Reinterpreting an Eocene amber tiger beetle

Reinterpreting an Eocene amber tiger beetle

Tetracha carolina from the Essig Museum collection.

There are about 3,000 species of tiger beetles (Cicindelidae) worldwide, many of which are in decline, and several listed as endangered or threatened. Known for their speed, predatory prowess, and beauty, they are a popular group among hobbyists and an active area for research.

There are only a few known tiger beetle fossils, but one of the most cited is the extant tiger beetle Tetracha carolina (Linneus, 1763) that was identified by Walther Horn over a century ago (Deutsche Entomologische Zeitschrift, 1906: 329–336). UC Berkeley Professor Kipling Will, who recently re-studied this amber fossil, provides some insight as to why this identification prompted further questioning: 

“There was this standing idea that a species of tiger beetle had persisted as a species level taxon for 30 or 40 million years without change. If you followed what Horn originally said, that this was Tetracha carolina, then you’d have to assume that there’s really been no significant evolution of this species over that long period of time which seems a little odd. We expect species turnover differences to happen at a much quicker rate than that. And the Baltic is nowhere close to the current distribution.”

Current distribution of Tetracha spp. (green shading) and location of amber fossil (green circle). From Schmidt, J., Scholz, S., Wiesner, & Will K. 2023. “MicroCT data provide evidence correcting the previous misidentification of an Eocene amber beetle (Coleoptera, Cicindelidae) as an extant species.” Scientific Reports 13, 14743.

Amber fossils can be difficult to analyze due to the natural visual obstructions, such as patina flow lines, dust particles, air bubbles, and corrosion cracks. Using standard optical microscopes, researchers are also limited in what traits can be used for identification, because they can only see what is visible to the eye. However, with recent technological advances, such as MicroCT scanning and 3D imaging, detailed and interactive models of fossil specimens can be recreated.  Because of this technology the team was able to challenge Horn’s identification.

Recording of the fossil specimen’s 3D model.

“With the MicroCT scanning, we can see through all of that, and then produce these images. Even though that fossil was never in my hand, I could see all of the images and I could study all the details. And once we publish it, if people in the future disagree with us, well, they have the exact same things to look at as we did.”

Will and colleagues discovered that Horn’s fossil was not an extant Tetracha, but an extinct Palaeoiresina cassolai.

“Both the age and the distribution make sense. If there are examples of things that persist unchanged for 30 or 40 million years, this is certainly not one of them. And we think that’s unlikely for pretty much any of the fossils of that age.”

Identifying fossils is important because of how other researchers will integrate the fossil data into their own work.

“We can build phylogenies and that tells us about relationships, and we can talk about relative divergence from an ancestor to all descendants. But those phylogenies are not time-calibrated. We want to look at things like diversification rates, the timing of evolution of novelties, and all the kinds of fun stuff in the context of everything else that’s happening on the planet. Like, what were the positions of tectonic plates? What was the climate like 30 million, 50 million, 100 million years ago? Correlating phylogeny and the forces that drove evolution and extinction. So having the fossils carefully studied allows us to calibrate those trees and then lets us look at that story through time. Understanding the events of the past will help us make more accurate models of the future.”

Professor Kip Will examining the model.

Story by:
Sloane Sim, Media Specialist
Essig Museum of Entomology

High resolution insect photography

Most insects are very small and cryptic, often escaping notice by the casual observer. Yet these tiny animals make up the bulk of biological diversity on the planet, pollinating our crops and native plants, decomposing organic matter, occupying key nodes in food webs, and acting as weather vanes of climate and land use changes, as well as vectoring diseases and reducing crop and orchard yields.

High resolution, focus-stacked imaging allows us to see not only the tiniest of insects, but also the minute features of larger insects. The Essig Museum of Entomology uses several different imaging system to photograph specimens. We use a Leica S9i digital microscope with Leica Application Suite software (purchased with funds generously donated by Vince & Cheryl Resh) for both specimen imaging, such as the flea slide example below, as well as giving digital tours of the museum via Zoom.

The Essig Museum also uses a MacroPod camera system (Macroscopic Solutions), purchased as part of our collaborative Big Bee grant from NSF to digitize the museum’s extensive bee collection. Using a programmable focus rail, indirect lighting, and Zerene stacker software we are taking hi-res, deep focus photographs of representatives of each species of bee and moth in the Essig collection. These photographs also provide training sets to autamated insect identification systems liked those used in iNaturalist and Google Lens.

The Insect Crisis – Oliver Milman

The Insect Crisis – Oliver Milman

Please join us on Thursday, May 4th, for a lecture by journalist Oliver Milman on “The Insect Crisis”.

Who: Author and journalist – Oliver Milman
What: Albright Lecture
Where: David Brower Center  (2150 Allston Way, Berkeley, CA)
When: (Thursday) May 4, 2023
Time: 6:00 – 7:30pm PST

Insects can seem to be everywhere, all at once, sometimes to an annoying extent. Three out of four of every four known animal species on Earth are insects, after all. But these dazzlingly adept creatures, which pre-date the dinosaurs, are suffering a silent yet hugely consequential crisis, with their numbers plummeting around the world. Oliver Milman, environment correspondent for Guardian US, has outlined the ramifications of this loss in his book The Insect Crisis: The Fall of the Tiny Empires that Run the World, a publication that has received widespread praise, from the environmentalist Bill McKibben to the New York Times.

Butterflies of Albany Hill mural project

The Albany Hill is nestled along highway I-80 / I-580 in the East Bay town of Albany. Trails along the north side wind through a native forest of oaks, hazel nut, and other native trees, which harbor birds, deer, and other wildlife. More trails to the south scramble up a mostly eucalyptus forest leading to open areas of grasses, shrubs, and wildflowers at the top.  And in the winter, a small aggregation of monarch butterflies clusters high up in the eucalyptus branches awaiting spring when they head inland to lay eggs on milkweed and start the next generation.

Friends of Albany Hill have worked tirelessly to secure the land for conservation, maintain trails, and foster environmental education through hands-on activities. Their latest project, spearheaded by artist Carole Fitzgerald, is a mural along Jackson Street on the the east side of the hill depicting the butterflies that occur on hill and the plants they depend on. Each butterfly species is accompanied by the host plant on which its caterpillar feeds. Citizen artists gathered for months to make sketches and eventually paint sections of the mural, paying close attention to biological details of both plants and insects. For the butterflies, their inspiration was a collection assembled in the 1990’s by Essig Museum research affiliate, Robert Langston

Robert Langston and Jerry Powell (longtime director of the Essig Museum) spent several seasons exploring the various habitats of the hill documenting all the Lepidoptera (moths and butterflies) they could find. For the moths this was done without setting out lights at night, but by hunting for caterpillars on their host plants and netting moths by day.

Recently the Albany Hill mural artists made a visit to the Essig Museum to learn more about butterflies and other insects found across California and how the museum continues to grow through ongoing research from faculty, staff, and students.

Monitoring Biodiversity in Post-Fire Santa Cruz Mountains

In August of 2020, a fire that began as a smoldering lightning strike, erupted into a firestorm that roared across the Santa Cruz Mountains, scorching over 86,000 acres of forest and surrounding communities. The CZU Lightning Complex Fire burned for over a month before being fully contained and was the most destructive fire to ravage Santa Cruz County in over a century.1

Today, as part of the Sponsored Projects for Undergraduate Research (SPUR) program, students from Professor Kip Will’s lab are helping to monitor the effects of post-fire removal of trees and underbrush at various intensities on the diversity and abundance of terrestrial arthropods, especially ground beetles (Carabidae). The project is part of a larger study being conducted by Professor Scott Stephen’s lab in ESPM, and in cooperation with the Amah Mutsun Land Trust Stewards, the Bonny Doon Fire Safe Council and the California Department of Forestry and Fire Protection (CalFire). The study area is located in San Vicente Redwoods Preserve in the Santa Cruz Mountains – a mixed hardwood forest dominated by oaks, douglas fir, madrone and bay trees – that burned in the 2020 CZU Lightning Complex Fire. 

Each pitfall trap is set with a cover to prevent rain from getting in

In an area of moderate intensity burn where the forest canopy remained intact following the CZU Complex Fire, students help to set up pitfall trap arrays and temperature and humidity data loggers in nine plots, each in one of three forest fuel and selective tree removal treatments.  The three treatment types are categorized as minimal, moderate, and intensive levels of cutting and removal of trees and underbrush. In addition, one round of spring and fall sampling across all nine plots was done prior to the treatments to act as a baseline control sample. 

Retrieving specimens from the traps

A total of 72 pitfall traps are set in the nine transects two times per year – once in spring and once in late fall. Each pitfall trap is left for a one-month period after which time the samples are collected into Whirl-Pak bags and brought back to the lab. At the same time, temporal and spatial data collected from the field are entered into the Essig Museum’s online database.

Digging to set the traps and retrieval of samples is dirty and physically challenging work, often on slopes where poison oak is abundant. In the process, students learn valuable field techniques including how to set up sampling regimes and record accurate environmental data. Back in the lab students also learn how to sort trap samples and identify arthropods. The project will yield thousands of specimens including hundreds of species over the three-year survey period.

Sorting specimens from the trap samples

The data collected from this ongoing project will provide opportunities to study how different post-forest fire fuel treatments affect not only the diversity and abundance of ground-dwelling arthropods, but how overall forest health, structure and resources recover following fuel reduction and subsequent prescribed burning in San Vicente Redwoods Preserve.

The value of data collected from long-term monitoring projects like this will long outlive the project itself. Locality data and identifications recorded in the Essig Museum’s online database and the specimens in the museum’s collections provide an important resource for current research as well as future research and education. These vital resources can help inform not only our understanding of current species distribution patterns but also help answer questions about the effect of future landscape and climate changes. – Roberta Brett

  1. 2022-5_CZUFire_Report.pdf

A Charismatic Cockroach in California

Figure 1: Mix of adult female and male three-lined roaches (Luridiblatta trivittata)

Scampering through leaf litter and grassy landscapes, upon first appearance these flashy little insects might not look like cockroaches, but in fact, they are. They are the smallest cockroaches we have in California, with adults averaging between 5-7mm in length. They are commonly known as the three-lined roach, or if you want to be more scientific, Luridiblatta trivittata; but either way, these charismatic cockroaches are not originally from California, they are native to North Africa and the Eastern Mediterranean.

Figure 2: Female Luridiblatta trivittata carrying an egg case called an ootheca

The three-lined roach first made its debut in California around 2004 in Marin County, but was not positively identified until the Essig Museum’s very own Cheryl Barr, aquatic beetle expert and former Collection Manager, submitted a specimen from her backyard in 2009 to the California Department of Food and Agriculture. Since then, Luridiblatta trivittata has slowly expanded its range to include the Bay Area, San Luis Obispo to the South, to the foothills of El Dorado County in the East, and to Mendocino County to the North.

Though the three-lined roach lives in some of the most densely populated parts of California, these are not the kinds of roaches that want to live in your kitchen. These critters prefer to live outdoors in partially irrigated or dry landscapes and can be found in matted thatch, compost bins, and leaf litter. Occasionally in summer and fall, adults will wander indoors through poorly sealed doors and windows.

We don’t fully understand Luridiblatta trivittata’s biology and ecology, but recent field observations reveal they only have one generation per year. Juveniles hatch around mid-April, and develop through spring and early summer, eventually maturing into adults during July and August. Once mature, females lay egg cases (called oothecae) that will overwinter until next spring. Interestingly, juveniles cannot hatch from their ootheca without precipitation in spring. On the other hand, too much water throughout the overwintering cycle will kill juveniles before they can hatch. It seems our Mediterranean climate, with long dry summers and short wet winters is the Goldilocks of ideal habitats.

Fun three-lined roach facts:

  1. Knowing your Latin roots in biology can be very helpful in understanding scientific names. Luridiblatta for example, can be broken down into ‘luridus’ meaning something has a wan or yellow coloring, and ‘blatta’, which is Lain for a light-shunning insect (incidentally, all cockroaches are in the group Blattodea). The species name trivittata refers to this particular species. ‘tri’ means to have three, and ‘vitta’ means stripe or line. Therefore, we can conclude that the scientific name is referencing a light-colored cockroach with three lines.

    Figure 3: Females with an ootheca at different stages of development
  2. Oothecae of this species start out mint green in color. As an ootheca develops, it turns olive green and then dark brown before they are eventually deposited into the landscape.

    Figure 4:  Left-Female, Right- Male
  3. Males and Females are relatively easy to tell apart. Males have long forewings that extend down the length of the body. Females have short forewings that leave the abdomen completely visible.


  1. California Plant Pest & Disease Report Vol. 25. 2009. CDFA
  2. Proposal for New Common Name Luridiblatta trivittata, Entomological Society of America
  3. Cockroach pest note, 2019
  4. Andrew Sutherland. Luridiblatta trivittata post on Linkedin, 2020

– Photos & text by Casey Hubble, please contact for photo usage


Meet the Essig Museum’s walkingsticks.

Watch this KQED Deep Look episode featuring our Australian spectres (Extatosoma tiaratum).


Watch the KQED Deep Look episode featuring our Indian walkingsticks (Carausius morosus).



Captive colonies of Giant Malaysian leaf insects (Phyllium giganteum) are known almost exclusively from females. But this year a “male” (left) emerged in our population (males appearing in all female populations are usually non-functional genetic anomalies). In nature, males and females both are very cryptic and hard to find, but sometimes males are attracted to lights. To learn more about leaf insects watch the Essig Brunch seminar presented by Royce Cumming (YouTube video).




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. 



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)


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.

Learn more about the Adopt A Drawer program.


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

            Orthoptera (grasshopers, crickets)                                       Hemiptera (true bugs)