Bees
There are 20,000 known species of bees, and some are vanishing at an alarming rate.
Colony collapse disorder causes significant economic losses because many agricultural crops worldwide are pollinated by western honey bees. A large amount of speculation has surrounded a family of pesticides called neonicotinoids as having caused CCD. Here, honey bees swarm in a tree as scouts look for a new hive location in Absecon Highlands, N.J., May 21, 2017. Original public domain image from Flickr