Give a moth a robot car, and it'll use it to cruise the streets for a female, Japanese scientists have discovered. Using a small, two-wheeled robot, a male silkmoth was able to track down the sex pheromone usually given off by a female mate.
The aim of the project wasn't just to help the silkmoth pull. The idea, says the team, is that autonomous robots could be designed to track down environmental spills and leaks through their smell.
The male silkmoth was chosen as driver because of its characteristic mating dance when reacting to the sex pheromone of the female. It really struts its stuff, with a distinctive pattern of straight-line and zigzagged walking, consisting of several turns followed by a loop of more than 360°.
"The simple and robust odour tracking behaviour of the silkmoth allows us to analyse its neural mechanisms from the level of a single neuron to the moth's overall behaviour," says Dr Noriyasu Ando of the University of Tokyo.
"By creating an 'artificial brain' based on the knowledge of the silkmoth's individual neurons and tracking behaviour, we hope to implement it into a mobile robot that will be equal to the insect-controlled robot developed in this study."
The researchers attached the silkmoth to a free-moving polystyrene ball at the front of the robot which was used for overall control. Two fans wafted the pheromone-containing air towards it.
A 1800 millimetre wind tunnel was used, with the pheromone and robot at opposite ends; fourteen silkmoths were used altogether,and all were able to successfully guide the robot towards the source.
Chemical sensors vary in the amount of time they take to respond, so the team looked at the effect of a time delay between the movement of the silkmoth and the response of the motor.
"Most chemical sensors, such as semiconductor sensors, have a slow recovery time and are not able to detect the temporal dynamics of odours as insects do," says Ando.
"Our results will be an important indication for the selection of sensors and models when we apply the insect sensory-motor system to artificial systems."