Thursday, January 22, 2015

Made for Maury

By: Jason Kent

     If you have ever seen Maury, which I haven’t, I doubt you would admit it either. It’s one of those guilty pleasures; the thing you know you shouldn’t be watching but do anyways. You can always tell when you aren’t the target audience of the show you are watching from the types of commercials. You know, during football games you see trucks, Brett Farve and Warangler jeans. During The Price is Right, you see pills, motorized chairs and someone yelling “Help I’ve fallen and I can’t get up!” Well, if you watch Maury, which I don’t, you would know that during the breaks, they advertise paternity tests if  you or someone you know suspects a significant other of having an affair with the next door neighbor, who also happens to be your brother, or dad, or something like that. You know what I mean. My friend who watches the show, sometimes wonders if those crazy stories are actually real. Do Samantha’s three kids each have a different father, none of whom are her husband? I don’t know. But you know what? I wouldn’t doubt it. Why? Because if there was an animal version of the Maury show on the Discovery Channel, all of these stories would very likely be true, and there would be worse. And by worse, I mean trashier- so better. Don’t believe me? Fine, I’ll show you. I will give you animal Maury. I’ll call it Animaury. No, that’s awful. Maurnimal. Okay, Animal Maury it is. I will open your eyes to the animal world of sex scandals, deception and manipulation; the world that makes the stories seen on Maury seem boring:

     “Today we have a special guest. Welcome Tribulium castaneum! T. castaneum, the red flour beetle who we’ll call John, is here to share his concerns about his significant other, Paula. You see, John and Paula recently had about 50 kids together. At first everything was fine; the eggs were laid in flour and started hatching after 10 days. However, John’s friends started mentioning how they don’t really look like him. Now that got John thinking. Paula had been spending a lot of time away and he never knew where. Well that’s where Ringo comes in! Turns out Ringo is another beetle who Paula had been seeing on the side.

 
     Before getting into the DNA results, there are a few things working against John. A study by Haurbruge and others showed evidence of successful double matings, meaning, it is possible for John and Ringo to both be the fathers to some. Unfortunately, it was also shown that the second male to mate had precedence over the first male; fertilizing 66% of the eggs. This precedence is thought to be due to the selective ability of males to remove rival sperm from previously mated females. Electron microscopy of the aedeagus, the reproductive organ which sperm is secreted through and is shown below (left), was found to have a concave furrow. Additionally, it is covered with chitinous spines (middle) which the sperm of the first male can adhere to, shown below (right), resulting in the removal of that sperm.
(a) Concave furrow of aedeagus of T. castaneum. (b) Array of chitinous spines. (c) Mass of sperm adhering to spines. 
     For John, this is potentially devastating. Not only did he find out Paula was sleeping around, but it turns out the lie detector tests showed Ringo wasn't the only one. In fact, all flour beetles are promiscuous- the average time it takes for beetles to mate (78 seconds) is actually longer than the average time it takes to move onto the next mate (69 seconds). Add on the fact that any of those mates could be the father of any of the offspring, and John finds himself in one complicated mess. So that brings us to where we are now. About to read the results of the paternity test, on Animal Maury…right after a word from our sponsors!

  
     Welcome back! The tests are in! In the case of 2 week old 50 kids, John, you are NOT the father! Okay, okay. Take a seat. There’s more. John, we asked you if you had ever been unfaithful to Paula and you said no. Well the lie detector determined, you were telling the truth. However, despite that result, while performing the paternity tests, we found that you actually are the father of another set of offspring, those of Ringo’s significant other, Georgina. Okay, this is getting confusing so let’s get some things straight. There are four beetles: John, Paula, Ringo and Georgia. Paula cheated on John with Ringo, and Ringo is the father of her kids. Then Ringo had sex with Georgia, and John is the father of her kids! Even though the two of them have never met! How is this possible? Well as it turns out, the Haubruge study also showed that upon sperm removal by a second male, the sperm can actually survive on the aedeagus for at least five minutes, and because the interval between mating is so short, that sperm can actually be translocated into new females. Let me repeat that for you: the sperm can actually survive on the aedeagus for at least five minutes, and because the interval between mating is so short, that sperm can actually be translocated into new females. Now let me repeat that for you in a simpler way rather than word for word. John got Georgina pregnant without having sex with her. Not only that, but it was shown that more than half of the progeny are from egg fertilization by the translocated sperm, rather than by the sperm of the mating male. This means that the selection generated by removing a previous male’s sperm has also developed into counter-selection, where the translocated sperm is able to outcompete new, rival sperm. 
     
     The implications of this finding are significant. While seemingly counter intuitive to aid in successful fertilization of rival sperm, it does suggest an alternative method for distributing genes that aid in the survival of a population. More importantly, the findings make it clear that no good will come of continuing paternity tests of these offspring. Unfortunately, most of them will grow up being unsure who out of the entire local male population their father is. Imagine what that could do to your self-image. Well that’s it for today’s segment of Animal Maury. Next time, we will meet a female house sparrow (Passer domesticus) and hear how her jealousy lead to her killing the first born of her significant other’s mistress. Also as a special treat, the female brown trout (Salmo trutta) reveals to us that she fakes orgasms for her lovers. Sound familiar? We’ll you’ll never believe why! Until next time, on Animal Maury!

Beetle Beatles

References:

Haubruge, E., L. Arnaud, and M.J.G. Gage. 1999. Fertilization by proxy: rival sperm removal and translocation in a beetle. Proceedings of the Royal Society B 266:1183-1187.

Pai, A. and G. Yan. 2001. Polyandry produces sexy sons at the cost of daughters in red flour beetles. Proceedings of the Royal Society B 269:361-368.


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