Selcective breeding: possible? ideal species and traits

[muleyyy]

of course traits can be bred into any creature that reproduces sexually, that is the advantage of sexual reproduction itself, how do you think so many species of mantid evolved in the first place? honey bee's have been kept by humans for a loooong time, the monks and buckfast abbey have been selectively breeding them for years

http://perso.fundp.ac.be/~jvandyck/homage/...methBW50en.html

and yes thier not mantids, but they are insects, they have a different lifecycle but they still reproduce sexually, they still exchange dominent and recessive genes so change is still possible

however the time scale you would be looking at to get a particular trait out of mantids... welll look at how long it takes to perfect a breed of dog, i dont see anyone being that determined or ever keeping that many mantids in the first place

the issue isn't is it possible, more, why would anyone bother?

check this artical i spotted on the bbc website;

http://news.bbc.co.uk/1/hi/england/devon/7296539.stm

and christian, i agree, sometimes generations of inbreeding can be a benifit to the species, like with communal spiders

http://www.sciencenews.org/sn_arc99/5_8_99/bob2.htm

of course sometimes it backfires for them and whole generations are wiped out, but it locks in certain traits

oh and finally... i think there is a max size for invertibrates anyway, i dont think an insect the size of the one in that picture would be able to lift its own body off the ground, maybe if it was aquatic? but i've never heard of an aquatic praying mantis lol but i believe there have been aquatic arthropods in the early chapters of earths life that were quite massive?

 

[Meiji]

Hey on this breeding subject, has anyone ever tried to cross breed two different sp. Idk if its possible but that would be sweet.

One instance in which it should certainly possible to hybridize is when population groups are named as species because they don't actually come into natural contact with one another but the mantises in question are essentially conspecific (that's a fancy word meaning "the same species"). The examples which come to mind are O. novaezealandiae and O. ministralis which is essential the same mantis in New Zealand and Australia, respectively.

The results of breeding these two species would probably be deemed an "intra-specific hybrid" -- a term used in discussing the interbreeding of sub-species. The Wikipedia article about O. novaezealandiae ( http://en.wikipedia.org/wiki/Orthodera_novaezealandiae ) mentions this probable conspecificity with O. ministralis. If you want to learn more about why some people consider these the same species, pursue the literature cited in the references notes.

 

[jason_mazzy]

of course traits can be bred into any creature that reproduces sexually, that is the advantage of sexual reproduction itself, how do you think so many species of mantid evolved in the first place? honey bee's have been kept by humans for a loooong time, the monks and buckfast abbey have been selectively breeding them for yearshttp://perso.fundp.ac.be/~jvandyck/homage/...methBW50en.html

and yes thier not mantids, but they are insects, they have a different lifecycle but they still reproduce sexually, they still exchange dominent and recessive genes so change is still possible

however the time scale you would be looking at to get a particular trait out of mantids... welll look at how long it takes to perfect a breed of dog, i dont see anyone being that determined or ever keeping that many mantids in the first place

the issue isn't is it possible, more, why would anyone bother?

check this artical i spotted on the bbc website;

http://news.bbc.co.uk/1/hi/england/devon/7296539.stm

and christian, i agree, sometimes generations of inbreeding can be a benifit to the species, like with communal spiders

http://www.sciencenews.org/sn_arc99/5_8_99/bob2.htm

of course sometimes it backfires for them and whole generations are wiped out, but it locks in certain traits

oh and finally... i think there is a max size for invertibrates anyway, i dont think an insect the size of the one in that picture would be able to lift its own body off the ground, maybe if it was aquatic? but i've never heard of an aquatic praying mantis lol but i believe there have been aquatic arthropods in the early chapters of earths life that were quite massive?

Think about ancient insects hug creature. I wouldn't mind seeing a 2 foot long 2lb mantis. though it would be scary watching it eat the neighbors cat!

 

[iain5]

This is an interesting topic. There does seem to be a limit on insect size, but it's apparently harder than we thought to figure out why. I remember learning about the giant dragonflies of the carboniferous period over the years and I always heard that they were able to grow that large because of the higher oxygen concentration on the atmosphere at the time. I wiki'd the subject and got the following article, which is pretty informative.

http://en.wikipedia.org/wiki/Meganeura

I suppose if someone had the equipment and the inclination, they could set up an experiment trying to grow larger mantids with supplimental oxygen, but who knows how modern insects designed for our present atmosphere would react to that. I'm sure it would also take a few hundred thousand generations to see any significant genetic predisposition to take advantage of that environment as well.

 

[kamakiri]

As far as evolutioin is concerned...I think it's just easier for insects in general to survive if smaller. Less food required...easier to hide. The limit being to stay large enough to survive inclement weather.

But if someone devoted their life to selectively breeding the largest of several generations of a particular species, I believe that you could end up with a mantis that is say 20% larger than the current average size for that species.

 

[kakistos]

colur is dependent on too many other things such as humidity, background and type of light to be able to "breed for" any certain colour. i'm not even sure if genetics comes into it at all. as for size, i think this may have alot more to do with nutrition (and maybe other factors) than with genetics. i'm not so sure about that one though. but EVEN if it was genetic and you bred the biggest ones you could find of a certain species, the most you could hope for would be a very incremental increase in size (IF anything). and no, if you kept doing this every generation they would not get incrementaly bigger each generation (if at all). there is a maximum size each species can be, let alone mantids, let alone insects. as for "traits" such as aggressiveness or docility, i dont think these are genetic either. a big "no" all round i think.

I'm sorry but I am sure what you say is not true.

Color is dependent on environmental factors, but only to a certain extent. An animal has an range of possible variation in color restricted by it's genetic information. Think about it: a Phyllocrania paradoxa can range in color from green to light brown to brown to almost black, but never blue or red (or pink or white like Hymenopus) because it has no genes for a red or blue pigment. No matter what kind of environment you put it in. If there would be no genetic information about the color, how would it have a color anyway? How would it sense the color of the environment and then make pigments to respond appropriately?

The same holds for body size. The genes of a mantis give a basic guideline for the maximum size a mantis can become, but if the mantis experiences environmental circumstances that impede it's growth it will never reach it's maximum length. No matter how much you feed a Pseudoharpax virescens, it will never reach the size of Hierodula, because it's genes (or the lack of some genes) restrict further growth.

Anything that is genetic can be bred for. But there are limits to the time we have to breed them. Small changes like making a population of mantids not show some color variation but be only one color (no variation with environment) is relatively easy and can be realised in a human lifetime I think (making a line of P.paradoxa that is only green for example from the current population that can be green or brown). But to make an Phyllocrania paradoxa blue takes WAY too much time, only nature / evolution can do that. It IS possible, because other organisms can be blue too, so it is possible to have genes that result in a blue body coloration. But you have to wait for mutations etc and that would take us WAY too long).

Agressiveness and docility are also genetic traits. They must be, because when you compare species with other species they are more alike within their own species than between species. For example Hierodula sp. always stalk their prey more than Phyllocrania paradoxa. If it was not genetic, if one would keep those species in exact the same envrionment they would be the same in every aspect (in every aspect that is not genetic).

I do agree with you that there is a limit in size for insects, like there is a limit to almost everything. The limit probably has something to do with oxigen (insects have a more passive breathing compared to for example mammals. Increasing size will decrease the effectiveness at which the inner cells can obtain oxigen) and with the principle that smaller things are better ' kept together' because of molecular forces and therefore they are stronger (why an ant can climb glass and we can't, is because the adhesion between the ants feet and the glass is a very strong molecular force and can counteract the pull of gravity on the ant. An ant as big as a cat cannot climb glass because the pull of gravity is stronger than the molecular forces).

Chun, I think you have a very good and interesting point about the selection we put on mantids just by breeding them. We indeed select on mantids that thrive more in captivity, and therefore the genes that are responsible for better survival in captivity should be increasing in frequency.

 

[iain5]

One more thing to consider is the limited variation of genetic material in the captive population. Most people who raise generations of a particular species seem to keep recycling the same genetic code.

Consider that every nymph that hatches from an ooth had the exact same two parents (which were probably also "littermates"). Even if the two parents were unrelated, the nymphs that result from their breeding will all be genetically identical. If the breeder then breeds the offspring, they are further concentrating the single genetic package because they are basically mating clones to each other. By the second or third generation, there would be no possibility for variation except through mutation. Any differences in the mantids that result from this process are then either the result of environmental factors or chance.

Selecting for genes would require keeping and trading for many distinct bloodlines and extensive record keeping to keep the thousands of mantids straight.

 

[kakistos]

One more thing to consider is the limited variation of genetic material in the captive population. Most people who raise generations of a particular species seem to keep recycling the same genetic code.Consider that every nymph that hatches from an ooth had the exact same two parents (which were probably also "littermates"). Even if the two parents were unrelated, the nymphs that result from their breeding will all be genetically identical. If the breeder then breeds the offspring, they are further concentrating the single genetic package because they are basically mating clones to each other. By the second or third generation, there would be no possibility for variation except through mutation. Any differences in the mantids that result from this process are then either the result of environmental factors or chance.

Selecting for genes would require keeping and trading for many distinct bloodlines and extensive record keeping to keep the thousands of mantids straight.

It is true that the genetic variation in our breeding stock is very limited. Inbreeding will limit the variation further. But it does not go as quick as you say it will. Siblings don't share all their genes, siblings from unrelated parents have 50% over their DNA in common, statistically. Brother - sister matings increase the genetic similarity of the offspring, so a brother and sister that are 50% related get 75% related offspring. So 3th generation has 87,5% of their genes identical by descent. But for the last variation to disappear (and get clones) it takes a lot of time because the chance the last different genes will be lost decreases.

Selecting for genes would require keeping and trading for many distinct bloodlines and extensive record keeping

That's true. But is can be done if we take the time and effort. I don's see why we would want to select for other things than increased life span and better survival in our captive environments.

 

[Christian]

It seems to be more a problem of you Anglophonics. You breed for colors in everything: snakes, geckos, dogs, cats, fishes. As if nature isn't beautiful enough like it is.

Chun was right in saying that not all siblings are genetically identical. Some good percent of their genes are still variable between specimens. Further, there is a mechanism called recombination which mixes up some genes in every generation. Mutations, on the other hand, are rare. Most people only know mutations as a evolutive mechanism, actually it takes (usually) too much time to be expressed. On a smaller time scale selection (= gene elimination) and recombination are more important.

Even if considering this, you cannot breed a, say, blue mantis. Blue pigments are rare in insects, most blue seen is caused by interference colors. Mantids have "green" and "brown" pigments, and every selection whatsoever has to work with this two groups. White and pink belong to the "green" pigments (carotinoids and biliverdins), while black is a brown one (melanine group). Brown pigments are housed in the cuticle, green ones under the epidermis. The brown ones superimpose the green ones, that's why some species can be green or brown. The color itself is not genetically determined, but the ability to produce and use both pigment groups is. Color experiments have shown some mantid species to be able to get every color except blue and violet.

Even if someone had the possibility to do a selective breeding experiment, you cannot get everything you want, regardless on what time scale. If something isn't genetically available to a certain group, you cannot get it expressed in the phenotype, regardless how long you're trying it.

 

[vafan13]

oh and finally... i think there is a max size for invertibrates anyway, i dont think an insect the size of the one in that picture would be able to lift its own body off the ground, maybe if it was aquatic? but i've never heard of an aquatic praying mantis lol but i believe there have been aquatic arthropods in the early chapters of earths life that were quite massive?

I don't believe weight has anything to do with it. Bugs have enormous strength:weight ratio. The limiter on insect size is their method of "breathing." It simply can't scale up with the increase in size, after a certain point.