A brine based bee trap trial

[Sam Droege]

All

The spring peepers just started calling today, my tell for when to start looking for active bees....

Most years we run trials of traps and trap modifications.  Some work well and others not so much.  We specialize in failure so everyone can learn.

Last year we tested some trapping techniques developed by beetle collectors that Mike Arduser mentioned were secondarily effective in trapping bees particularly in desert conditions.  We were not interested in beetles but thought the idea worth a go with modifications to largely eliminate beetle capture. 

Basically the trap was a single serve plastic soda bottle painted yellow/white/blue and partially buried in the ground.  They did catch bees but not as many as various bowl/cup configurations....though they were useful in situations where they needed to sit for long periods of time (months) without tending and filled with propylene glycol.  

This year we will be running traps (see picture below and subsequent email with 2 more shots) based on our old survey techniques of using 12 ounce beer cups filled with propylene glycol....but with several modifications.

• Instead of Propylene glycol (expensive ~$30/gallon, yielding bees tricky to clean) we are using saturated salt brine (thanks to the several suggestions on this from the group).  
• Salt brine saturates at roughly 1 cup per gallon water and has a reduced evaporation rate compared to plain water, but still needs added soap to reduce surface tension.
• Salt is incredibly cheap and available (hardware store water softener salt today ran me $11 for 40 lbs).  
• We are working in woodlands now and instead of using stands for the cups we drill holes near the tops of the cups, drive a finish nail into a tree and hang the cup on the cup.
• We will be testing the differences between captures using traps 5' up a tree versus traps at ground level (both affixed to a tree) while trialing out the technique.
• Note the aluminum crab mallet...very convenient both because it is small and light and in that it has a large head and drives the finish nails easily without the smashing of fingers that occurs when you try to hit a very small nail with a regular heavy iron hammer.
• Traps will be left out continuously and tended once a week...traps replaced if dismantled by animals and topped off if there is too much evaporation.
• Purchased "stadium" cups could be used in the future and can be custom colored as well as having things printed on them such that it might speak to the curious: "Stinging Insect Trap Do Not Disturb".
• We will also be trialing hanging these cups using wire handles and placing them in the edges of blooming trees using telescoping pool poles.
• In the summer we will playing around with putting bowls on fence posts, telephone poles, and stakes.
• One of the biggest advantages here is that we found with previous experiments that once an array/transect is set up volunteers are happy to tend the traps.  In fact out of 100 arrays in a previous study we had only 2 people fail to run their traps.  This is quite different from giving people traditional bee bowls and letting them deploy them on their own schedule.  Too many decisions to make I suppose and most people don't participate or fail to do more than one survey.

More to come.  We think the combination has many benefits and we shall see if the salt loving deer and other animals become a problem.

sam

Stars,I have seen them fall

VII

Stars,I have seen them fall,

But when they drop and die

No star is lost at all

From all the star-sown sky.

The toil of all that be

Helps not the primal fault;

It rains into the sea,

And still the sea is salt.

- A.E. Housman