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That is extremely unlikely if not impossible to take a sample of 50 out of 100 (in a 50/50 situation) and all of them be the same gender.
Ratio of Males to females
- Thread starter Bengal21
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Yes i agree, Just an example of the possibility. My point: If you dont take the whole sac then you cant really make an accurate conclusion.
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Well it would be a good start by taking a sample so you can generalize the findings for that species. Raising a whole sac would be too time consuming. In order to get an accurate conclusion you would have to raise more than one whole sac. Either way, it would be a good study.
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Arachnosquire
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Some species can be sexed since they are lings on their first instar (I mean, after the postembryo).
I have done it myself with Poecilotheria spp. with excellent results.
So, sex an entire generation of Poecilotheria spp. is not so time-consuming. Even if you can't sex them on their first ling instar, they grow up very fast. All you need is a good stereo microscope (and an eggsac, LOL).
I have done it myself with Poecilotheria spp. with excellent results.
So, sex an entire generation of Poecilotheria spp. is not so time-consuming. Even if you can't sex them on their first ling instar, they grow up very fast. All you need is a good stereo microscope (and an eggsac, LOL).
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I have tried sexing a 2nd instar molt from a pokie and its no walk in the park.
Im curious. How many 2I pokies have you sexed with a microscope and you turned out correct when they got upto the 2" mark?
i belive its not 50/50 sac but more like 50/50 per egg depending on unknown variables, (here is a random thought source: my mind) slow growing tarantulas = more females becouse of the lack of adquate growth rate, faster growing tarantulas = more males becouse of the rate of growth alows for males of one generation to mate with femles of older generations ... hmmmm lack of sleep malkes me think of bad ideas
The longer life span of females makes me think that there would have to be more males. If your average male lives to be 4-5 years old vs females being 4 to 5 times that number, the number of females out there would very quickly outnumber the number of males if the sac ratio was 50/50.
Murphy's law also tells me that since I want a pet that lives for 20 years instead of having to replace one every 5, I will get tons and tons of males, while hoping for females instead.;P;P;P;P;P;P
Murphy's law also tells me that since I want a pet that lives for 20 years instead of having to replace one every 5, I will get tons and tons of males, while hoping for females instead.;P;P;P;P;P;P
how many do u think out of a wild sack make it to adult hood? i doubt there is a hight survival rate natural predators, elements, and the countless ways to die
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Heres my theory: You can talk circles about your theorys all day and get nowhere. I could say theres more males because they have to take a greater risk by moving in the night searching for females that dont wander.. :liar: That doesnt make it true. On the other hand i could say there are more females because they are needed to produce sacs. Sacs that have a great risk of them being abandoned, eaten or going bad. :liar: These are just theories i pulled out of my butt in 2 minutes with no evidence to support it. :razz:
Offkillter
Arachnosquire
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Imagine how much you could pull out in an hour!:barf:
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Heres the truth! Theres more females.. because thats what people want more of!!
It all depends on the species/genus and the environment that they naturally live in. A place with ALOT more predators I would think to have more males than females per sack... Or heck, maybe in a place with more predators the sack will contain MANY more slings to do the higher danger/fatality rate while they grow. Heck, there could be more males to females in a species because the ladies in that species because the ladies are always hungry when the men come to call. Many many many contributing factors for each and every species/genus.
I just pulled all them outa my bunghole too, in like 5 minutes though lol
I just pulled all them outa my bunghole too, in like 5 minutes though
lol
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Nobody really knows because it hasnt been experimented with..
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Arachnosquire
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I would like to have an eggsac to practice more, hehe. I have tried to sex about 15 first and second instar (as lings of course, not as legs with eggs) Poecilotheria, most of them ornata, some rufilata and a few fasciata.
The 2 fasciata are still lings (and I can't tell the sex, they seem to me more difficult to sex than the other species); the other spiders were sold. The cases I was sure of the sex, I didn't failed. There were other cases (about 3) I just couldn't tell until they were third instar, but as I said, they grow fast and were accurately sexed.
And, BTW, I didn't sexed them looking for the spermathecae (or uterus externus) in the exuvia. They were sexed directly from the ventral view, observing the epigastric furrow zone in the (alive) spider itself. Of course I need more practice, and I think it can't be accurately done with all species (some are easier to be sexed, as Ceratogyrus spp.), but I also think it has been done before by some breeders who want to keep some females for themselves (or for selling them later).
Man, I think I suck at grammar.:?
Anyway, I have some new slings and I have tried to sexed them. I'm going to sell them, but I will stay in contact with my clients to know what they turned out to be (M or F). Also I'm keeping some for myself, so when they grow up I will see how the microscope sexing works in other species.
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Honestly sexing a 2I and 3I molt from a pokie is like tranlucent epiandrous fusillae sexing. You would have to make very keen observations and take pictures and then check back when they are older to be sure. I have an 80X microscope and even then its just really hard because the hairs are so massive and get in the way. Ive sexed 1" molts from a Aphonopelma and they have massive furrows as slings!! Avics are also alot like pokies.. small furrows and massive hairs that cloud everything..
Maybe we can shave our 2I pokies and Avics vents so we can see the furrow if its there?
Maybe we can shave our 2I pokies and Avics vents so we can see the furrow if its there?
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Arachnosquire
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Not in my opinion, it is a lot more difficult to sex Avics for me. But everyone have different experiences, and it's OK.
The shape of the epigastric furrow (and the zone between the anterior pair of book lungs) in Poecilotheria slings is quite different between males and females, IME. Anyway, more results are needed to conclude something like an average accuracy of "X" percent in ventral sexing of slings.
But the possibility is interesting, isn't it?
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I've been wondering about this topic myself lately. I study wasps, with sex ratio dynamics as my focus, so I've come up with some theories...
We tend to see shifts in sex ratios away from the normal 1:1 ratio when there is an advantage to doing so, plus there is a mechanism that allows this to happen. Wasps happen to have both. Unfertilized eggs develop into males, so the mother can simply choose which eggs not to fertilize, and viola: she can choose to make sons or daughters.
I'm not keen on how tarantula sexes are determined, but it's likely to be something similar to how insects do it (there are several ways). Anyhow, I'd say there would be a benefit to Ts to produce more sons. Since female Ts live much longer than males, if equal numbers were produced, you'd have a lot more females around than males after a few generations. Whenever one sex is more plentiful than the other, the rarer sex is more "profitable" to produce. The dangers of seeking out mates wouldn't really explain a different ratio, but that's complicated to explain.
I'd love to see some scientific work done to see what the sex ratios of tarantulas are. My guess is that we'd see more males in species where females lives much longer than males and where males are not likely to mate multiple times.
We tend to see shifts in sex ratios away from the normal 1:1 ratio when there is an advantage to doing so, plus there is a mechanism that allows this to happen. Wasps happen to have both. Unfertilized eggs develop into males, so the mother can simply choose which eggs not to fertilize, and viola: she can choose to make sons or daughters.
I'm not keen on how tarantula sexes are determined, but it's likely to be something similar to how insects do it (there are several ways). Anyhow, I'd say there would be a benefit to Ts to produce more sons. Since female Ts live much longer than males, if equal numbers were produced, you'd have a lot more females around than males after a few generations. Whenever one sex is more plentiful than the other, the rarer sex is more "profitable" to produce. The dangers of seeking out mates wouldn't really explain a different ratio, but that's complicated to explain.
I'd love to see some scientific work done to see what the sex ratios of tarantulas are. My guess is that we'd see more males in species where females lives much longer than males and where males are not likely to mate multiple times.