Identificaciones de bumbleguillen

Link to Rush Milkweed (Ascepas subulata) host plant observation: https://www.inaturalist.org/observations/75316215

Crotch's Bumble Bee (Bombus crotchii) Endemic in California.
Conservation Status: Endangered (EN) (IUCN Red List).

Genus Bombus (Bumblebees) are our only native social bees. They are warm blooded allowing them to fly at cooler temperatures than most pollinators.
Kaufman Field Guide to Insects of North America, Eaton and Kaufman, 2006, p. 344-345.

BugGuide: https://bugguide.net/index.php?q=search&keys=bombus+crotchii

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How to identify if it’s a Male or Female Bumble Bee:
Male has no stinger so it can be handled if necessary.
“Generally, male bumblebees have hairy hind legs without a pollen basket (though beware female cuckoo bees, which also have hairy hind legs). Males also usually have more facial hair than females (either queens or workers) – and in several species this is a bright, obvious yellow. Males also generally have longer, more straggly hair, so if your bee has hairy legs, a moustache, and looks slightly unkempt it’s probably a male.
Behavior can be a useful tool to separate males from workers and queens: because males do not have to collect pollen for the nest, they tend to sit lazily on flowers. They may also be observed flying along hedgerows searching for a mate. They do not feed during this time, so will land briefly on a surface, and then fly off again. They often patrol the same area for a while, so you may see the same bee repeating the circuit over and over again. In contrast, females tend to be much busier, flying quickly from flower to flower, and rarely wasting time by resting on flowers.
The time of year can also be helpful – males become common in late summer and autumn, whereas females are present throughout the whole lifecycle."

Bumble Bee I.D. Tips: https://www.bumblebeeconservation.org/identification-tips/

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"There are 6 taxonomic families of Bees:

Apidae; (ap-ih-dee)
These are the really common, really big bees. Included in this family are the European honeybees, BUMBLE BEES and carpenter bees.

Andrenidae; (an-dren-ih-dee)
These bees tend towards being small and hairy. They make their homes in the ground so are often called mining bees, or sand bees. Generally, they are so small they can fit in tiny flowers, like the bell-shaped blossoms that hang from Manzanita (Arctostaphylos).

Colletidae; (co-lect-ih-dee)
Included in this family are two genera (Colletes and Hylaeus) that are identifiable by their unique faces. If you are lucky enough to study the face of a landed Colletes, you can identify it by its distinctly triangular face. Hylaeus usually has a black body that is contrasted to the yellow markings on its face that make it look like it’s wearing a mask.

Halictidae; (ha-lect-ih-dee)
These bees are commonly called sweat bees because apparently, they like to land on human skin and drink sweat, although I’ve never observed this. I like to call them jewel bees because they often are metallic in sheen and bright in color.

Megachilidae; (mega-chill-ih-dee)
These bees include the mason or the wool-carder bees. They make their homes inside hollowed out twigs or in tunnels made by other insects like beetles. The invasive and common Anthidium manicatum is a regular visitor to the Santa Cruz mountains.

Melittidae; (mel-it-tih-dee)
The most-rare of the bee family types in California. Feeding exclusively on Clarkia flowers in the California chaparral, Hesperapis regularis is one of a small number of native species"

Native Bees: Get to Know Native Bees of the Santa Cruz Mountains (California) with Obi Kaufmann. https://openspacetrust.org/blog/native-bees/