|Tips and Reminders - Spring Mason Bees
It's a busy month for mason bees! A mason bee survives during hibernation by living off its stored fat reserves and we recommend that you let your mason bees emerge from their cocoons by May 1st.
Your bee house should already be installed on a non-moving south-southeast facing wall, post, or fence, tall enough for you to peek into easily. In March we described how to set out nesting materials and we're sharing some of the tips again for your success. Three things are vital: the correct nesting holes, available pollen, and good clayey mud.
IT'S TIME FOR MASON BEE ACTIVITY!
What to look for! Males emerge first, followed by females. Males have long antenna and a white patch of hair on their face. We think the long antennas look cute! Males have one purpose - to mate with as many females as possible in their short 2-week lifespan. They drink nectar and will hang around the mason bee house.
Females are typically bigger than males, have shorter antenna, no white hair, and large jaws for carrying clayey mud. After mating, a female mason bee stores sperm, using it to fertilize eggs. Eggs that are not fertilized grow into male bees, fertilized eggs grow into female bees.
It may take a few days for the females to mate, scout the area for suitable nesting holes, pollen, and mud. They then choose their home and leave a scent in the tunnel that says "MINE!" to other mason bees.
You'll see many of the bees nesting in their holes in the evening or early morning. These are timid bees, don't be afraid to get close!
What to do if your mason bees haven't emerged from their cocoons: In general, spring mason bees will emerge when it's the right time of year (now) and daytime temperatures are about low to mid 50°F (10°C). One word: patience. Let them emerge when they are ready. However, if you are impatient or want to check if they're alive, see this video on how to open a cocoon with scissors.
If the bee is dead, open a few more cocoons. If all bees are dead, did they dehydrate in your refrigerator? Did they bake in the house from unusually hot weather or direct sunlight? We still have bees in our coolers for the month of April to restock if your weather or an unknown reason caused frustration.
What to do if your bees aren't nesting in the holes you provide: Again, patience. While not all bees might be nesting in your house, a few may be. You can check for guests by using a flashlight at night looking for heads or bums in the nesting holes. If no bees have nested, they could be nesting in your yard or your neighbors, or they could have flown elsewhere, typically for lack of clayey mud. We understand they also don't like lawn treatment odors from neighbor's lawns.
Watch mason bees fill the nesting holes: A female mason bee will cap the end of her nesting hole with an extra thick layer of mud to protect her precious young. She will then move on to a new nesting hole and begin the hard work all over again. Keep an eye on your mason bee nesting activity, if you see about 40% of the nesting holes filled you may want to think about adding more holes. Simply add new holes on top of the previous ones. If you need to make space, take filled nesting holes out at night. We'll teach more on this next month.
A word about the weather: Here in the Pacific Northwest, spring is arriving several weeks later than last year. We have heard that the rest of the country is having a late spring, too. Mason bees can fly in light rain but the cold and dark weather of a heavy spring rain may keep them in their cocoons or in their nesting holes.
Reminders from our last issue:
Holding spring bees through April in the fridge: Add water to your HumidiBee and set the refrigerator temperature around 34°F. Place the Humidibee into a paper bag which provides a darkness that helps the bees stay asleep. Continue to watch for moldy cocoons and quickly wash the cocoons using instructions at the bottom of this page .
If bees are emerging in the fridge: These emerged bees have run out of stored fats (fuel) and must have food or perish. You can feed emerged bees with a cotton ball soaked in a 50/50 mix of water and white table sugar. While not a perfect food, it should keep them alive until your spring weather and flowers are ready.
Releasing bees: Mason bees emerge from their cocoons when the daytime weather begins to warm above 53°F, nighttime temperatures do not bother them. Watch the weather and be wary of a late snow. If you have enough cocoons, stagger your bee release by placing a few out now and a few more in a week or two. (Don't separate large cocoons from small as you want both large female and small males to be out at the same time.) Place cocoons on top of or behind the nesting holes (inside the mason bee house) so that the bees can get to know their home as they emerge. Protect cocoons from the wind by placing them inside a small paper cup or box. As the weather warms, beware of placing your bee cocoons in direct sunlight (place them in the back of the bee house), as this can bake your bees.
Protecting from hungry birds: If birds become a problem you can install wire cloth at the front of your bee house. Choose a wire cloth that has openings that are 1/2 - 3/4" wide, this size should be big enough for mason bees but small enough to keep birds out. Do not attach the wire flush against the nesting holes because the bees need space for landing and leaving. Instead, bubble the bird wire 2-3" away from the front of the bee house.
Mason bee attractants: If you have our older model blue attractant sheets, place one sheet between the nesting holes as you put your bees out, and the other a few weeks later. For our newer Invitabee spray attractant, apply about 10 squirts over the front of the holes before placing out the bees. The spray evaporates within minutes, leaving the nesting scent pheromone behind. (There are about twenty sprays in the container.) This attractant was patented by the USDA to be an attractant for more than the blue orchard mason bee. We're pleased to license it!
Keep mason bee mud moist: Mason bees use mud to protect each egg chamber and they will not nest in your bee house if there is no usable mud nearby. Wet soil is not clay and wet garden dirt has too much humus in it and can't be gathered, carried, and packed. Mason bee mud should have a clay-like texture and bees need it to be moist so that they can gather and work with it. If your yard’s soil is silty or sandy, you can supplement with our mud mix. We believe moist clayey-mud in the ground is most natural, but if your soil is too porous and you have to keep watering it, we developed the Mud Box which keeps mud moist for a long time and protects bees from frogs and birds as they gather mud.