How many species of native bees are there in North America?
Native bees have been on this continent for tens of millions of years, co-evolving with the native flora that need help to spread their pollen. That partnership birthed a dazzling diversity of creatures that come in as many sizes, shapes and colors as the flowers they pollinate. There are 4,000 native bee species in the world. California is home to 1,600 different species; 700 of them live in San Diego County.
Do all bees make honey?
Less than 4 percent of all bees (fewer than 800 species) make honey. The most well-known bee in the honey-producing bee group is the honeybee, Apis mellifera. This bee species is used commercially to pollinate many agricultural crops and it is reared for honey in the beekeeping industry. The remaining 19,000-plus bee species make no honey at all.
Not all bees collect pollen?
No, not all bees collect pollen. Cuckoo bees lack the physical structures (body hair, pollen basket, or scopae) necessary to collect pollen. Instead of collecting pollen, cuckoo bees lay their eggs in the nests of other bees, and their larvae consume the food stored by the host bees. They are therefore called brood parasites, relying on other bees to provision their nests with food for their young. Male bees do not actively collect pollen. They visit flowers to collect nectar to fuel their flights. Vulture bees: found in Central and South America have evolved to feed on rotting meat instead of pollen
Do native bees sting?
Some bees sting. However, many species have evolved to not have stingers. Within the subset of species that do have stingers, only female bees can sting. The stinger, or sting, is a modified egg-laying device, which only females have.
Unlike colonial nesters such as honeybees and wasps, solitary bees (native bees) rarely sting potential predators (including humans). Bees in general are not very aggressive, stinging only when they are bothered and feel threatened.
Where do native bees live? Do they have hives?
About 30 percent of solitary bee species use abandoned beetle burrows or other tunnels in dead trees. The other roughly 70 percent nest in the ground, digging tunnels in bare or sparsely vegetated, well-drained soil.
Native solitary bees fall into four general categories regarding nest locations: ground nesters, leafcutters, cavity nesters, and masons. Ground nesters excavate burrows into sandy soil or cliff banks. Leafcutters cut out semicircular swatches of leaf material, which they form into a cylindrical vessel to hold the pollen cake upon which they lay their egg. Cavity nesters use beetle emergence holes in trees, the hollow stems of plants, or crevices under bark. Mason bees collect pollen and pack it into natural cavities before laying a single egg on the pollen loaf. The cavity is then sealed off from predators and the elements with a mud plug. Mason bees are also readily attracted to artificial nest boxes, as are native bumblebees.
Where are the native bee’s hives? Most nest in the ground, really?
Most native bees are solitary creatures. They don’t live in a hive but instead build nests underground or use hollow stems or holes in trees.
What are some predators of native bees?
Among the predators that attack and kill adult bees are robber flies, assassin bugs, spiders, mammals, lizards and birds.
How long do bees live?
Solitary bees usually live for about a year, although humans see only the active adult stage, which lasts from three to six weeks. These insects spend the other months hidden in a nest, growing through the egg, larval, and pupal stages.
Honeybees are social insects that exhibit striking caste-specific differences in longevity. While honeybee queens can live up to 5 years, workers usually only live two to six weeks in the summer and about 20 weeks in the winter. Bees spend the first weeks of their adult life performing tasks within the hive but then switch to foraging activity that exposes them to hazards such as temperature, predation or dehydration all of which reduces their overall life span.
Where are the male bees?
Depending on the bee species and flowering season, bees emerge from their nest between February and September. Typically, male solitary bees emerge before the female, hanging around the nest or nearby flowers, waiting for the females to emerge . Although the ovaries of newly emerged females are not mature yet, females can store the sperm in a special organ (spermatheca) in which the sperm is kept alive and viable throughout the lifespan of the female bee. The female decides if eggs passing by the spermatheca will receive sperm or not. Eggs that receive sperm develop into females, unfertilized eggs become males.
During their brief, several-day to several-week adult life, male bees mate with as many females as possible.
Where are the bees now? (Winter)
California native bees overwinter, most do so as larvae or pupae, some do so as adults. The specific life stage they overwinter in depends on the species and their nesting habits.
Most bumblebee species overwinter as reproductive female queens, while the rest of the colony dies off in the fall. Mason bees overwinter as dormant adults in their nests. Carpenter bees emerge in the spring, mate, and then lay eggs in tunnels within wood. The young adults then overwinter within the nest tunnels. Some mining bee species, like those in the Andrenidae family, also overwinter as adults in the ground.
What is so special about native bees? Why should people care about native bees?
Native bees pollinate plants that are critical for healthy forests, wildlife, and watersheds. Native bees are vital to sustainable pollination of crops.
About 75% of North American flowering plants depend on insects to move their pollen from one plant to another to bring about pollination. Among the pollinators, bees are the most important ones. Except for a few species of wasps, only bees deliberately gather pollen to bring back to their nests for their offspring.
For almost all crops, native bees are the primary pollinators, or they significantly supplement the activity of honeybees. Many crops, such as tomatoes, eggplants and blueberries, need to be "buzz pollinated" — a process bees use to remove and collect pollen from flowers via vibrations. Kiwis, watermelons, pumpkins and squash would not reproduce without native bees. Apples, apricots, blueberries, cherries, mangoes, peaches, plums, pears, raspberries, avocados, almonds, cashews, kola nuts would have a yield reduction of 40 – 90%. Even crops like cotton, soybeans, and peppers that don’t need a pollinator have a higher yield if they’re visited by bees.
Finally, pollination by native bees acts as a buffer in the face of local honeybee declines.
How are native bees doing?
We do not know the status of most bees because there are so many species. What we know is that 20 % to 40% of native bees are pollen specialists, meaning that they use only pollen from one species (or genus) of plants. This restricted diet is due to bees of a certain size, tongue length or ability to vibrate flowers at a specific frequency (buzz pollinators). If that specific plant is removed, the bees go away. If bees are removed, the plant doesn’t reproduce.
A systematic review of the status of all 4,337 North American and Hawaiian native bees, conducted by the Center for Biological Diversity seems to indicate that bee populations are in decline. A primary driver of these declines is agricultural intensification, which includes habitat destruction and pesticide use. Climate change, urbanization and invasive plant growth are also adding pressure. In addition, honeybees and bumblebees managed by humans can cause problems for wild species by spreading disease and competing for food.
What are you taking pictures of?
Native bees. Specifically, we try to capture as many angles as possible of the bee for iNaturalist observations. A clear shot of the wing is very useful. We also note bee behavior, and we take a photo of the host plant.
This is community science. What is that?
Community science (also called "participatory science" or "citizen science") allows non-scientists to participate as volunteers in data collection and analysis for scientific projects. By engaging interested community members, researchers can collect a larger amount of data, and often cover more geographic regions, in a shorter amount of time.
The oldest community science project is the Audubon Society's Christmas Bird Count, which was initiated in 1900.