Andrenid bees at the FWG

by Christine Hanrahan

Originally posted in May 2011

About 5 years ago, I discovered an aggregation of Andrenid bees nesting on the north slope of the Amphibian Pond. At that time they were in one location only. The next year I went back to the pond in early spring, hoping to find them. It wasn’t until late April that they appeared, in the same location, at the time a nearby willow was in flower. Eventually, I discovered that they were Andrena dunningi, a species known to time its emergence to coincide with the flowering of willow trees.

Andrenid bee. These bees were very active in early afternoon under a warm, sunny sky. I would guesstimate about 30-40 were seen, fewer than the number of nest holes.

Over the next few years, I found them mostly in the initial location, but in 2007, I also found some nesting in another section of the north slope, where an abundance of non-native plants, mostly mustards and Chenopodium species, were growing (for that one year). The nesting, of course, took place before these plants had grown to full height.

This year, 2011, the bees were first noticed in late April, and, interestingly, I saw they had spread from their original site to the upper section of the track around the pond (not the Bill Holland Trail, but the “informal” track that was created when the bridge was closed last year), and to the west side of this track. I counted about 30 entrance holes at that point.

Constant foot traffic on the track meant that the burrows were continually being closed over, although new holes appeared regularly.

Andrenids prefer areas of bare soil with scattered vegetation, such as sparsely growing grass, and show a distinct preference for the tops of slopes. Their burrows are about 4-6 inches in length, as best as I can determine, so we don’t want to plant species with deep spreading roots that might prevent them from burrowing. Reading I have done since last week indicates that they will nest under exposed tree roots, but they are much happier with bare soil.

Some of the plants we have considered for this location (and we are not restricting the list to native only) include clover, grasses and sedges that form clumps (such as poverty oat grass and peduncled sedge), and possibly vines that will grow down the slope such as wild grape or virginia creeper.

Freshly dug nest site: you can see the mound of soil around the hole.

Andrenid nest entrance. Freshly dug holes often have a mound of soil around them (see photo above), but rain washes this away. Many of the nest holes are not apparent at first, especially if not surrounded by a mound of soil. They are also very small, approx. 1/4 inch or less.

NOTE: As of May 2017, we have found at least 7 species of Andrenid bees at the FWG: Andrena cressonii, A. dunningi, A. miserabilis, A. nasonii, A rufosignata, A. vicina, and A. wilkella (the last one is the only non-native). In addition to this location next to the pond, we’ve also seen them in the Old Woodlot.

FWG on May 1, 2013

by Christine Hanrahan

It was our first real scorcher of a day at 25 degrees C (anything above 15 C is a heat wave to me). I was expecting to see butterflies, even perhaps a few spring azures, as I’ve seen them elsewhere recently, but no butterflies showed themselves to me. However, bees were abundant! Bumble bees, nomada bees, various andrenid bees, sweat bees, scores of all of them. They were nectaring on magnolias, scilla, daffodils, and the few willow catkins still with pollen.

Many of the birds that were present in good numbers last week have left to carry on their migration. Still present are a few white-throated sparrows and juncos. I also saw many song sparrows, goldfinches, chickadees, red-winged blackbirds, a male kestrel with a meadow vole, a sharp-shinned hawk flying above our interpretive centre, many tree swallows, one pursuing the kestrel! White-breasted nuthatches, but the red-breasted nuthatches seem to have given up on nesting in the snag. Not a bad idea, as it was a terrible location.

However, exciting news: a pair of eastern phoebes are building a nest above one of the security lights on the side of the building. I watched for some time as they went back and forth with tiny bits of moss and other plant matter, carefully placing each bit on top of the light, fussily moving the pieces around until just so. Such laborious and lengthy work – quite impressive. Whether they actually nest remains to be seen, but so far, so good. Last week, they were exploring the nest site the robins used in 2012, on the front of the building. Fortunately for them, they thought better of it. If they do nest, it will be the first nesting record for phoebe at the garden.

Speaking of nesting, red squirrels have been using some of the bird nest boxes for years. Typically, they take over ones that birds no longer use, usually because trees have grown up around them making them difficult for swallows to access, but perfect for squirrels. We have many bird boxes up and I reason that, if we leave the old ones hidden by trees for the squirrels, they’ll leave the other ones alone. So far this has worked well, and everyone is happy.

Bloodroot - These beauties are among the first to appear in spring. They are now in full bloom in many locations throughout the woods, spread over the years by ants that carry off the seeds.

Bloodroot – These beauties are among the first to appear in spring. They are now in full bloom in many locations throughout the woods, spread over the years by ants that carry off the seeds.

In the woods, bloodroot is in full bloom. Each year new clumps grow up, thanks to ants who help transport the seeds. Red trilliums are about to burst open at any moment. Other flowers can’t be far behind. I mentioned magnolias – the two magnolias in the garden are in bloom and beautiful to see.

Photos were added to the April blog over the last week, including some beautiful bird photos by Diane. I added a shot of a red squirrel feeding on a mouse. Not particularly pleasant to see, and I admit I felt a bit queasy taking the photos. I posted the least offensive one! Of course, reds are omnivores, and while vegetable matter makes up a good proportion of their diet, they will eat birds and other small mammals that they catch. They are also scavengers, eating dead critters when times are tough.

April blog

More photos on the new May blog

Bee boxes, houses, condos and hotels…Part 2: The photos

by Christine Hanrahan

It is said that a picture is worth a thousand words and, bearing that in mind, I am posting some photos of a couple of bee nesting structures.

The large nest box made by Agriculture and Agri-Food Canada scientists has holes of varying sizes and contains rolled up tubes of paper that can be removed. At the end of summer, these paper tubes would be placed in a container in a refrigerator or unheated building for the winter and brought out in spring in a place where the bees can emerge safely. The nest box itself would be disinfected before being re-used.

The old bee box from 2009 was made for us by Bruce Burns and used as part of a display on pollinators. Later, in mid-summer, we placed it in a south-facing site, protected from intrusion and, within days, leafcutter bees (Megachile) were using it.

Bee bundles are another method of providing homes for tunnel-nesting bees and, in this photo, you can see how the bamboo bundles were placed inside a plastic plant pot for protection from the elements.

The next two photos are of two different bees using the bee boxes. The Megachile is checking out the old box in 2009, while the mason bee is investigating the newer box in 2012.

There is a close up of the rolled paper tubes in this next photo.

The last photo shows a tree swallow nest at the FWG, removed when the box was cleaned in early November. Inside were many dead bumble bees and, beneath the straw of the swallow nest, were many “honey pots” made by the bees.

Bee boxes, houses, condos and hotels…

by Christine Hanrahan

This is a simple overview of various types of accommodations for bees. I won’t be providing instructions for building bee boxes, but I do provide a reference below for the best all-round source for creating different types of bee houses.

Much media attention has been given to declining honeybees (Apis mellifera), but less well-known is the decline in many native bee species, such as bumble bees (Bombus) and others. Our native bees are facing habitat loss, pesticide contamination, disease, and who knows how many other problems. Studies are ongoing with more research devoted to this issue.

The good news is that people are becoming more aware of bees as beneficial. I spoke with a pest control official recently who said that although he still gets calls from people worried about bees, such calls are fewer than in the past. The ongoing media attention about disappearing honeybees and subsequent attention paid to bees in general, and their importance to pollination, has moved this group of insects into a more benign category.

One indication of the changing attitude is the recent interest in placing bee boxes (bee nest sites) in gardens. Although I am happy about this trend, there is also a downside. Buyers are not usually told that if they want to help bees, nectar rich plants must be available or bees won’t be interested. The importance of hygiene in bee boxes is rarely discussed either. Unfortunately, some commercially produced bee boxes are more concerned with making cute ornamental art for the garden than with the requirements of bees.

Many of our native bees are ground nesters and won’t use bee boxes. This brings up a whole different issue, which I’ll leave for another time, as this article is looking only at tunnel-nesting bees, the ones most likely to use bee boxes.

The natural nesting sites of these bees is the hollow stems of plants, such as wild raspberries, or holes in standing dead trees (snags). When we build bee boxes for them, we are emulating their natural nest sites, much as we do for cavity nesting birds when we install nest boxes.

The most common tunnel-nesting bees we see around the Ottawa are leaf-cutter bees and mason bees (both in the Megachilidae family). These are the ones that will be most attracted to bee boxes. Bumble bees may also be attracted to man-made nest sites. At the Fletcher Wildlife Garden (FWG), a newly installed bee box in summer 2009, attracted leafcutter bees (Megachile) within days. In 2012, scientists from Agriculture and Agri-Food Canada (AAFC) placed a number of bee boxes as well as bee bundles, around the garden in a variety of sites, and these too were very well-used, particularly the nest boxes.

There are innumerable ways to provide nesting sites for these bees, the simplest being to leave snags standing, and to grow plants that bees would use in the wild for nesting. Creating artificial nesting sites is the other option, and ways and means are varied and many.

First and always, when making any bee structure, think of hygiene, as parasites and disease are a serious problem for bees. With simple bee blocks, essentially a wooden cube with holes in it, there are two options: you can replace them every year or you can use removable cylinders in each hole. These can be straws or rolled tubes of paper, which can be discarded when the bees have finished nesting. The bee block can then be disinfected, instructions for which are given in the native pollinator book listed in references below.

Bee blocks work best if they have holes of varying diameters (to accommodate different bee species) and of sufficient depth to allow bees a long tunnel to work in. Some people suggest drilling the holes slightly upward to prevent rain from getting in. Logs with drilled holes can also be used for this same purpose. Old, weathered logs are best as they emulate the snags that bees would naturally use. At the FWG, I’ve noticed bees making nests in some of our old well-worn wooden posts (used for habitat signs) and the split-rail fences.

Other types of simple nest accommodations include bee bundles, which can be made from lengths of hollow stems, such as bamboo, phragmites (abundant in the region, although very invasive so make sure you don’t distribute the seedheads elsewhere), cup-plants. These are best if situated within some sort of cover (large black soft plastic plant pots were used by scientists who set up bee bundles at the FWG in 2012) to protect them from rain and located in a sheltered site. At the FWG, I’ve noticed mason bees checking out plants for nest sites, and they also used the AAFC bee boxes.

Bumble bees frequently nest in the ground, but they will also nest in piles of stones, brushpiles, under decks, and even in bird nest boxes (which I’ve seen several times at the FWG). I’ve also seen them nesting in the foundation of my house and in sheds. In other words, while their sites are varied, what they are seeking is a warm, dry, sheltered cavity.

Finally, some very creative ideas for creating “condos” or “hotels” for bees (and other insects too) come via the Pollinator listserv. These examples show how bee and insect condos can be constructed fairly simply, using found objects, such as plant stems, bricks, logs, etc. Ingenious designs from across Europe are shown, ranging from small and simple to quite large and more elaborate, all of which can be used and adapted for our area. General information about cleaning out bee blocks, and maintaining sites is given, as well as tidbits of other interesting information. Some of the photos show carefully constructed structures that will hold about 8 or 9 separate bee boxes. Others are created with boards or pallets, separated by bricks, and stuffed with a variety of material that will attract not only bees but other insects such as ladybeetles. The site is fun to peruse and is sure to generate a desire to emulate at least one of the structures. At the FWG we are already planning to create several and will be keeping an eye on them throughout the summer to see who uses them.

References:
***Attracting Native Pollinators. Protecting North America’s Bees and Butterflies. 2011. By the Xerces Society. Storey Publishing. I can’t say enough good things about this marvellous book. It provides excellent information, complete with photos, of different types of bee structures, good instructions for how and when to install, how to keep nest boxes and bundles clean, and much more. Buy it!!! It is the best source around; you need no others!

Bee and insect condos and hotels: inspirationgreen.com/insect-habitats.html

NAPPC Pollinator listserv: pollinator.org/nappc/listservrules.htm Provides a variety of topical and worthwhile information with much current information about bees and their conservation and efforts to protect them.

North American Pollinator Protection Campaign: pollinator.org/nappc/index.html The premier site for all things to do with conservation of pollinators.

Pollinator Partnership (NAPPC): pollinator.org/index.html Provides information about all pollinators, with an emphasis on bees.

Xerces Society: www.xerces.org/ One of the best all-round websites dedicated to bees and all pollinators, with a wealth of good, trustworthy information. Check under: www.xerces.org/fact-sheets/ for information on bee boxes.

More references for building bee boxes will be added when I find ones that are suitable.

Leafcutter Bees (Megachile sp.)

By Christine Hanrahan

Megachile constructing nest

As spring very slowly chugs its way into our region, many of us find our thoughts turning, longingly, to gardens and gardening. Those of us inclined to create and maintain gardens for wildlife, are also interested in the various things we can do to enhance our site for birds, bees, and other creatures. Bird boxes, bird baths, squirrel houses, roosting boxes, toad houses, and bee boxes are just some of the things that can be installed to help our fellow creatures. In this article, I’d like to focus on bees, and more specifically, on one type of bee that readily comes to bee boxes: the leafcutter bee in the genus Megachile.

First, a word about accommodation for bees. There are any number of plans for building bee boxes, ranging from the very simple to the extremely elaborate. In another article I’ll talk about the wealth of information available, but here I want to mention one very simple bee box we installed at the Fletcher Wildlife Garden a few years ago and how it attracted a number of Megachile leafcutter bees. Made for us by Bruce Burns, it was initially part of a display we had created to celebrate pollinators. In mid-summer 2009, I installed the bee box on a south-facing post behind the compost bin. A few days later I went back to see if anything might be using it (not really expecting any activity, but what did I know!). To my surprise, I found several leafcutter bees busily investigating the holes in the box. Within a couple of weeks it was very apparent that this bee box was being well used by a number of these bees, and I watched, fascinated, as they carried leaf sections, cut from rose bushes, into the boxes. When an AAFC scientist installed temporary bee boxes at the FWG in the summer of 2012, leafcutter bees were common inhabitants.

The family Megachilidae, typically called the leafcutter bees, includes a variety of genera, but the ones I am especially interested in are those in the genus Megachile. They are very common at the FWG, as indeed, they are throughout this region. Some years before I installed the bee box, while out exploring near Carleton Place, I’d come across nest sites containing a few leafy cells made by Megachile bees, and they were so remarkable that I began looking for similar cells in other areas. Most of the ones I found were under rocks, but they could equally be in rotting wood, in tunnels in the ground, in and around human made objects such as pipes, under bricks, or, as at FWG, in bee boxes.

The bees cut nearly perfect circles from leaves in the Rosaceae family, to construct tubular shaped cells, beautifully formed, and sealed with a leaf circle. In these cells a ball made of pollen and nectar is placed and an individual egg laid on top. A nest site can contain several cells, each closed off with a leaf circle. Some of the ones I have found were newly constructed, the leaves still fresh and green, others old and the leaves dried out. Some had obviously been disturbed by a predator. Some were half buried in the soil, others were jumbled together on top of the soil but under a rock.

I don’t know the exact species of Megachile that made these nests, but two common species are Megachile frigida and M. latimanus (the latter I have photographed at FWG, and the photos were identified to species by an expert). I tend to call all the Megachilid leafcutter bees I see, Megachile sp. These bees are easy to spot, as they carry pollen on their abdomens, instead of in pollen sacs on the legs, as most bees do.

Following are photos of the bees and their nests, including a bee busily constructing her nest. Many of these photos were taken at the FWG.

Wiggle, waggle, woo: Hey, Bee, Vote for Me!

The recent American election once again highlighted that electoral politics in the United States are very different in structure than in Canada – electoral colleges, simultaneous elections of Congress and Senate, ballot initiatives and the fact that based on remit of powers, an American President has far less influence over his country than a Canadian Prime Minister (PoliSci 101 and a great digression from our topic at hand!)

However, did you know that HONEYBEES also have their own elections, complete with smear campaigns, speechifying and converting as many undecided voters into supporters as possible? This week’s PBS’ Nova Science Now showed how Honeybees decide on a new nesting site. The knowledge was presented as part of understanding how information is shared and how the human brain may function more like a hive mind in and of itself than previously thought. Continue reading