Gardening: Solo Bees

When you mention bees people automatically think about Honey Bees and the sweet gold they produce. We have all seen bee hives, know about the Queen Bee, the drones, and of course the hula dance they do to communicate. Who among us have not been stung at least once? But Honey Bees do not make up the majority of the bee population. According to the The Xerces Society for Invertebrate Conservation, of the approximate 3,600 bees in North America, almost 90% are Solitary (Solo) Bees.
Most people have not heard of Solo Bees that, as their name suggests, lead a solitary life, do not produce honey, and are not aggressive. You have heard the saying: “It takes a village.” Well in the case of bees, it takes a colony. Making honey is labor intensive and Solo Bees don’t have the manpower to make honey. It is the lack of having to protect a stash of honey that makes Solo Bees less aggressive and less apt to sting. Though Honey Bees pollinate flowers, Solo Bees are super pollinators because there are so many more of them. There are at least 300 types Solo Bees in Florida alone.
Some Solo Bees are particularly helpful in pollinating specific crops. There is the Squash Bee for squash and the Blueberry Digger Bee’s (Habropoda Laboriosa). The Digger’s high wing speed blows pollen onto the bees making it easier to pollinate the blueberries.
As a whole, Solo Bees are better pollinators because they:

  • Fly faster so they pollinate more plants.
  • Work on cloudy days – they are not fair weather buzzers.
  • Work long hours, their day starts before 7am and ends late in the afternoon.
  • Have a great attitude despite their long hours so you can work in your garden with them and not have fear of getting stung.
    The foraging distances between Honey Bees and Solos are significant. Worker Honey Bees travel 600 – 800 yards whereas Solo Bees keep closer to their pollinating source by flying only 300 – 500 yards. This means that their nests are closer to our homes and we can have a favorable impact not just on their source of pollination but their nesting habitat.
    Solo Bees are often categorized by type or category (Miner, Leaf Cutter) but Sally Scalera, (Urban horticulture agent and master gardener coordinator for the University of Florida’s Institute of Food and Sciences) categorizes them simply as either soil or wood dwellers. “… approximately 70% nest in the ground by digging a tunnel in bare or semi-bare, well-draining soil. Soil-dwelling bees include bumble, digger, sweat and squash bees.”
    As with Honey Bees where the focus is on the Queen Bee, it is also a woman’s world with Solo Bees. After mating, the female Solo builds her nest with no assistance. Whether the nest is built under the soil or in wood, the nests are similar in that they are tubular and have chambers. Nests made underground can be identified by mounds of dirt with an entrance hole. Though they are solitary in nature and have their own chamber, it is not unusual for Solo Bees to live “condo” style with several bee chambers next to each other. They may even share the same entrance and branch out to individual chambers.
    The female may lay anywhere from one to twenty eggs, depending on the species. With some bees the males are laid up front so if the nest is compromised, the males will be sacrificed and hopefully the females located in the back of the chamber will survive. Each chamber is provisioned with pollen and nectar so that once the egg hatches, which may be close to a year later, it has enough to eat while it develops from a larva to a pupa. Emerging males wait around until females emerge so they can mate. Because male Solos are homeless, they can often be found sleeping within flowers during the evening. Males die within weeks of mating.
    Habitat destruction has negatively affected our pollinators so it is important that we provide an environment where they can pollinate and procreate. There are many kits for wood dwelling bees that you can buy and instructions on how to build your own. Most kits have multi-sized holes to accommodate different types of Solo Bees. It is recommended that the tubes are replaced every other year so that pathogens don’t grow in them. But what about the soil dwellers? Of course there are no rolls of lawn pre-drilled with holes but we can make our gardens more hospitable for them. We can provide space in our yard for our mining bees; it is not that difficult and doesn’t involve building anything. Using Florida Friendly Landscaping guidelines is a great start. Providing sunny bare spots or areas that are sparsely vegetated will provide areas for mining bees. This doesn’t mean that you can’t mulch but devote some areas for them or don’t mulch over an area where you see their tunnels. Their tunnels may be anywhere from a few inches to three feet deep. In 2016 a study was made at UC Santa Cruz as part of a larger study and they found a negative correlation between the area of a garden with mulch cover and the number of bee species.
    A plus for us who live in Flagler County is that our sandy soil is very suitable for these bees. Mining bees can also be found in lawns and they will resemble ant hills. In looking at the pictures of mining bee nests I think that I have mistaken them for ant nests and may have had them destroye d. When my exterminator comes again, I am going to make sure that I look for these miner bee nests and educate them also.