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Message: <blockquote data-quote="Stan Schultz" data-source="post: 226225" data-attributes="member: 28438">First, as far as I have ever known (note that important qualification), the genetics of sex inheritance among tarantulas follows the same rules as that of most other animals on planet Earth. (Aphids and alligators, among others, are distinct exceptions however.) That is, approximately equal numbers are produced during normal reproduction. (More qualifiers!) But, if any of you have reliable references to literature discussing tarantula genetics, especially with specific reference to genetic determination of sex, I would appreciate being sent an E-mail pointing me to your reference source. (My E-mail appears in my sig, below.)But this seems to refute my theory of equality between tarantulas' sexes!  The following story may shed a little light on the matter. A dealer I knew several decades ago by the name of John (all names are fictitious to avoid my being sued for defamation of character or a visit by the "Boys from Detroit!") had a major portion of his house turned into a warehouse for all manner of creepy-crawlies. Arachnids occupied what used to be the master bedroom (the "tarantularium") filled with an assortment of shelves, bookcases, and tables. (John slept on a couch in one corner of the living room. A sacrifice by a true devotee!) And each kind of tarantula had its own assigned space somewhere in this labyrinth. A local high school kid (I'll call him Bill) would come in about every second evening and search through the hundreds to thousands of various vials, bottles, and deli cups, looking for freshly molted tarantulas. He'd collect these containers, with their inhabitants, placing them on the end of a small desk near the room's entrance. John had also supplied him with an inexpensive, binocular, dissecting microscope, and the various tools and supplies required for the job of sexing these tarantulas. And Bill would spend several hours going through the containers, shed skin by shed skin, looking for proven females, and marking each such container with the symbol for female with a felt tipped marker.At the end of each session, all the containers with their tarantulas would be returned to the shelves from whence they came. (This is an important datum!)During the course of filling various orders for tarantulas, John would go back into the tarantularium, grab the appropriate number of vials, bottles, and/or deli cups of the required kinds. If no sex designation was given in the order, John grabbed the unmarked containers. However, if a female had been ordered (at an appropriately higher price), he grabbed a container specifically marked as female.Now, think about this for a moment. If I am correct in that tarantulas come into this world with approximately equal numbers of males and females (notice that qualifier again), and if John had 100 tarantulas, then there should be very close to 50 males and 50 females on that shelf. And if you ordered a dozen of them, on average you should get 6 of each sex, right? (But see the note at the end of this posting.)But, if someone places an order for five guaranteed females, after filling that order, there would be only 45 females left on the shelf, plus the original 50 males. Hence, if you walked in immediately thereafter to buy a tarantula of any random sex, the probability of you getting a female was lessened by a fraction, and skewed in favor of you getting a male. (See an explanation for this in the footnote at the end.) And each time this scenario recurs, the relative number of females continues to diminish until John has little or nothing but males to sell! In which case, eventually, you're almost 100% guaranteed that you're going to get a male unless you specifically request that you want a female.And thus, around the world, I'm seeing dozens, if not hundreds of light bulbs blinking on over tarantula enthusiasts' heads. It's a glorious sight indeed!StanFootnote:Before the transaction noted above, your probability of getting either sex would be 50 out of 100 = 50/100 = 50%.After this specific transaction, the probability of getting a female would be 45 out of 95 = 45/95 = 47.3%. And the probability of getting a male would be 50 out of 95 = 50/95 = 52.6%. Thus you have about a 5% better chance of getting a male than a female! (52.6% - 47.3% = 5.3%)If the same transaction happened a second time in succession, the probability of getting a female would be 40 out of 90 = 40/90 = 44.4%. And the probability of getting a male would be 50 out of 90 = 50/90 = 55.6%. AND, you now have an 11% better chance of getting a male than a female! (55.6% - 44.4% = 11.2%)Your homework assignment is to repeat this process until there are no more females left. <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite12" alt="o_O" title="Er... what?    o_O" loading="lazy" data-shortname="o_O" />Hint: Remember that probabilities are never hard facts, but rather chaotic approximations, and therefore highly variable. In reality, after some number of instances for each such transaction, the percentages would only mark the center point for the results of all similar tests (instances). [Probability and Statistics 101 <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile    :)" loading="lazy" data-shortname=":)" />]</blockquote>

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