It’s Bee Week!

Thanks to a return visit by Mike Arduser of the Missouri Department of Conservation, it’s bee week in the Platte River Prairies.  Mike came out to our sites a year ago to help us start thinking about our prairies from the perspective of bees and other pollinators.  This year, he made a return visit and we’ve given him a full plate of activities.

Mike Arduser (right) talks about bees with Sam Summers and Anne Stine earlier this week.

Mike Arduser (right) talks about bees with Sam Summers and Anne Stine earlier this week.

On Monday, Mike and I spent the day inventorying bees at several of our prairies, assisted by Anne Stine (Hubbard Fellow) and Sam Summers (TNC volunteer).  We are building upon the initial list of 57 bee species we found in 2012.  Several new species have already been added to the list, and more are likely as we continue to look.

We hosted a pollinator ecology workshop on Tuesday, attended by about 40 people – mostly biologists who assist private landowners with habitat projects or who manage conservation lands.  The objectives were to have Mike help us better understand basic pollination ecology and the needs of pollinator species – particularly bees, and to help us better incorporate bee habitat into our prairie restoration and management strategies.  It was a great day, and everyone had their heads buzzing (sorry) with new information and ideas.

At our pollinator workshop on Tuesday, we spent time talking about prairie restoration and management strategies, as well as general pollinator ecology.

At our pollinator workshop on Tuesday, we spent time talking about prairie restoration and management strategies, as well as general pollinator ecology.

On Wednesday and Thursday, Mike is leading a smaller group of us through an intensive bee identification workshop.  I’m looking forward to peering closely at the faces and private parts of bees through microscopes, and learning to differentiate between Melissodes, Colletes, Lasioglossums, and all the other bees in our prairies.

Less than a month ago, we saw Mike at the Grassland Restoration Network workshop in Columbia, Missouri.  He gave a presentation in which he talked about a variety of pollinator-related topics, including some potential ways to use bees to assess the success of prairie restoration projects.  One of Mike’s suggestions was to see what percentage of bee species in a prairie are specialist pollen feeders (oligolectic bees) and compare that percentage between restored (reseeded) and remnant (unplowed) prairies.

Pollen specialist bees feed only on pollen from one to a few flower species, whereas pollen generalists can feed from a wide variety of plant species.  Specialists tend to be less common in small isolated prairies than in larger prairies, in part because they need a certain minimum population size of their host plants, which can be difficult to obtain in small prairies.  Restored prairies might also lack that population size threshold, especially during the early establishment phase of a new seeding.  In addition, restored prairies that are isolated from remnants might be missing specialist bees simply because the bees in those remnants can’t find them.

According to Mike, a couple of recent surveys in Iowa found that about 20% of the bee species in remnant prairies are pollen specialists.  However, some early data from re-seeded Iowa prairies is showing much lower percentages of specialist bees – especially when those sites are isolated from large remnant prairies. If pollen specialists are not easy to attract to restored prairies, comparing the percentage of specialist bees in restored prairies to the percentage in nearby remnant prairies might be an important way to assess restoration success.

This bee is (probably) Lasioglossum pruinosum, which is a generalist pollen feeder.  It's not suprising to see it in a restored prairie.  Pollen specialist bee species seem to be more sensitive to habitat fragmentation, and may be less likely to occur in restored prairies - especially if those restorations are isolated from large remnants.

This bee is (probably – according to Mike) Lasioglossum pruinosum; a generalist pollen feeder. It’s not suprising to see it in a restored prairie. Pollen specialist bee species, however, seem to be more sensitive to habitat fragmentation, and may also be less likely to occur in restored prairies – especially if those restorations are isolated from large remnants.

Mike suggested that another useful metric could be the number of cleptoparasitic bee species present in a prairie.  Cleptoparasites, or cuckoo bees, are the cowbirds of bees – they lay their eggs in the nests of other bee species.  Because each cleptoparasitic species tends to specialize on the nests of certain species or groups of bees, their presence could another interesting indicator of restoration success.

From our 2012 bee inventory data, I can make some preliminary, and very tentative, conclusions about the number of pollen specialists and cleptoparasites in our prairies.  Of the 38 species we found in remnant prairies last year, 10 (26%) are pollen specialists and only 1 (3%) is a cleptoparasite.  By comparison, of the 47 bee species we found in restored prairies, 12 (26%) are pollen specialists and 7 (13%) are cleptoparasites.

Those data are encouraging, but pretty sketchy because we were really just doing broad inventory work – not collecting data in a way that would allow for a good comparison.  In addition, it clumps all our prairies together, so we can’t look at each one individually.  Anne Stine (one of our two Hubbard Fellows) is going to help remedy that during the next couple months by conducting a short study.  She do some standardized collection of bees from a variety of remnant and restored sites and then compare the percentages of specialists and cleptoparasites between those prairie types.  That should give us a better feel for what’s going on.

In the meantime, it looks like a relatively high percentage of the bee species in our restored prairies are pollen specialists.  That probably reflects positively on both the plant species diversity in those restored prairies and the fact that they are adjacent to remnant prairies – making bee colonization pretty easy.  Since the main objective of our prairie restoration work is to enlarge and reconnect our remnant prairies, those early results are very promising.  …But let’s see what Anne finds before we get too excited.

Now if you’ll excuse me, I have to go learn to tell the difference between Melissodes agilis and Melissodes desponsa.  Wish me luck…

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About Chris Helzer

Chris Helzer is an ecologist and Eastern Nebraska Program Director for The Nature Conservancy. He supervises the management and restoration of approximately 4,000 acres of land in central and eastern Nebraska - primarily along the central Platte River. Chris is also the author of "The Ecology and Management of Prairies in the Central United States", published by the University of Iowa Press.
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12 Responses to It’s Bee Week!

  1. James C. Trager says:

    Interesting post, Chris. There is a wonderful world of small animals to learn about in our prairies and prairie reconstructions, now that we’ve scratched the surface of the biota with a relatively good knowledge of the vascular plants.
    I think there are parallels in other groups, too. E.g., in leaf beetles (Chrysomelidae) or moths (much more diverse than butterflies), those with highly specialized larval and/or adult feeding habits could be indicators of restoration success as with the oligolectic bees; or in Formicidae, in which estaablished populations of specialized predators and especially of the social parasites could be indicative.

    • James C. Trager says:

      PS – The leaf beetles and moths might also probably exceed the value of the Hymenoptera groups (bees, ants) in providing metrics to understand fire and grazing effects.

      • Chris Helzer says:

        Thanks James. I’d love to learn more about Chrysomelidae. I think I’d better take one group at a time, though…! How do you sample for social parasites in Formicidae?

        • James C. Trager says:

          The hard way! Many cannot be attracted to baits, since they depend on their hosts for feeding. So one has to search for nests and get lucky, or they may show up in pitfall traps (good for sampling spiders and carabid beetles, etc., as well as ants). You may remember I found the “slave-maker” Formica pergandei there by postponing “Beer Hour” and going out during that later afternoon stretch, and fortuitously encountering them raiding for pupae of their host Formica subsericea – a combination of “self-sacrifice” and dumb luck. :)

  2. Heather Holm says:

    It’s interesting you find more cleptoparasites in the restored prairie. I find and photograph more species in my small restored suburban landscape than I do in large restored prairies or remnant prairies.

    • Chris Helzer says:

      Heather – I think it’s much too soon to say that we’re finding more cleptoparasites in restored than remnant prairie. It’s very possible (probable?) that the discrepancy is due to sampling effort differences rather than a real difference. We’ll see!

  3. I want to sort of piggyback off of Heather’s comment, Chris — is there any way for this information to translate to suburban native plant gardeners wishing to gauge the success of their much smaller work? I’m sure most of that success hinges on what the acres and acres around are doing. But every time I read your posts I wonder how what you’re saying can be brought down to a smaller space, even if it can be at all.

    • Chris Helzer says:

      Ben (and Heather) – You might be interested in reading my post on how to manage small prairies (http://prairieecologist.com/2012/03/05/how-should-we-manage-small-prairies/ ) Much of that applies to prairie gardens too. There’s no right or wrong way to manage or treat gardens – I think you just want to be clear about your objectives and then manage toward those. I’ll try to do some thinking on the topic and will write something more detailed if I come up with something. For the most part, what you’re going to be doing is supporting prairie species that are able to move and find your sites, so isolation is already limiting you. That’s not bad – in fact, it frees you from worrying about managing for creatures that might be impacted by things like mowing down all your plants at the same time… It doesn’t really matter if you eliminate species temporarily from your site (I’m thinking insects, primarily) because the ones that are there are likely the ones that can easily recolonize anyway…

  4. Piggybacking off of both Heather and Ben, I’m interested in learning about a good source to teach myself more about identifying the native bee species. I’m fascinated by the insects that I’m finding on our small acreage, which we are working to restore to native tall grass. Any suggestions would be greatly appreciated.

    • Chris Helzer says:

      Cynthia – it’s tough. I’m finding that there are a lot of bees that look very similar to each other, and it takes a dichotomous key and microscope to tell them apart. That said, try bugguide.com and the Xerces society website for some good information. Wish I could help more. I’d recommend starting with something like bumblebees – a group that has limited numbers of species that can be relatively easily told from each other.

    • Heather Holm says:

      Cynthia – I use BugGuide.net all the time, very helpful if you like to take photos of your native bees. I have some native bee posters on my blog that may also be helpful if you are in the midwest, click on my name above.

  5. Michael Eckenfels says:

    Native Bee Identification-
    Sam Droege at the USGS Bee Inventory and Monitoring Lab in Maryland coordinates a bee indenfication site at Discover Life. It’s one of the very best resources though the is complex. http://www.discoverlife.org/mp/20q?search=Apoidea He has two You Tube tutorials on how to use the site, easily found by Googling his name.
    He also has a Yahoo Group on bee monitoring that you can access.
    From what I can tell from my reading, the best method to learn native bee ID
    is by use of a reference collection that’s already ID’ed (in conjuction with a low powered scope and key).

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