- Author: Kathy Keatley Garvey
Butterfly guru Art Shapiro, UC Davis distinguished professor of evolution and ecology, spotted a female monarch butterfly at 1:35 today.
As he mentioned in his email: "So, at 1:25 p.m. a female monarch flew directly over my head, roughly 8' off the ground, near the corner of Oak Avenue and 8th Street. It was headed northeast very lazily."
Shapiro noted that Kathy Keatley Garvey saw a monarch in Benicia on Jan. 23, "so this is the second sighting known to me this year in this general area. If there are really only 3000 or fewer overwintered in the whole state, I guess we won the lottery!"
So, the count as we know it:
- Monarch butterfly, gender unknown, flying over 115 West G St, Benicia, on Feb. 23, Garvey sighting
- Monarch butterfly, a male, that the Garveys reared in west Vacaville and released on Feb. 25
- Monarch butterfly, a female, flying near the corner of Oak Avenue and 8th Street, Davis, on March 2, Shapiro sighting
Now some folks are blaming tropical milkweed, Asclepias curassavica, a non-native, as a serious threat in the massive decline of the monarch population.
Don't blame tropical milkweed, agree Shapiro and monarch researcher David James, an entomologist and associate professor at Washington State University (WSU).
James told us in an email: "I have been involved with monarchs for 43 years, and the single, overriding thing that I have learned is that the monarch is a highly adaptable creature! It has an incredible ability to adjust to changing environmental circumstances. In Australia, it took less than 100 years to change its core physiology as part of adaptation to a different climate. Adapting to man-made environmental challenges may take monarchs a while but I believe it can happen."
"I believe that the widespread and intensive use of neonicotinoid insecticides is one likely factor behind the current monarch population decline," James says. "But even with insecticides, insects can develop resistance over generations. The few monarchs that are alive and well in California currently are the survivors, those that have beaten the perils stacked against them. Clearly, we need to try and make life as fruitful as possible for these survivors, to aid in their population recovery. These monarchs will produce progeny that are also ‘fitter' than the general population and we need to ensure that milkweed is there for them, particularly during spring in California."
"The monarch as a species is particularly good at trying different things," James points out. "Thus, while the majority of the population does one thing (like migrate and overwinter), there is always a significant subset exposed to the same environment, that decides to do something different, like not migrate. Most of these of course will die but in some circumstances, some locations, the outcome may be good, giving another option for continuation of the species, should it become necessary. We may be seeing this now with the rise in winter breeding of monarchs in warmer parts of interior California like the LA Basin and SF Bay Area. There is also evidence for the first time of breeding winter monarch survival in far southwestern Oregon."
A post on texasbutterflyranch.com touched on the native/non-native milkweed controversy. "David James takes issue with the loud and persistent claim that non-native milkweeds pose serious threats to monarch butterflies and the viability of their migrations. When asked if he thinks the technically non-native tropical milkweed poses a dire threat to monarch butterflies, James' answer was emphatic."
No, he does not. "Not at all, in fact," he told them.
You can follow David James' research and observations on his group's Facebook page, Monarchs of the Pacific Northwest at https://www.facebook.com/MonarchButterfliesInThePacificNorthwest.
On Jan. 12 James posted a graph showing "the number of observations of monarch larvae/pupae (as recorded on I-Naturalist) in the San Francisco Bay area during November/December for every year since 2015. The graph showed a huge (>5X) increase in observations in 2020 compared to each of the the previous 6 years. I have now extracted data on monarch reports for January 2021 and compared them to the previous six years (see graph below). Once again, the data show a large increase in reports of both adult and immature stage monarchs during the past month in the SF Bay area. In fact, the increase is greater than for Nov-Dec. The average number of larvae/pupae reported on I-Nat during January from 2015-2019 was 1.0. This year the number was 63. Similarly an average of 5.0 adults were reported for January during 2015-19, yet this year there were 58 sightings reported to I-Nat. Of course some of this increase can be explained by increased use of I-Nat in these covid times to report sightings, but I doubt that this explains it all. Interestingly, there were signs last January of an increase in sightings when 10 larvae and 12 adults were reported. But the numbers in January 2021 are on another level."
James' work draws such comments as "You rock, Dr. David James! Thank you for speaking common sense and not regurgitating a hard line which equates to death for the monarchs when milkweed is purposely cut and no milkweed is available for the next generation to consume! I look forward to more findings from you and your honest research reporting. Thank you so much for all you do to help the monarchs thrive not just survive!"
Meanwhile, anyone else see any monarchs flying around the Bay Area and/or in Yolo and Solano counties?
- Author: Kathy Keatley Garvey
Don't tell the honey bees.
They will forage where they want to--whether it's on bee balm, a dandelion or that controversial tropical milkweed, Asclepias curassavica.
Just before we cut back the tropical milkweed for the season, the honey bees got their last hurrah--the last bit of nectar for the year.
Why cut back tropical milkweed? Scientific research shows that this plant disrupts the monarch migration patterns when it's planted outside its tropical range, and can lead to the spreading of OE, orophryocystiselektroscirrha, a protozoan parasite that infects monarch and queen butterflies. So we gardeners cut it back AFTER the monarchs have quit laying their eggs for the summer (or early fall) and BEFORE the monarch migratory season.
Honey bees, however, do love that milkweed. (Note that some scientists, conservation organizations and horticulturists urge folks NOT to plant the non-native tropical milkweed, and if they do, cut it back before the migratory season. See post from Xerces Society of Invertebrate Conservation.)
Connie Krochmal's article on "Milkweed as Honey Plants" in the Aug. 23, 2016 edition of Bee Culture magazine points out just how much bees love milkweed.
"Very fond of milkweed blossoms, bees will desert other flowers when these are available. The plants provide a good nectar flow. Bees discard the pollen. Assuming enough plants are available, milkweeds can bring a good crop of honey."
Milkweed, Krochmal writes, "are major bee plants in the North Central states, the Northeast, Southeast, the Plains, and the mountainous West." The honey is typically light colored and mild-flavored, she added.
"Generally, milkweeds are considered beneficial to bees. However, there are potential negative aspects to milkweed flowers. It is conceivably possible for bees and other small pollinators to become trapped in a blossom. Also, the sticky pollen masses might cling to a bee's head or legs, thereby affecting her mobility or appearance."
Yes, it does. We've seen many a bee struggle to free herself from the pollinia. Some lose their legs. Some perish.
But that nectar--that nectar--the bees keep coming back for more.
- Author: Kathy Keatley Garvey
Hi, I'm a jumping spider.
I see that you found me on the tropical milkweed, Asclepias curassavica.
I'm just here for the prey, and you are definitely not prey, so not to worry.
I'm a member of the Salticidae family and my family contains more than 600 described genera and more than 6000 described species. I have eight eyes. Actually, that's four pairs of eyes and three secondary pairs. How many eyes do you have? What, only two? You got robbed!
I'm a pretty good hunter. When I detect a potential prey, I orient myself and swivel. When I'm close enough, I pause and attach a dragline and then I sprint onto my prey. Pretty cool, huh?
People don't really notice me until Halloween and then they craft those awful-looking sticky webs and all kinds of weird looking spiders just to scare everybody. Do you need scaring? Please be kind and not yell at me or throw things at me. Think of Halloween as "Be-Kind-to-a-Spider Day."
So, if you see me, a real rendition of the fake Halloween spider, don't poke me or crush me or ask me how high I can jump. Or how far. I don't get into logistics.
I'm just here for the prey, not the questions.
- Author: Kathy Keatley Garvey
We don't normally name the monarch butterflies we rear, but we decided that the first one reared from an egg "The Greg Way" would be named for Greg--naturalist Greg Kareofelas, associate at the Bohart Museum of Entomology, UC Davis.
The first one, however, is a girl, so she's "Greta" instead of "Greg."
Over the last five years, we've reared more than hundred monarchs from caterpillar to chrysalis to adult. We collect the 'cats from the three species of milkweed in our Vacaville pollinator garden. This summer, however, we decided to collect a few eggs after seeing Mama Monarchs depositing them on tropical milkweed, Asclepias curassavica, and narrowleaf milkweed, Asclepias fascicularis. (As recommended, we cut back the tropical milkweed before the migratory season begins.)
Here's "The Greg Way":
"I put a single egg on its leaf in a small salsa container (the little plastic ones you would get at a Mexican restaurant)," Kareofelas says. "I take a square of toilet paper and fold it into a small square (3/4 of inch), dampen it and squeeze it so it is not sopping wet, just damp, and set the leaf and egg on the top. Put the lid tightly on the container. This keeps a level of moisture in the container. I check the containers daily, changing the toilet paper square to keep from molding."
The egg hatched. The caterpillar ate. And ate again, again and again. Did we mention "Again?" Again, again and again. She went through five instars, and then she j'd and formed a chrysalis on the ceiling of our indoor, netted butterfly habitat. The entire cycle from egg to larva to chrysalis to adult takes about a month. (See more on Bug Squad blog, Joy of Rearing Monarchs)
So Greta eclosed this morning, big, bold and beautiful. We released her in the pollinator garden, near where Mama deposited her as an egg. Greta inched up on a Mexican sunflower (Tithonia rotundiflora) and then took flight. A blur.
Hopefully, she will mate and overwinter in coastal California, avoiding the wildfires, adverse weather conditions and predators.
Safe travels, Greta! (And thank you, Greg!)
- Author: Kathy Keatley Garvey
We plant three species of milkweed (the host plant for the monarchs), but both the monarchs and the honey bees gravitate toward A. curassavica, a non-native. So do syrphid flies, carpenter bees, bumble bees, leafcutter bees and assorted other insects.
If you haven't heard, planting tropical milkweed is controversial. Scientific research shows that it disrupts the monarch migration patterns when it's planted outside its tropical range, and can lead to the spreading of OE, orophryocystiselektroscirrha, a protozoan parasite that infects monarch and queen butterflies. (See Exposure to Non-Native Tropical Milkweed Promotes Reproductive Development in Migratory Monarch Butterflies, published by the National Center for Biotechnology Information, U.S. National Library of Medicine, Bethesda, Md. Also see the Xerces Society for Invertebrate Conservation website on the issue.)
UC Davis alumnus and monarch expert Anurag Agrawal of Cornell University, the James A. Perkins Professor of Environmental Studies at Cornell University and the author of the celebrated book, Monarchs and Milkweed: A Migrating Butterfly, a Poisonous Plant, and their Remarkable Story of Coevolution (2017 Princeton University), knows the controversy well.
"Tropical milkweed is an interesting and complex issue," he recently told us. "I love the plant for various reasons, but there is growing evidence that as it has become weedy (and self-seeding) in the southeastern United States and California. It is affecting monarchs, mostly by disrupting their migration. The key issue here is that when it is flowering 'out of season' this can be 'confusing' to monarchs. Having said this, we don't live in a pristine world, so my position is that we need moderation in the approach to tropical milkweed. It is certainly an easy plant to grow and monarchs can make good use of it during the caterpillar season. If you love the plant, go for it, but I would recommend cutting in back before the migratory season starts."
Agrawal received his doctorate from UC Davis. Read a review of his Monarchs and Milkweed book from the journal Ecology and read the first chapter here. You can order the book here.
Three Milkweed Species
We offer monarchs a choice of milkweed species in our Vacaville pollinator garden. In addition to the non-native A. curassavica, we plant two native species: narrowleaf milkweed, A. fascicularis, and showy milkweed, A. speciosa. In July, we collected 11 caterpillars from the narrowleaf milkweed; we rear them to adulthood and release them into the neighborhood. But in the numbers game, the tropical milkweed won. From July through today, we have collected a whopping 43 eggs or caterpillars from A. curassavica. How many from A. speciosa? Sadly, none.
As recommended, we cut back or remove the tropical milkweed before the migratory season. In the meantime, we grow it for three reasons: (1) for the monarchs (2) as a food source for other insects and (3) as an ornamental garden plant. We like the brilliant colors and the diversity of insects it attracts.
On one afternoon in late July, we photographed foraging honey bees on the spectacular blossoms. They just couldn't get enough of it.
