Winning the Ig Nobel Prize for Research on "Sex-Role-Reversed Insects" - New Discoveries from Simple Research

Associate Professor Yoshitaka Kamimura, Faculty of Business and Commerce

2018/10/18

Keio University is home to many leading researchers in a wide range of fields. One of them, Associate Professor Yoshitaka Kamimura of the Faculty of Business and Commerce, who teaches biology and other subjects at Hiyoshi Campus, was a co-recipient of the Ig Nobel Prize last year, an award given for unique scientific research. "New discoveries are born from simple research," says Associate Professor Kamimura.

The award was for research on an insect called *Torikae-chatate* that lives in Brazilian caves. Associate Professor Kamimura has been participating in this research since 2012 at the invitation of Associate Professor Kazunori Yoshizawa of Hokkaido University. While in most insects the male inserts his reproductive organ into the female's body to deliver sperm, they discovered that with *Torikae-chatate*, the female inserts her reproductive organ into the male's body to receive sperm and nutritional substances.

"*Torikae-chatate* is a small insect, about 3 mm in length, that inhabits caves in Brazil. I visited the site in 2016, and after searching with only the light of my headlamp, I came face-to-face with the real thing. The caves where they live are dry environments with scarce food. They depend on things like bat and rat droppings for survival. The males probably provide a portion of the nutrients they've gathered to the females as seminal substances. I suspect that in order to obtain this gift, the females became more proactive in mating, leading to the phenomenon where the shapes of the male and female reproductive organs were swapped."

Insects, which boast the greatest diversity in the biological world, have about 30,000 species reported in Japan alone, and yet there are still many undiscovered insects. "Even among insects that have many similar-looking species, you can often tell them apart by looking at the shape of their reproductive organs. This is because the shape of these organs evolves quickly. Why does it evolve so fast? That's the mystery I'm pursuing," says Associate Professor Kamimura, who says he has loved living things since he was a child, from the fish swimming in a nearby river to the insects he found in his garden. He became interested in the parenting behavior of earwigs, and from there, he says he got "hooked" on researching the strange shapes of their reproductive organs. "I still often collect insects in nearby places like the Tama River. Even the shapes of familiar insects hold many unsolved mysteries."

In his seminar-style classes at Hiyoshi Campus, first- and second-year students from the Faculty of Business and Commerce read Ig Nobel Prize-winning papers written in English, presenting and discussing the research content with each other.

"Reading original English-language papers is a way to access the wellspring of knowledge in the world. It's a high hurdle at first, but the award-winning research is generally 'interesting,' and many of the papers can be read with interest even by non-specialist students. I never thought I would receive the Ig Nobel Prize myself. A sense of humor and finding things interesting are very important, and from there, ideas for one's own graduation research may emerge."

He says what impresses him about Keio students is their wide circle of friends. "For example, in class, when a student voluntarily conducts a survey and shows it to me, an incredible number of their friends have cooperated. It's truly surprising, and I think that good teamwork in a pinch is also a hallmark of Keio."

"There are many things we can understand more deeply about humans by looking at living creatures, including insects, rather than just looking at humans alone. The rapid evolution of the shape of reproductive organs is said to be due to the conflict between males and females. Changes due to conflict also exist in our world. Companies compete in price wars, and students vie for spots in entrance exams... the world is full of conflict. Like insect evolution, this conflict is a major driving force that moves the world, and methods common to biology are proving powerful in analyzing society and the economy," says Associate Professor Kamimura.

"Much of the research I'm involved in doesn't require large equipment, massive manpower, or a lot of funding. It consists of microscopic observation and simple experiments. I'm convinced that in any field, new discoveries are born from simple questions and simple research."

Yoshitaka Kamimura

Graduated from the Faculty of Science, Tokyo Metropolitan University in 1999. Completed the Master's Program in Biological Sciences, Graduate School of Science at the same university in 2001, and withdrew from the Doctoral Programs after earning the required credits in 2003. Received his Ph.D. in Science from the same university in 2004.

After serving as an assistant at the Faculty of Geo-Environmental Science, Rissho University, and an assistant professor at the Faculty of Agriculture, Hokkaido University, he became a full-time lecturer at the Faculty of Business and Commerce, Keio University in 2008, and has been an associate professor there since 2013.

Received the Entomological Society of Japan Award and the Entomological Society of Japan Young Investigator Award in 2012. Co-recipient of the Ig Nobel Prize in Biology in 2017.

Specializes in evolutionary biology and entomology. His publications include "Konchu no kobi wa, ajiwaibukai..." (Iwanami Shoten, 2017).

*Affiliations, titles, etc., are as of the time of the interview.