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New role for majors in Atta leafcutter ants
journal contribution
posted on 2023-06-07, 22:47 authored by Sophie E F Evison, Francis Ratnieks1. Atta (Hymenoptera: Formicidae) leafcutter ants display the most polymorphic worker caste system in ants, with different sizes specialising in different tasks. The largest workers (majors) have large, powerful mandibles and are mainly associated with colony defence. 2. Majors were observed cutting fallen fruit and this phenomenon was investigated in the field by placing mango fruit near natural Atta laevigata and Atta sexdens colonies in São Paulo State, Brazil. 3. Ants cutting the fruit were significantly heavier (mean = 49.1 mg, SD = 11.1 mg, n= 90) than the ants carrying the fruit back to the nest (mean = 20.9 mg, SD = 9.2 mg, n= 90). 4. Fruit pieces cut by majors were small (mean = 15.9 mg), approximately half the weight of leaf pieces (mean = 28.5 mg) cut and carried by media foragers. It is hypothesised that it is more difficult to cut large pieces from three-dimensional objects, like fruit, compared to two-dimensional objects, like leaves, and that majors, with their longer mandibles, can cut fruit into larger pieces than medias. 5. The study shows both a new role for Atta majors in foraging and a new example of task partitioning in the organisation of foraging.
History
Publication status
- Published
Journal
Ecological EntomologyISSN
0307-6946External DOI
Issue
5Volume
32Page range
451-454Pages
4.0Department affiliated with
- Evolution, Behaviour and Environment Publications
Full text available
- No
Peer reviewed?
- Yes