Cryptic Sexual Selection

[mtolypetsupply]

Was watching a show on PBS last night about sexual selection of different species. It was awesome, because there was a segment about Garters, Red-Sideds specifically. I think they were at the Narcisse Dens from the writhing mass of breeding balls that made the ground come alive!

Anyway, they talked about "cryptic sexual selection". It's "cryptic" because it is not observable- it happens within the dam.

We know what happens:

Garters emerge from dens, males first, who then lay in wait for the females to emerge. When they do, the horny little buggers pile on, and whomever manages to get the hemipenes where they need to be gets to breed her. The lady, indignant from the assault, high-tails it away from the group of horny boys, with a sperm plug preventing further mating at that time.

After 36 hours or so, the plug falls out, and she again becomes attractive to males. Now, however, she's warmer, and smarter, and attempts to select a mate from the suitors that find her. Still, often upwards of 10 males can find her and attempt breeding. Now that she has her wits about her, she challenges them by racing away. Whomever can keep up, or whatever other criteria they use to choose a mate, gets to mate with her. After their mating, she may mate with more males, after the plug falls out, etc. etc. etc.

Now, here's the coolest part, IMO.

The biologists say that now that she has sperm from two or more males, somehow, (they didn't explain how) she can CHOOSE which sperm to use. They didn't get into mechanics, or whether it's truly conscious choice, or a function of something else entirely. The "choice" has evolved as a mechanism so that the early breedings, which may just be an undesirable male who truly "got lucky" and took advantage of her slow metabolism, can be discarded in favor of a superior mate.

They also did not get into whether or not, if bred by only one unacceptable male, she could reject the sperm and not fertilize the eggs.

Does anyone else have info on this? Does this apply to other genus? I'll do some poking around the net.

:)

[drache]

that is so cool, Stephi
thanks a ton
do you remember the title of the show?
- was trying to find it on their site

[mtolypetsupply]

Okay, here's the link:

Video: Full Episode - What Males Will Do - Mating and Sexual Selection | Nature (http://www.pbs.org/wnet/nature/episodes/what-males-will-do/video-full-episode/5374/)

Chapter 4 is what talks about the garter and cryptic selection

[guidofatherof5]

Very interesting.

[mtolypetsupply]

Very interesting.



LOL I have an image of the old school Laugh In, Artie whats-his-name in a german outfit saying "Very Innnnnteresting"

LOLOL!

[drache]

can't wait to see it
while we're on the subject . . .
I just picked up "Dr Tatiana's Sex Advice to all Creation" from someone's "free" box
I don't think garters are mentioned in it though, or at least not sufficiently to make it into the index

[Nafun]

"Dr Tatiana's Sex Advice to all Creation" sounds like a porno.

[drache]

"Dr Tatiana's Sex Advice to all Creation" sounds like a porno.
well, yeah . . .
except I don't think it's not got that much on human sex, but I could be wrong
the impression I got, as the dog was pulling me on to the next smelly spot, was that it's more about the weird mating strategies of other species. Who knows - there may be analogies drawn to our species at some point
I'll let you know if it turns out to be truly exciting despite the lack of garters

[ConcinusMan]

That was a very cool video. I think it might be a little misleading? I think perhaps the female holds off on ovulation, ejects the sperm, mates again, then ovulates, thus fertilizing her eggs with the second mating.

T.ordinoides have been found to mate up to 3 times in spring, then ovulate, then having babies from 3 different fathers in one litter in mid summer! Some of them skip the spring mating, and mate in fall, hold the sperm, ovulate in late winter, then have late spring babies.

[drache]

at last got to watch it - very cool
I have to say that I'm a bit entranced with the lyre bird - especially when it makes the camera shutter sounds

[ConcinusMan]

at last got to watch it - very cool
I have to say that I'm a bit entranced with the lyre bird - especially when it makes the camera shutter sounds

We have european starlings (I'm not going to mention how I feel about them being here) that mimic creeking gates, other birds, children playing, frogs croaking, horns honking, you name it. They are excellent at mimicry.

[mtolypetsupply]

That was a very cool video. I think it might be a little misleading? I think perhaps the female holds off on ovulation, ejects the sperm, mates again, then ovulates, thus fertilizing her eggs with the second mating.

T.ordinoides have been found to mate up to 3 times in spring, then ovulate, then having babies from 3 different fathers in one litter in mid summer! Some of them skip the spring mating, and mate in fall, hold the sperm, ovulate in late winter, then have late spring babies.


Since they didn't explain the mechanics, if it does happen how you hypothesize, I can't see how it would truly be "misleading". But you bring up a good point, what ARE the mechanics of it??? Do you know of research to back up your hypothesis?

I poked around the 'net a while, and didn't find anything specific to garters. However, I wasn't able to be thorough in my research as I was dealing with my daughter who was most disgustingly ill. I'll spare the details of THAT little experience.

:)

[ConcinusMan]

What I meant by "it's misleading" is that it gives you the impression that the snake can hold sperm from both males, and somehow magically choose which sperm fertilizes the eggs. The "mechanics" of it would make that assumption absurd. Sperm from one male must die or be ejected before ovulation happens, otherwise, the eggs could be fertilized by any sperm the female is holding, including sperm from multiple males. In that sense, the female is in control. She doesn't have to ovulate and use the sperm from the first mating. Unlike humans, she can and sometimes will, delay ovulation or not ovulate at all.

As far as the T. ordinoides are concerned, they have been the subject of many studies due to their odd reproductive behavior and polymorphism. It is well established that what I said about them is true but I'm not going to go searching for articles to show you. I've observed the same thing in captivity,(fall and spring matings) in the wild, and read many published papers on it. T. ordinoides do give birth to multiple-sire litters and some mate in fall, some mate in late winter/early spring. I have seen mating balls of them happen in late winter when they emerge, at the same time other females are giving birth. Same thing happens in the fall. Some have just given birth, others are mating right before brumating.

In other words, some mate upon emerging, some mate before going into the dens for winter. Female T. ordinoides are notorious "floozies" (didn't want to use the "s" word). They sleep around, then ovulate, and litters can have multiple fathers. The end result is two different times of the year for mating, two different times of the year for birthing. No one snake does twice a year mind you.

[mtolypetsupply]

It is well established that what I said about them is true but I'm not going to go searching for articles to show you. .


Richard, maybe it's just me, but you seem a little miffed that I asked for research. I apologize if you think I was being a jerk.

It's just that I am a TOTAL NERD, and seriously LOVE scholarly articles. I'm not being a wise guy one bit when I say this. Pop culture snippets spark my interest, but I'll then spend hours perusing any journal articles or research I can find.

I just figured if you knew of an author, or paper, or could quickly point me to something more, it would be a nice read. It's 98 degrees with 100% humidity outside, and the a/c is on inside. I usually have an hour while the little one is napping. Until things get more bearable outside, info you passed along would be a fun read during the kid's nap time.

Again, sorry if you thought I was being a jerk.

:)

[adamanteus]

I've not read through this whole thread in any real detail, so please excuse me if I'm missing the point....
It's interesting to read what you said, Richard, about no one female ordinoides mating and producing young twice in the same year. By contrast I've observed marcianus females mating (and producing litters) twice in one year.

[ConcinusMan]

Richard, maybe it's just me, but you seem a little miffed that I asked for research. I apologize if you think I was being a jerk.

It's just that I am a TOTAL NERD, and seriously LOVE scholarly articles. I'm not being a wise guy one bit when I say this. Pop culture snippets spark my interest, but I'll then spend hours perusing any journal articles or research I can find.

I just figured if you knew of an author, or paper, or could quickly point me to something more, it would be a nice read. It's 98 degrees with 100% humidity outside, and the a/c is on inside. I usually have an hour while the little one is napping. Until things get more bearable outside, info you passed along would be a fun read during the kid's nap time.

Again, sorry if you thought I was being a jerk.



I don't think you're being a jerk and asking for research is perfectly reasonable. I just don't feel like finding it for you. Much of what I said about ordinoides reproduction was in books, long before the internet. In fact, If I remember right, one of the books was the very first "Reptiles and Amphibians of the Pacific Northwest"


I've not read through this whole thread in any real detail, so please excuse me if I'm missing the point....
It's interesting to read what you said, Richard, about no one female ordinoides mating and producing young twice in the same year. By contrast I've observed marcianus females mating (and producing litters) twice in one year.

It wasn't MY determination that no one female produces young twice a year, it's just something I read in a book. Also, two litters in one season has never happened in my experience keeping them. You do have to consider the short season that most T. ordinoides have. Around my area, they have perhaps 5 or 6 months of activity, and only about 4 months of that is warm weather. 5-6 months of the year here, it's impossible for ordinoides to even survive on the surface. Marcianus on the other hand, due to their range and the climate, have all the time in the world and pretty much don't even need to brumate.;)

My red striped T. ordinoides girl is very gravid and should pop any day now. My closest reasonable guess is that she mated in Feb, and ovulated some time later. She still hasn't given birth (but she's close). Even if she mated again immediately, there's no time to have another litter before winter sets in. They only have about 90 more days before they den up underground again. And yet, at the time she mated, other snakes could be observed giving birth. :cool: There were newborn babies everywhere, and yet other snakes were just now at that time, getting fertilized. The snakes that gave birth in spring will be mating this fall when it's time to "den up"