Load-size selection by recruited Acromyrmex lundi workers depended on the information about food quality transferred by a single recruiter ant. Workers that found a piece of Parafilm after being recruited to a drop of 10% (w/w) sugar solution cut smaller fragments than workers recruited to a more diluted solution (1% w/w). The proportion of recruited workers that were engaged in trail-laying behaviour when carrying the load back to the nest was higher for those recruited to 10% than for those recruited to 1%. Since recruited workers in both conditions found the same material at the food source and they had no contact with the sugar solution, their responses did not depend on individual food evaluation, suggesting that the initially recruited ants relied on the decisions made by the first successful recruiter worker. The velocity of recruited ants also depended on the information about food quality transferred by the recruiter ant. Ants ran faster, irrespective of the load carried, when recruited to the more concentrated solution. For the small range of loads in the present study, velocity was not related to the load carried. Individual mass transport rate to the nest increased with increasing load size. Owing to the small sizes cut, workers recruited to the more concentrated sugar solution were less efficient as individual carriers, despite their higher velocity, than workers recruited to the more diluted one. Carrying performance, therefore, appears to be an inadequate parameter to analyse individual foraging efficiency. The results suggest that the decision to transfer information about the quality of the encountered food motivates a worker to return sooner to the nest, displaying recruiting behaviour, than with a full load. © 1993 The Association for the Study of Animal Behaviour. All rights reserved.
