I’m pleased to announce that I have a new paper out in the Proceedings of the Royal Society B – Biological Sciences. My coauthors and I (Ulrich Mueller of UT Austin and Rosalind James of the USDA) studied the bacteria and fungi associated with the alfalfa leafcutting bee (ALCB for short) Megachile rotundata. The ALCB is the second most important field crop pollinator (after the honey bee), but it also has a nasty fungal pathogen that causes the disease chalkbrood (the fungus is Ascosphaera aggregata).
We wanted to look for interactions between microbes, so we applied several treatments to the pollen provisions of the bees: 1) antibacterials 2) antifungals 3) Ascosphaera aggregata spores and 4) a no treatment control. We then sequenced bacteria and fungi from the guts of the larvae that we applied these treatments to.
We found that when we applied antifungals, fungal diversity went up. This seems odd at first, but when we looked at the data we saw that we were knocking down chalkbrood, which seemed to be allowing other fungi to grow. This could have been just been an artifact of sampling, i.e. the other fungi could be showing up simply because there were so many chalkbrood sequences in the other treatments that they were swamped out and not detected. So we did some more analyses that suggest that the finding is not an artifact but due to some sort of inhibition (competitive, inhibitive, or otherwise, we don’t know yet) of other fungi by A. aggregata.
One other really interesting thing we found was that my current favorite bacteria, Lactobacillus kunkeei, was resistant to the antibiotic cocktail that we threw at it. Nancy Moran’s group found that a honey bee-associated bacteria is resistant to antibiotics. L. kunkeei is also associated with honey bees (though not as part of the core honey bee gut microbiota), and we think that L. kunkeei may be exposed to antibiotics while associated with honey bees. This suggests that antibiotic treatments to honey bee colonies may have far-reaching effects on wild bees, which is a really novel result. This is a really interesting hypothesis that we need to test further.
If you want to see the whole paper, check out my publications page. Here is one of the more important figures in the paper, which shows the relative abundances of fungi and bacteria from our different treatments. Note that L. kunkeei is present in the antibacterial treatments, and fungi are more diverse in the antifungal treatment, but A. aggregata shows low relative abundance.
I will be giving a public talk at Peeve’s Public House at 7:00 PM on January 6. The talk will be non-technical and I will talk about my work as well as that of others. Peeve’s is in downtown Fresno on a pedestrian mall, and I hear it is a pretty great place.
The talk is part of Cafe Scientifique, which is a forum for public science talks in an informal environment. So come on down, get some food and drinks (Peeve’s has a great beer selection from what I hear), and learn about bee research.
I am very excited to start a new job as an Assistant Professor at California State University Fresno. Today is my first day teaching, and I’m looking forward to getting back into the classroom. I’m also starting up a lab here, and I’ll be looking for Undergraduate researchers and Master’s students soon. I probably won’t have the lab functioning until winter, so contact me towards the end of the semester if you are interested in undergraduate research. If you are interested in a Master’s degree, please get in touch sooner rather than later.
I grew up in the central valley, so I know this area well. My favorite ecosystems are here in California, and I’m looking forward to working with California bees again. Fresno is also a hub for agriculture, so my work in pollinator conservation will be especially topical here. I already have some project ideas brewing!
Summer vacation started this week, so I took the opportunity to take my daughter into the field with me. We had a great time catching bees, and she is a very good bee catcher! We went to two of my field sites near Austin, and had great bee collecting. Here is my daughter netting bees on flowers: And here she is with a catch (I haven’t looked at it closely yet but I think it is Svastra): At the other field site we found some Anthidium (still need to id her) nests. Here is a mom from one of the nests: And here is a nest. Note the pebbles that are incorporated in the nest. The female collects resin to construct the nest, hence Anthidium are sometimes called resin bees, as are other bees in the same family, the Megachilidae.
It has been a really great spring here in Texas. At first I was worried it would be too dry, as March had little rain. But it rained at the right times for a good bloom. So the bees have been really good as well. Here is a photo of one of my field sites from a few weeks ago, with Helenium and Opuntia in bloom. Check out the water on the ground in the foreground. It has been raining down in Texas! At least a little.
This sets up possible competition between larvae for food and also spread of good and/or bad microbes between brood. I also find nests where each brood has its own leaf partition, so this trait varies. We don’t know why, and I don’t think this variation has even been described before. I hope to work on these bees more in the future to figure out why they vary in how they build nests. Lots of possible hypotheses to test. This kind of natural history is super fun for field biologists, as just wanting to know more about the organisms we study is what motivates many of us in the first place. Unfortunately, there is not a lot of value placed on natural history nowadays, so if you want to do it you have to do it as side projects here and there, like I’m hoping to do with M. inimica. There is still so little we know about these critters, so natural history is still desperately needed!