Submitted by Neil Tsutsui on
Argentine ants (Linepithema humile), infamous invasive pests of California, are tiny brown ants
that most Berkeley students have likely seen in their homes or around campus before. Invasive not just to
California, these ants have invaded every continent (except Ant arctica), dominating the native insect
communities of many habitats due to the intimidating “supercolonies” they form. Comprised of billions (if
not trillions) of ants all showing no aggression towards each other, freely mixing queens and workers
across nests, the supercolony is an impressive social phenomenon, made possible only because all the
ants share the same “colony identity”. The ants all share the same identity because they all share the
same smells: cuticular hydrocarbons on the surface of their exoskeletons. Understanding colony identity
helps us understand the secrets to the success of invasive ants around the world, and is the central focus
of the Tsutsui lab. This project, more specifically, explores a related tangent, following interesting
questions that arose from witnessing Argentine ants seemingly change their colony identity over a short
amount of time in the lab.
To the student who accepts this project, you will help us investigate how ants might “update” their
colony identity when new smells are experimentally added onto their bodies. Under the co-advisement of
three lab members (two grad students, one post-doc) who will conduct the chemical experiments, you will
take charge of the behavioral experiments, pairing ants against each other in fighting arenas, observing if
changes to their colony identity can make them no longer fight enemies from rival supercolonies. While
the results of this work will offer fascinating insights into the social psychology of ants, it also has
implications for the study of invasive biology. If we can understand more clearly how colony identity
changes over time, we can foresee a future where giant invasive supercolonies held together by their
shared identities might fragment and collapse over time, decreasing the harmful impacts their invasion
has had on habitats around the world.
Lab work. Beginning with preliminary tasks and helping us troubleshoot experimental designs, we will
teach you valuable methods of chemical ecology, before having you focus on independent work,
conducting aggression assays, filming behaviors, and analyzing videos.
Independent and enthusiastic. Ideal candidates have genuine enthusiasm for the fascinating social lives
of ants, interested in a scientific understanding of the battles they fight with each other, willing to dive into
their chemical language to understand why aggression occurs. Valuable experiences include credits in
animal behavior courses, and previous research opportunities in animal behavior.