Vosnesensky’s Bumble Bee (Bombus vosnesenskii), San Francisco, CA
1. In the spring, a new queen bumble bee incubates her eggs in a little nest of straw much like a mother bird. By placing her abdomen over the eggs she is able to control their temperature, speeding up the development of her young. Once the eggs have hatched and the larvae have emerged, she will continue to keep her daughters warm until they are old enough to leave the nest for foraging. In order to retain her sitting position eggs for as long as possible she first constructs a little wax pot filled with sweet nectar next to the nest that she can sip from so that doesn’t have to leave her young too often.
Male Cuckoo Bee (Nomada sp), Chatanooga, TN
2. After copulation, a male cuckoo bee in the genus Nomada transfers an ‘invisibility cloak’ of pheromones to his mate that allows her to slip, undetected, into the nest of her host bee species. The entrances of solitary bee nests are lined with a unique chemical signature that serves as a type of intruder detection system for unwanted visitors. However a female cuckoo bee is able to pass by without much trouble thanks to this unique gift from her mate.
Night-flying Sweat Bee (Megalopta sp), Kanuku Mountains, Guyana
3. Most bees fly during the day. However a few North American species (such as a sweat bee, Lasioglossum texana) are able to navigate by the light of the moon and stars, which allows them to collect pollen and nectar from nocturnally blooming plants such as the evening primrose. Nocturnal species, such as the night-flying South American sweat bee shown here, have enlarged simple eyes known as ocelli (the 3 small eyes centered between the larger compound eyes) that help them to navigate in very low levels of illumination.
Fuzzy-legged Leafcutter Bee (Megachile melanophaea), Madison, WI
4. Leafcutter bees are raised in narrow, tube-like nests that are lined with leaves by their mother. Typically, the bees hatch from the entrance (the last eggs laid) to the back of the nest so that everyone can leave in an orderly fashion. Occasionally, a young bee may ‘sleep in’ too long, blocking the exit and causing a traffic jam for the remainder of its nest mates. When this happens, the nest mate who is next in line will give her drowsy sibling a gentle nip on the end of the abdomen as a cue that it is time to wake up and get moving.
Thistle long-horned bee (Melissodes desponsa), sleeping on a goldenrod
5. Solitary bees, as you might guess from their name, don’t live in colonies like honey bees. Since there is no communal home to return to, many solitary species such as the thistle long-horned bee will rest at night by clamping their mandibles onto a bit of vegetation. After finding a suitable roosting site at dusk, the bee will enter in a state of suspended animation until the next morning when the sun’s warmth makes it possible for it to fly once again. This is a trait that is also still shared by some of bees’ ancient wasp ancestors in the family Sphecidae.
A Beewolf (Philanthus gibbosus) holds a Sweat Bee (Lasioglossum pilosum) beneath her abdomen before transporting it back to her nest as paralyzed, living food for her young.
6. Which came first, bees or wasps? Many evolutionary biologists believe that bees are essentially a lineage of pollen collecting wasps that are directly descended from a group of predatory wasps in the family Crabronidae. Wasps in this family –Bee Wolves, for example– often visit flowers in search of insect prey to feed their young. The captured prey is often coated in pollen when fed to the young wasps. In the beginning this served as an additional source of protein for the young wasps but over time one or more species began to feed their young a strict pollen diet. This eventually led to the rise of the insects that we now call bees. Bees feed strictly on nectar and pollen and utilize uniquely shaped hairs called scopa that allow a female bee to collect pollen for her young.
Southeastern Blueberry Bee (Habropoda laboriosa)
8. Native bees deserve more credit for producing the foods that we enjoy each day. Did you know that honey bees are not always the most efficient pollinators of native North American crops such as blueberries and squash? Blueberry pollen is held tightly within the flower’s anthers, which makes it very difficult for honey bees to access it. Bumble bees and specialist species such as the Southeastern blueberry bee use a technique known as buzz pollination or sonication to release this pollen. To do this, the bees unhinge their flight muscles and vibrate them at a rapid pace, dislodging the pollen and causing it to fall from the blueberry flower onto their bodies. It has been estimated that a productive Southern Blueberry Bee will visit as many as 50,000 flowers in its lifetime, resulting in the production of somewhere in the neighborhood of 6,000 blueberries. Not bad for a little bee!
Rusty Patched Bumble Bee (Bombus affinis). Photographed in Madison, WI
9. While there are approximately 4,000 species of native bees in North America many are in serious trouble due to a variety of factors including loss of habitat and the use of pesticides such as neonicotinoids. In many cases, pesticides don’t directly kill a pollinating bee but rather do so indirectly by affecting its ability to reproduce or store body fat, resulting in a slow death. A tragic example of a North American bee in serious decline is the rusty patched bumble bee (Bombus affinis), whose numbers have dropped 87% in the past 15 years. This beautiful bumble bee and other closely related species have been inflicted with an internal pathogen that was introduced into North America when bumble bees imported from Europe to pollinate greenhouse tomatoes escaped into the wild and came in contact with wild bees. Franklin’s bumble bee (Bombus franklini), a relative of the rusty patched bumble bee that has also been affected by this pathogen has not been seen since 2006.