Wild Bee End Cap Guide

Wild Bee End Cap Guide

Wild bees and solitary beneficial wasps can both move into your bee house or bee hotel.

Each bee and wasp species has their own nesting preferences and their own way of building their nests. Here are our tips that can help you understand some of the most popular or common guests:


1) The first clue is the nesting hole size the bee or wasp chose. Hole-nesting bees and wasps come in a variety of sizes and each species has their preferred nesting hole size. For example, there are very small mason bees and aphid-hunting wasps that prefer 4mm size nesting holes. 


2) Next, the natural nest building material used to build the capped end is another clue. Mud, pebbles, whole leaves, chewed leaves, tree sap, grass, plant fuzz, and wood are all natural materials that wild bees and wasps can use to protect their nests. Some bee house guests will even use a combination of nest building materials.


3) Finally, our refining clue is the texture or look of capped ends can tell use if a guest was a bee or a wasp. For example, solitary wasps use mud tend to sonicate or vibrate the mud, resulting in a mud capped end that is very smooth and looks like cement. Capped end mud that is bumpy instead of smooth may have been filled by a native bee in the mason bee family.


Another example of capped end texture is the way leaves are used. Alfalfa leafcutter bees will leave the leaf bit intact so that you can still see the leaf veins. Take a close look at our summer leafcutter bee cocoons and you should still be able to see the bite marks as the mother bee cut the leaf to carry it home. There are many members of the mason bee family that also use leaves but instead, they chew the leaves and build protective walls between nesting chambers. 

A common bee house guest are the grass-carrying wasps who build very messy looking nesting holes with large pieces of grass sticking out. Watching grass-carrying wasps stuff their nesting hole is really interesting as the wasp spirals the grass in order to form a mat to protect and divide each chamber. As the grass dries it can lose color and look like straw. Grass-carrying wasps tend to like hunting crickets and they like 8-10mm size nesting holes.

Sometimes a tube looks like it was stuffed with grass at first glance, but bees or wasps can actually use strips of wood to build their nest walls! And again, there are bee or wasp species that will either chew wood or gather sawdust to protect their nesting holes.

Taken all together, the three features listed below will all work together to help you manage your bee house guests.

Keep nesting holes of the same size, same nest building material, and same texture together. Take notes of when your guests were active. There is a lot to learn about our wild hole-nesting bees and beneficial wasps and your notes can help other gardeners learn how to care for their bee house.


Nesting hole size: each bee has their preferred size from 4-10mm
Natural material used: mud, leaves, fuzz, grass or even wood
Texture or look of the material: ie bumpy or smooth



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