Body size predicts ant worker longevity: A hierarchical analysis of field and laboratory survival across phylogenetic lineages

Lifespan is a key life history trait that shapes ecological strategies and colony fitness in social insects, yet its drivers remain unclear. We evaluated whether intrinsic traits—especially worker body size, a principal pace-of-life axis, and phylogeny—predict survival across 18 ant species from five subfamilies monitored in the field and in captivity. Mark–recapture data analysed with hierarchical models accounting for imperfect detection showed that larger workers lived longer in both environments, highlighting intrinsic physiological properties as the strongest determinant of longevity. Worker lifespans ranged from 23–394 days, and field and lab survival were positively correlated. Body mass scaled negatively with colony size: small colonies invested in large, long-lived workers, whereas large colonies relied on smaller, short-lived workers. In captivity, survival was modestly higher for some clades and comparable for others, indicating mixed lab–field differences consistent with haz..., Data collection We conducted our study at the La Trobe Wildlife Sanctuary, a 28-hectare reserve on La Trobe University’s Melbourne campus in southeastern Australia (Fig. S1a). The sanctuary has a mesic, temperate climate, with mean annual minimum and maximum temperatures of 9.7 °C and 20.2 °C, respectively (Bureau of Meteorology, 1973–2017), and average rainfall of ~656 mm. During sampling, near-ground temperatures ranged from 5 °C to 40.5 °C. The site includes revegetated and remnant river red gum (Eucalyptus camaldulensis⁶²) woodland. Daily temperature and precipitation data were obtained from the nearby Bundoora weather station (BOM #086351, 2024). Ants typically inhabited low-productivity, sparsely vegetated areas with open ground, under large rocks or dead red gums. We sampled ants across microhabitats and nests, recording activity from 8 am to 7 pm throughout the study. Field study design Nest sampling We sampled 18 species from 5 subfamilies and 10 genera (Table S1), covering 39 ..., # Body size predicts ant worker longevity: A hierarchical analysis of field and laboratory survival across phylogenetic lineages ## Directory structure (root = `DATA/`) ``` DATA.zip/ exports/ cohort_effects/ TableA_cohortsig_by_species.csv TableA_sigma.csv TableB_ICC_by_species.csv figures/ source/ # figure-source CSVs (.csv), listed below models/ antsSBB.txt antsSBB_fixed.txt antsSPECIES18.txt .RData dic_comparison.csv Field_ants_final_3.csv Final_Markdown_LS_Riskas.html JUSTMASS_cohort_nodes.rds Lab_ants_final_3.csv mr_phylo.tre nest_locations.xlsx README.txt # this file sessionInfo.txt species_averages.csv species_posterior_draws.csv ``` ## File inventory (exact names) `Field_ants_final_3.csv` — Daily field encounter/survival data with covariates (see dictionary). `Lab_ants_final_3.csv` — Individual-level laboratory survival (time-to-event) with covariates (see dictionary)....,