6 colonies of Myrmica sabuleti ants were used to study the effects of exposure to the electromagnetic field by comparing their behavior before (control) and during/after exposure. These ants had been used in a previous study by the authors (Cammaerts et al. 2012) and had already been exposed to electromagnetic fields there. To ensure their suitability for the present study, their behavior was compared with ants never experimentally exposed to electromagnetic fields prior to exposure. Only slight differences were found and the colonies were deemed adequate. The exposure consisted of 3 periods of 60 h (12 hours prior to and 2 days during each experiments on pheromone response) and one period of 18 h (12 hours prior to and 6 hours during the test on food collection) with a delay of 3 days between each period. A pheromone is a chemical factor for information transfer between members of the same species.
cognitive/behavioral endpoints: response to pheromone trail (accuracy of following an artificial pheromone trail on a piece of paper), response to area-marking pheromone (count of ants entering and remaining in area scented with that pheromone on a piece of paper), response to alarm pheromone (ant orientation toward the pheromone source, linear and angular speed of ants near the stimulus), social food collection (count of ants at food side, ability to return to nest and recruit helpers)
The responses to the pheromone trail, area-marking pheromone and alarm pheromone as well as the ability for social food collection were significantly deteriorated in exposed ants compared to before the exposure. Exposed ants followed marked trails for only short distances, did not recognize marked areas, no longer orientated themselves to a source of alarm pheromone and became unable to return to their nest during food collection and recruit helpers. The authors conclude that exposure to a 900 MHzelectromagnetic field might impair pheromone response and social food collection behavior in ants.