- Author: Kathy Keatley Garvey
The podcast, "The Buzz on Native Bees in Your Neighborhood," is online.
"When I say 'bees,' you probably think of a neat stack of white hive boxes and the jars of honey on the store shelves, right?" Flatow began. "But there's a lot more to bees than that. Because around the world, there are over 20,000 known bee species, and 4,000 of them are native to the U.S. And while these native bees that live in the wild play a key role in pollinating our plants, they don't get a ton of recognition or support like the ones that live in a box."
Professor Williams discussed a number of bee species, including bumble bees, carpenter bees, squash bees, mining bees ("bees that burrow into the ground or soil") and mason bees and leafcutter bees.
Mason bees, Williams said, build their nests "partly out of mud, which then dries. And the leafcutter bees are chewing pieces of leaves and making their nests out of those leaf pieces, either as whole chunks of leaves or as chewed up bits of leaves. We have a series of other small to large bees that nest on the ground or nest above ground that fall into other families. But probably those are the most familiar for most people."
Williams called attention to research led by his then graduate student, and now postdoctoral fellow, Maureen Page, who compared "the quality of honey bees at pollinating flowers versus the quality of other bees. And in general, we find that honey bees are sort of equal or slightly less good than many other bees. And the old adage, the jack of all trades is the master of none--the honey bee is really that jack of all trades. It's very wide in the number of flowers that it will visit, but doesn't tend to be particularly effective on any one flower visit relative to some of the other bees we have."
The alfalfa leafcutter bee "is a really effective pollinator relative to the honeybees at pollinating alfalfa," he told Flatow.
"So your bumble bee is sort of the lab animal, then," Flatow commented. "It's not a white mouse. It's a bumble bee."
Williams agreed. "It's become a pretty useful organism for studying things in the lab. I should say the other group that we work a lot with are mason bees and leafcutter bees. And because of the way they nest, they have been really useful for studying other sorts of questions. So there are a couple of groups that we work well with."
Williams also touched on the threats faced by native bees. In addition to pesticides (insecticides, fungicides, and herbicides), "they're threatened by the loss of reliable foraging floral resources," Williams said. "They are threatened by a set of emerging diseases. And this is, again, where the honey bee gets a lot of attention, right? This colony collapse may be resulting from certain viruses, but wild bees, native bees, also have some substantial problems with certain viruses and also other kinds of pathogens."
"And then a really big one is climate change. So we have to fully recognize that changes in rainfall and also changes in temperature patterns seem to be stressing bees in different parts of the U.S., for sure."
Flatow, whose colleagues say has "revived many an office plant at death's door," asked: "Can I plant a little patch of wild flowers in a pot or in the yard and really help out?"
"This is also one of these questions that's a complex one, but we'll try not to make it too complex," Williams said. "I mean, in general, planting flowers for bees is a useful thing. The one thing we'd want to be careful about if we were planting flowers in the yard is that we were also being careful about the use of some of these chemical pesticides. But I think also recognizing the importance of natural areas and broader stewardship of habitat for bees across the landscape is really important. And this tricky one with climate change, too--what are we going to do? We don't solve climate change with the sorts of things that we would do– small-scale actions--to help bees."
"But we can do some things probably--providing shady spots, where they have what we call microclimates that are maybe protecting them from times where there are heat waves that are particularly problematic--things like that that could be useful."
Williams, who joined the UC Davis Department of Entomology and Nematology faculty in 2009, was named a Chancellor's Fellow in 2015, a five-year program supporting his research, teaching and public service. He was named a a Highly Cited Researcher by Clarivate Analytics in 2018, and a Fellow of the California Academy of Sciences in 2021.
A native of Madison, Wisc., he received his doctorate in ecology and evolution from Stony Brook University, New York in 1999.
- Neal Williams, biography, Wikipedia
- Neal Williams lab, UC Davis Department of Entomology and Nematology
- Evidence of exploitative competition between honey bees and native bees in two California landscapes by Maureen Page and Neal Williams, June 2023, Journal of Animal Ecology
- Honey bee introductions displace native bees and decrease pollination of a native wildflower by Maureen Page and Neal Williams, December 2022, Journal of Ecology
- A meta-analysis of single visit pollination effectiveness comparing honey bees and other floral visitors by Maureen Page, Charlie Nicholson, Ross Brennan and Neal Williams, October 2021, American Journal of Botany
- Author: Kathy Keatley Garvey
California's 2021 western monarch Thanksgiving count, directed by the Xerces Society of Invertebrate Conservation, recorded 250,000 overwintering monarchs, as compared to a mere 2000 in 2020.
Executive producer and host Ira Flatow of Science Friday set out to "unpack the news" for his listeners. On Feb. 4, he interviewed community ecologist Louie Yang, professor, UC Davis Department of Entomology and Nematology, and a faculty member of the Center for Population Biology. (Listen to the interview, 'How Long Will California's Butterfly Boom Last?')
"OK, so how did the population bounce back so dramatically?" Flatow asked. "And is this number a blip on the radar or the start of better times for the beleaguered butterfly? Here to help us unpack the news, Dr. Louie Yang, a professor and ecologist at the Department of Entomology and Nematology, UC Davis."
"It seems reasonable to say that an increase of this magnitude would probably require a series of fortunate conditions throughout the breeding season that would sustain population growth across multiple generations," the UC Davis professor told him, adding "What we've seen is a long-term trajectory of declining populations, even before the recent population variability."
Yang focuses his research on "understanding the seasonal dynamics of milkweed-monarch interactions. How do monarch caterpillars develop on their milkweed host plants? And what are the conditions that allow them to develop well and survive to adulthood? And what are the conditions that cause lower survivorship?"
Bottom line. The 100-fold increase in monarch population may or may not be a sign of what's to come. As Yang said: "So we shouldn't be complacent or assume that populations will always bounce back from low densities...I think a lot of folks are breathing a sigh of relief that the population has increased as much as it has over the past year. And I think we all share that sense of relief and joy that the population has increased. But also, there is that note of caution that there is a lot about the dynamics of this population that we don't yet understand and we're still working on."
Social media responses to the podcast included: "Great podcast! I learned even more today about the timing of milkweed availability and monarch eggs--now I understand why late season eggs have a higher percentage of survivorship. Everyone should listen to Professor Yang's interview. It's just a little over 10 minutes, but packed full of information."
Yang, who joined the UC Davis faculty in 2009, holds a bachelor's degree in ecology and evolution from Cornell University, (1999) and a doctorate from UC Davis (2006).
Lauded for his advising and teaching skills, in 2018 Yang received an international award from NACADA, also known as the Global Community for Academic Advising. He co-founded and co-directs the campuswide program, Research Scholars Program in Insect Biology, with UC Davis distinguished entomology professor Jay Rosenheim and professor Joanna Chiu, vice chair of the UC Davis Department of Entomology and Nematology,
Yang, born in Australia but raised in West Virginia, says on his website: "When I was in elementary school, I wanted to be a pet shop owner. In high school, I wanted to be a veterinarian. As a college freshman, I thought I wanted to make nature documentary films. As it turns out, I was really interested in ecology and evolution. After I graduated, I traveled and started a PhD. I've been faculty at the University of California, Davis since 2009. I'm still learning new things all the time."
His current research?"I am working to develop a temporally explicit view of ecology that examines how ecological communities combine complex, coordinated and changing interactions over time. I am particularly interested in the effects of climate change on species interactions, community responses to strong perturbation events, phenological cues and phenological shifts, and seasonal changes in the nature and outcomes of species interactions. I study several different organisms in a wide range of ecological communities, each of which contributes to a broader understanding of how species interactions change over time." (See The Yang Lab website.)
So, in today's Bug Squad, a brief spotlight on Professor Yang:
Question: "How long have you been doing scientific research on monarchs?"
Answer: "I visited the overwintering monarch population at the Coronado Butterfly Preserve in Santa Barbara in 2006, and I started doing research with them shortly afterwards."
A: "Because monarch can travel long distances, it struck me that when they leave their overwintering grounds they might not have very good information about the environmental conditions at their destination. It seems like this lack of information could create the potential for phenological mismatches between the monarch and its host plant."
Q: "What are some of the results?"
A: "Broadly, our results indicate that western monarchs show “seasonal windows of opportunity”--periods in the year with increased developmental prospects. These seasonal windows are constrained by a combination of abiotic (i.e., climatic), bottom-up (i.e., host plant-related), and top-down (i.e., natural enemies-related) factors. In our region, we see two windows of opportunity (late spring/early summer and late summer/early fall) separated by a 'mid-summer slump' on their most common host plant, narrow-leaved milkweed (Asclepias fascicularis). However, plant traits matter: for example, the defensive traits of showy milkweed (Asclepias speciosa) tend to increase across the season, and the monarchs on this species only seem to show one early season window. On showy milkweed, success in the late season window seems to be constrained by host plant defensive traits. Our work has also shown that these seasonal windows appear to be constrained by different factors in the early and late part of each breeding season, and that climatic variation strongly shapes the timing and relative importance different limiting factors."
Q: "What is the role of tropical milkweed, Asclepias curassavica, in monarch conservation?"
A: "I've not studied this in detail myself, but there is a concern that tropical milkweed could change the life history of western monarchs and expose them to more diseases. Unlike our native milkweeds, tropical milkweeds don't senesce during the winter. They continue to grow year-round and are very attractive to monarchs. As a result, this non-native host plant might encourage monarchs to continue breeding longer into the winter than the would normally. In addition, because these milkweeds persist year after year, there are concerns that they can build up higher densities of Ophryocystis elektroscirrha spores, exposing monarch caterpillars to a greater risk of disease."
Q: "What can area residents do to help in monarch conservation?"
A: "I'd encourage folks interested in helping monarch conservation to learn as much as they can about the many and complex factors that can affect monarch populations. Recent variability in the western monarch population illustrates the potential for rapid declines and resilience in this population, but it also shows us the limits of our current understanding about the ecology of western monarchs. Ecology ain't rocket science--it is much more complicated. There is a lot we don't yet know, but there is also a lot that has become clearer over time. We probably know enough now to say that the combined and interactive effects of climate change, land use change, novel environmental chemicals and the global transport of organisms have played a role in the decline of monarch butterflies and many other insects. Scientists will continue working to understand this in more detail, but working now to limit those drivers makes sense."
Q. "What milkweed do you recommend folks should plant in Central California?"
A. "I'd encourage folks to learn about and cultivate the species of milkweed that grow wild in their local area. California has a remarkable diversity of milkweed species, and each occupies a unique niche. Websites like iNaturalist can help folks learn about the species that grow naturally in their area. Visiting established populations of wild milkweed will give folks a sense for the specific habitats that these milkweeds need to survive and thrive. The Xerces Society has also compiled some great information how and where to cultivate milkweed in California." (See Xerces Society website.)