Orchard mason bee facts for kids

Quick facts for kids Orchard mason bee
Scientific classification

The Osmia lignaria, often called the orchard mason bee or blue orchard bee, is a type of bee that builds its nests in natural holes or hollow reeds. It creates small rooms, called cells, for its babies. These cells are separated by walls made of mud. Unlike carpenter bees, orchard mason bees cannot drill holes into wood.

These bees are very common in Canada and the United States. They are often used to help pollinate fruit trees in early spring. Many other types of Osmia bees are also used to help with pollination.

Where They Come From

The orchard mason bee is one of about 4,000 bee species native to North America. This species is split into two groups by the Rocky Mountains. The western group is called O. l. propinqua, and the eastern group is O. l. lignaria. Most of what we know about these bees comes from studying the western group in fruit orchards.

It can be tricky to get these bees to live outside their natural areas. For example, they do not survive winters in Florida or along the Gulf Coast. This is because they need cold winter temperatures to develop properly. Farmers sometimes trick these bees into waking up early. They do this by controlling the temperature. This makes the bees emerge just when almond trees start to bloom.

It is usually best to keep these bees within their natural home ranges. This helps them stay healthy and happy.

Life Cycle of the Orchard Mason Bee

The life of an orchard mason bee goes through several stages. It starts as an egg and grows into an adult bee.

Spring: Waking Up and Building Nests

When the weather warms up in spring, usually around 14°C (57°F), the bees start to come out of their cocoons. The male bees come out first. They wait near the nesting spots for the females to appear. This can take a few days or even weeks.

The first thing female bees do is mate. A female usually mates only once or twice. After mating, she flies away from the nest for a few days. She feeds and waits for her eggs to be ready.

When a female bee is ready, she looks for a good place to build a nest. O. lignaria bees like narrow holes or tubes. They have even been found nesting in keyholes! People who raise these bees often put out special nesting materials. These can be reeds, paper tubes, or wooden trays. This helps to keep the bees close to the fruit trees they need to pollinate.

Having the right kind of mud is also important. The mud needs to be silty or clay-like and have the right amount of moisture. This helps the bee grab and pack the mud. A female bee might check out several holes before choosing one. Once she finds a favorite spot, she does a special dance in the air. This helps her remember the way back to her nest after she has been out foraging.

Orchard mason bees build their nests with many small rooms, called partitions. Each room holds one egg. The female bee starts by collecting mud. She builds the back wall of the first room. Then, she flies back and forth to nearby flowers many times. Unlike honey bees, which fly long distances, mason bees visit flowers very close to their nest.

One bee can visit about 75 flowers on a single trip. It takes about 25 trips to collect enough pollen and nectar for one baby bee. The female bee works hard all day. She only stops when the sun goes down. When the sun rises the next morning, she warms herself in its rays. Then she starts foraging again.

Once there is enough pollen, the female bee backs into the hole. She lays an egg right on top of the food. Then, she collects more mud to seal off that room. This new wall also becomes the back wall of the next room. She keeps doing this until the nest hole is full of her offspring.

O. lignaria bees can choose the gender of their eggs. If an egg is not fertilized, it will become a male bee. If it is fertilized, it will become a female bee. The mother bee lays female eggs deeper inside the nest. She lays male eggs closer to the entrance. On average, she lays about three male eggs and one or two female eggs in each nest. Female bees are bigger than males. They need more pollen, so the size of the nesting hole can be important.

When the egg hatches, the tiny larva eats all the food. It goes through many changes before it becomes an adult bee. It spends most of its life alone in this dark cell.

When the female bee finishes a nest, she plugs the entrance with a thick mud wall. This wall is thicker than the walls between the cells. Then, she looks for another place to build a new nest. She works very hard until she dies. An O. lignaria female lives for about four to eight weeks. In her lifetime, she can fill about four six-inch tubes. Each tube can hold about eight eggs. Her work includes visiting nearly 60,000 flowers! This is why farmers like to use these insects for pollinating their fruit orchards.

Summer: Growing Up

By early summer, the larva has eaten all its food. It then spins a cocoon around itself. Inside the cocoon, it enters the pupal stage. The adult mother bee dies as the season continues.

Fall and Winter: Resting and Waiting

The young bee is now fully grown inside its cocoon. It goes into a deep sleep called diapause for the whole winter. To stay warm, it uses up its stored fat. If the weather stays cold for too long, the bee can run out of food and die. But if the temperature rises too fast, the bee might wake up too early. This can be a problem if there are no flowers yet or if the weather turns cold again. Farmers often use this knowledge to time when they release the bees. They want the bees to emerge just when the first orchard blossoms appear.

How They Defend Themselves

Orchard mason bees, like all mason bees, are very shy. They only sting if they feel they are in serious danger. They do not attack to defend their nests. Their stinger is actually a tool for guiding eggs. Because they are so gentle, mason bees are a good choice for people who want pollinators in cities or towns.

Enemies of Mason Bees

Mason bees can have several different enemies, called parasites.

One enemy is the pollen mite, Chaetodactylus krombeini. These tiny mites can eat the pollen meant for the bee larvae. This can cause the bee larvae to starve. The Sapygid wasp, Sapyga sp, is also a parasite. Its larvae eat the pollen that the mason bee collects. Stelis montana is another type of bee that sometimes invades mason bee nests. Both Stelis and Sapyga larvae spin cocoons and grow inside the mason bee nest.

Several kinds of parasitic wasps attack mason bees. They do this by piercing the bee larva in the nest and laying their own eggs inside it. The wasp larvae then eat the bee larva or pupa. These wasps include tiny black Monodontomerus species and brown Melittobia chalybii wasps. There is also a larger yellow and black wasp called Leucospis affinis. Monodontomerus can be a big problem for O. lignaria.

Some metallic green wasps, called Chrysidid wasps, also eat Osmia larvae. These wasps grow next to the young bee and eat it from the outside.

The nest of a mason bee can also be home to the six-spotted spider beetle, Ptinus sexpunctatus. This beetle eats other dead or decaying insects. It was first found in North America in 2004. It was accidentally brought over with Osmia bees that were being used for research.