7. How to Harvest Bee Cocoons


7.3 Harvest Summer Leafcutter Bee Cocoons

7.3 Harvest Summer Leafcutter Bee Cocoons

Summer leafcutter bees hibernate as delicate larvae inside of leafy, non-waterproof cocoons.

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

  • Ensure the health of your leafcutter bee cocoons.
  • Take inventory of your leafcutter bee population.
  • Plan ahead for summer pollination.
  • Share extra leafcutter bee cocoons with local friends and neighbors.

Because summer leafcutter bee cocoons were built by the mother bee, all of the common leafcutter bee pests and diseases are usually tucked within the leafy cocoon and are not easily seen. Loose cocoon management is recommended because it allows healthy bees to emerge without having to walk through nearby unopened and infected nesting chambers.

Harvesting Steps:

  1. Open nesting materials and remove healthy cocoons.
  2. Store cocoons in a BeeGuard Bag in your garage or shed.
  3. Incubate leafcutter cocoons in a BeeGuard Bag in a warm location.
  • When to harvest: Start in early spring when dandelions begin to bloom. Allow your leafcutter bee cocoons time to develop into adult bees: they may need about six weeks of incubation to be ready for your summer garden to bloom.
  • What You’ll See: 
    • Healthy leafcutter cocoons
    • Leafcutter cocoons made of petals
    • Capped ends made of stacks of leaves
    • Empty leafcutter cocoons of second-generation bees
    • Common pests like meal moths

If you find large, chubby, or plump larvae that fill the nesting chamber or non-leafcutter bee cocoons, these may be a wild bee or beneficial wasp. Learn how to take care of wild bee cocoons in the 6.1 How to Raise Wild Bees and 7.4 Harvest Wild Bee Cocoons pages.

  • Tools you need: scissors, a stiff wire brush or old toothbrush, a BeeGuard Bag or a CococonGuard Bag for leafcutter bee cocoon incubation.
  • Set up a workspace: a newspaper or a pan for catching cocoons and debris, a Phillips-head screwdriver or Popsicle stick for removing cocoons.
  • 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 summer.

Pro Tip: Easily check for leaves at the small hole at the back end of our cardboard BeeTubes.

How to Open Summer Leafcutter Bee Nesting Materials (6mm)

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 unused with cardboard backing and rubber bands attached to trays.

2. Smaller Natural Reeds - Pinch the leaf-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 cocoons in a BeeGuard Bag or smaller CocoonGuard Bag in your garage or shed. We recommend that you lightly break leafcutter cocoons apart from the line of cocoons to help healthy bees emerge from their cocoons without walking through diseased cocoons. Follow leafcutter bee cocoon incubation steps below.

Leafcutter Bee Cocoon Incubation

Leafcutter bees hibernate as larvae inside of their protective leafy cocoons and they need warm temperatures to develop into adult bees, this is called incubation. Leafcutter bee cocoons purchased from Crown Bees are incubated until adult bees begin to emerge.

To incubate your own harvested leafcutter cocoons, plan ahead to time their emergence with your summer weather and open blooms. Place the BeeGuard Bag or a CococonGuard Bag full of harvested cocoons into a dark warm location, like your water heater room. Remember to check periodically for any sneaky pteromalus parasitic wasps and emerged adult bees.

Development is dependent on time spent in warm temperature:

  • At 84F/30C, adults emerge after about 20 days.
  • At 70F/21C, adults emerge after about 42 days.
  • Some native leafcutter bees have shorter development cycles, release these bees as they emerge.
  • Pteromalus parasitic wasps will emerge after about 9-14 days and will attack developing leafcutter cocoons. Squish them in the incubation bag as they appear.

Pro Tip: To provide leaves for the bees to build their leafy cocoons, plant peas, beans, or strawberries around the same time that you start incubating leafcutter cocoons.

Once adult leafcutter bees start to emerge, you can release cocoons by placing unopened cocoons into the bee house on top of their 6mm sized nesting holes.

  • Pro Tip: Intact cocoons can’t regulate their temperatures above 90F/32C, bring them indoors and release adult bees as they emerge until weather cools.

Topic Completion

How to Harvest Bee Cocoons

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