DOI: 10.5061/dryad.6j984
title: Data from: Context-dependent defences in turtle ants: resource defensibility and threat level induce dynamic shifts in soldier deployment

description: 1. Induced defences involve the dynamic deployment of limited and
 specialized defensive resources across multiple locations, to maximize
 organismal defensive function and fitness. They have been studied
 intensively in plants and solitary animals, but the induced defences of
 complex animal societies are poorly understood by comparison, despite the
 coordinated defensive actions of these taxa. 2. Here, we ask whether the
 level of environmental danger induces shifts in the deployment of limited
 and morphologically specialized soldiers across multiple nests in colonies
 of the turtle ant Cephalotes rohweri. Specifically, we test whether less
 defensible nests induce greater soldier deployment, and whether elevated
 enemy threat induced further increases in deployment, or reduced
 deployment consistent with a risk-limiting strategy. 3. We used
 colony-collection data to provide natural ecological context to our
 experiments, a field experiment to address how nest-entrance defensibility
 and soldier number impact defensive performance, and laboratory
 experiments to test whether differences in nest defensibility and threat
 level induce dynamic shifts in soldier deployment to new nests. 4. Less
 defensible nests were lost rapidly in our field experiment, irrespective
 of soldier number, but soldier deployment significantly increased
 survivorship of more defensible nests. Concordantly, less defensible nests
 induced the deployment of more soldiers per nest under low threat in
 laboratory experiments. Nevertheless, high-threat conditions revealed a
 risk-limiting soldier deployment strategy: with more danger, the number of
 soldiers per nest was significantly reduced in less defensible nests, as
 was the overall number of new soldier-defended nests. Total deployment to
 new nests was also consistently lower under high threat, dropping from 40%
 to 30% across colonies. 5. Induced soldier-based defences in turtle ants
 are therefore context-dependent, and dynamically scaled back at multiple
 levels when the environment is more dangerous. This dynamic, risk-limiting
 strategy is in strong contrast to stable patterns of soldier production in
 ants, and to typical task-allocation dynamics in members of the worker
 caste. Moreover, these findings establish that the evolution of
 specialized defensive agents can be coupled with sophisticated and
 inducible deployment strategies in complex social taxa, as we see for
 organisms at other levels of biological complexity.
description: Nest Collection Data for
 Cephalotes rohweriData for nests of
 Cephalotes rohweri colonies collected in Tucson Mountain Park, Tucson AZ.
 Data include colony identity, nest identity, the number of workers and
 soldiers in each nest, and the area of each nest
 entrance.Cephalotes_rohweri_collection_data.csvNest Survival Experimental Data for Cephalotes rohweriData for the survival of experimental nests populated with Cephalotes rohweri ants and transplanted onto experimental trees. Data include the identity of each experimental tree, the entrance size of the experimental nest, how the nest was populated with ants, and the week the nest died within the 12-week experiment. Entrance size is coded as either B (big; 13 mm²) or S (small; 3 mm²). Nest population codes include entrance size (B or S) prefix, followed by the number of soldiers in the nest (0 for nests with no soldiers and 30 workers; 1 for nests with 1 soldier and 29 workers; 6 for nests with 6 soldiers and 24 workers). The week of nest death is coded as week number, and a – (dash) symbol is used for nests that remained alive at the end of the 12-week experiment.Cephalotes_rohweri_field_expt.csvDeployment Data from Lab Experiments with Cephalotes rohweriData for the deployment of ants and brood to new cavities that differ in entrance size and threat environment in laboratory experiments with Cephalotes rohweri ants. Data include the experimental colony, the threat environment, the position of each nest (acting as a nest identifier) within a 16-box experimental setup, entrance size, the treatment phase, and the worker, soldier, and brood populations of the nests. Treatment was either with no introduced ant threat (no_threat) or an introduced ant threat present (threat). Position of nest within each experimental setup was denoted by the number of the box within the 4x4 16-box experimental setup, with numbering running from left to right and top to bottom. Entrance size is coded as either a small entrance of an original nest (o_s; 3.0 mm²), a new nest with a small entrance (s; 3.0 mm²), or a new nest with a large entrance (l; 13 mm²). Treatment phase is either the initial setup phase (1_s) with a standardized number of original nests, or the phase after the introduction of new empty nesting cavities (2_a). Ant and brood population counts were either as numbers, or simply presence/absence (y/n) in the setup phase.Cephalotes_rohweri_lab_expt.csv