margriet dogterom

On facebook, in the Beediverse bee group  I was asked why only 50% of their cocoons hatched.  This looks like a complicated puzzle, but I have seen it once and think I know why this happened.

 I think the problem is that the bees that did not emerge did not have any fat body reserves left by the time spring came around. 

It is truly amazing that the female lays the egg with enough pollen and nectar reserves to grow a bee that has enough fat stores for the bee to eat her way through to the outside world, and never mind the overwintering metabolism. It is all about whether the bee uses all her fat bodies while she is going through the autumn and overwintering period. If temperatures are unusually high in the fall, the bees’ metabolism is also unusually high, and the worse case scenario is that the bees run out of fat stores and perhaps die. What I have seen is when bees are kept in a warm basement over part of the fall and winter, there is the little energy or fat stores left to eat through the cocoon to the outside world. Sometimes bees are still moving, but after manually removing the bee from the cocoon, she ends up dead. More usually, you find a perfectly normal dead bee inside a cocoon. I don’t expect that bees can look ‘wasted’ because their exoskeleton keeps them in one shape only, no matter how wasted they are on the inside. Hope this helps.

During the summer months, remove nests from hot sites that for example, face the hot afternoon sun.  Store them under cover, away from direct sun.

Tim started harvesting his mason bee cocoons from his wooden trays last week using our fabulous SCOOP. He emailed me this photo showing a very good harvest. 60 cocoons in just one layer.

See what your harvest looks like per female cocoon.  And see what your mite infestation is to tell you how well you removed mites from cocoons before setting them out in the spring.

HARVEST RESULTS
In spring before setting cocoons out, count the number of total cocoons. This will help in calculating if your harvest is a good one.
Total at site in spring = 600 or 300 females ( about half of total)
Tot cocoons harvested = 1540
Lets look at the numbers:
Each female produced 1540/300 or 5 offspring. Nothing wrong with this production.

MITES
Before removing all the cocoons, count the total number of cells with or without cocoons

TOTAL CELLS with cocoons  and CELLS WITH MITES

8 and 0 (First tunnel at the top)

9 and 0

9 and 1

9 and 2

9 and 0

7 and 0

10 and 0

2 and 0

_________

63 and 3
Number of cells with mites/ total cells x 100 = Percent of mite infested cells

or 3/63 = 4.76%

If the percentage of mite infested cells is less than about 5%. You have done a good job of cleaning mites of cocoons and nests.

In this case mite infested cells is 4.76%
Good job Tim!

Things you might see while harvesting and cleaning cocoons 

Cleaning cocoons and freeing them from pests is like any gardening adventure.  Keep pests low and you will have a great harvest.

Pollen lump amongst cocoons.
These  are cocoons harvested from nesting tunnels and placed in water just prior to washing..  Cocoons are still covered with various debris.  At the top left hand corner of this picture is the tip of a Beediverse scoop.  It is pointing to a pollen lump.    A pollen lump found in a nesting tunnel means that the bee larvae died and did not consume the complete pollen lump.  This most often happens when a period of cold weather makes it impossible for the bee larvae to live and feed on the pollen.   Various debris still adhere to cocoons.

Wriggling larva.
These larvae are in the nest because earlier in the spring a fruit fly laid her eggs on top of a mason bee pollen lump.  These fruit fly larvae eat the pollen and leave nothing for the developing bee larva. This new species of fruit fly has been on the west coast of NA for more than 5 years now.  Removing these pests will  remove potential pests from next year’s nest.

Healthy cocoons
Here are two rows of healthy looking cocoons.  But look closely, they are lightly covered by tiny pollen eating mites (white specs).   Pollen eating mites feed on pollen lumps left behind for the bee larva.  These pollen mites feed on the pollen and leave nothing for the bee.  In the lower right hand corner is a cell fully loaded with mites. Mites are always present and can be a real problem for bees if these are not removed every year.  Mites can easily be washed off under running  water while rolling cocoons in a sieve.

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• Keep other animals from eating cocoons
• Store in a cold place with approx. 70% humidity for two months to ensure proper overwintering.

1.  Storing cocoons outside works well when outside humidity is at least 60% and winter temperatures dip around or below freezing for about 2 months.  The key to success is protection from other animals.  Our Beediverse Hatching box is made from solid wood and keeps animals out.  This method works well until temperatures go over 2-4C.  Before temperatures go above this range, rotate lid of hatching box and bees can emerge as temperatures rise

WHAT YOU NEED FOR CANDLING:
1.  6v flashlight with a bulb
2.  A plastic candling dish
3.  “Feather” touch forceps
4.  A dark room

PHOTOS
These photos below clearly show what is a ‘good’ cocoon and a cocoon that needs to be discarded.  In one cocoon a bee is clearly outlined showing its feet and mouth parts. The next photo is  empty with the remains of a dead larvae. These are discarded.  (You may want to have a closer look at what is inside these cocoons).  The most common parasitic wasp species have about 10 little wasps per cocoon.

A cocoon filled with a healthy mason  bee. Mouthparts and the forelegs are clearly visible.

An empty cocoon.

Set up candling set up, and turn lights off in teh room.

A cocoon with a parasitic wasp exit hole.

Remove this one! This cocoon contains developing parasitic wasps.

1. Harvesting cocoons begins by opening nests and carefully removing cocoons with a scoop.
2. Cocoons are placed in water to remove sand and mud and some mites.
3. Then cocoons are rinsed under running water while in a metal sieve to remove remaning mites,
4. The final rinse is in a weak bleach solution  (0.05%)
5. Cocoons are dried for about 1 hr on a paper towel.
6. Dry cocoons can then be candled.   Candling is done over a flashlight (6V with an irridescent bulb) in a candling dish in a dark room to remove any parasitized cocoons.
7. The final stage is cleaning the nesting trays .

If you are planning on ordering mason bee cocoons and or nesting supplies- do it before spring.  Mason bees emerge when it gets warm, and having things prepared for them is the way to proceed.  What is this insect?

We were at the wholesale Green Industry conference this week.  Met up with lots of retailers and people interested in getting mason bees and leafcutter bees into their stores and making this line of products available  to their customers.  The viewing home was a highlight.  An innovative bee home for sure.  And it is beautifully crafted.  If was a very exciting 2-day show. We showcased our Beediverse line of products and they liked what they saw.

“Beediverse is the One supplier for all things Mason Bees and Leafcutter bees that are needed in the Home and small orchard markets.”  Garden shows are fun events where we can meet up with our customers.