The Zoological Society of Japan, Hokkaido Branch, 611th Branch Lecture

We are pleased to announce that the 611th Meeting of the Zoological Society of Japan, Hokkaido Branch, will be held as follows.

The 611th Meeting of the Zoological Society of Japan, Hokkaido Branch

Date: Friday, March 6, 2026, 17:00–18:00
Location: Hokkaido University, Faculty of Science, Building No. 5, 8th Floor, Room 813

Speaker: Dr. Yoshiya Tanaka (Graduate School of Science / Institute for Advanced Research, Nagoya University)

Title: Neural mechanisms generating species-specific courtship behavior

Abstract: Male insects exhibit species-specific courtship behaviors. In the fruit fly Drosophila melanogaster, a model species in behavioral genetics, males vibrate their wings to produce a "courtship song." Meanwhile, males of the congeneric species Drosophila prolongata regurgitate gut contents and present them to females as a "gift." What kind of brain mechanisms generate such species specificity in courtship behavior?
In Drosophila melanogaster, it is known that neural circuits expressing the fruitless (fru) gene are important for shaping courtship behavior. Therefore, aiming to understand the mechanism leading to the evolutionary acquisition of nuptial gift-giving behavior, we visualized the neural cell populations expressing fru in Drosophila prolongata and searched for the neurons involved in this behavior among them. As a result, we discovered that approximately 18 insulin-producing cells in the brain control the gift-giving behavior. In D. prolongata, the expression of fru in insulin-producing cells caused neurites to elongate and connect with courtship command neurons. On the other hand, although insulin-producing cells also exist in the brain of D. melanogaster, they do not express fru; consequently, their neurites were short and did not connect with courtship command neurons. When the connection between insulin-producing cells and courtship command neurons was reproduced in D. melanogaster through genetic manipulation to ectopically express fru, males were observed regurgitating gut contents toward females. These results suggest the possibility that courtship behavior can undergo major evolution through the action of a single gene in just one type of neuron.

Caretaker:
Noriyuki Taji (Hokkaido University, Institute for the Advancement of Higher Education)
toji[a]sci.hokudai.ac.jp
Please change [a] to @.

Ezo squirrel (Provided by Minorukaz Nagahara, Asahikawa Medical University RI Research Facility)