Monday, February 13, 2012

Mr. Reedy's Students- Read this!

Hello Mr. Reedy's students!  You may remember me as that guy who came to your class to talk about turtles in December, or you may remember me as Mr. Reedy's BFF (I know are curious who Mr. Reedy's best friend forever is, and now you know).   You also may remember I am a scientist at Iowa State University, and that I work with a Middle School classroom in Des Moines, Iowa.  We are hoping that our classes are going to get to know each other, and share our science experiences with each other over the coming months.   

I believe that you are knee deep in your animal behavior studies at this point, and we would like you to read about an experiment with seed beetles published in a peer reviewed journal (check them out in the photo by CW Fox).  When scientists do research, they share that research through posters, talks, and through papers.  For a paper to be peer-reviewed, it means the paper was critically examined by other expert scientists. The paper could be published only after these other scientists approved of the experimental design, statistical analyses, and the conclusions drawn by the authors.   The paper we would like you to read is titled "Smaller beetles are better scramble competitors at cooler temperatures."

 Mr. Reedy should have given you a copy in class.  What I would like you to do is answer the following 4 questions.  Please write them as comments to this post!

Moya-Laraño J, M El Tigani El-Sayyid & CW Fox. 2007. Smaller beetles are better scramble competitors at cooler temperatures. Biology Letters 3: 475-478.  

1) These authors designed an interesting experiment to help answer some questions they had.  After reading this paper, in your own words, write what question or questions motivated this experiment.

2) Figure 1A shows that most of the selection differentials are negative.  What does that mean?

3) In this experiment, the authors discovered that smaller male beetles were substantially better at finding females than larger male beetles, particularly at cool temperatures. However, finding a mate is just one part of this beetle's life.  Do you think it is always better to be smaller for these male beetles?  Can you think of other parts of a beetles life where it might be advantageous to be larger?  Do you think it is better for females to be smaller as well?  

4) Suppose that we went and found some beetles in their natural habitat, studied them for a year, and found that in every situation, it was better to be larger.  What do you think would happen over a very long time (many thousands of generations)?  Would we find beetles as big as a human some day?  


  1. 1) Does having bigger body mass an advantage in reproducing or is it a disadvantage when it come to seed beetles (Stator limbatus)?
    Does temperature affect the different S.limbattus body mass when it come to find a mate?

    2)Most of the selection differential did not favor the S.limbattus with the big body mass.

    3)I think it is better to be a smaller male insect; the small one is the the easier it is for one to hide or to run away from predators. Yet being a big male insect also may have its advantages, such as being able to defend them self against other enemies.I think females shouldn't be smaller since they are the ones who would have the off springs, and would bear less off springs.

    4)I don't think someday we would come across insects as big of humans because selection pressure who play a big role; birds, reptiles and other predators would mostly eat the larger insects since they are easier to spot and slower to escape, therefore keeping the insects at an average size.

  2. Yessenia
    1.Advantages and disadvantages within reproduction caused by temperature.
    Different behaviors caused by temperature such as sunlight attracting beetles.
    3. I do think it is an advantafe to be a small male. Apart from the fact that they have a greater chance to mate they can hide easily from predators as well as run. However, being a big male can have a good advantage by defending himself from others and when fighting.As for females they should be ig because they are the ones who carry the offspring and the bigger the female the more eggs it can carry.

  3. 1)How does temperature affect selection of body size in seed beetle (Stator Limbatus)?
    How does temperature affect sexual and natural selection among (Stator Limbatus) and does it differ between males and females?

    4) It may be possible that beetles may grow to a very large size in many years if selection pressure demands it. on the other hand, to grow to an average human size is highly unlikely. there are still various selection pressures that push forth for a smaller size. for instance, to remain small to be able to hide from prey.

  4. Javier.

    1. If the species has a bigger body mass does it increas the animals chance of reproducing? is there a specific degree temperature that they will be more successful in reproducing?

    4. I think that the following generations of beetles will be bigger due to the fact that their ancestors were a big size. they will be more successful in their life cycles and the followiing "offspring" will be great in size as well. i wouldnt say that they will be as big as humans i think that this is an exaggeration. but i do think that they will be big but not as big as humans.

  5. 1. Does temperature have a positive effect on the smaller or larger seed beetles (S.limbatus)?
    Does temperature have any impact on sexual and natura selection.

    3. I think that it is an advantege to be smal because the larger the beetle is the easier it is for the predator to see them. The advantage of being large is that if the beetle engages in a fight then their chance of winning is high. I don't think it's a gret thing for the females to be small because then they don't carry as much eggs as a larger female might.

  6. Edmund WU!
    1. The purpose of this experiment was to answer whether temperature can affect body size selection.

    2. I do believe that over a thousand(s) generations we will find significant larger beetles but, I do not believe that they will be as large as humans because there will be a evolutionary pressure where predators will spot the bigger beetles easier.

  7. Raymond Duran

    1. How does temperature affect the process of mating in seed beetles? Does body mass in males contribute to the effect on mating in seed beetles?

    3. I honestly think that it is advantageous to be smaller for the seed beetles because they can move around more in their environment. Not only that, but they can also reach a mate quicker than a larger beetle as it was proven in this experiment. Larger males have the advantage to fight off other beetles and/or protect their mate. Females should be smaller because like the males, they could scurry away from predators much quicker than a larger beetle would.

  8. 1. Does the change in temperature affect the success rate of male seed beetles(stator limbatus) when scrambling for mates?
    Does the size of the male seed beetles matter when placed in different temperatures?
    Would speed be affected if seed beetles were placed in colder temperatures?

    3. I believe that it is beneficial to be a smaller male in this case. We have learned from the lectures in class and the many different readings that we've had that one of the key goals of an animal is to procreate. In the case of the seed beetles this goal has been achieved by the smaller males. It is also a major advantage to be smaller for these beetles because they are more likely to escape from their predators. The size of the beetles makes it difficult for the predators to spot them and as it is stated in the paper; the smaller beetles have a speed advantage over the much larger males. Now I am not saying that being small is the only way to survive, since there are still large seed beetles around then that means that they are still succeeding on their own. Being larger would mean that they would have a higher chance of success in fending off predators. It might also mean that they would be able to attain food more efficiently. The females should remain as they are. If they were smaller they might end up producing less eggs because of their smaller body size. Therefore, if they wanted to pass on their genes and give their offspring a better chance of survival being smaller would mean sacrificing these things.

  9. 1. To see if temperature have an effect on the body size of the beetles, if smaller beetles have an advantage over larger beetles and if the advantage is effected by the temperature.

    4. I think that it is possible for the beetles to be as big as human after a very long time if larger body size benefits them in every way including escaping from the predators. If the beetles are able to grow into a very large size, the predators would probably be scared by their size and hide from them instead of preying on them. The beetle could possibly turn into predators of other animals to help survival.

  10. alex li

    1.Determining if the role of temperature on body size when it comes to female choosing a mate.

    4.The beetles would gradually grow larger till the point where natural selection would take affect and favor the small body type since the larger body size will be more likely to be target by their prey. the possibility for beetles to become the size of human is low since the larger beetles would be killed faster by it prey.

  11. 1. Does a smaller body size affect the speed in which a beetle finds a mate. How does temperature effect different body sizes in their ability to find females.

    4. I do not think that beetles if it is advantageous to be larger will eventual evolve to be the size of a human because it would be difficult for them to maintain their body temperature and water balance.

  12. Julia Mei

    1. To determine if temperature have an affect on body size for male.

    4. Beetles would slowly increase their body size over many generation to the point where they are large enough for preys to spot them easily. This would reduce the chance of beetles to become human size as well at a certain point the pressure would cause the exoskeleton to cave in on itself.

  13. Ashley Lucero

    1. To evaluate if temperature plays a key role on the selection process of mating.

    4. If beetles were the size comparison of humans, their lives would be definitely different. Since they are as large as humans, they will be more prone to being hunted down by larger prey. The smaller beetles will be safe, an thus reign supreme among the larger beetles.

  14. 1. To see if tempature was a factor on the process selecting a mate.

    4. We would find that the beetles would keep growing becuase they need to be bigger to keep surviving.Eventualy over time i think there would be beetles the size of humans.

  15. Jiao

    1. To see if the temperature affect different size males.

    4. I think it is possible for beetles to be grown to the size of a human many generation later. There will be a lot of advantage for them. Instead of being hunt by other animals they can be the hunter instead. They can scary away animals that wants to hunt them. They many have longer lives too.

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  17. 1. Does temperature play a role in the affect of the size, mating, and natural selection between females and males on seed beetles?

    2. Beetles growing big over thousands of generation is possible but as big as a human, I think that is too overwhelming. Beetles would not only be easier to spot for prey but they would have a higher chance in defending themselves. There can be new traits in the future but I don't think they will grow as big as a human.

  18. 1.) To determine if temperature is a factor on the process of selecting mates.

    4.) I think that if beetles were human size that they would have a lot of advantages (i.e). They would have a much greater chance to successfully mate and pass on their genes year after year.

  19. 1. To see if temperature was a factor in the process selecting a mate, in the affect of the size, and the natural selection of both male and female seed beetles?

    3. I think it would be better to be a smaller male, according to this experiment. It is a huge advantage to be smaller for these beetles because it would be easier to escape from predators. The size of the beetles make it difficult for the predators to see them, just like he paper said. The small beetles also have better speed and they can also reach a mate faster than a larger beetle as it was shown in the experiment. A larger beetle would have a better chance in fighting off predators. I also think female beetles should stay at a small size because they could escape predators as well and they would be able to carry enough eggs without worry of losing them.