Milkweed bugs gained the nickname of "seed eaters" for primarily eating the seeds of milkweed.
Actually, they are opportunistic and generalists, says Hugh Dingle, emeritus professor of entomology at the University of California, Davis.
They will eat monarch eggs and larvae (milkweed is the host plant of monarchs), as well as the oleander aphids that infest the milkweed.
We recently watched a large milkweed bug (Oncopeltus fasciatus) munch oleander aphids on a narrow-leafed milkweed (Asclepias fascicularis) in our pollinator garden in Vacaville, Calif. Between the milkweed bugs and the lady beetles, aka ladybugs), they absolutely cleaned off all the aphids, the first time in years.
Milkweed without aphids? Unbelievable! That's like macaroni without cheese, a pencil without paper, or a hammer without a nail. It's a "given" that if you grow milkweed, you'll get aphids. Some monarch butterfly enthusiasts kill the aphids with a soapy water mixture (which we've done in the past), but this year, we let biocontrol reign.
It worked wonderfully!
"Milkweed bugs will get protein from wherever they can find it," says Dingle, an insect migration biologist and author of the textbook, Animal Migration: the Biology of Life on the Move. They've been known to feed on insects trapped in the sticky pollen of the showy milkweed (Asclepias speciosa). And on nectar.
Dingle served as a professor at UC Davis Department of Entomology from 1982 to 2002, achieving emeritus status in 2003. National Geographic featured him in its cover story on “Great Migrations” in November 2010. LiveScience interviewed him for its November 2010 piece on“Why Do Animals Migrate?”
A fellow of the American Association for the Advancement of Science and the Animal Behavior Society, Dingle has done research throughout the world, including the UK, Kenya, Thailand, Panama, Germany and Australia.
Dingle is a former secretary of the International Society for Behavioral Ecology and past president of the Animal Behavior Society. He received the Edward A. Dickson Professional Award in 2014 to do research on "Monarchs in the Pacific: Is Contemporary Evolution Occurring on Island Islands? (See news story on Department of Entomology and Nematology website.)
Wait! They may NOT have been ladybugs, scientifically known as lady beetles, family Coccinellidae.
“I'm still not convinced that the swarms are ladybugs,” Lynn Kimsey, director of the Bohart Museum of Entomology and professor of entomology at UC Davis, told us Friday. “It's pretty late in the season for them and apparently there's no hard evidence for ladybugs except anecdotes that folks have seen a lot of ladybugs in the region. We were seeing a lot of ladybugs in the Imperial Dunes when we were there in March.”
Scientists spotted the cloud, about 10 miles wide and a mile above the ground around 9 p.m. They ruled out bats and birds. The temperature in the air? About 40 degrees or lower—considered too cold for ladybugs.
“Forty degrees is too cold for their flight muscles, but if there's a wind and they've already warmed up, it's possible they could stay airborne,” Kimsey said, adding she'd like to see some hard evidence that these were indeed ladybugs. “Otherwise this is all just speculation.”
The ladybugs were thought to be the migratory convergent lady beetles, Hippodamia convergens. Some 200 species of ladybugs reside in California. (See information on this beetle on the UC Statewide Integrated Pest Management Program website.)
Speculation abounds. Why the huge swarm? Maybe it was the result of a combination of cues, such as temperatures and length of day, climate change (wildfires?), and lack of food? A perfect storm?
Kimsey told reporter Maanvi Singh of The Guardian in a June 7th news story: “It's too bad there wasn't anyone in a private plane up in the air at that time. We could've figured it out based on which dead insects were splatted across the wings.””
Kimsey knows about those bug splats. She was the nation's only entomologist selected for the NASA SPLAT/Boeing team to research how to decrease bug splats on aircraft and thus increase fuel efficiency in commercial jets. NASA engineers developed four different surface treatments designed to repel bugs and Boeing developed wing modifications to test an aircraft at Shreveport, La.
By the way, a Boeing EcoDemonstrator 575 took flight, reaching an altitude of 5000 feet to maximize bug splats. The panels generated 100 and 500 splats each. Kimsey identified all the insects and found that a relatively small number of species caused the bulk of the splats. They included flower flies, aphids, thrips, muscid flies, midges, mosquitoes and love bugs. Kimsey's excellence in teaching, research and public service led to her being named the 2016 recipient of the Academic Senate's Distinguished Scholarly Public Service Award and a comment from her nominators that her SPLAT research was a "great public service to NASA, the airline industry and worldwide passengers who depend on air travel."
Naturalist Greg Kareofelas, an associate at the Bohart Museum of Entomology, has never seen such a cloud but has photographed lady beetles overwintering in California's Coast Range. "When they are at the place they will spend the winter, they hide under leaves and other detritus and unless you dig down to the ground level, you don't really see them or notice they are there. I guess this is the way they are protected from the cold. I know the places I have found them are under snow for the winter. It is only when they are ready to disperse in the spring, do they congregate like on tree trunks and other places above ground level."
UC Davis emeritus professor Hugh Dingle, author of Migration: The Biology of Life on the Move (second edition, 2014, Oxford University Press), a sequel to the first edition published in 1996, says the cloud may have been lady beetles. "I guess lady beetles, but I suspect other insects were in the swarm as well."
"This one was especially large, but yes, there have been other swarms showing up on radars, especially locusts, some moths," Dingle said. "Could also have been moths, grasshoppers, etc. I confess, though, that the swarm was so large that I wonder if there was a glitch somewhere on the radar or something?"
Now if there had just been a plane near that cloud, as Kimsey pointed out, we'd have known exactly what was in that swarm.
Birds, bats, bloom? Unidentified objects?
Splat! Identified objects.
Have you ever heard anyone say that when they see the larva of a lady beetle (aka ladybug, family Coccinellidae)?
Unfortunately, it's quite common among non-gardeners and non-insect enthusiasts.
The larvae of lady beetle are mostly black and look like tiny, spiny alligators, but they're beneficial insects just like the adult lady beetles. In the adult and larval stage, they're both predators that prey mainly on aphids, but they'll also eat thrips, spider mites, scale insects, and other soft-bodied insects.
An adult lady beetle can eat as many as 5000 aphids in its lifetime, scientists say. Who knows how many a larva can eat! Who's counting?
"Young lady beetle larvae usually pierce and suck the contents from their prey," according to the UC Statewide Integrated Pest Management Program's website. "Older larvae and adults chew and consume their entire prey. Larvae are active, elongate, have long legs, and resemble tiny alligators."
You've seen lady beetle jewelry and t-shirts and the like (check out the gift shop at the Bohart Museum of Entomology at UC Davis, located in Room 1124 of the Academic Surge Building on Crocker Lane), but the larvae? They aren't represented.
They're well represented in many gardens, however. In our garden, the adults and larvae are polishing off the oleander aphids on our milkweed plants.
Have you ever seen the larva of a lady beetle (aka ladybug) dining on an aphid?
Lights! Camera! Action!
So here is this charming little immature lady beetle chowing down on an oleander aphid that has the audacity to infest the milkweed in our pollinator garden. Chomp! Crunch! Slurp! And then another aphid arrives on the scene. It does not flee. Aphids are not the smartest of insects.
Can you just wait! Hold on! I'm not finished eating this one, yet!
And then an adult lady beetle arrives. She ignores a fat aphid right before her very eyes. Shall we prey?
Can you just wait! Don't go away! I'll eat you when I'm hungry!
A lady beetle (it's not a bug, it's a beetle!) belongs to the family Coccinellidae. Scientists have described about 5000 species worldwide, and about 450 in North America.
How many aphids can a lady beetle eat in her lifetime of three to six weeks? An estimated 5000 aphids, according to the University of Kentucky Cooperative Extension Service.
That's great pest control!
One thing is for sure: the lady beetles and their offspring patrolling our milkweed plants will never experience famine. This is an all-you-can-eat buffet, and the aphids just keep on a'coming. They do not flee. Aphids are not the smartest of insects.
Now, where are the monarchs? We have milkweed waiting./span>
Mark your calendars!
The next open house at the Bohart Museum of Entomology, located in Room 1124 of the Academic Surge Building on Crocker Lane, UC Davis campus, is set for 1 to 4 p.m., Sunday, Nov. 18. It's free and family friendly.
"The focus is urban entomology," said director Lynn Kimsey, UC Davis professor of entomology. "We'll have out examples of all the wonderful household pests/friends and garden pests, along with the kinds of things they inspect restaurants for."
Think of such beneficial insects in the garden as lady beetles (lady bugs) and praying mantids, and such pests as cockroaches and booklice in homes and restaurants.
What are booklice? These nearly microscopic insects, Liposcelis bostrychophila, or "psocids" (pronounced "so kids"), are common pests in stored grains. They're usually unseen because they're about a millimeter long--about the size of a speck of dust--and are transparent to light brown in color.
At the open house, look for scores of displays dealing with urban entomology. The UC Statewide Integrated Pest Management Program (UC IPM) will take part. A family arts and crafts activity is also planned.
The Bohart Museum, home of nearly eight million insect specimens, is the seventh largest insect collection in North America and houses the California Insect Survey, a storehouse of insect biodiversity.
In addition, the Bohart features a live "petting zoo," comprised of Madagascar hissing cockroaches, walking sticks, tarantulas and praying mantids; and a year-around gift shop, which is stocked with T-shirts, sweatshirts, books, jewelry, posters, insect-collecting equipment and insect-themed candy.
Public weekend hours for the academic year 2018-2019 are:
- Sunday, Nov. 18, from 1 to 4 p.m.: "Bring It Home: Urban Entomology"
- Saturday, Jan. 12, from 1 to 4 p.m.: "Time's Fun When You're Studying Flies"
- Saturday, Feb. 16, times vary: (campuswide) Biodiversity Museum Day
- Saturday, March 9, 1 to 4 p.m., "Eight-Legged Wonders"
- Saturday, April 14, 10 a.m. to 3 p.m., (campuswide) UC Davis Picnic Da
The Bohart Museum's regular hours are from 9 a.m. to noon and 1 to 5 p.m. Mondays through Thursdays. It is closed to the public on Fridays, Saturdays and Sundays and on major holidays. Admission is free. More information on the Bohart Museum is available on the website or by contacting (530) 752-0493 or emailing email@example.com.