"The population, counted by citizen scientists at monarch overwintering locations in southern California, dropped from around 300,000 three years ago to just 1,914 in 2020, leading to an increasing fear of extinction. However, last winter large populations of monarchs were found breeding in the San Francisco and Los Angeles areas. Prior to last winter, it was unusual to find winter breeding by monarchs in those locations."
So begins a news release, "New Monarch Butterfly Breeding Pattern Inspires Hope," posted on EurekAlert by the communications specialists at Washington State University, Pullman, Wash., in citing the peer-reviewed research of WSU entomologist/associate professor David James. He's been studying monarchs for 43 years and spearheads a migratory monarch tagging program in the Pacific Northwest.
The WSU news release quotes the monarch scientist: "There's more to it than just counting overwintering butterflies. It seems that monarchs are evolving or adapting, likely to the changing climate, by changing their breeding patterns."
The impetus for the news release? James recently authored "Western North American Monarchs, Spiraling into Oblivion or Adapting to a Changing Environment?" in the journal Animal Migration. He called attention to the huge declines of monarchs--and their resiliency--in Australia when he was working on his PhD dissertation there 40 years ago.
James says that climate-wise, San Francisco is very similar to the area around Sydney. And he thinks that monarchs will adapt well to the changing climate in the western United States, just as the monarchs in the Sydney area have.
The WSU entomologist is now connecting with citizen scientists in California to collect more data on winter breeding that "can show this evolution and adaptability." His research includes data on what milkweed species the monarchs frequent. They include tropical milkweed, Asclepias curassavica, which has thrived in California for more than 100 years. Some advocate a "no grow" policy, declaring that A. curassavica impedes migration and carries more of the Ophryocystis elektroscirrha (OE) spores than the native milkweeds because it can survive the winter in many areas of California, while native milkweed species usually go dormant. Others argue that tropical milkweed is not the cause of the declining milkweed population--that habitat loss and pesticides are. "Just cut it back before the fall migration or cut it back when monarchs are no longer laying eggs" to limit the transfer of OE, they say. Still others insist on planting a variety of milkweed species, including tropical, to give monarchs a choice, that "monarchs know what they want."
When we contacted the WSU entomologist earlier this week, he pointed out that "the milkweeds that monarchs were using during winter last year in Santa Clara County were not solely tropical. There are good numbers of Gomphocarpus physocarpus and Gomphocarpus fruticosus being used as well, although these two species are difficult to tell apart."
Where are the monarch butterflies? They're MIA on the four species of milkweed in our Vacaville pollinator garden
But milkweed attracts other insects, including honey bees, carpenter bees, bumble bees, assassin bugs, syrphid flies, leafcutter bees, Anthophora (genus) bees, wasps, praying mantids, and butterflies, including Gulf Fritillaries, Agraulis vanillae, and gray hairstreaks, Strymon melinus. And yes, arthropods such as crab spiders and orbweavers visit, too.
On Sept. 19, we witnessed a gray hairstreak laying eggs on the buds of a tropical milkweed, Asclepias curassavica, which we planted in a container with another milkweed, butterflyweed, A. tuberosa. (Yes, we give the monarchs a choice; we also offer them showy milkweed, A. speciosa, and narrowleaf milkweed, A. fascicularis, and we cut back the A. curassavica before the fall migration, as noted entomologists recommend.)
Butterfly guru Art Shapiro, UC Davis distinguished professor of evolution and ecology, says this about the gray hairstreak on his website, Art Shapiro's Butterfly Site:
"This is one of the most polyphagous butterflies known, recorded on host plants in many families. Its most frequent hosts in our area are mallows, including the weedy species of Malva; legumes, including Spanish Lotus (Lotus purshianus), Bird's-Foot Trefoil (Lotus corniculatus), White Clover (Trifolium repens) in lawns, Alfalfa (Medicago sativa) and many others;and Turkey Mullein (Eremocarpus or Croton setigerus, Euphorbiaceae)."
So, we mentioned the gray hairstreak laying eggs on the buds of the milkweed. "Is this a host plant, too?"
"Apparently on the flower buds! Never before recorded--in fact, I have no records on Asclepiadaceae/Apocynaceae at all," Shapiro said. "They lay on Callistemon (bottlebrush) too..."
Meanwhile, update: no monarchs, no eggs. We're still waiting.
But "yes" on the gray hairstreak, Strymon melinus, and "yes" on her eggs.
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?
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.
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.