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1. Seed dispersal by ants, i.e. myrmecochory, is important in drylands because ants may contribute to overcoming the typical resource limitation imposed on plants in these environments. Dispersal distance and directed dispersal of seeds to nutrient‐enriched ant nests benefit plants by reducing parent or sibling competition and improving growth, survival, and reproduction. 2. This study investigated the role of ants as seed dispersers in the semi‐arid Patagonian steppe. In particular, this study surveyed native and exotic plants potentially dispersed by ants (i.e. those with nutritive tissues attached to seeds that could attract ants), identified seed disperser ants, and compared their effectiveness as dispersers (i.e. number of removed seeds, transport distance, and seed fate). 3. It was found that 9% of plant species could be potentially dispersed by ants, and field experiments were carried out with five of them (three natives and two exotics). Six ant species dispersed seeds, with Dorymyrmex tener being the most effective seed disperser, interacting preferably with an exotic seed. Finally, the types of nutritive tissues of the seeds are important in determining the attractiveness towards different ant foraging groups. 4. This study's results highlight that ant foraging group and seed's nutritive tissues are relevant traits that could help in understanding ant–seed interactions. Furthermore, in the Patagonian steppe, there are effective seed disperser ants that could play an important role in the distribution of native plants, as well as the spread of invasive species, being especially relevant in nutrient‐poor drylands due to the benefits provided by myrmecochory. [ABSTRACT FROM AUTHOR]

Ants are social, and their metabolism should be measured on at least two levels: (i) the individual workers and brood of which the colony is composed and (ii) the colony in its entirety. Whole colony respiration, tempo (size-free running speed in body lengths per second) and whole colony activity were simultaneously measured for 15 species of ants in four subfamilies, and these data are related to average worker and whole-colony weight, activity, percentage brood and percentage fat. Across all 15 species, whole colony respiration rate (μL CO2 h−1) is linearly related to whole colony live weight (log-log slope = 1.0). Colonies composed of large workers respire less than colonies composed of an equal live weight of small workers, and colonies with high tempos respire more than lower tempo colonies of equal weight. The tempos and respiration rates of smaller ants tend to be higher, and a higher tempo exacts a cost in higher respiration independent of the effect of small body size. Individual worker respiration (μL CO2 h−1) scales to worker live weight with an exponent of 0.76. Whole colony specific respiration rate (μL CO2 g−1 h−1) is unrelated to colony live weight. The regressions of respiration rates against colony and worker dry weight, lean weight and metabolic weight have similar slopes to those of live weight but different intercepts. Respiration is not related to worker percentage fat, percentage brood or activity. Ant ecology, tempo, body size, polymorphism and colony size are discussed in relation to respiration. [ABSTRACT FROM AUTHOR]