7. How to Harvest Bee Cocoons


7.4 Harvest Wild Bee Cocoons

7.4 Harvest Wild Bee Cocoons

Wild bees can hibernate in cocoons or as exposed larvae.

Harvesting wild bee cocoons is easy, quick, and allows you to:

  • Ensure the health of your wild bee cocoons.
  • Take inventory of your bee population.
  • Get to know your local native bees.
  • Share extra bee cocoons with local friends and neighbors.

We recommend harvesting wild cocoons because it allows healthy bees to emerge without having to walk through nearby unopened and infected nesting chambers. Loose cocoon management is the best way to know important facts about your local native bees. You don’t need to harvest all of your wild nesting materials, instead you can open a sample and decide what to do with the rest of the similar capped ends of your sample.

There are times when harvesting wild cocoons is not recommended. During wild bee harvest, you may find large larvae that are lacking a cocoon or you may find a larvae surrounded by uneaten insects (like grubs, caterpillars, crickets, even spiders - these are food stores for a beneficial solitary wasp). If you can, it’s best to close the Natural Reeds or BeeTube so the exposed larvae can develop into adult bees and emerge when they are ready. If you can’t close the nesting hole, carefully place the large larvae into the smaller CocoonGuard Bag and store them in an unheated garage or shed.

Harvesting Steps:

  1. Open nesting materials and remove healthy cocoons.
  2. Store cocoons in a BeeGuard Bag in your garage or shed.
  3. Watch for emergence of adult bees during early spring and warming weather.
  • When to harvest: Start in early spring when dandelions begin to bloom. 
  • Similar capped ends: Keep like capped end materials together, open one sample and continue based on what you find.
  • What You’ll See: 
    • Healthy wild bee or wasp cocoons
    • Uneaten pollen loaves and small flecks of bee frass
    • Protective walls that separate nesting chambers
    • Extra thick capped ends at the open end
    • Empty cocoons of second-generation bees
    • Common pests like meal moths and small beetles
  • Exposed larvae: If you find large, chubby or plump larvae that completely fill the nesting chamber, these are a wild bee or beneficial wasp that needs more time to develop. If you can, close the nesting hole and store intact nesting holes in a BeeGuard Bag in your unheated garage or shed. Watch for emerged adult bees and release the rest of the intact nesting holes in your bee house.
  • Tools you need: scissors, a stiff wire brush or old toothbrush, a BeeGuard Bag or CocoonGuard Bag for wild bee storage, a Phillips-head screwdriver or Popsicle stick for removing cocoons.
  • Set up a workspace: A cool room to help keep wild bees in hibernation (try opening a window) and newspaper or a pan for catching cocoons and debris. 
  • Gauge Stick: Check to see if your Natural Reeds or BeeTubes have been partially filled by making a gauge out of a thin stick or bamboo skewer. Mark the stick at the length of the nesting tube and place the gauge into the nesting hole. If the mark protrudes, there is a filled nesting chamber inside. If not, the nesting hole is empty and you can set it out for use next spring and summer.

Pro Tip: Easily check for wild nest-building materials at the small hole at the back end of our cardboard BeeTubes.

How to Open Wild Bee Nesting Materials (4-10mm)

1. Wood Trays - Remove the big green rubber bands and the cardboard backing (save the cardboard to reassemble the trays). Lift up the first tray and using the Phillips-head screwdriver or Popsicle stick, gently remove cocoons. Keep your removal tool at a 45-degree angle. Check both sides of the nesting trays for cocoons and brush away any debris. Lightly spray Clean Bee on both sides of wood trays to remove mold and fungal infections.

a. Reassemble nesting trays by aligning the side notches, ensuring that the nesting holes are snug and there are no gaps. Store with cardboard backing and rubber bands attached to trays.

2. Natural Reeds - Pinch the capped end between your fingers and the reed will start to split. Don’t worry, there is no cocoon at the open end of the reed. Pry the reed apart along the split and use the Phillips-head screwdriver or Popsicle stick to gently remove cocoons.

3. Cardboard BeeTubes - Tear or snip one end of the BeeTube and it will begin to unravel.

Store harvested cocoons in a BeeGuard Bag or CocoonGuard Bag in your unheated garage or shed. We recommend carefully breaking apart any cocoons that are stuck together to help healthy bees emerge without having to walk through a nearby infected cocoon.

It’s a good idea to take notes of observations of your wild bee activity and place the notes in the BeeGuard Bag or CocoonGuard Bag. For example, when were they active, what size nesting hole did they prefer, and what kind of capped end material did they use. The information you gather will help you learn how to take care of your bees next year.

Wild Bee Cocoon Emergence

Some wild bees hibernate as larvae and they need warm temperatures to develop into adult bees, this is called incubation. Each species has their own set of cues that wake them up and tell them when to emerge.

To wait for your harvested wild cocoons to emerge, place the BeeGuard Bag or CocoonGuard Bag full of harvested cocoons back into your unheated and un-air-conditioned garage or shed. Incubate them in a location that is easy to monitor for emergence of gnat-sized parasitic wasps and adult bees.

Development in a location with outdoor temperatures will give you the clearest understanding of when your wild bees are naturally active. For example, wool carder bees incubated in our office at 70F/21C started to emerge right around the 4th of July. Incubation in outdoor temperatures may have woken the wool carder bees earlier in the season.

Pro Tip: Take note of when your wild bees emerged and under what conditions they were incubated if outdoor temperatures are not feasible.

Many summertime bees and beneficial wasps hibernate as large exposed larvae that lack cocoons. When you incubate larvae in their own CocoonGuard Bag, you can set the bag into the bee hotel when you see them develop into white pupae with darkening eyes. The development of pigment is one of the final stages before they become flying adults.

Once adult bees start to emerge, you can release the rest of the cocoons by placing them into the bee house on top of their fresh and clean nesting holes.

Topic Completion

How to Harvest Bee Cocoons

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