Tuesday, February 11, 2014
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)