Data from: Mate competition and relatedness among males mediate the evolution of lethal fights in bulb mites
Data files
May 22, 2025 version files 30.72 KB
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Data_Main_Analyses.csv
2.53 KB
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Data_Mating.csv
1.77 KB
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MITES_Aggression_Analysis.R
23.86 KB
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README.md
2.56 KB
Abstract
Aggression can enhance direct fitness by aiding the aggressor’s in securing reproductive resources, but it negatively impacts inclusive fitness when directed toward kin. We investigated the trade-off between the indirect fitness costs of aggression among kin and the direct benefits of increased success in mate competition using the bulb mite Rhizoglyphus echinopus, a male dimorphic species in which male fighters kill rivals with their modified third legs, while unmodified male scramblers seek unguarded females to mate. Our experiments showed that fighter aggression was never directed toward females, suggesting that fighter aggression evolved as a tactic to monopolize mates. Fighters grab other males before killing them, and grabbing behavior increased in the presence of a female, regardless of the presence of kin. Scrambler mortality increased with fighters’ grabbing activity, but whereas the presence of mate competition increased lethal aggression, kinship decreased it, as higher mortality was observed among non-kin. These findings suggest that aggressive behavior intensifies under mate competition, but the decision to escalate aggression to lethal levels is influenced by kinship. In conclusion, this study provides insight into the trade-offs underlying kin-discriminatory aggression and direct benefits.
Description of data and files
MITES Aggression Analysis.R
This script conducts all multi-model analyses and data visualizations included in the manuscript.
Data_Main_Analyses.csv
This dataset includes three explanatory variables — relatedness, female presence, and fighter presence — and three response variables — number of kills, number of grabs by fighters, and number of grabs between scramblers.
Description of columns (variables):
- Relatedness: Relatedness between the focal fighter and scramblers ("Related" = full-siblings; "Unrelated" = non-siblings).
- Female: Presence of a female ("Present" or "Absent"); the female was unrelated to both the fighter and the scramblers.
- Fighter: Presence of a focal fighter ("Absent" = fighter-absent control groups).
- Fighter_family: Family ID of the focal fighters. Initially planned for use as a random effect, but it was not included in the final model analyses for the response variables below, as models without this random effect were more parsimonious. (However, it was used as a random effect in the mating-status analysis; see below in 3. Data_Mating.csv.)
- Killing: Number of dead scramblers per group (maximum = 4, as each group included four scramblers).
- Grab: Number of observed grabbing behaviors by the focal fighter (defined as prolonged handling of a scrambler).
- Wrestling: Number of grabbing interactions observed between scramblers. Recorded only in female-present treatments, as scrambler interactions were otherwise brief and lacked typical fight-like behavior when no female was present.
Data_Mating.csv
This dataset was used specifically to analyze the killing rate depending on the fighters' mating status. Only replicates where fighter mating was observed are included.
Description of columns (variables):
- Relatedness: Same as above.
- Female: Same as above.
- Fighter_ID: Family ID of the focal fighters. Included as a random effect, as "Before" and "After" observations are paired within each fighter family.
- Mating: Mating status of the fighter ("Before" or "After" mating).
- Killing: Number of dead scramblers in the group for the given duration.
- Duration: Number of days over which deaths occurred, before and after mating. (Duration varied because mating occurred on different days across replicates.)
- Killing_rates: Killing (number of scrambler deaths) divided by Duration (number of days). This was calculated to graphically represent the combined effects of mating status and duration, especially given the small sample size.