by Ann Barnes
When I think about pollinators, bees are the first creatures that come to mind. Honey bees, which were brought to North America by settlers from Europe, may get the most attention, but there are around 4000 species of native bees in the US, with more than 500 species in North Carolina. Native bees are important pollinators and are worth getting to know. Here are two that I see in my garden every day:
Bumble bees
Bumble bees are easily recognized by their shape and their fuzzy yellow and black bodies. Like honey bees, bumble bees are social insects that form colonies with a queen and workers, although their colonies are not as long lasting as honey bees and are usually much smaller. Bumble bees nest in the ground, often using old rodent holes or other cavities, as well as in tufts of grass. A small amount of nectar is stored as a food source, but only enough to feed the queen and members of the colony. In spring, the queen chooses a nest, forages for pollen, then lays her first batch of eggs. These will become workers, and are all female. Once these workers have pupated, they take over the job of collecting nectar and pollen, and the queen remains in the nest to lay more eggs. Workers will defend the nest when disturbed and do not lose their stingers when they sting. Both males and females are produced in broods that hatch in summer. Males generally leave the nest attempting to find mates. New queens mate, feed, then overwinter. Most of the rest of the colony, including the old queen, dies out by winter.
Bumble bees can use a technique called “Buzz Pollination”, in which the bees use flight muscles to shake self fertile flowers (flowers that have both male and female structures). Tomatoes and blueberries are two crops benefit from buzz pollination. In fact, bumble bee colonies are sometimes farmed to aid in pollination of tomatoes in greenhouses. Bumble bees frequently have longer tongues than honey bees, so they can sip nectar from flowers with a longer shape. This makes them important pollinators for wild flowers that are food sources for birds and wildlife. Shorter tongued bumble bee species will sometimes cut a hole in a flower to feed on nectar without pollinating the flower. Many bumble bees will forage in lower light, in cooler temperatures, or even in rain; conditions that aren’t favored by honey bees.
Carpenter bees
If you have a wooden fence or porch railing, carpenter bees might not be on your list of favorite insects, but they are important native pollinators. These bees do not live in colonies like bumble bees or honey bees and do not have a social system with a queen and workers. Males are territorial and seem aggressive to anyone nearby, but they do not have stingers. While females do have stingers, they rarely sting unless provoked. Carpenter bees tunnel into wood to build nests, which may extend six or more inches along the grain of the wood. Nest sites are generally in dead but not decayed wood, but these bees will also build nests in fences, porches, and other wooden structures around our homes. Females lay eggs in spring and seal the eggs in chambers using a substance made from chewed wood and saliva. The larvae feed on pollen balls left in their chambers, pupate, and emerge as adults in late summer. Adults overwinter in cleaned-out tunnels and can live up to three years..
Carpenter bees look similar to bumble bees, but instead of being fuzzy all over, carpenter bees’ abdomens are shiny and black. Like bumble bees, Carpenter bees visit a wide range of flowers and use buzz pollination to shake pollen grains from flowers’ anthers. If you love tomatoes, peppers, and eggplant, you may want to overlook the occasional hole in your fence because of their skill at pollinating these plants. Because of their large size, carpenter bees don’t fit inside some tubular flowers and may rob them of nectar by cutting a slit at the base of the flower in the same manner as the shorter tongued bumble bees. Carpenter bees eat nectar and pollen, but do not feed on wood.
In honor of Pollinator Week, here is a list of foods that are dependent on pollinators: http://pollinator.org/list_of_pollinated_food.htm
Want to attract native pollinators? Try planting some native plants from the list here
Sources:
http://www.xerces.org/pollinator-conservation/native-bees/
http://www.clemson.edu/extension/beekeepers/factsheets/bumble_bees_as_pollinators.html
http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5306468.pdf
https://growingsmallfarms.ces.ncsu.edu/growingsmallfarms-pollinatorlinks/
https://www.ces.ncsu.edu/depts/ent/notes/Urban/carpenterbees.htm
https://bumblebeeconservation.org/about-bees/lifecycle/