DOI: 10.5061/dryad.0p2ngf2c8
title: Static allometries of caste-associated traits vary with genotype but not environment in the clonal raider ant

description: Polyphenic traits in animals often exhibit nonlinear scaling with body
 size. Static allometries (i.e., scaling relationships) themselves can
 exhibit plasticity, such that individuals of the same size and genotype
 differ in body proportions across different environments. In ants, both
 the larval environment and genotype regulate the expression of
 caste-associated traits, including body size and the number of ovarioles.
 However, it remains untested whether environmental variables independently
 regulate caste-associated traits or if they covary due to coupled
 developmental mechanisms. If caste traits are regulated independently,
 developmental plasticity should affect both trait expression and the
 scaling relationships between traits. Using the clonal raider
 ant, Ooceraea biroi, we tested this by manipulating the rearing
 environment of genetically identical larvae. We found that caregiver
 genotype, temperature, and food quantity influenced caste morphology
 strictly in tandem with body size, producing similar static allometries
 across rearing conditions (i.e., no allometric plasticity was detected).
 In contrast, clonal genotypes differed in average body size and their
 static allometries. Thus, size-matched individuals of the same genotype
 from different rearing environments exhibited no differences in mean caste
 trait expression, while those of different genotypes did. This absence of
 plasticity in the static allometries of different caste traits suggests
 that they are developmentally coupled due to systemic regulatory factors.
 Our findings contrast with reports of allometric plasticity in other
 insects, suggesting that ant caste traits are exceptionally interconnected
 and therefore constrained in their independent responses to environmental
 variation. We discuss how these results inform contemporary hypotheses for
 ant caste development and evolution.
description: # Static allometries of caste-associated traits vary with genotype but not
 environment in the clonal raider ant Dataset DOI:
 [10.5061/dryad.0p2ngf2c8](10.5061/dryad.0p2ngf2c8) ## Description of the
 data and file structure We use the clonal raider ant *Ooceraea biroi* to
 investigate whether the developmental plasticity of caste-associated
 traits is strictly tied to plasticity in body size, or whether the static
 allometries of these traits themselves can shift. Additionally, we test
 whether static allometry differs among three closely related clonal
 genotypes—A, B, and M. **Experiment 1:** To assess environmental effects
 on intercaste development and trait allometry, we established four
 experimental conditions. Ten colonies with line B caregivers were
 maintained at 28°C and fed every 48 hours with 16 frozen *Solenopsis
 invicta* pupae and/or larvae (i.e., well-fed). Ten colonies with line A
 caregivers were also well-fed at 28°C, while another ten were well-fed but
 kept at 23°C. A fourth set of ten colonies with line A caregivers was
 maintained at 28°C but subjected to a restricted feeding regime (i.e., fed
 every 96 hours with only eight *S. invicta* pupae and/or larvae). These
 four conditions varied by caregiver genotype, temperature, or feeding
 frequency, enabling us to test the influence of each environmental factor
 on the likelihood of intercaste development, body size, and the allometric
 relationship between body size and caste morphology. **Experiment 2:** To
 evaluate differences in average body size among clonal lines A, B, and M,
 we used a previously published dataset (Jud et al., 2022, *Proceedings of
 the Royal Society B*) that measured adult body length under standardized
 experimental conditions. To estimate trait-to-body-size allometries for
 the three clonal genotypes, we assessed body size, ovariole number, and
 eye development in 100 ants from each of three stock colonies representing
 line A (C16), line B (STC14), and line M (BG14). For each colony, 40 ants
 were haphazardly collected, and the ten largest individuals (based on
 qualitative assessment) were sampled. This procedure was repeated ten
 times to obtain 100 ants per stock colony. ### Files and variables
 **DatasetS1.xlsx (separate file).** Test of plasticity in the static
 allometry of caste traits. Sheet 1 contains body size measurements and
 scores for ovariole and vestigial eye morphology for sampled individuals
 of clonal line B reared across various environmental backgrounds, which
 varied in caregiver genotype, temperature, and food availability. Sheet 2
 includes raw body size measurements of individual body segments (head,
 thorax, petiole, gaster) for all ants. Sheet 3 includes additional data on
 colony-level traits, such as the number of days it took for &gt;50% of
 larvae in the colony to become prepupae, the number of callows eclosed per
 colony, and intercaste proportions. Caste score 0 = less than 4
 ovarioles; Caste score 1 = 4 or more ovarioles; Eyes column: 0 = absent; 1
 = present. Bodysize = length (mm) of head, thorax, and first tergum from
 dorsal view. **DatasetS2.xlsx (separate file).** Test of genotypic effects
 on body size. Set of previously published data (Jud et al., 2022), which
 includes the measured body lengths of focal individuals of three different
 clonal genotypes (A, B, and M) reared in identical conditions. Line_W =
 genotype of caregiving workers; Line_L = genotype of larvae; bodylength =
 distance from the most anterior part of the head to the posterior end of
 the gaster in dorsal view. **DatasetS3.xlsx (separate file).** Test of
 genotypic effects on the static allometry of caste traits. Dataset for
 body size measurements and scores for ovariole and vestigial eye
 morphology for sampled individuals from three different clonal genotypes
 (A, B, and M). Ovarioles score 0 = less than 4 ovarioles; Ovarioles score
 1 = 4 or more ovarioles. Bodysize = length (mm) of head, thorax, and first
 tergum from dorsal view. **Piekarski_PNAS.R: R code for statistical
 analyses (separate file).** R file, outlining statistical tests employed
 in this study (Piekarski2025_PNAS.R). This R code contains all statistical
 analyses referenced in the main text, as well as power analyses.
 **CSV_file_S1.csv (separate file).** Input file for statistical analyses
 related to the experiment testing for allometric plasticity. This metadata
 file, for use in R, contains each sample’s colony ID, body size index,
 ovariole score, eye score, and assigned experimental condition.
 **CSV_file_S2.csv (separate file)**. Input file for statistical analyses
 related to testing for genotypic differences in body size in a controlled
 environment. This dataset is from Jud et al. (2022). Dataset for body size
 measurements. CSV meta file for use in R, containing each sample’s colony
 identification, body length, and assigned experimental condition.
 **CSV_file_S3.csv (separate file)**. Input file for statistical analyses
 related to genotypic differences in static allometry. This metadata file,
 formatted for use in R, contains each sample’s genotype, body size index,
 ovariole score, and eye score. ## Code/software R Studio ## Access
 information Other publicly accessible locations of the data: * None Data
 was derived from the following sources: * Dataset S2 is data originally
 published in Jud et al., 2022. Data available from the Dryad Digital
 Repository:
 [https://doi.org/10.5061/dryad.n02v6wx0v](https://doi.org/10.5061/dryad.n02v6wx0v)