Genetically engineered ants show smell’s role in social interaction

NEW YORK, Aug. 15– A new study by U.S. researchers finds ants
engineered to lack a gene that enables their “sense of smell” will lose the
abilities to communicate, forage or compete to be a queen in their colony.

Without the “sense of smell,” female ants wander off on their own, bring no
food back to the nest, and fail to mate. These mutant insects live lives
seemingly separate from their social fellows, said the study.The study,
published in the journal Cell last week, was led by researchers from New
York University (NYU), Arizona State University, the University of
Pennsylvania, and Vanderbilt University.”We found that a species of ant may
be the first model to enable in-depth functional analysis of genes that
regulate social interaction in a complex society,” said corresponding study
author Danny Reinberg at NYU, as well as an investigator for the Howard
Hughes Medical Institute.

The research was based on the fact that ants communicate through
pheromones, secreted chemicals that trigger responses.Past studies had
shown that both the right odorant receptor protein and a shared, common
partner protein called Orco must be present for any pheromone to be
processed in an ant’s brain.The current team successfully engineered the
genetic loss of Orco protein, which made ants unable to perform some, if
not all, pheromone-based social interactions.Specifically, the mutant ants
spent much of their time wandering out of the nest. They failed to interact
with other members of the colony, and were unable to forage.Furthermore,
mutant females are unable to go on to produce progeny, which is essential
for colony survival.

The current research focused on the Indian jumping ant, Harpegnathos
saltator, which is unlike many other ant species, in which the queen is the
only female that can lay eggs. In the nest of Harpegnathos saltator, any
female adult worker can be converted into a “pseudo-queen” after the
removal of the queen.This is because the queen secretes a pheromone that
suppresses workers’ ability to mate. If the queen is removed, the most
aggressive females can lay eggs after winning a series of antenna
duels.Without Orco gene, the females cannot process pheromones, which makes
them much less likely to engage in dueling, the study reported.-XINHUA