When people say “Pollinators” many of us think of Honey Bees first. Honey Bees, those bees that live in the hive boxes and produce the honey we dearly love in our hot tea or on our peanut butter and honey sandwich, are not native to North America. But they’ve been with us a long time; probably they came with the first European settlers. They have become naturalized to our climate and our crops. And of course they are quite valuable in that they pollinate crops and produce honey. We depend on them. So, when we hear about “colony collapse”, the mysterious condition where seemingly overnight a whole colony of bees disappears or dies, we are frightened and concerned. And we should be. The life cycle of the Honey Bee is fascinating. And the Honey Bee is valuable to agriculture. http://en.wikipedia.org/wiki/Western_honey_bee
But, there are many more native bees that our native plants depended on for pollination long before the European Honey Bee arrived. There are perhaps 4000 species of native bees! And these insects are declining in numbers as well.
There are many factors that contribute to the decline of pollinators but surely one that we can do something about is the inappropriate use of pesticides and herbicides. While you may be trying to preserve your vegetable garden from the evil tomato worm or the pesky aphids you might be killing off the friendly pollinators that help your plants produce the fruit and vegetables you crave. So, stop and think. Read the labels. Better yet, don’t use those poisons.
http://www.xerces.org/pollinator-conservation/native-bees/
Another concern: http://abcnews.go.com/blogs/headlines/2014/06/bee-friendly-gardeners-may-accidentally-poison-their-bees-study-says/
Here are the instructions for building a bee house to attract Mason Bees: http://www.nwf.org/How-to-Help/Garden-for-Wildlife/Gardening-Tips/Build-a-Bee-House.aspx