Science Buddies: "Ask an Expert"

I wasnt organizing making this expirement
1 day i.had a new fish tank and i had guppy fishes which are known for their colours
I had 1 male and 2 females in this tank , in the beginning the male began to approach both of the females
But when he started to mate he mated only with one if the females leaving the other 1 not mated
!!!
So when i noticed this i waited for a week and i had another female extra 1 and added it to the tank it looked exactly the same like the female 1 that the male chose to mate with as a test of me to him
,

But also he left it and the other and began to mate with te same female only that he had chosen from the beginnig!!!

So i separated the female he mated with to see what happens!
After a while he began to mate with the other 2
But when i returne the female he likes again with them he left them and began to mate with it again

( I thinks this may mean that animals also can choose which mate is better for her and it is not randomly as thought i think this was my conclusion)

When we come to the genetic part here !!!!!
After
Both fishes became pregnant and had fries the babies of the fish he liked was more healthy lived longer grew faster and their number was much more than the babies of the other fish !!!!!!


And genetically i concluded that animals may have the ability to choose and determine which mates can be more suitable with it genetics ! As their offsprings are more and better

What do you think of this expirement guys ?
And when i noticed this i began to read more and i discovered that a similar expirement was made in lab on an insect and they had same results



Love = Genetics
Done

Hi Andrewisac,

That’s a very interesting set of observations that you made on the fish. Male animals often fight other males for the mating privilege or else, like birds, have fancy feathers and displays to capture the female’s attention; but it is usually the female that selects the male not vice versa.

What you saw was a male choosing one female of a pair to mate with, then when you removed her and put her back, he went back to her. Did you look up mating in fish to see whether a male and female might stay paired after mating? That could explain why he went back to her after you returned her to the tank. I don’t know about guppies, but I have read that some fish do stay together after mating.

Was your hypothesis that the mating of guppies is random? If so then you seem to have disproved it. However, you have only tried your experiments with one male and that is not a large enough number of subjects to draw a conclusion. I would suggest testing it with at least three different males all of the same age that have never mated. You could make it even more challenging by putting in three females, all the same age and color pattern, and see if he selects and stays with only one.

The second part of your project is even more interesting. If I understand what you are suggesting correctly, you think the male fish selected the ‘best’ female in terms of her genetics that produced the healthiest and the greatest number of fry. Here again, you need to repeat the experiment several times to get a statistically meaningful answer, comparing the fry from the first-selected female to fry from a ‘random’ mating several times.

I would do some more reading about fish and their mating habits and plan another set of experiments with more guppies. If you have a public aquarium near where you live, you could talk to the people there and ask them if they have seen this sort of behavior. Try to make sure all your potential variables are the same in each case—like the time of day, the temperature of the tank, the way you introduce the females into the tank, when you feed the fish, etc.

You are thinking like a real scientist and that is great! If Science Buddies can help you more with your project, please let us know.

Best wishes,

SciB

SciB wrote:Hi Andrewisac,

That’s a very interesting set of observations that you made on the fish. Male animals often fight other males for the mating privilege or else, like birds, have fancy feathers and displays to capture the female’s attention; but it is usually the female that selects the male not vice versa.

What you saw was a male choosing one female of a pair to mate with, then when you removed her and put her back, he went back to her. Did you look up mating in fish to see whether a male and female might stay paired after mating? That could explain why he went back to her after you returned her to the tank. I don’t know about guppies, but I have read that some fish do stay together after mating.

Was your hypothesis that the mating of guppies is random? If so then you seem to have disproved it. However, you have only tried your experiments with one male and that is not a large enough number of subjects to draw a conclusion. I would suggest testing it with at least three different males all of the same age that have never mated. You could make it even more challenging by putting in three females, all the same age and color pattern, and see if he selects and stays with only one.

The second part of your project is even more interesting. If I understand what you are suggesting correctly, you think the male fish selected the ‘best’ female in terms of her genetics that produced the healthiest and the greatest number of fry. Here again, you need to repeat the experiment several times to get a statistically meaningful answer, comparing the fry from the first-selected female to fry from a ‘random’ mating several times.

I would do some more reading about fish and their mating habits and plan another set of experiments with more guppies. If you have a public aquarium near where you live, you could talk to the people there and ask them if they have seen this sort of behavior. Try to make sure all your potential variables are the same in each case—like the time of day, the temperature of the tank, the way you introduce the females into the tank, when you feed the fish, etc.

You are thinking like a real scientist and that is great! If Science Buddies can help you more with your project, please let us know.

Best wishes,

SciB

My Reply

Thanks for your care information and interest in my project , actually in the beggining of my topic i said that the whole experiment happened suddenly and then well organised after me observing the fishes,,
After your advices i began googling reaearching and surfing internet and i realy could find pretty interesting topic that supports my observation in the first part of my topic in which male ve chosen his mate and specialy the most inportant part which is that mating monogenous pairs can realy depend on GENES and give more offspring healthy ones
Look at this

http://www.abc.net.au/science/articles/ ... 354460.htm

And tell me what do you think Scib

I also want to tell you additional thing that may be important to you as an extra observation as you told me to try 3 females
I would love to tell you that now my tank is full of well frow. Mature guppies over 40 guppies now ,,, and my Male fish still mate again and again with the same female he had mated with since they were only the 2 fishes in the tank till now !!

Pretty faithful strange magnifecent observation

That is way cool! I read the article and it looks like you have seen something similar in your guppies to what they reported. And now you tell me that in a tank full of females, the male still goes to the same female. Hmm!

This is really interesting, but what I'm thinking is that you need to quantitate this behavior somehow and try to be as rigorous as possible in controlling any variable that might be affecting your results. I can't see what that could be, but scientists have to be suspicious of everything so they don't get nailed by something they overlooked in their experiment.

The researchers in the article measured shoaling distance among the siblings of one father compared to two fathers. What do you think should be measured in your case? You can count the number of offspring from a chosen mating and compare that to a random mating, but you also said the fry were healthier. How can you measure that?

How does the male identify his girlfriend out of a bunch of others? Is it visually or maybe by odor (pheromones in the water?). If you could test this, I think you would really have a great project with some important data. I wonder what would happen if you put the male into a big tank--say 50 or 100 gallons and then put in 6 females including his mate. You could time how long it takes him to find her. If he finds her within a minute, I would think that means he is using his eyes rather than his 'nose', although i have no idea how long it would take for a chemical like a pheromone to diffuse through the water. I'm betting on visual as the cue.

Keep us posted on what you are doing and keep googling the topic so you can learn what else others have seen about guppy behavior.

Cheers,

SciB