged birds with shortened wings can serve as a model object for such studies. It seems to me that a simple percentage of full-winged individuals among non-half-winged individuals is not enough. Here you need to use a molecular machine. As for the use of f. macroptera wings, it seems that there are specifics of each specific species, plus the specifics of gender and environmental factors (temperature, light), time of day.

28.09.2011 2:11, PVOzerski

I would also like to add some more information. Pravdin and Mishchenko's monograph shows that B. roeselii, introduced to North America, spread there and are found in the form of a full-winged form (at least from the text, I understood that this form has become the norm there). At the same time, I have read or heard somewhere (although I may be confused-it was a long time ago) that full - winged males of this species in the Old World are supposedly sterile. Such are the cases - if I, again, did not mix up anything (but it seems that there was some Ramme work about it).

About gender specifics. Well, you chose your own nickname

: remember who flies in Bryodema s. str.and who doesn

't, and this genus isn't the only one. Here is Psophus - exactly the same story, although in a different tribe. This option is suitable for transferring genes from one local population to another, but not for developing new territories.

Now about the relationship between gender and selection. I do not know how well the data obtained for beetles is portable to Erectus. I did a web search on the inheritance of sex in coleoptera and found a link to an interesting full-text article (http://www.carabidae.ru/index.php?name=Downloads&op=down&files=4c60e93a4d7101decbb7347f1944a381). It shows that the beetles are characterized by the XY male karyotype and XX female karyotype. But orthopteroids, with a few exceptions, are characterized by the X0 variant. This can be a significant difference, affecting both sexual dimorphism and the possibility of selection.

As for research on the flight abilities of the erect f. macroptera-I would start not with "molecular", but with the banal anatomy - the state of the wing muscles. However, there is a problem: how can I get a sample in a reasonable amount of time?.. That's unless in such "flash" populations to look at-however, it will "ride" only if the degree of development of wings and the ability to fly are not tightly linked genetically.

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28.09.2011 17:12, Dmitrii Musolin

Quite a lot is known about bedbugs in this regard, especially about aquatic and near-water ones. And everything is fairly clear in general. Wing polymorphism is both genetic and controlled by external conditions (seasonal). There is also polymorphism in the degree of development of wing MUSCLES. In some species, their histolysis occurs after the settlement period (a full-winged individual remains, but it is not able to fly).

Of course, full-wings are associated with dispersal, migration, and migration to and from wintering grounds, while short - wings and muscle histolysis are associated with reproduction.

A huge amount of literature on this topic (including on bedbugs, including our book, available in PDF in Russian).

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28.09.2011 19:02, PVOzerski

And here is the bibliography of the Ramme works you are looking for:

Ramme W. 1931. Verlust odef Herabsetzung der Fruchtbarkeit bei macropteren Individuen // Biol. Zentralbl. 51:533-540.

Ramme W. 1951. Weitere Ergebnisse zur Frage "Macropterie und Fruchtbarkeit bei Orthopteren" // Zur Systematik, Faunistik und Biologie der Orthopteren von Südost-Europa und Vorderasien. Mitt. Zool. Mus. Berlin 27:1-431.

Finally, a link to the full text of Vickery's (1965) article on the distribution of B. roeselii in North America, which does not claim to be a complete summary, but discusses the role of macropteria:
http://www.google.ru/url?sa=t&source=web&c...f4P3e2Q&cad=rjt

And from myself I will add. So far, I have the impression that the same phenotypic effect (macropteria) in B. roeselii is achieved in at least two different ways. When one of them is implemented (in the Old World), there is a side effect of sterilization (possibly a pleiotropic effect of some gene), while when the other one is implemented, there is no such effect. From which we can conclude that brachypteria is not the collapse of the molecular mechanisms of the formation of a normal wing, but their blocking by an additional mechanism, and this additional mechanism most likely involves at least 2 substances (which correspond to at least 2 genes) (the variant with 3 alleles of one gene is also possible, but it seems less likely). But in general, all this should be checked experimentally.

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03.10.2011 17:31, PVOzerski

Plastinokryly (Ph. falcata) generally fly great - this year, finally, I watched, without leaving the North-West. But with whose musculature to compare their muscles? In my opinion, this is not the most suitable object (except with some Far Eastern Kuwayamaea). And with the" long-winged " forms of already long-winged species, other questions arise rather. For example, whether they have discrete "shapes" or smooth transitions from "ordinary "individuals to"especially long-winged" ones. As for me, in my deep childhood I met a couple of times such "long-winged" Tettigonia cantans (c viridissima and caudata could not be confused). Even more interesting is the variability in the wing length of brunneus / biguttulus Chorthippus: the impression (again, unverified and therefore subjective) is that they have different wing lengths and different flight ranges in different stations. But the problem of distinguishing closely related species (especially important for females) may still interfere here, so we can't approach it yet. If someone finds reliable signs at least to distinguish females of brunneus or biguttulus from similar species-it will already be possible to take up the case

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