Dr. James LaClair and Dr. Jack Bantle wondered if methoprene that was exposed to sunlight could cause deformities in frogs. They knew from earlier tests that fresh methoprene did not cause frog deformities, so they did an experiment to see if sunlight could make methoprene more dangerous.
Dr. LaClair and Dr. Bantle exposed fresh methoprene to sunlight. Then they raised some African Clawed Frog tadpoles in water that had some of the sunlight-treated methoprene added it to it. They also raised some tadpoles in water with fresh methoprene that had not been exposed to sunlight.
Here are photos of the heads of the frogs from Dr. LaClair and Dr. Bantle's experiment.
Image courtesy of Dr. James LaClair
Photo A is a frog treated with fresh methoprene. This is what a normal frog looks like at this age. Photos B,C,D, and E are all frogs that were exposed to methoprene that had been left in the sun. You can see how the eyes are deformed or almost missing.
Experiments like this one show that sunlight-treated methoprene can cause some deformities in frogs. Other scientists have discovered that high levels of methoprene all by itself can kill young tadpoles. But the scientists who are testing methoprene still have not been able to produce the types of limb deformities found in Minnesota.
Original Article: http://wise.berkeley.edu/WISE/evidence/167.html