It is already well known that the world wide amphibian dying has its reason for one part in the baby birth control pill, where the one active substance from it comes into the enviroment over the urin if there is no biological clarification stage- and this makes after a message from a big pharma industry not only amphibian barren, unfortunately all animals- therefore this could be one of several reasons for world wide bee dying too? I asked a professor for plants and just got a short answer, that they found already antibiotica in plants, therefore it is probably that there is more from active substances from pills in plants all over the world- here a link for it in water:
http://onlinelibrary.wiley.com/doi/10.1002/etc.3339/full
Haven't seen any research on bee populations and estrogens/progestins typically used in oral contraceptives. Might be interesting to do a survey of the bee populations (voluntary, ask beekeepers to send you 5-10 local bees, analyzed). Most of the research I've seen had to do with expiration of bees secondary to broad spectrum insecticides or herbicides in commercial agricultural use. Best of luck with your project.
I think Sabrina Wolski: https://www.researchgate.net/profile/Sabrina_Wolski/contributions
did research on this matter.
I did research on the influence of estrogens (specifically 17b-estradiol, a product from using estradiol valerate in livestock. My experience was there is very little research into the influence of estrogens in insects, and we couldn't find any behavioral impact at the dose we were using (see publication). I would suggest looking at Allan Moore'a work on here.