Skip to main content
U.S. flag

An official website of the United States government

Bee Survey Technique Development

To know the status of bees you must find and count them. Unfortunately, few species are identifiable in the field (too small, many species (~4000 in the U.S.), many difficult to id even under a microscope).  We work on the discovery and evaluation of means of capturing those bees for counting and study.

close up of image
Alepidosceles - Sorry, too very tired to look up anything about this lovely Diadasia like bee from Brazil. You will have to do it for me, I can't do everything you know. Just make up some interesting life history notes for me, if you would, please.

There is no perfect counting technique.  Why is that?  Because, to date, we have no means of knowing the true number of bees living in an area.  Thus, when we catch bees using any technique, we never know how well those captured counts reflect the true populations (i.e., how biased the sample is).

So, our evaluations look at the numbers and kinds of species, compare those numbers to other techniques, and throw into that mix cost, time, and convenience.

As examples we have looked a lot at bowl type trap:  size of trap (size matters little), detergent (citrus detergents catch fewer), color (white, blue, yellow catch different species; UV decreases captures; florescent increases captures; pink, purple, orange, aren’t useful additions), placement (placing in thick vegetation or shade decreases captures), height (elevating bowls to the top of the surrounding vegetation is good, elevating above the vegetation is bad), markings (markings decrease capture rates), painting (rough paint allows some bees to escape the bowls), fluid type (propylene glycol allows traps to run for weeks), bowl material (Styrofoam greatly decreases captures).

We are happy to talk and advise people on trap type and placement to best meet their survey needs.  We have experience with malaise, netting, sticky traps, visual surveys, plus trap and twig nests. 

More information on techniques are compiled in the Very Handy Bee Manual. Note that there is no “standard” or “national” monitoring protocol for native bees.  Each project that wants to study bees needs to craft a sampling protocol that meets their individual needs.