I might do beetles because the ants over here there abdomen aren't transparent a and I FORGOT TO ADD ONE MORE IS A POTATO MORE EFFICENT THAN A BATTERY USING A SIMPLE BULB
Check out www.awesomescienceprojects.com my son did a crystal radio this year for 4th grade, and got best in show for the entire school. Bragging just a bit. My advice is to do something different, there were about 8 potato clocks/lights and 3 ant projects.