Decline in Monarch Butterflies: Milkweed grows around corn and soy bean plants that are in pesticide drenched fields. Milkweed is a large source of food for these butterflies, and the pesticides are affecting them, causing the plants to die off. Therefore there's a lack of food.
Decline in Bee's: -Entomologists at Purdue University observed honey bees exhibiting tremors and uncoordinated movement and convulsions, all signs of insecticide poisoning. -Crops that were genetically modified, some which now contain toxic insecticides within their genetic structure, are also responsible for poisoning and wreaking their immune systems.
Other causes: The pesticide chemicals found in GMO crops fog the honey bees' brain, not allowing them to find their way back home, causing their food supply in their hive to reduce greatly.