Morphological measurements of the ant stinging apparatus associated with: Evolutionary simplification and functional shifts of the ant stinger
Data files
Oct 15, 2025 version files 18.47 KB
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README.md
2.40 KB
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stinger_measurements.txt
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Abstract
Morphological evolution reflects a balance between the emergence of novel traits and the reduction or loss of existing traits, and both of these processes shape the diversity of life. Trait simplification, which involves the reduction or loss of structures, is a common phenomenon that provides adaptive advantages in novel ecological contexts. In this study, we examined the evolutionary dynamics and morphological outcomes of the reduction and simplification of the stinging apparatus in ants to elucidate the effect of these changes on broader evolutionary trajectories. Using a phylogenetically informed sampling of 98 ant genera, we explored how stinger morphology evolved in conjunction with behavioral and ecological changes, employing linear morphometrics and phylogenetic comparative methods. Our results revealed that transitions from piercing to nonpiercing stingers were substantially associated with dietary diversification and shifts in foraging strategies, thus reflecting the evolutionary compromises between defense, predation, and ecological specialization. Piercing stingers promoted predatory efficiency and ecological specialization, while nonpiercing stingers imparted behavioral and dietary versatility, such as herbivory and cooperative foraging. These findings highlight that morphological simplification is a key adaptive mechanism in driving ecological transitions and diversification and promoting evolutionary innovation.
Dataset DOI: 10.5061/dryad.kkwh70shf
Description of the data and file structure
This dataset (stinger_measurements.txt) contains measurements of individual muscle areas and linear traits of the ant stinging apparatus, recorded from one side of each specimen using 3D Slicer. All linear and cross-sectional measurements were obtained directly from 3D volume renderings. The dataset includes muscle cross-sectional areas, lengths of stinger components, and head width (HW) as a proxy for body size.
Variables:
- t8domm – Tergo-tergalis orthomedialis of segment VIII;
- t8dpmm – Tergo-tergalis paramedialis of segment VIII;
- t8dolm – Tergo-tergalis ortholateralis of segment VIII;
- t8dcm – Tergo-coxalis (solus);
- t8ccim – Coxo-coxalis interior;
- t9domm – Tergo-tergalis orthomedialis of segment IX;
- t9dcm1 – Tergo-coxalis anterior externalis;
- t9dcm2 – Tergo-coxalis anterior internalis;
- t9dcm3 – Tergo-coxalis lateralis;
- t9dcm4 – Tergo-coxalis medialis;
- t9cam1 – Coxo-apophysealis major anterior;
- t9cam2 – Coxo-apophysealis major posterior;
- t9cam3 – Coxo-apophysealis minor;
- t9ccim – Coxo-coxalis interior;
- gap9 – Stylet length, measured along the venom canal from its origin in the valve chamber to the stylet tip, following either a straight or curved path depending on the canal’s course.
- st_leng – Stinger length, measured as a line extending from the articular process of the sting bulb along the venom canal, from its origin in the valve chamber to the stylet tip.
- HW – Head width, used as a proxy for overall body size.
Notes
- Measurements are in mm² for muscle cross-sectional areas and mm for linear dimensions.
- All measurements were taken on the right-hand side of the stinging apparatus.
- Stinger proportion (not in the table) was calculated separately as stylet length (
st_leng) / stinger base length. - Stinger base length (not in the table) was not measured directly but calculated as the difference between stinger length (
st_leng) and stylet length (gap9). - Muscle group assignments (MG1–MG4) follow anatomical and functional divisions (see manuscript).