Tuesday, February 11, 2014

Picky Spiders


             One of the best things that can make a person’s day is to receive a gift. Nothing like a free present from another person makes you as happy as possible, but only if it’s good. Like humans, animals also give gifts to other members of their species, but usually it is with the intent to mate and not just a kind gesture. A big part of sexual selection for animals has to do with choosy females, who choose their mates based on color, markings and - in this case - the gifts the males provided. One such species that provides a good example of this is the spider species Paratrechalea ornate.

             In an article from Discovery News - which you can read here - explains research done that shows that females of Paratrechalea ornate choose males not just based on the gift, but on the color of the gift as well, specifically the “whiteness”. The females do this because based on the gift the male gives clues the female in on his physical condition, thus indicating he has good genes to pass on. Now when it comes to the “whiteness” of the gift, scientists theorize that it has to do with when the spiders are the most active, which would be during the nighttime. So the males that produce the brightest silk wrapping are easy for the female to spot and that in turn shows how the male is very viable. For in order to make a gift that bright and white takes a lot of silk, something a weak male spider could not do.

             Now not all gifts are what they seem. The species of spider Pisaura mirabillis will disguise their gift, so instead of something the female would want like food, she will then receive her favorite gift ever, ant husks! Now who wouldn't love that? So the male gets what he wants and the female gets hustled.

          So the next time you receive a gift, try and think of what's going on. We humans aren’t so much different from the animals that play this game of sexual selections with gifts. We like gifts and we like the person who gave the gift, yet the reproductive lives of spiders and other species revolve around this concept. Just another great area of biology that continues to amaze.

Posted by Jacob Geier (2)

4 comments:

  1. Interesting take comparing female spiders and us women. Going off of what you've said, I think that it is pretty safe to say that spiders and women use the same methodology to pick whom they choose to pair themselves off with. Paratrechalea ornate females want a nice, white gift. Women want a nice engagement ring, or flowers just because, or a decent piece of jewelry. The nicer the gift, the better indicator of said male's viability. This is true to both spiders and humans. Female Paratrechalea ornate use the whiteness of the gift to determine if that male will produce the best offspring with them; women use the gifts (just receiving the gifts at all, let alone the gift actually being something nice) to determine the man's willingness/ability to provide for her and her future children with the man. More viable spider means more viable offspring; more viable human means more/better support for future or potential offspring. When it all comes down to it (based on what you've posted), all us girls really want is a man to buy us things and contribute to some offspring that will survive to adulthood!

    Taylor Schille

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    1. This is kind of what I was trying to get at little when making my post, so I'm glad you were able to pick up on it. Now its not all alike, but there are some similarities.

      Posted by Jacob Geier

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  2. Definitely an important concept in mating and reproduction. The better "characteristics" the male has, the bigger chance he is getting the female. This type of sexual selection occurs in many different animals and as you and Taylor pointed out, in humans too. Interesting read.

    -Samuel Ustayev

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    1. Thanks for the comment Samuel! This topic has always had my interest since I first learned about it in high school and then that knowledge was compounded due to my evolution classes in college. In my mind its always interesting to learn the mechanisms of how an organism actually finds a suitable mate and this article is just one example out of many.

      Posted by Jacob Geier

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