Oak moths return to Cal campus

Oak moths return to Cal campus

Eggs, caterpillars, pupa, and adult of Phryganidia californica.

The California oakworm or oak moth (Phryganidia californica), returned to the UC Berkeley campus for the second year in a row.

In June 2019 the Essig Museum received a call from a reporter at the Daily Cal asking about moths flying around oak trees on campus. Normally people do not notice the moths, but they certainly notice the onslaught of caterpillars eating the leaves of coast live oaks (Quercus agrifolia), and occasionally other oak species. By August many trees on campus were stripped bare. But by the end of October they recovered. In May-June 2020 we are witnessing the return of the oak moth.

The same tree at Sproul Hall: defoliated (August 15, 2019), recovered (October 3, 2019)

Oak moths typically have two generations per year – one in the spring and one in the fall. As of June 2020 we are seeing the spring caterpillars emerge as adult moths and laying eggs. These eggs will turn into caterpillars that will continue to defoliate trees in August and September. The caterpillars seem to focus on individual trees, rather than attacking all trees equally. This probably has to do with where the females lay their eggs, but the defensive chemistry of the oak trees may play some role.

This chemistry may also play a role in protecting the caterpillars and moths from birds and other predators. Many non-toxic moths and caterpillars hide during the day and feed at night. But oak moths and their caterpillars are very active during the day and do not seem to attract flocks of birds. Their main predators seem to be parasitoid wasps.

Feeding damage by Phryganidia caterpillars.

Once finished feeding on a tree, the caterpillars lower themselves by silk threads that can blow them to another tree to continue feeding, or two the ground where they will wander in search of a place to pupate. In nature these caterpillars would find a crack in the tree bark or side of a rock to anchor their pupal case (which looks more like a butterfly chrysalis). On campus these caterpillars can form masses on the sides of buildings, and sometimes crawl  into utility access tubes.

Masses of caterpillars at Campbell Hall in August 2019.

As if the oak trees are not suffering enough, this year is looking like a big year for tussock moths as well. Females of the western tussock moth are flightless and crawl a short distance from their cocoon to lay large masses of eggs. Caterpillars have distinctive tufts of white or cream hairs that can sometimes irritate skin. 

Tussock moth caterpillar and cocoons on coast live oak. 

 

PCOC at UCB

The Pest Control Operators of California infested the Essig Museum on 19 February 2020. They were in town for the Termite Academy, hosted by our own Dr. Vernard Lewis at the Richmond Field Station. The two-day event included lectures, discussions, and events that covered the history of pest control research at UC Berkeley (including a tour of the Villa Termiti), regulation updates, and a lavish dinner at the Faculty Club. Many were surprised to know that the Essig Museum holds the most comprehensive collection of Cimicidae (bed bug family) thanks to the research of Dr. Robert Usinger. We also reassembled the damaged-wood display that was on exhibit at the San Francisco Internation Airport (SFO) last year.

Special thanks to Chris Reardon & Sarah Conrad (PCOC), Andrew Sutherland (UC ANR), and Vernard Lewis (UCB) for making this happen. Photo credits: PCOC (except Villa Termiti by UC ANR)

Adopt-A-Drawer

Leave your mark! Or honor family, friends, or a mentor, by adopting a specimen drawer at the Essig Museum. Special exhibit displays (“Oh My” drawers) are available for donations of $1000. Curated drawers in the main collection are available for $500. Alumni, add your year of graduation. Choose your favorite insect group and make a donation through our Give To Cal secure online donation portal. In the memo/notes field indicate you want to adopt a drawer and we will follow up with you.

Your name and/or message will be laser-engraved on a maple plaque.


ADOPTED DRAWERS

Chris Otahal & Mary HortonBombus fervidus (golden northern bumble bee)

 


“OH MY” DISPLAY DRAWERS

               Lepidoptera (butterflies, moths)                             Hymenoptera (bees, wasps, ants)

            Orthoptera (grasshopers, crickets)                                       Hemiptera (true bugs)


CURATED COLLECTION DRAWERS

 

The Love Bugs

 

Join the Essig Museum and the Pacific Coast Entomological Society

for a special screening of “The Love Bugs

8:00pm on 5 September 2019, at 2040 Valley Life Science Building

Over the course of 60 years, Lois and Charlie O’Brien, two of the foremost entomologists and pioneers in their field, traveled to more than 67 countries and quietly amassed the world’s largest private collection of insects. He was the Indiana Jones of entomology and she was his Marion Ravenwood. Their collection is a scientific game-changer with more than one million specimens and more than 1,000 undiscovered species. During the past several years, however, Charlie and Lois have grappled with the increasingly debilitating effects of Charlie’s Parkinson’s disease and the emotional toll it takes on Lois. They realize that a chapter of exploration and discovery is coming to an end in their lives. But they live in a time when the beleaguered field of science needs them most, and the O’Briens know they need to keep fighting for it. So they turn to their 1.25 million insects for a little help! The Love Bugs interweaves the O’Briens’ present day journey with animated watercolor illustrations that reveal their past in a humorous and poignant documentary short that explores the nature of Love–and the love of Nature–and what it means to devote oneself completely to both.

Charlie and Lois garnered worldwide attention in 2017 when they announced that they would be donating their $10 million dollar insect collection to Arizona State University. Their collection will reshape entomology for years to come, but outside of entomology circles it was not widely known that such a valuable collection existed. We live in a time when insect populations are declining worldwide at an alarming rate. This decline has a domino effect that could impact all other aspects of an ecosystem and humanity as a whole and the O’Briens’ collection is not only a snapshot of the past of insect life on this planet. It is also a valuable key to providing insights into the potential future of insect life and biodiversity patterns. We want this film to inspire wonder and reverence for the complexity and beauty of insects. We also live in a time when the value of teaching science and the value of investing in science is being questioned at a federal level. We deeply need stories that can help foster a paradigm shift by showcasing scientists as human beings–not only as people who passionately dedicate their lives to something that others might see as trivial, but as human beings whose work is crucial and with whom we can empathize.

Students making a difference

Visit the Restoration Project website for the latest on our pollinator gardens.

Weed warriors: Allie, Shiran, Cameron, Taylor, Alba, Pete, Tim, Marissa, Sakina, Leslie, and Zeal after 2 hours of pulling and rolling ivy. Not in photo – Theron, Ellen, Lily, Kyra.

Thanks to everyone who helped out at our weed pulling party on May 7, 2019! The Essig Museum and Entomology Club teamed up with CalPIRG and others to pull ivy and other weeds outside the Valley Life Science Building to prepare the area for restoration of native plants. The “Essig Garden” will be an outdoor education space to learn about how insects, spiders, birds, and other wildlife interact with their habitats, and the value of native plants to reduce irrigation needs. The Garden is also part of CalPIRG’s effort to make UC Berkeley a Xerces Society Bee Campus.

 


Volunteers pulling and rolling 15 ft strands of Algerian ivy.


Before the battle: The area between VLSB and LSA before the weed warriors launched their assault.
 

On the wings of butterflies

Have you ever touched the wings of a moth or butterfly and gotten some “powder” on your fingers? That powder is actually tiny scales, like on a fish or lizard, or like the feathers of a bird. These scales give butterflies and moths their scientific name Lepidoptera (from the Greek Lepido = scale, and ptera = wing). Each scale can be a different color and when placed next to each other, the mosaic makes up the color patterns we see. Some are brightly colored to warn that this species does not taste good (aposematism), or look like distasteful species (Batesian mimicry), while others look like eye spots to startle predators (image to the left), and still others form a camouflage pattern to blend in with their background.

Most colors are caused by pigments that form inside the individual scales and reflect light through holes on the scale surface (image to the right), while others, especially blues, are structural and result from light refracting off of ridged surfaces, like looking at the underside of a DVD. For more information on how blue (structural) colors are formed on butterflies watch KQED’s Deep Look episode “What gives the morpho butterfly its magnificent blue?” featuring the research of Essig Museum faculty affiliate, Dr. Nipam Patel

To see butterfly scales under a microscope visit the Lawrence Hall of Science.

 

 

Ed Ross Photograph Collection

Annu. Rev. Entomol. 2009

Edward S. Ross (1915-2016) was a pioneer of close up photography. Ed received his PhD in 1941 with the Department of Entomology at UC Berkeley, where he was a teaching assist for E.O. Essig.   Before finishing his degree he was offered the position of Curator of Entomology at the California Academy of Sciences in San Francisco in 1939, and two years later became chair of the entomology department, a position he held for 41 years. Initially Ed was interested in Histerid beetles, but soon switched to webspinners (Embiidina), a group for which little was known at the time. His studies took him around the world, particularly to the tropics where webspinners are most diverse. During his travels Ed photographed arthropods, plants, mammals, people, and natural landscapes. His images appeared in numerous publications including National Geographic Magazine, Insects Close Up, and Insects and Plants. In 2018, Ed’s collection of ~100,000 35mm slides were generously donated to the Essig Museum of Entomology by his wife, Sandra Miller Ross, to be digitized and made available for research, education, and outreach. Once digitized, the images will be available through CalPhotos.

Ascend with Bay Area Insects

Ride, walk, or jog along the Greenway in Emeryville and you will be greeted by a swarm of Bay Area “bugs”. Commissioned by the city of Emeryville, Joey Rose created two murals, titled “Ascend”, depicting some of the Bay Area’s most important inhabitants – the insects. Part of Emeryville’s park system, this green space cuts through the heart of Emeryville connecting Oakland to Berkeley. “The Greenway hopes to connect people with nature and serves as an “escape” in a historically industrial city,” says Rose. “My murals reflect this ideal. The intended audience is anyone who may happen to see them. It’s important for people of any age or demographic to feel connected to nature and see the importance of preservation.”

For inspiration, Joey visited the Essig Museum to photograph and sketch his subjects. I asked him why insects for this project. “Insects are an often ignored part of the ecosystem. Unfortunately, there is a stigma against insects. They are usually portrayed as being disgusting or scary. I wanted to show the true beauty of insects. This is a sight-specific mural, so I wanted to highlight local and native Bay Area insects. I hope people will be reminded of my painting when they see these insects around the Bay and vice-versa.”

The murals were unveiled on May 10, 2018 at 5768 Peladeau Street in Emeryville to an enthusiastic crowd. “The two figures in the murals are literally being carried by these insects,” says Rose. “I think that is really the core of what I want people to come away with. It’s not so important that they can identify each and every insect. What’s important is to get people thinking about how essential every creature is to not only our ecosystem, but to us (humans) as fellow members of that ecosystem. Even the little guys are important!”

by Peter Oboyski

Fall is for pumpkin spiders

You have probably noticed a lot of these critters around town lately; they seem to be just about everywhere this time of year. These eye-catching little beasts go by many names, including “Cross Orb-Weaver,” “European Garden Spider,” and “Pumpkin Spider,” among others,1,2 but their proper scientific name is Araneus diadematus. (Note: common names like “Garden Spider” or “Pumpkin Spider” may refer to a number of different spider species, which is understandable given that there are an estimated 47,000 (or more)3 spider species on earth! Since we have not come up with 47,000 unique common names for all of these species, it is best to use scientific names to avoid confusion.)

Araneus diadematus are tan, brownish or orange, with yellow, white and black markings and a distinctive “T” or cross pattern on the back of their spade-shaped abdomen. Adults can range from about 6-20 mm in body length, not including the legs.4 Females are much larger than males and have been known to cannibalize hopeful suitors who approach them to mate.5 You are most likely to find these spiders on their characteristic “orb webs”: those beautifully geometric, Charlotte’s Web-style constructions of spiral-shaped silk supported by spokes radiating from a central hub. This web shape is typical of the spider family Araneidae (“orb weavers”).

Although A. diadematus can be found in the Bay Area throughout the year, their numbers and visibility peak in the fall because this is when they reach maturity. They are not native to this region, they originated in Europe, but their range now extends across the U.S. and into many parts of Canada.1 A. diadematus can occur at remarkably high densities in both natural areas (like woods and parks) and urban environments. Whether they truly qualify as “invasive” (which, by definition, would require having a negative impact on the environment) is debatable, but one thing is for sure: they are enormously successful here.

So what are they doing on those lovely spiral webs? Mostly lying in wait for prey, which consists of insects like flies, beetles and aphids.6 The spiral on the web is made of sticky silk, and when unwitting insects blunder into this structure, they get stuck. The insects struggle, creating vibrations through the web. The spiders, although they have poor eyesight, are incredibly sensitive to vibrations, and by resting in the center of the web – where the “spokes” converge – the spiders can detect exactly where to find the prey based on which silk strands are vibrating.7 The spider then uses a combination of biting and silk-wrapping to immobilize the hapless prey before settling down to eat. Since this whole process damages the web, A. diadematus builds a fresh web each day, eating the old one to recycle the silk.

Some people may find A. diadematus creepy or frightening, and these spiders do look formidable when they are fully grown (not to mention that we usually see a lot of them around Halloween!). However, there is no reason to fear these autumnal creepy crawlies: they are completely harmless. Although they do possess venom – as do almost all spiders – the venom’s function is to paralyze insects, not to hurt large vertebrates like us. And while a bite from one of these guys might be painful and cause a small localized reaction8 (much like a bee sting), the chances of being bitten are so slim that it is a non-issue. These spiders are not the least bit aggressive; they like to keep to their webs and mind their own business, and would only bite as a last resort (i.e. if they were about to be squished). So next time you walk through a huge web that a resident A. diadematus thoughtfully constructed right in front of your door, do not panic – the spider is running for the hills as we speak. If you are lucky, your little 8-legged buddy might stumble into your hands and let you take a closer look!

by Susan Kennedy

See also common Bay Area spiders.

References

  1. “Cross Spider.” Washington NatureMapping Program, naturemappingfoundation.org/natmap/facts/cross_spider_712.html.
  2. Bowline, Mariah. “Pumpkin Spider – Araneus diadematus.” BugGuide, Iowa State University Department of Entomology, 2005, bugguide.net/node/view/33907/bgpage.
  3. “World Spider Catalog (2017).” World Spider Catalog. Natural History Museum Bern, wsc.nmbe.ch, version 18.5, accessed on 12 September 2017. doi: 10.24436/2
  4. Araneus diadematus (Cross Orbweaver).” Spiders.us, 2017, spiders.us/species/araneus-diadematus/.
  5. Elgar, M. A. and D. R. Nash. 1988. Sexual cannibalism in the garden spider. Animal Behaviour 36(5): 1511-1517.
  6. Ludy, C. 2007. Prey selection of orb-web spiders (Araneidae) on field margins. Agriculture, Ecosystems & Environment 119(3): 368-372.
  7. Landolfa, M. A. and F. G. Barth. 1996. Vibrations in the orb web of the spider Nephila clavipes: Cues for discrimination and orientation. Journal of Comparative Physiology A: Sensory Neural and Behavioral Physiology 179(4): 493-508.
  8. McKeown, N., R. S. Vetter, and R. G. Hendrickson. 2014. Verified spider bites in Oregon (USA) with the intent to assess hobo spider venom toxicity. Toxicon 84: 51-55.