Friday, April 10, 2009

Let Sleeping Bees Lie

One of the many fascinating aspects of the lives of solitary bees is that males will often come together, right now, over me…No, wait, that can’t be right. That would be the Beatles. Male solitary bees, however, frequently gather in “sleeping aggregations” where they spend the night, or rest during inclement weather.

Over the last few weeks I have been fortunate enough to witness a few of these low-key bachelor parties here in Tucson, Arizona. My walk home from work in the evening would reveal longhorned bees of the tribe Eucerini (family Apidae) bedding down atop desert marigolds. There were generally at least two per flower, sometimes several, and occasionally one lone maverick. Only male longhorned bees have the long antennae that give this tribe its common name. Females have much shorter feelers.

You would think that being so exposed, the stingless males would be highly vulnerable to nocturnal predators, but this does not appear to be the case. Indeed, I often found them just beginning to stir the next morning.

A different kind of perch, and sleeping posture, is adopted by male cuckoo bees, Xeromelecta californica. Here, three individuals are clinging to twigs on a mesquite sapling. They are gripping the plant with only their jaws. That cannot be comfortable. I originally noticed only one member of this trio, in restless flight, seeking a better “bunk” to land on. They were also taking after the geriatric set, retiring early, at about four in the afternoon. One ultimately re-settled on the tip of a thorn.

These social gatherings are very modest in size. I am hoping to capture images of much more spectacular events later in the year. Stay tuned for entries on sleeping wasps as well. For more on this and other odd bee-haviors, check out the Urban Bee Gardens website.


  1. I have noticed the jaw-gripping sleep posture by what I thought were wasps (philanthinae?) but I'm far from sure about that ID. They seem very selective of the plants they favor, and like your bees they would begin to bed down in the late afternoon well before sundown. I'll be looking out for your sleeping wasp post!

  2. These are fascinating, both the bees and their behaviour. Do any of these groups get as far north as me? I don't recall ever having noticed them, though that doesn't necessarily mean they're not here.

  3. Vanessa: It was likely bees in the genus Nomada that you observed. They are very wasp-like, and easily mistaken for beewolves....Seabrooke:-) You should have Eucerini bees up there, at least genus Melissodes. I know Xeromelecta is primarily southwestern.

  4. Cool, I'll have to watch for them this year. :) They seem to be a summer species up here, July/August for BugGuide submissions.

  5. Eric - a quick quesiton... I know you are busy and don't want you to spend any time on this, but do you know of any resource for distinguishing between different bees? For example, I can't tell the difference between a honey bee and a sweat bee simply by looking at pictures. Bug Guide is pretty deficient.

    I also had the same question with Salticidae. I can't tell the difference between Phidippus, paraphidippus, etc. Thanks so much! Again, if you know something, that would be great. You don't need to go find anything.

    Great blogging!

  6. resource...


  7. I had photographed some "sleeping bees" this morning, in a desert marigold, in Tucson, and was googling to find some info (well, really to make sure I wasn't imaging the 'sleeping' part) and I came across your blog.
    Real live Sleeping Bees, in a desert marigold, in Tucson.
    Whaddaya know.

  8. I don't know the scientific name for them; but we call them bumble bee. huge fat docile bees that wont sting unless provoked. where i am in Connecticut; when i garden- usually i find some sleeping bumblers once in a while. I also have very good photos of this.


Blog author currently unable to reply to reader comments, nor comment himself. Working to resolve this.