As if we didn’t already have enough to thank bees for…
Bees have an odor perception that is on a level of acuity many leagues beyond ours, with their being able to detect infinitesimal quantities of certain molecules. Their odor perception is even more acute than sniffer dogs and is reported to be in the parts per trillion range!
It has been discovered that the bees can be trained using a simple Pavlovian reward system to select and move towards specific odor sources.
This gives potential for them to be used to detect pregnancy and diseases including cancer – which can be indicated by specific odor markers in the breath: Bees can be trained to respond to the presence of various chemicals, including biomarkers associated with early stages of diseases such as tuberculosis and various types of cancer. 
Special glass devices (as pictured) have been devised by Portuguese designer Susana Soares in order to facilitate such tests. The subject breathes into the curious glass apparatus, which at first glance seems somewhat reminiscent of a kind of strange hashish smoking contraption. The pre-trained bees make a “bee line” (couldn’t resist it) for the diagnosis chamber if the target odor is present.
Early detection is mission critical to saving lives from cancer as the chances of turning it around are often greater if it is discovered sooner. Regular health checks and screening are essential but could this become a new tool in the fight against the world’s worst disease? Let’s hope so.
Bees may also have potential to be used in other applications requiring detection of minute quantities of chemicals, for example detecting explosives in security operations. 
What else could we use them for? Detecting fake or adulterated foods or essential oils? How about the obvious: Detecting fake honey. Sounds feasible to me.
The glassware project depicted was originally exhibited at MOMA back in 2007. 
Important – Bees are under threat: Indiscriminate pesticide use is wiping out bee habitats in vast numbers – we really do need to protect these treasures of nature. This is no joke. In addition to NOT spraying pesticides (PLEASE don’t do it!), something simple you can do to help bees is to plant flowers that bees love. Here’s a great list: