An online resource based on the award-winning nature guide –

Unequal Cellophane Bees

5-12-14  cellophane bee  205Ninety percent of bees are solitary – the fertile females create their own cells and feed their own young, with no help from a colony of worker bees. They often nest underground, rarely sting and are excellent pollinators, even though they don’t store honey. Colletes inaequalis, a type of Plasterer Bee also known as the “Polyester Bee,” and “Unequal Cellophane Bee,” is a solitary bee. It derives its common names from the practice of lining its underground nest cells with a secretion that, when it dries, forms a smooth, cellophane/polyester-like lining. This cell holds one egg suspended above a collection of pollen and nectar on which the larva will feed. The Unequal Cellophane Bee is crepuscular, which can be deduced by the large size of its eyes. It is one of the earliest species to become active in the spring, sometime between March and May, when adults bees emerge from underground chambers off a vertical tunnel dug by their mother last spring. (Why it is called an “Unequal” Cellophane Bee I have not been able to determine.)

Naturally Curious is supported by donations. If you choose to contribute, you may go to and click on the yellow “donate” button.

7 responses

  1. Suzanne

    Love learning about different bees and wasps. Maybe the term is unequalED bee, with such talent! I enjoyed the rose-breasted grosbeak photo last week, and that very day on my mile-long walk to the mailbox I heard my first one of the spring. Such a distinctive voice — always gets my attention.

    I am curious about 3 current things going on and wondering if you’ve written about them, or would like to:

    1) How do birds get the first twigs or strands of nest material to stay in place while they go gather more? I’m thinking oriole nests, or others that aren’t really wedged into a branch crotch or corner of a building, etc. But even those latter kind seem really difficult – one little breeze or a touch of gravity….

    2) Phoebes – we have a pair (or their kids?) who nest every year on our front door light fixture. They seem to sit on the nest only at night for a couple weeks, even after all the eggs have been laid. This year, it was really cold during the day and only now are they incubating during the day.

    2b) What are your thoughts about coming and going while they’re there? Sometimes we completely switch to another door. My husband (an ornithologist, but doesn’t know the answer to #1 or #2) believes we can go in and out freely except while she’s laying (when she’s more likely to desert b/c not yet fully “invested” energetically) and except when the young are getting close to fledging and might leap prematurely if startled.

    3) Our first hummingbird is back; he came up to me 3 days ago to say, “Hey, where is the feeder?” What else is he eating before any hummingbird-friendly flowers are open? Is he building the nest while waiting for the female to arrive?

    Just some thoughts for topics!

    Suzanne Weinberg

    Sent from my iPad


    May 12, 2014 at 12:14 pm

    • Hi Suzanne,
      I’m afraid I don’t know the answer to #1. As for #2, perhaps you’ve seen a phoebe on the nest before eggs have been laid?

      Birds of North America Online says:

      “Females usually begin diurnal incubation with the last egg, although fidelity does not reach a peak until the second day…however, observed seasonal variation in the onset of incubation, beginning with the last egg in spring and with the penultimate egg in summer. FEMALES SLEEP IN THE NEST CUP EACH NIGHT, WELL BEFORE EGG LAYING BEGINS; such nocturnal incubation has some impact on embryo development. Eggs are evidently quite hardy against temperature stress during the cold weather of the early spring nesting period; nocturnal covering of eggs prevents possible freezing. Extended periods of egg neglect lengthen incubation period and increase embryo mortality.

      Hummingbirds almost always arrive well after yellow-bellied sapsuckers, and rely heavily on sapsucker “wells” to obtain sap and insects before flowers are plentiful.

      Hope this helps! Mary

      May 13, 2014 at 11:10 am

  2. Susan Holland

    This is very cool! It continually amazes me that you eye sees these tiny, but oh so important occurrences, and then up you can capture them with your camera to show us! It always makes me think about what must be happening around me, under my nose (or my feet) that I miss because I do not pay enough attention. Thank you for being my eyes and bringing me these small wonders that I have missed!

    May 12, 2014 at 12:23 pm

  3. Ricker Winsor

    Hi Mary, Do you know what happened to the evening grossbeaks which used to be at the winter feeders in large numbers- forty or fifty at a time, flocks. They were the most exciting bird of the winter for years and then they just disappeared.. Thanks, Ricker

    May 12, 2014 at 1:59 pm

    • Hi Ricker,
      While I know that the population has dropped significantly (one study said it had dropped 91% since 1967), I can’t find any decent explanation. Here are some theories, each of which may contribute, but it feels like there’s something bigger going on.

      Evening Grosbeaks feed their nestlings insects, including (possibly preferentially in some places) spruce budworm. Controlling spruce budworm has been an important forestry goal for many decades, with heavy use of pesticides over enormous swaths of northern forest. One of the pesticides currently used is Bacillus thuringiensis, which isn’t known to harm birds, but regardless of the pesticide used, the loss of larval insects during the nesting season may well be implicated.

      Adult and young Evening Grosbeaks feed heavily on maple and, especially, box elder seeds. In recent decades, forest management in huge swaths of northern forests has focused on fast-growing softwood trees for paper and wood products rather than on slower-growing hardwoods such as maple and box elder. This may have reduced another important food source.

      Exploitation of “tar sands” has also been implicated in the loss of huge swaths of Canadian forest habitat.

      Large numbers of Evening Grosbeaks are killed by cars during winter, when they are drawn to roads to pick up road salt and grit. In a single incident reported in 1981, over 2,000 Evening Grosbeaks were killed along a 16-km stretch of a British Columbia road, with many more dead birds seen off the road that weren’t counted (Smith, W. G. 1981. Observations on a large highway kill of Evening Grosbeaks in British Columbia. Syesis 14:163.)

      Evening Grosbeaks are killed in much larger than average numbers at windows. Klem in 1989 listed them as the tenth-most frequently reported species killed by collision with building windows.

      May 13, 2014 at 10:59 am

  4. I think I may have seen some of these near my front walk on the edge of the garden going down little tunnels. I love all my pollinator friends!

    May 12, 2014 at 5:18 pm

  5. Kathie Fiveash

    I have never even heard of unequal cellophane bees before. Thank you Mary!

    May 12, 2014 at 10:07 pm

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s