At the Seedy Saturday on the weekend where I was selling mason bees, I met Dr. Elaine C. Humphrey, Fellow of Microscopy Society of America, and a Past President Microscopical Society of Canada. She works at the Advanced Microscopy Facility.
Bob Wright Science Centre A015, University of Victoria.
These mites are similar in name only to the mites that infect Mason bee tubes, Chaetodactylus krombeini, (Krombein’s hairy-footed pollen mite).
According to Wikipedia: ” The common name is somewhat misleading, as pollen mites consume more nectar than pollen. Both their feeding habits and their size differ significantly from Varroa destructor, the mite very harmful to the European Honey Bee. Although both are classified as mites, varroa mites are more closely related to ticks and only distantly related to Chaetodactylus. ”
So you can expect to have hairy-footed pollen mite contamination if you are not conscientious about cleaning out your tubes in the fall. See this reference on mason bee mites:
Last year (2023), I first heard about the Houdini fly and I posted a message here about them occurring in the Duncan Area. Recently while i have been cleaning out my tubes I have found them in two of the locations where I provide bee boxes for my neighbours . One was in the Tower Point area where most of the tubes in one bee house were affected. The other was in the William Head area of Metchosin.
So it is essential that any old boxes with tubes should be eliminated or cleaned regularly if they are going to be reused. The Houdini flay maggots will consume all the cocoons in a tube . They are much larger than the Mono wasp larvae which are always inside a cocoon case. Also note the twisted purple mass of what I assume are feces
Cacoxenus indagator is a species of fruit fly.[1] It is a kleptoparasite, laying its eggs in the pollen-filled nest cells of mason bees.[2] On account of its ability to break out of those cells once hatched, it is commonly known as the Houdini fly.[3][4]
Recently there is a concern in the Pacific Northwest about an invasive species, the Houdini Fly (Cacoxenus indagator) . which is a kleptoparasite which invades mason bee homes and destroys the developing larvae and source of food pollen.
Brian Guzda of Brian’s Mason Bees (https://www.instagram.com/briansmasonbees/?hl=en) provided this picture. Note that the white maggots are not contained within the cocoon as they are with the Mono wasp, another kleptoparasite which I profile in other posts here. It is essential to clean out whatever kind of tubes your mason bees have capped any time from October to December in order to catch these flies before they mature and cause further damage.
The following video gives more information about this invasive species and emphasizes the importance of taking good care of your bees.
One house had a better-than-average set of mason bee tubes filled, but many ended up with very few cocoons.
The past season was not a good one for mason bees on southern Vancouver island. Cool temperatures delayed hatching and there was poor fertilization in some of the locations . I had mason bee houses stocked with Phragmites tubes and mason bee cocoons in eight different farms of neighbours.
As I have been cleaning out the tubes and getting the cocoons in the refrigerator for storage, I have noticed a significant increase in a species of native mason bee that is much smaller than the native blue orchard bees.
Another interesting observation. was that at the bottom of the tube below the cocoons in several tubes there was a pocket of the dead but hatched parasitic mono wasps.. I cant explain that one (my best hopes would be that this smaller mason bee cocoon has some super power over the parasitic wasps…lol)
male?
smaller species of mason bee (female?)
smaller species of mason bee
Cocoons of smaller species
note frasse on the outside of one cocoon
final compartment with dead mono wasps
one of the few tubes with mono wasp larvae still alive
dead Mono wasps removed from bottom compartment
note long ovipositor for penetrating softer tubes
another end packet with dead mono wasps
pollen packets in tubes where there were no eggs laid
So once the house had all the tubes and trays removed,. The cleaned trays were reinserted and the bamboo tubes were replaced with very short Phragmites reed grass tubes. Now its ready to be placed outside
Any time from September on it is safe to open the Phragmites tubes to collect the mason bee cocoons inside. The earlier you do this the better as it prevents further development of pollen mites. Below are some photos from this years crop.
The ideal tube that you want to find will look like this
One side of the tube will show clear cocoons like this . note the neat arrangement with the plugs of mud where the pollen supply was deposited and the egg was laid, now holding the individual cocoons.
If opened from the other side they will appear like this. The small black cigar-shaped objects are frasse, or larval waste, indicating a healthy cocoon
Beneficial wasp pollinators.. do not destroy!When one of these tubes shows up I simply carefully replace the other half of the phragmites tube and tape it together. I incubate these in a separate container in the refrigeratorSo this is what a successful bunch of tubes looks like. These tubes are about 18 cm in length.
PARASITES of MASON BEES
Pollen Mites
When a brownish orange material fills a cocoons space
These are cleptoparasite iparasitic mites. They steal the pollen of the bees.See the video below
With a hand lens or as above, a closeup view on a cellphone you can see this mass of mites on the move. When I come across a tube with these mites, I segregate all other cocoons from the tube, and give them a thorough wash and cleaning before storing them in the refrigerator. I am also careful not to sell any of the cocoons from that batch. Mason bee houses that are not cleaned will have a build up of mite infestation so bad that eventually very few bees will be produced.
However, some other bodysnatcher parasite did get in and eat cocoons in a few tubes, typically leaving half the cocoon casings. I am not sure what this one is , but usually all the cocoons in a tube will have been opened if these have entered.
Mummification:
A hard dark colored mummified larvae on the right is produced inside a cocoon. Probably spores of the fungus would be released from this form.
This is similar to a fungal infection called chalkbrood in honeybees.
UNKNOWN?
A new parasite turned up this year in a few of the plastic cases with channels which a neighbour gave to me. This one is like a cutworm larvae. I find the plastic containers are very bad for parasites, especially mites.
I know I should have put the chicken wire fencing up sooner, as a bird, probably a woodpecker or a rat pulled out the top 4 cm of tubes from two of my boxes, Fortunately it never opened all the tubes but a few were broken so I was able to open them and see the larvae stage inside
tubes pulled out
tubes scattered on ground
you can see the larvae attached to the plug of pollen in each section of the phragmites tube. At this stage one should not move or jar the tubes as the larvae can fall off the plug of food. I was able to tape back up the tubes and the larvae inside should survive OK as long as they can reattach to the food pellet.
So that’s what we call them when people drill holes into blocks of wood and then never clean them out. The result is an eventual loss of the colony from an ever increasing infestation of mites.
If you aren’t willing to look after and properly clean your colony every year in the fall, then you are not doing a service to help in pollination, you are harming it.
