Inside Look: MacArthur Fellow Joe Parker’s Insect-Themed Office

Joe Parker in his office in the Mabel and Arnold Beckman Laboratories of Behavioral Biology. Credit: Lance Hayashida

By Omar Shamout

Joe Parker calls California “frontier territory” for undiscovered insects. The Caltech entomologist estimates he has found dozens of new species since arriving at the Institute in 2017 and possibly thousands during his lifetime. “I would need several more lifetimes to actually put names on everything,” he says.

While Parker unearthed many of these specimens doing field work in the nearby San Gabriel Mountains, he did not even have to leave home to make one recent find. “We wanted to study the chemical defense gland of a beetle species attracted to flesh flies, which gather on rotting mammal carcasses,” says Parker, an assistant professor of biology and biological engineering, director of the Center for Evolutionary Science (CES), and a Chen Scholar. “So, my kids and I put dead rats behind our fence in South Pasadena. As soon as the rats started getting munched by flesh-fly larvae, some beetles showed up. It turns out, there’s a species that had never been found that was living, literally, in our backyard, and we now have a whole genome sequence for it.”

Parker, who was recently named a MacArthur Fellow, has loved bug hunting since he was a kid growing up in Swansea, Wales. A childhood hobby turned into a lifelong passion at age 7, when Parker visited the National Museum of Wales with his father and toured a zoology exhibit. “There was an insect display with a giant south-east Asian cicada,” he recalls. “It was completely mesmerizing with its bulbous eyes,almost mechanical body segments, and huge wings. I just thought, ‘There’s a parallel world on planet Earth, and it’s the world of insects.’”

Surrealist painting
Parker’s father, John, a sociology professor, made this small painting, along with several others of a similar style, for his son. John has always enjoyed making art, though wood sculpture is his usual medium. A few years ago, John began to experiment with painting on thick blocks of wood. “Each one of them is kind of surrealist,” Parker says, noting this piece contains shapes and figures that could be construed as insects. “Sometimes they converge into things that you recognize.”

Today, Parker’s lab focuses on the symbiotic relationship between insect species, particularly rove beetles and ants. Rove beetles (Staphylinidae), which live in soils and dead leaves around the world, represent a sprawling radiation of over 66,000 species, making them not only the largest known beetle family but the largest known family in the entire animal kingdom. Parker’s team studied one group of rove beetles that has evolved to mimic ant pheromones or produce chemicals that pacify aggressive worker ants, enabling the beetles to live symbiotically with the ants and even prey upon them.

Velvety tree ant nest chambers
Colonies of the velvety tree ant build these intricate nest structures inside oak trees. Each colony contains perhaps a million ants, which together transform theinsides of a trunk into a labyrinth of microchambers. “We call it the crunchy magic material,” Parker says, noting the rove beetles studied by his lab, which pose as ants, also live in these nests. “Inside the tree is this incredibly complex microenvironment with probably thousands of these tiny chambers.” Velvety tree ants bite, however, so collecting specimens can be dicey. “If you find a hole in a tree and reach inside to pull out the nest, you will get annihilated by the ants,” he says.

Recently, Parker and colleagues, including Caltech professor of biology Mitchell Guttman, assembled whole genomes from species spanning the rove beetle’s evolutionary tree. They analyzed the genes expressed in two cell types found in a gland on the abdomen of rove beetles; this enabled the researchers to uncover a genetic toolkit that evolved over 100 million years ago to equip these insects with their powerful chemical defenses. “What you have in these beetles is a virtuoso example of organisms evolving new ways to interact with other species,” Parker says.

Beetle treadmill
Parker’s lab uses this tiny sphere, affectionately known as a beetle treadmill, to study how the insects behave and interact with ants and other stimuli in real time. It was given to Parker by his colleague Michael Dickinson, the Esther M. and Abe M. Zarem Professor of Bioengineering and Aeronautics, who wrote the names of Parker, Parker’s wife, Heidi, and their oldest two children, Jonah and Eden, on the tiny white ball, which is about 1 centimeter in diameter. “The beetle walks along on this air-supported spherical treadmill,” Parker says. “You can prod it with an ant or another stimulus to see if it deploys its chemical defenses. The names on the ball serve as landmarks so we can calculate its path and trajectory. This ball is older than my youngest son Oscar; he has his own.”

Through his role as director of the CES, Parker is able to offer seed funding to a wide variety of research projects across the Institute. “The center has managed to start nascent projects in labs that may not previously have had the opportunity to do something with an evolutionary dimension to it,” he says.

Beetles encased in amber
Parker keeps this 99-million-year-old amber deposit on the shelf above his desk. Inside are some of the first species of rove beetles to evolve on Earth, found in the same amber that encases the earliest-known ants. “This encapsulates a very important time in insect evolution, just as ants and other social insects were starting to appear,” Parker points out. “It embodies an ecosystem before ants rose to ecological dominance.”

The design of Parker’s office in Caltech’s Mabel and Arnold Beckman Laboratories of Behavioral Biology is appropriately insect themed: The hexagonal shelving and floor tiles are inspired by insects’ compound eyes, and the carpet pattern is reminiscent of an insect’s wings. Framed insect specimens sit around his desk, which also contains thousands of tiny nonliving specimens housed in custom glass-encased drawers. Glass walls in his office and lab are adorned with enlarged versions of his own insect line drawings.

Beetle line drawing
Parker himself sketched this line drawing (at left) of a rove beetle based on a confocal image of the insect. The image was made by placing a specimen sample under a microscope and shining a laser on it, thereby illuminating its autofluorescent exoskeleton. Autofluorescence is naturally emitted light from cells and tissues. Many similar drawings of beetles and ants made by Parker decorate his lab and office.

Despite working in such a buggy sanctum, Parker enjoys going outside to hunt for new colonies to study. “I love being in the field,” he says. “I worked in sterile biomedical campuses as a PhD student and postdoc, but I grew up rooting around in the dirt. Bringing those two ways of looking at insects together was always something I wanted to do.”

The Guests of Japanese Ants (2013)
This book, which documents every species of organism in Japan that lives inside a colony, was co-written by entomologist Munetoshi Maruyama, a friend of Parker’s. Japan, Parker says, is fertile ground for studying insects due, in part, to the humid climate and mountainous terrain. The field of entomology has also attained an uncommon level of mainstream attention in the country. “The best entomology in the world happens in Japan, and they have an appreciation for insects that is unique,” he says. “This book would never have any market over here, but this is a popular book in Japan. Each one of the authors frequently appears on TV shows. They’re almost like celebrities.”