Experimental study of brood transport in red wood ants: from individual to group task performance

Preliminary results of the validation of original methods to study the division of labor in ant groups of diff erent sizes during the brood transport to the shelter using the model species Formica aquilonia (Yarrow, 1955) are presented.Task performance depended on group size: when brood:worker ratio was about 4 or greater, the highest proportion (86 %) of successful tests was in groups of 10 and 30 individuals, 58 % in pairs of individuals, and 29 % in single workers.The following behavioral roles of inner-nest workers were identifi ed: transporting the brood to the shelter (17 (14, 25) % of the group), brood care inside the shelter (47 (40; 70) %) and outside the shelter (20 (0; 39) %), and no contact with the brood (9 (3; 13) %).Brood transport was performed mainly (92-100 %) by a small number of highly active carriers (11 (7; 25) % of the group).Task effi ciency (% brood transferred to the shelter) is assumed to be similar in group (59 (50; 78)) and pairwise (70 (45; 100)) tests.Pairwise tests may be used to analyze the eff ects of the behavioral role and experience of workers on their task performance.Social signals (jerking motor displays) may infl uence the decision to transport the brood.In the context of brood care tasks, the proposed methods were quite sensitive to variations in individual and group behavior of ants and eff ective for estimating the role of key individuals and communication in collective decision making.. Formica aquilonia (Yarrow, 1955). : : 4 (86 %) 10 30 , 58 % 29 % . : (17 (14, 25) % ), (47 (40; 70) %) (20 (0; 39) %), (9 (3; 13) %). (92-100 %) (11 (7; 25) % ). , (% ) (59 (50; 78)) (70 (45; 100)) . . ( ). .