# Inbreeding



## specy (May 16, 2005)

Hello,

The other day my friend asked me if inbreeding is going to cause problems with mantis. That is, when you hatch an ooth, raise the nymphs, mate them, produce another ooth, raise the nymphs, mate them, ......... , until forever, is that going to make the mantis smaller, weaker or more vulnerable to diseases because of the lack of genetic variation?


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## Jackson (May 16, 2005)

with most animals i believe the first few times you mate them there will be no problems with inbreeding...however, mantids are not like most animals. Interesting topic, it will be good to see the answers to this.


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## Max (May 16, 2005)

Do people breed mantids like dogs for desired qualities or traits?


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## Jesse (May 16, 2005)

A lot of people assume inbreeding is harmful to insects and other invertebrates, but this is not necessarily true. As far as I know/last I checked, there is no hard evidence that proves inbreeding is harmful to insect populations. A matter of fact many exotic/introduced insects were introduced in very small numbers or from the same eggcases and have flourished in their new habitats despite very low genetic variation. A lot of people attribute lost cultures/weak cultures to the effect of inbreeding, but that may not be the case at all (I could list examples but I won't at this time). There are some people that have kept the same bloodline of a species of mantid for many, many generations and still have yet to notice any ill effects. There are many examples of other insect cultures that have been inbred for up to 5 decades without any harmful effects.


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## Orin (May 16, 2005)

Mantis inbreeding reproductive inability is an extremely common myth (somewhat like females eating the males head as a requirment to remove breeding inhibition).

Mantids are not easy and most people can not keep them going for more than one or two generations, if that, so they use the excuse of inbreeding.

As you become very experienced with mantids (takes many years by definition as even the fastest species take time to go through many generations) the inbreeding myth melts in the face of reality.


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## Oneida (May 16, 2005)

concider this, after the last ice age there where but few thousand Humans on all the earth, now we are 5billion strong.

Sure there will be some genetic issues, but hey odds are you can chulk that up to Evolution, not to mention in the insect world, specially the Mantid world, the strong will eat the weaker, so any deformed births will not likely make it to breeding age, and will not be able to pass any negitive genes on to the next Ooth

At least this to me seems logical, i could be completely wrong


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## Jesse (May 16, 2005)

> concider this, after the last ice age there where but few thousand Humans on all the earth, now we are 5billion strong.Sure there will be some genetic issues, but hey odds are you can chulk that up to Evolution, not to mention in the insect world, specially the Mantid world, the strong will eat the weaker, so any deformed births will not likely make it to breeding age, and will not be able to pass any negitive genes on to the next Ooth
> 
> At least this to me seems logical, i could be completely wrong


You've got the right idea or at least your on the right track anyway.


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## specy (May 16, 2005)

Thanks for the replies. So it seems that inbreeding isnt a problem for mantids. I remember reading an article about wolf spiders a while ago:

http://news.bbc.co.uk/1/hi/sci/tech/3218509.stm

I suppose these guys just dont really care much about inbreeding. I guess, statistically speaking, with the amount of nymphs produced at each generation and the relatively short time span of each generation, enough genetic variations could be developed?

It would be interesting to see if mantids exercise the same behavour, (i.e., female less likely to eat the male if it looks familiar) coz for some species, the male also matures faster than the female.


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## Steve (May 23, 2005)

All this talk about inbreeding having no effect on mantids is a bit irresponsible if you ask me. Most mantid species have a wide dispersal upon hatching, and in many species, adult males have been known to fly great distances. The purpose of this dispersal is can't simply to ensure availability of food. Mantid keeping/breeding has only recently become popular, unlike other insects in the orders diptera or hymenoptera which have undergone breeding for more than 60 years. Just because some people have not noticed any complications within a short time period, doesn't mean there will be none in the long term. Insects CAN be susceptible to inbreeding depression, as a few studies have shown in dealing with ants, honey bees, and cockroaches. As we all know, cockroaches are very closely related to mantids being members of the order orthoptera. Some cockroach species have shown a decline in ooth fertility with longterm inbreeding, and successive ooths have been more fertile with a single instance of outbreeding. When I once kept Acanthops falcata, I noticed a similar trend. My initial success with inbreeding acanthops yeilded 20 or so nymphs per ooth. After 3 more generations, my hatch rate decreased to under 10. The noteworthy part of my experience, is that upon exchanging one ooth with another breeder, my hatch rate increased to around 25 when mantids from his ooth were bred with my own. Perhaps this is a coincidence. Perhaps not. I had also bred other mantid species with seemingly no effects with inbreeding. I suscpect that while inbreeding may have shown little effect in many mantid species, perhaps there are some that are more sensetive to it? Another thing to consider is that perhaps inbreeding has already had an unseen effect on captive inbred mantids. Being raised in an environment with hardly any fluctuations in temperature, humidity, percipitation; or exposure to pretadors, pathogens and whatnot; might eventually yeild weaker mantids. You wouldn't know if they were weaker having been babied in captivity. How would you know if your 5th or 6th generation mantids would still be able to survive as well if released back into the wild? I don't propose to be an expert in genetic sciences. But just out of curiosity, who here is? All I'm saying is that there is too little real research in this area to assume inbreeding is harmless to mantids or other insects in general. If you do some research into the purpose/exhistance of gender in evolution, you might find why nature in general, tends to have mechanisms to naturally avoid inbreeding. I'm not trying to get anyone hot-headed here. I'm open to the possibility of being wrong. I'm just providing my take on this issue. I really want to hear from more people on this issue!!! Anyone else want to step up? :wink:


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## Markus D. (May 23, 2005)

Hi,

yes, i agree with Steve. I think inbreeding could be aproblem, but it need a long time to be noticeable.

Wishes

Markus


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## Jesse (May 23, 2005)

A lot of the problems that appear to be caused by inbreeding could very well be attributed to nutrition. Different insects (even within genera) may need minute amounts of specific minerals/vitamins and amino acids to flourish. These specific minerals/etc. may be rare in the insects natural environment and non-existent in the insects artificial environment. Because of the rarity of these substances the insect female has adapted to be able to pass a portion of this substance to each of her eggs. In captivity this substance would be further and further diluted unless wildcaught stock was breed with the lab stock every so often (unless you figured out what the substance needed was and where it could be found). I hope that what I just wrote makes sense. I learned this bit of info from my Insect Biochemistry and Physiology course that I took a couple of years ago as an undergrad.


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## Steve (May 23, 2005)

An excellent/valid point Jesse! This has been well documented with all sorts of plant and animal species once thought to be impossible to cultivate and/or breed in zoos, aquariums, etc. Further research often resulted in meeting these needs and allowing captive cultivation/breeding. Thanks for mentioning that! It's definately something to be considered.


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## Joe (May 23, 2005)

theres a farm shop that has a breeding program breeding chinese mantids for their eggcases and they've been using the same bloodline for 13 years and i've never seen any problem when i hatch their ooths. they seem very normal like wild ones.

Joe


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## Andrew (May 23, 2005)

Well, if its a whole farm of mantids, there may have been a large gene pool to start out with. Probably plenty to go 13 generations w/out any harmful effects.

Thanks,

Andrew


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## Steve (May 23, 2005)

> theres a farm shop that has a breeding program breeding chinese mantids for their eggcases and they've been using the same bloodline for 13 years and i've never seen any problem when i hatch their ooths. they seem very normal like wild ones.Joe


I'm curious. How are you familiar with their methods as I've often wondered about this? Are you sure they are from the same bloodline? In the horticulture/agriculture trade, Chinese mantids are often bought from such farms. With the amount of ooths these farms must produce for retail sale, I'd imagine they initially started this buisiness with a large amount of collected ooths. As Andrew suggested, perhaps they initially collected enough genetic variation to further produce consistantly healthy stock? I highly doubt that all the ooths these farms sell across the country were from the same bloodline. I could be wrong. Having worked in the horticulture/botany field for many years, I have noticed something noteworthy. Have you noticed that the ooths from your mail order farm are rather small compared to ones you may find in the wild? Maybe the ones from your farm are just fine. I personally have observed Chinese mantid ooths that have been purchased from a few different suppliers, and the ooths received are sometimes very small. They also tended to yield fewer nymphs compared to wild collected ooths. Just an observation. Such things could be diet related though. Sorry to be so long winded on this subject. I just think this inbreeding thing is worth more conversation and consideration.


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## Andrew (May 24, 2005)

Sometimes the ooths that you recieve through the mail have been deprived of any moisture, causing them to shrink. After you give them a day or two with higher humidity they tend to expand and get bigger. I noticed this with some wild-collected parasphendale ooths that I recieved, and with a couple tenodera ooths that I picked up at a local nursery(the nymphs inside were shriveled up and did not hatch). However, I purchased two ooths from a different garden center(ooths were from a different company, too) and they were pretty small, and did not expand with increased humidity. One hatched indoors a couple of weeks ago(about a hundred nymphs), and I have around 14 strong nymphs left from it. Lack of a proper diet could have caused the small size of the ooths.

Maybe some nymphs dry out and die from the ooth being deprived of moisture, but I dont know for sure. Just thought id throw that out there.

Thanks,

Andrew


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## Christian (May 24, 2005)

Hi.

I followed the discussion for a while. Jesse, Steve, and Andrew are partially right: inbreeding exists; ooth size depends on size; inbreeding differs among taxa. So long there is an agreement.

The problem with the effect of good nutrition to the success of breeding is, that all carnivorous animals rely on comparable nutritional traits. There is, of course, bad food. But, one can solve this problem by enhancing food quality by wild-caught food and by nutrients and vitamines.

In Europe mantid breeding has a longer tradition. And there are in fact problems with those species that are rarely kept or for which no other bloodlines are available. But: it is also due to the low populations most persons keep. If you just retain one or two females for breeding, your success will not last but for a few generations. I often read things like this in this and other forums. In order to keep the genetic diversity of your captive population high for years, you need at least (!) 5 adult females and 10 to 15 males which have to be paired as often as possible. Too much effort, you think? Well, who said mantids are easy to keep? For one or two, say three generations - ok. But a real breeder needs only rarely fresh blood. And this is not for inbreeding, but for other reasons.

That is: When talking about inbeeding, most people think of degenerative inbreeding. But this form of inbreeding manifestates itself only after many years. Most bloodlines, though, dissapear earlier. This is because there is another problem which works here: the genetic diversity (diversity of alleles of one particular gene) decreases and thus the attractivity of a sister female to a brother male decreases. There are fewer pairings and the ooths hatch badly. Insects as well as some other animals (and humans) can detect the degree of genetic similarity by the pheromones emmited. And, the success of fertilization decreases with increasing genetic similarity.

Secondly, a low genetic diversity means a high degree of homocygoty (see genetics). Every new blood and thus new genes increase the degree of heterocygoty. For natural populations, a high degree of heterocygoty means a fitter population, which is able to face many naturally ocurring problems. That's why new bloodlines are needed: in order to keep the degree of heterocygoty as high as possible. That's why larger captive populations are much more stable than smaller ones: they retain much more different alleles ("kinds") of a particular gene, which can be variably recombined by every pairing. This is also the reason why you should pair your females (preferably after every ooth laid) with as much males as possible. Quantitatively, one mating is sufficient for fertilizing the eggs. Qualitatively, more than one is better!

Regards,

Christian


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## Orin (May 24, 2005)

> All this talk about inbreeding having no effect on


*The only thing truly irresponsible is to use the inbreeding myth as an excuse for lousy care of mantids. *

While genetic theoretical discussions may be fun to play with, the fact remains that old-time breeders have kept the same lines of many species for 15 plus generations with only an improvement over time. 'New blood' is avoided on purpose.

(Examples related to breeding: Cockroaches are mantids closest relatives and there are 'inbred' hisser lines more than 40 years old. Breeders don't mate different breeds of dog together for new blood because you ruin what was bred for in the old line).


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## Oneida (May 25, 2005)

per the original question, i honestly dont feel that inbreeding in mantids, could ever pose a real problem, becuase the sheer number of babies per, also the fact that any negitive mutation from inbreeding will never see a chacke to pass it along as it will have long since died due to nature liking to select only the strong to servive.

but i suppose that in captivity if someone was to experement they could keep the mutated Nymph help it servive attempt to reproduce it and see what happens

im not sure what the length the life cycle of a mandis is, but i dont see it being more than a year, so it would be a relitively easy experement i suppose


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