Help on my Hottentotta hottentotta

[tabor]

yes it can, I have seen some centruroides species giving birth at 6th instar

which species? there are quite a few centruroides species that mature at that instar.

I didn't realize they reproduced ONLY by parthenogenesis. Some animals can switch back and forth depending on the availability of partners, I mistakenly thought this was one of those cases.

in theory I be they could switch back if some how males were introduced to their population. in fact I would bet money on there being populations of H. hottentotta out there in the wild of Tanzania or some such place that still reproduce sexually.

I think I read an article that there is some species of Tityus (serrulatus perhaps?) that have confirmed both asexual populations and sexual populations. But I could be mistaken on this.

It just so happens that all of the Tityus serrulatus and H. hottentotta are parthenogenic, it doesn't mean that there aren't sexual populations of the species in the wild.


Again parthenogenesis isn't really my strong point but just of the top of my head and typing as the thoughts pop into my head that is what I pulled out of my memory banks... :?

 

[phear_me]

they are all females, they EVOLVED parthenogenesis as a means to survive. It is rare in scorpions but quite common in the animal kingdom. I mean, if there's no males around to breed with, they have to "come up" with something or go extinct.

Remember Jurassic Park? All the dinosaurs were females yet they some how managed to reproduce (parthenogenesis)

It's a perfectly sound and logical means of reproduction, there are plenty of asexual animals out there. Wikipedia it man!

For the record, evolution cannot possibly work that way. Organisms don't suddenly 'realize' they are missing a large number of one sex and then their genes somehow know about it and suddenly "make" another set of chromosomes. That would imply that genes have the ability to react to outside stimuli, which is simply false. Evolution, if it is indeed correct in its current description, is moved forward by mutation and natural selection. The mutation that elicits change is a random happening. Suddenly running out of males is wholly irrelevant to a random and impersonal process.

I don't mean to be a stickler about it, but it amuses me that every time someone talks about evolution they wind up making subconscious arguments for design.

 

[tabor]

For the record, evolution cannot possibly work that way.

I realize they don't "sense" a sudden shortage of males and instantly turn parthenogenic.

I'm looking for a good article describing how it evolved online, the two books I have, which are consindered must haves, just talk about parthenogenesis (but dont mention how it evolved) but go into way more detail about scorpions that give birth multiple times from one mating. It says that this strategy evolved in population where females outnumbered mature males by a number as high as 2:1.

My interest in the evolution of parthenogenesis is high, so if you can explain it before I find an article on it that would be nice

 

[tabor]

here is a good read:

http://www.scielo.br/scielo.php?pid=S0104-79301995000200002&script=sci_arttext&tlng=en


it's interesting, and one of the best articles i've read on the subject. to be honest i dont think anyone knows how long it takes something like that to evolve in a species of scorpions. They give reasons for WHY it evolved, but not how. And the article also touches on the benefits of parthenogenesis versus conventional bisexual reproduction.

 

[tabor]

I'm talking to a very good board of people about how it evolved, as well as the two leading scorpiologists in the world about how it evolved. So, they all admit its a really gray area, i mean, the know the benefits of it, and possibly why it happened, but i mean, scorps have been around for 400mil years... The fossil record is sparse, and almots non-existance for modern day species. Plus, if you find the fossil of a scorp, there is no way to say OH it was parthenogenic!

So i am trying my best to figure out WHY rather than when, but believe me, it is in line with evolution. Scorps are a "survivor" (k or r in science talk, i cant remember) species, they want to get as many of their off spring out there as efficiently as possible, especially buthids.

Once I piece together as best I can I will post a new thread with links to articles or atleast quotes from scorpiologists to back up my best guesses.

that's all im posting in this thread as i dont like arguing with people who completely misinterpret what i wrote.

 

[alexi]

For the record, evolution cannot possibly work that way. Organisms don't suddenly 'realize' they are missing a large number of one sex and then their genes somehow know about it and suddenly "make" another set of chromosomes. That would imply that genes have the ability to react to outside stimuli, which is simply false. Evolution, if it is indeed correct in its current description, is moved forward by mutation and natural selection. The mutation that elicits change is a random happening. Suddenly running out of males is wholly irrelevant to a random and impersonal process.

I don't mean to be a stickler about it, but it amuses me that every time someone talks about evolution they wind up making subconscious arguments for design.

Pretty sure that wasn't a subconscious argument for design. All he was saying was that if a group of female scorps run out of males and they don't have a different mode of reproduction they die out. So in a species that has a high female-male ratio, evolution favors them if they can reproduce parthenogenically when the need arises. I know he said "come up" with something else, but those quotes seemed to "suggest" to me that it was a "figure" of "speech." I know what you mean, but evolution is just a lot easier to talk about as if it had intentions. It's kinda like physics or chemistry - you always hear people say "the atom wants a full valence shell." Of course an atom doesn't have any desires, but physical laws operate in such a way saying they "want" a full valence shell gets the point across easily enough. It's a lot easier than a long winded description about orbital stabilities. Sorry if I'm coming off like a jerk or something, but as long as we're being "sticklers"...

 

[tabor]

thank you for helping clarify stuff alexi

i understand evolution, but i challenge ANYONE to try and make an educated, easy to understand, explanations of how parthenogenesis evolve in scorpions. And oh, keep in mind, no one knows exactly why it happened, and just hint at theories and inevitably involves a break-off population that emerged from a sexual population that began to run low on the ratio of mature males to females.

 

[alexi]

and just hint at theories and inevitably involves a break-off population

Isn't that how most new separate species are supposed to be formed?

 

[tzuruchi]

Wow, this topic has gotten to another level, well anyway I just got my camera back after having it cleaned, here's a few decent pictures of one of them. Are they fat, thin or just right? Don't know what instar they are right now but they are around more than an inch from their mouth to the tip of the tail.

 

[tabor]

Isn't that how most new separate species are supposed to be formed?

yes, so in most cases they are a new species, who knows what happened to the other part of the population? Remember 400 million years of evolution.

There are some cases where there are parthenogenic populations of a species AND sexual population species. In these cases, the parthenogenic population has the benefit of rapid, steady growth, enough to out number their non-parthenogenic counterparts. What are the cons? Swapping of DNA and the benefits of sexual reproduction stop.

What about the sexual populations? Are they a different species? I mean, physically they seem to be the same, but they reproduce entirely differently. Scorpion taxonomy is a mess as it is, and with so few cases of parthenogenic populations and sexual population of the same species i think it will be a while before things are sorted out. Will they eventually be described as a seperate species? It is possible, perhaps likely.

Here's a thought experiment for you - What if you started reintroducing males into the parthenogenic population that is nothing but females? Would they begin to breed sexually? Would the males even attempt to breed with them? Furthermore, how would we know (if they did breed) that the resulting offspring were the result of a sexual breeding and not parthenogenesis? (the likely answer the the last question is that there would be males and females in the brood.)

We're talking cutting edge research in the field of scorpiology. I can't wait until someone smarter than me figures it all out

 

[tabor]

Wow, this topic has gotten to another level, well anyway I just got my camera back after having it cleaned, here's a few decent pictures of one of them. Are they fat, thin or just right? Don't know what instar they are right now but they are around more than an inch from their mouth to the tip of the tail.

they look to be about 3i (maybe 4i) and average weight/bulk. keep up the good work. they can be slow growers at times, but the pay off is worth it :clap: