This Weather !!

IMG_5633I’m glad for the moisture, and I love the snow day (and cookies we baked).  The bees will be fine.  It was too early for 70F weather anyway.

Enjoy the snow.

An Isodontia cocoon where the larva will pupate and develop into an adult.

As snug as a “bug” in a cocoon.  (Isodontia mexicana cocoon)


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Welcome to The Bees’ Needs 2016

153215_2015-04-15We have started passing out bee blocks for 2016.  If we have not already contacted you to come get your block, you should be hearing from us within the next few days.

Our Data Entry Portal and Basic Survey are not ready for 2016, so hold off on doing those things.  In the meantime, get your bee block out in your yard and expect to hear from us again soon.

Thanks for participating!


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2016 Bee Season

Osmia ribifloris returns home

Osmia ribifloris returns home

Due to limited funding, the 2016 season of The Bees’ Needs is going to be reduced in scope and primarily for volunteers who have participated in the past.  Those people who have requested bee blocks will be contacted over the next few weeks as blocks become available.  With this seemingly early spring, we want to get the block installed soon.

We will try to continue the blog posts this summer, though they may be a bit more irregular in frequency.  Stay tuned.

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The Bee Guru

Since The Bees’ Needs focuses much attention on bees, it seems reasonable to mention Dr. Charles Michener, arguably the most knowledgeable human on the subject of bees – ever. His treatise, The Bees of The World, is THE comprehensive work on bees.

Rather than regurgitate the statistics of his 80 years as a professional entomologist, with over 500 publications, over 600 described species, and around 100 species named for him – all things that you can read about by clicking on the reference links below – I’d rather focus on his connection to Boulder.

As a teenager, he became interested in bees and ended up corresponding with T.D.A. Cockerell, our Entomology Collection’s first curator and, at the time, a world expert on bees.  In fact, Mich ended up coming to Boulder, from Pasadena where he lived, to spend a summer with the Cockerells and learn about bees. That was 1935, the same year he published his first professional paper which happened to be on the nesting habits of a California species of Dianthidium.  Not bad for a 16 years old!

The first time I met Mich, I was a shy, insecure, beginning Master’s student at Michigan State, and I was giving a presentation on Hylaeus nesting biology at the Entomological Society of America meetings. Because of a scheduling conflict, he couldn’t attend my talk. At his request, we went down to the slide screening room and I was able to give a personal encore presentation to both Mich and Walley (LaBerge, another bee systematist). I was totally frightened at first – mortified actually – in the presence of THE world’s authority on bees, but I soon came to realize Mich wanted to hear what I had to say. The talk became a discussion. He wanted to learn from me, but I think he also wanted me to learn from the discussion, not through him telling me, but from me telling him. It’s a concept that I have come to appreciate over the years – and that is, the best way to learn something is by teaching it.  By doing that, you refine your own thinking on the matter, you see ideas from other people’s perspectives, and often times you absorb what they have observed and shared with you. Our Citizen Scientists, our wonderful volunteers, remind me of that, quite often.

Another thing I learned is that when you study bees, all roads lead to Kansas. Mich was hired on at the University of Kansas in 1948 and has remained active there for 67 years, building a world-wide collection of bees that dwarfs our entire entomology collection here at CU. I’ve visited several times over the years, and was always welcomed with open arms. Mich also has amassed a large collection of students, grand-students, and great-grand students. All living bee workers are somehow “related” to him, academically. He built a legacy studying what he loved.

Several days ago, Mich passed away peacefully at the age of 97. By all accounts, he had a good life — a life full of bees.

Links to reference: (limited access)

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Preparing for Winter

The inevitable!

The inevitable!

Well, we are jumping the gun by a few weeks for those of us who live down low, but since we live in Colorado, we know it will snow sometime very soon. Some of you at higher elevations may have already been visited by Jack Frost or Susie Snowflake so it’s time to discuss what happens next for your bees and their bee block homes.

It’s sad to think about the fact that all the bees and wasps that were busily pollinating your flowers this summer will soon die. But it’s an amazing thing to realize that every bee you enjoy next summer is currently a larva or adult, and that your bee block is harboring many of next year’s pollinators. It’s a veritable pollinator nursery, so how can you take care of it?

Winterizing your block is easy – just leave it be.  These insects have evolved here and expect it to get cold.  In fact, if it doesn’t get cold enough for long enough, they won’t properly develop into adult bees to pollinate your garden next summer. If your block is cracked or damaged, after the first frost is a reasonable time to try repairing it. Just don’t bring it into a warm, indoor space for any length of time to avoid shocking the young inside.

If you want to move your block to a new location in your yard, now is a great time to do that. If you’re moving, or don’t think you want a bee block in your yard next year, please send us an email ( and we’ll make arrangements to take your block.

And what do you do with your block next summer? Just leave it be.  Once the adults emerge next summer, some will move back in while others will move on to find another place to nest.  Since the tunnels are full of baby bees and wasps, you don’t want to “clean them out”.  The bees are great housekeepers and will do that themselves.

Note: we won’t ask our current citizen scientists to monitor their 2015 bee blocks next year, so it will simply be yours and the bees’ to enjoy for as long as they last.

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Resin with Debris Plugs & Dianthidium

Dianthidium uses resin and bits of debris to build her nest plug.

Dianthidium uses resin and bits of debris to build her nest plug.


As the nights cool and the leaves start to turn in the high country of Colorado, we find one of our Autumn bees laboring away. She’s collecting pollen to provision her nest, along with a smattering of sticks, stones, and resin that she’ll use in her elaborate, and highly variable nest plug.  These “Resin with Debris” plugs that are now showing up across the Front Range foothills are the work of Dianthidium bee species.


Dianthidium nest plug made from bits of wood and a pebble held together with resin.

Dianthidium nest plug made from bits of wood and a pebble held together with resin.

A nearly finished work in progress, Resin and Debris nest plug.

A work-in-progress, this Resin and Debris nest plug is almost complete.









In contrast to the narrow, black Aphid wasps (Passaloecus sp.) which also construct nest plugs from resin and top them off with scraps of whatever they find lying around, these artistic bees tend to nest in somewhat larger diameter tunnels (3/16″ – 5/16″ or the column 2 and lower column 3 holes in the 30 tunnel blocks) and use larger bits of debris and pebbles.  They are, after all, larger and more robust insects!  And rather than just topping off their resin plus with a layer of debris, the Dianthidium incorporate the debris into their nest plugs – almost using the resin as mortar.

Dianthidium on gumweed.

Dianthidium on gumweed. Notice all the pollen dusting the bee’s face and legs.

Like their fuzz-loving cousins, the wool-carder bees (Anthidium sp.), Dianthidium superficially resemble yellowjackets, in that their integument (exoskeleton) is boldly marked with yellow and black.  Unlike yellowjackets, these insects are solitary bees!  Look for these bees on gumweed and asters.

We hope you have enjoyed this summer’s Plugs & Bugs series.  Stay tuned for additional blog posts on a variety of subjects throughout the next few months.

Posted in 2015, Nest Plugs, Plugs and Bugs | 1 Comment

Mud “Plugs” (part 2) & Auplopus

Auplopus sp. constructed a series of mud lined cells in a bee block in Longmont

A series of Auplopus sp. cells constructed in a bee block in Longmont, Colorado

What is THAT?  Looking a bit like a dried up worm, this is a series of mud-lined cells constructed by a wasp in the genus Auplopus.  This unique nest is one of the more bizarre we have found in our nest blocks so far.  While it is not new to science, it was new to us.

The same nest with cells removed from the nesting tunnel.

The same nest with its 12 bead-like cells removed from the nesting tunnel.

This nest was constructed in the largest diameter nesting tunnel.  The wasp is much smaller than that, allowing for the overlap of several intertwining stands of bead-like cells.  Auplopus is a spider wasp (Family Pompilidae) and one of only two spider wasp genera that nest in our blocks.  They are called spider wasps because they provision each of their cells with a single spider for their young to feed upon. It is reported by previous scientists (Medler and later Krombein) that the “mom” wasp amputates the legs of the spider prior to bringing it back to the nest.  Ironically, this nesting tunnel was usurped by a spider, so the mom wasp never completed the nesting tunnel with a plug at the entrance. It was obvious (prior to the spider usurpation), that this nest contained mud cells, although they looked pretty much like dried slugs.

An Auplopus specimen with the mud cell from which it was reared.

An Auplopus sp. specimen with the mud cell from which it was reared.

A apecimen of Auplopus sp. Note the metallic blue color of the wasp.

A closer look at the specimen of Auplopus sp. Note the metallic blue color of the wasp.


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Plant Fuzz Plugs & Anthidium

White Plant Fuzz nest plugs made by Anthidium sp.

White Plant Fuzz nest plugs made by Anthidium sp.

What’s white, furry, sits in a bee block, and looks like a joke? An Anthidium nest plug made from Plant Fuzz! Seriously, it looks like someone stuffed a cotton ball into the nesting tunnel(s). Well, someone – or something – did, and she was a wool-carder bee.

These uncommon nest plugs tend to be found in groups, so if your block has one, it is likely to have many. These plugs tend to be in the larger diameter tunnels, since the bees that make these plugs are fairly good sized.


Anthidium oblongatum

Anthidium sp. visiting a flower. (Photo by D. Wilson)

The bees superficially resemble yellowjackets in that they are robust black bees with yellow marking and not terribly hairy. The bees are a rounder, shinier and nest in the blocks, which the yellowjackets don’t do (although next year’s queens may spend the winter in your block). Two of our more common species are introduced, but we do have native species that nest in our blocks.

Unlike most our other bees, the males of a given Anthidium species tend to be larger than their female counterparts, and are often reared from the innermost (first constructed) cells in a nest. The males can be territorial over a patch of their favorite flowers and may be seen, rather aggressively, chasing away anyone who dares enters “his” turf.  Fear not, he doesn’t have a stinger (though he does have formidable mandibles and can dispatch smaller insects, including honey bees).

Where do the females get the fuzz for their nests? Not from the end of a Q-tipTM, that’s for sure.  They are very adept at finding hairy plants (sagebrush, lamb’s ear…), scraping the hairs into a ball and carrying them back to their nests. They are, after all, in the family Megachilidae, with the rest of the Leaf-cutting bees. They could be called the leaf-scraper bees, but they are known as with wool carders, since they card the “wool” of plants. They not only make nest plugs from plant fuzz, but they line their cells with it as well. These larvae have it made, lying in a bed of fluff, eating pollen all day long!

A female Anthidium scrapes fuzz of plant leaves as wads it up into a ball in preparation for carrying back to her nest.

A female Anthidium scrapes fuzz of leaves and wads it up into a ball in preparation for carrying it back to her nest.

Balded leaves indicate Anthidium have been here.

Bee pattern baldness on leaves indicates Anthidium have been here.

Posted in 2015, Nest Plugs, Plugs and Bugs | Leave a comment

Colorado’s “newest” bee

A female Megachile apicalis, the first specimen documenting this species now occurs in Colorado.

A female Megachile apicalis, the first specimen that documents this species in Colorado.

Megachile apicalis, a species introduced from Europe and a close relative of the alfalfa leaf-cutting bee, has made its way to Colorado, and what a stunner she is!  We reared this bee from one of The Bees’ Needs 2013 bee blocks that was located in Golden, Colorado.  This individual was just recently identified, adding yet another bee species to our ever growing Colorado list.

It will be interesting to watch over the next few years to see how, or if, it will move across the state.  You can check out its worldwide distribution (minus a Colorado dot that has yet to be added) at .

Slightly recessed whole leaf piece plug with veins and hairs clearly visible.

Slightly recessed whole leaf piece plug with veins and hairs clearly visible. Isn’t it cute?

And in case you were wondering — this species uses several overlapping whole leaf pieces to plug their nests, similar to our ever popular and also introduced, alfalfa leaf-cutting bee.

Posted in 2013, Bee Blocks, Nest Plugs, Uncategorized | Leave a comment

Silk Plugs & Hylaeus

A male Hylaeus shows off his yellow face while sunning on an alyssum leaf.

A male Hylaeus shows off his yellow face while sunning on an alyssum leaf.

One of the less common types of nest plugs we get in our bee blocks are the Silk plugs made by the yellow-faced or masked bees, Hylaeus species.  They are a real treat for those who do see them, often blindingly shiny due to their cellophane-like texture. These filmy plugs are essentially dried bee saliva.  They come in a several colors (white, clear, or yellow) and depths (recessed, flush, or plastered to the outside of the bee block), but are all made by one of our 16 species of Hylaeus that occur here in Colorado.

A shiny Hylaeus nest plug made from Silk, flush with the nest entrance.

A shiny Hylaeus nest plug made from Silk, flush with the nest entrance.

The other plug types that they are most commonly confused with are the resin plugs and spider webs.  The easiest way to separate silk plugs from resin plugs is to poke the plug with the point of your pencil.  If your pencil point tears a hole in the now-obviously filmy plug, you have silk.  If it gets all gummy or if it barely scratches the surface of the super hard plug, you have resin.  As for the spider webs, OK, they’re silk too, but we couldn’t really refer to the Hylaeus plugs as “dried bee-spit” plugs, now could we?  I suppose we could call them “cellophane” plugs, but it seems like cellophane has decreased in popularity despite Lady GaGa using it as clothing.  But back to spiders– their “plugs” are a compilation of threadlike filaments, where as the Hylaeus silk is more sheetlike.  If you do the pencil point poke test to a spider web, you’ll feel a definite spring-like or cushiony bounce.  Hylaeus nests are made in the small tunnels, 1/4 inch in diameter or less.  Some will even nests in tunnels as small as 1/16 inch in diameter. Now that’s a small bee!

A recessed yellow Silk plug made by Hylaeus verticalis.

A recessed yellow Silk plug made by Hylaeus verticalis.

Hylaeus are wildly different from the leaf-cutting and mason bees in the family Megachilidae.  In fact, they are in a whole different bee family – the Colletidae.  Other cool facts about Hylaeus are that they carry pollen in their crop (stomach) rather than on their legs or “bellies”, the larvae do not spin cocoons before pupating, and the adults produce a chemical that makes them smell like lemons if you handle them. (I don’t recommend it though– their potent, yet short-lived stings feel like hot needles.)

Female Hylaeus

Female Hylaeus

Hylaeus adults superficially resemble wasps more than bees.  They are small, black and, since they carry pollen internally, are rather bald.  The yellow face markings on the females are on the inner edges of the eyes (sometimes with an additional central spot about their mandibles).  Of course our largest species lack any yellow markings at all, and one of our most common (introduced) yellow-faced bees actually has white markings, not yellow.  The easiest way to know you had Hylaeus nesting is to identify the plug!  So get out your pencil points and poke ’em.

Hylaeus female working on her nest, note the very liquid pale pollen provisions in the silk lined cells.

Hylaeus female working on her nest, note the very liquid pale pollen provisions in the silk lined cells.

Posted in 2015, Nest Plugs, Plugs and Bugs, Uncategorized | Leave a comment