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Data for: Multiple behavioral mechanisms shape development in a highly social cichlid fish

Cite this dataset

Harmon, Isabela et al. (2024). Data for: Multiple behavioral mechanisms shape development in a highly social cichlid fish [Dataset]. Dryad. https://doi.org/10.5061/dryad.s4mw6m9bh

Abstract

Early-life social experiences shape adult phenotype, yet the underlying behavioral mechanisms remain poorly understood. We manipulated early-life social experience in the highly social African cichlid fish Astatotilapia burtoni to investigate the effects on behavior and stress axis function in juveniles. Juveniles experienced different numbers of social partners in stable pairs (1 partner), stable groups (6 fish; 5 partners), and socialized pairs (a novel fish was exchanged every 5 days; 5 partners). Treatments also differed in group size (groups vs. pairs) and stability (stable vs. socialized). We then measured individual behavior and water-borne cortisol to identify effects of early-life experience. We found treatment differences in behavior across all assays: open field exploration, social cue investigation, dominant behavior, and subordinate behavior. Treatment did not affect cortisol. Principal components (PC) analysis revealed robust co-variation of behavior across contexts, including with cortisol, to form behavioral syndromes sensitive to early-life social experience. PC1 (25.1 %) differed by social partner number: juveniles with more partners (groups and socialized pairs) were more exploratory during the social cue investigation, spent less time in the territory, and were more interactive as dominants. PC5 (8.5 %) differed by stability: socialized pairs were more dominant, spent less time in and around the territory, were more socially investigative, and had lower cortisol than stable groups or pairs. Observations of the home tanks provided insights into the social experiences that may underlie these effects. These results contribute to our understanding of how early-life social experiences are accrued and exert strong, lasting effects on phenotype.

README: Data for: Multiple behavioral mechanisms shape development in a highly social cichlid fish

“Initial_Fry_StandardLength.csv” contains the standard length (mm) of juvenile Astatotilapia burtoni fish at approximately 7-days post-fertilization from each brood. Juvenile fish at this early developmental stage can be called “fry.” The experimental fish were selected from these individuals (data for these experimental fish is included below in “HomeTank_Behavior.csv” and “BehAssay_Hormone_Data.csv”).

Descriptions of variables:

  • BroodNumber:  Arbitrary number assigned to broods of fish collected on the same day at the start of the experiment. A. burtoni (common name Burton’s Mouthbrooder) is a mouthbrooding fish, meaning mothers will keep the developing eggs in her buccal cavity (mouth) until they are fully developed. A brood is the group of juveniles that come out one mother’s mouth.
  • StandardLength: The standard length of the juvenile fish, measured from the tip of the jaw to the caudal peduncle (the point where the body meets the tail). Measured in mm using ImageJ.

“HomeTank_Behavior.csv” contains behavior scored in the home tanks (also called the rearing environments), including the total number of approaches, displacements, carouseling, fighting, lateral displays, entering the territory, and exiting the territory.

Descriptions of variables:

  • HomeTank: A unique identifier for each tank containing experimental fish during the rearing phase of the experiment.
  • TestDate: The date that behavior data were recorded. Behavior was recorded two times for each tank.
  • Treatment: This experiment tested the effects of early life experience on the social behavior and cortisol levels (a hormone involved in the stress response) of juvenile fish. The three treatments are: stable groups (“StableGroup”), stable pairs (“StablePair”), and socialized pairs (“SocializedPair”). In the stable groups, juveniles remained together for 5 weeks in groups of 6 fish. In the stable pairs, juveniles remained together for 5 weeks in groups of 2 fish. In the socialized pairs, juveniles were always in a group size of 2 fish, but every five days, one fish was removed from the tank and a novel fish was added. By the end of the 5 week rearing period, fish in the stable groups and socialized pairs had each experienced 5 unique social partners. Fish in the stable pairs only experienced 1 unique social partner.
  • TotalApproaches: For all of the fish in the social group, the total number of social approaches occurring during a 10 min observation period. An approach is defined as one fish swimming directly towards any part of another fish’s body, within 3 body lengths.
  • TotalDisplacements: For all of the fish in the social group, the total number of displacements occurring during a 10 min observation period. In response to an approach (see above), if the approached fish moves away from the approacher in any direction, that is scored as a displacement.
  • Carousel_Fight: For all of the fish in the social group, the total number of fights or instances of carouseling occurring during a 10 min observation period. A fight includes fish nipping or other physical contact with each other. Carouseling involves fish rapidly circling one another. Both fighting and carouseling may be a part of escalated aggressive behavior.
  • LatDisplay: For all of the fish in the social group, the total number of lateral displays occurring during a 10 min observation period. A lateral display involves fish lining up head to tail. Fins may be raised. The fish may swat each other with their tails or fins. The fish may turn slowly or quickly in a circle. A lateral display may lead to carouseling.
  • TotalEscalatedAggression: A summary metric of other escalated aggressive behavior occurring during the 10 min observation period. This includes fights, carouseling, and lateral displays.
  • IntoTerritory: In every tank, there was a small terracotta pot for a shelter / territory. Into the territory is a count of the total number of times any fish entered the territory (crossed into the pot with more than 50% of its body) during a 10 min observation period.  
  • LeaveTerritory: In every tank, there was a small terracotta pot for a shelter / territory. Leaving the territory is a count of the total number of times any fish exited the territory (crossed out of the pot with more than 50% of its body) during a 10 min observation period.

“BehAssay_Hormone_Data.csv” contains behavior recorded in the individual behavior assays: an open field exploration (OF), social cue investigation (SC), dominance behavior (Dom), and subordinate behavior (Sub) assays. In the OF and SC, the number of times entering each zone of the tank, and the time spent in each zone of the tank, was scored using the free software BORIS. In the Dom and Sub assays, the number of approaches, displacements, approaches received, and submissions were scored. The R package compete was used to calculate the directional consistency index (DCI) for the Dom and Sub assays, for patterns of approaching and displacing. This package was also used to calculate the dominance index David’s Score. The code was adjusted so that the calculation took both approaches and displacements into account when calculating dominance. Water-borne cortisol was collected after the behavior assays and quantified using enzyme-linked immunosorbent assays.

Descriptions of variables:

  • HomeTank: A unique identifier for each tank containing experimental fish during the rearing phase of the experiment.
  • FishID: Unique identifier for each fish undergoing individual behavioral testing.
  • HormoneID: Unique identifier for each fish’s hormone sample.
  • Treatment: This experiment tested the effects of early life experience on the social behavior and cortisol levels (a hormone involved in the stress response) of juvenile fish. The three treatments are: stable groups (“StableGroup”), stable pairs (“StablePair”), and socialized pairs (“SocializedPair”). In the stable groups, juveniles remained together for 5 weeks in groups of 6 fish. In the stable pairs, juveniles remained together for 5 weeks in groups of 2 fish. In the socialized pairs, juveniles were always in a group size of 2 fish, but every five days, one fish was removed from the tank and a novel fish was added. By the end of the 5 week rearing period, fish in the stable groups and socialized pairs had each experienced 5 unique social partners. Fish in the stable pairs only experienced 1 unique social partner.
  • NumberSocialPartners: The number of social partners experienced by each individual. In general, stable pair fish experienced 1 social partner, while socialized paired fish and stable group fish experienced 5 social partners. If a fish died in the course of the experiment, it may have been replaced in the home tanks, thus exposing experimental fish to an additional social partner.
  • TestTank: Unique identifier for each experimental test tank.
  • BehaviorTestDay:  The individual behavior tests took place over 2 days: Day1 and Day2.
  • FocalSL: The standard length of the juvenile fish on the day of the individual behavior assays. Standard length is measured from the tip of the jaw to the caudal peduncle (the point where the body meets the tail). Measured in mm using ImageJ.
  • FocalMass: The mass (g) of the juvenile fish on the day of the individual behavior assays.

Behavior testing involved an open field exploration (OF), social cue investigation (SC), dominance behavior (Dom), and subordinate behavior (Sub) assays. In the OF and SC assays, we scored the number of times the focal fish entered each zone of the tank (territory, close, far, and investigate), and the time the focal fish spent in each zone of the tank, during a 10 min observation period.

  • OF_Close_Duration: Time spent (s) in the close zone during the open field exploration.
  • OF_Close_Frequency: The number of times the focal fish entered the close zone during the open field exploration.
  • OF_Far_Duration: Time spent (s) in the far zone during the open field exploration.
  • OF_Far_Frequency: The number of times the focal fish entered the far zone during the open field exploration.
  • OF_Investigate_Duration: *Time spent (s) in the investigate zone during the open field exploration.
  • OF_Investigate_Frequency: The number of times the focal fish entered the investigate zone during the open field exploration.
  • OF_Territory_Duration: Time spent (s) in the territory zone during the open field exploration.
  • OF_Territory_Frequency: The number of times the focal fish entered the territory zone during the open field exploration.
  • SC_Close_Duration: Time spent (s) in the close zone during the social cue investigation.
  • SC_Close_Frequency: The number of times the focal fish entered the close zone during the social cue investigation.
  • SC_Far_Duration: Time spent (s) in the far zone during the social cue investigation.
  • SC_Far_Frequency: The number of times the focal fish entered the far zone during the social cue investigation.
  • SC_Investigate_Duration: Time spent (s) in the investigate zone during the social cue investigation.
  • SC_Investigate_Frequency: The number of times the focal fish entered the investigate zone during the social cue investigation.
  • SC_Territory_Duration: Time spent (s) in the territory zone during the social cue investigation.
  • SC_Territory_Frequency: The number of times the focal fish entered the territory zone during the social cue investigation.
  • OF_CloseTerr_Frequency: The number of times the focal fish entered the close + territory zones during the open field exploration.
  • OF_FarInvest_Frequency: The number of times the focal fish entered the far + investigate zones during the open field exploration.
  • OF_CloseTerr_Duration: *Time spent (s) in the close + territory zone during the open field exploration.
  • OF_FarInvest_Duration: *Time spent (s) in the far + investigate zones during the open field exploration.
  • SC_CloseTerr_Frequency: The number of times the focal fish entered the close + territory zones during the social cue investigation.
  • SC_FarInvest_Frequency: The number of times the focal fish entered the far + investigate zones during the social cue investigation.
  • SC_CloseTerr_Duration: Time spent (s) in the close + territory zone during the social cue investigation.
  • SC_FarInvest_Duration: Time spent (s) in the far + investigate zone during the social cue investigation.

In the dominance behavior and subordinate behavior assays, the focal fish was paired with a smaller “cue” fish (dominance) or a larger “cue” fish (subordinate).

  • Dom_CueMass: Mass (g) of the cue fish paired with the focal fish in the dominance behavior assay.
  • Dom_CueSL: Standard length (mm) of the cue fish paired with the focal fish in the dominance behavior assay.
  • Dom_cue_app: The number of approaches by the cue fish to the focal fish in the dominance behavior assay in a 10 min observation period.
  • Dom_cue_disp: The number of displacements by the cue fish of the focal fish in the dominance behavior assay in a 10 min observation period.
  • Dom_focal_app: The number of approaches by the focal fish to the cue fish in the dominance behavior assay in a 10 min observation period.
  • Dom_focal_disp: The number of displacements by the focal fish of the cue fish in the dominance behavior assay in a 10 min observation period.
  • Sub_CueMass: Mass (g) of the cue fish paired with the focal fish in the subordinate behavior assay.
  • Sub_CueSL: Standard length (mm) of the cue fish paired with the focal fish in the subordinate behavior assay.
  • Sub_cue_app: The number of approaches by the cue fish to the focal fish in the subordinate behavior assay in a 10 min observation period.
  • Sub_cue_disp: The number of displacements by the cue fish of the focal fish in the subordinate behavior assay in a 10 min observation period.
  • Sub_focal_app: The number of approaches by the focal fish to the cue fish in the subordinate behavior assay in a 10 min observation period.
  • Sub_focal_disp: The number of displacements by the focal fish of the cue fish in the subordinate behavior assay in a 10 min observation period.

Directional consistency index (dci) is a measure of directional symmetry within a social group. A score of 0 indicates no directional asymmetry (i.e., perfect symmetry) in social interactions (approaches or displacements). A score of 1 indicates completely unidirectional (i.e., perfectly asymmetrical) social interactions (approaches or displacements).

  • dom.dci_app: Directional consistency index of approaches in the dominance behavior assay.
  • dom.dci_displ: Directional consistency index of displacements in the dominance behavior assay.
  • dom.dci_app_pvalue: Whether the DCI (based on approaches) of a social group (focal + cue fish) in the dominance behavior assay were significantly more directional than expected by chance (p<0.05).
  • dom.dci_displ_pvalue: Whether the DCI (based on displacements) of a social group (focal + cue fish) in the dominance behavior assay were significantly more directional than expected by chance (p<0.05).
  • sub.dci_app: Directional consistency index of approaches in the subordinate behavior assay.
  • sub.dci_displ: Directional consistency index of displacements in the subordinate behavior assay.           
  • sub.dci_app_pvalue: Whether the DCI (based on approaches) of a social group (focal + cue fish) in the subordinate behavior assay were significantly more directional than expected by chance (p<0.05).
  • sub.dci_displ_pvalue: Whether the DCI (based on displacements) of a social group (focal + cue fish) in the subordinate behavior assay were significantly more directional than expected by chance (p<0.05).

Social status in the dominance behavior assay and subordinate behavior assay was calculated for the focal and cue fish using David’s Score (DS).

  • Dom_Cue_DS.adj.Rank: The social status (“dominant” or “subordinate”) of the cue fish in the dominance behavior assay. Status is based on David’s Score, with the higher David’s Score indicating dominance and the lower David’s Score indicating subordinate.
  • Sub_Cue_DS.adj.Rank: The social status (“dominant” or “subordinate”) of the cue fish in the subordinate behavior assay. Status is based on David’s Score, with the higher David’s Score indicating dominance and the lower David’s Score indicating subordinate.
  • Dom_Focal_DS.adj.Rank: The social status (“dominant” or “subordinate”) of the focal fish in the dominance behavior assay. Status is based on David’s Score, with the higher David’s Score indicating dominance and the lower David’s Score indicating subordinate.
  • Sub_Focal_DS.adj.Rank: The social status (“dominant” or “subordinate”) of the focal fish in the subordinate behavior assay. Status is based on David’s Score, with the higher David’s Score indicating dominance and the lower David’s Score indicating subordinate.
  • Cue_dom.DS.adj: David’s Score for the cue fish in the dominance behavior assay.
  • Cue_sub.DS.adj: David’s Score for the cue fish in the subordinate behavior assay.
  • Focal_dom.DS.adj: David’s Score for the focal fish in the dominance behavior assay.
  • Focal_sub.DS.adj: David’s Score for the focal fish in the dominance behavior assay.
  • Cortisol: Levels of the water-borne hormone cortisol measured in pg/mL/hr/g using enzyme-linked immunosorbent assay (ELISA).

Methods

Juvenile A. burtoni body size was measured as mass (g) and standard length (mm). Length was measured at the very start of the experiment for all juveniles that could be included in the experiment. Length was measured from digital images with a ruler for scale using ImageJ. Individual identification was not feasible at this early developmental stage; therefore, these size data are not connected to behavior, hormone, or later size data. Mass and length were also measured at the end of the experiment, after the individual behavior assays. Behavior was video recorded in the home tanks and the individual behavior assays. In the home tanks, the total number of approaches, displacements, caroseling, fighting, lateral displays, entering the territory, and exiting the territory were scored using BORIS. Individual identification was not feasible in the home tanks. The individual behavior assays consisted of an open field exploration (OF), social cue investigation (SC), dominance behavior (Dom), and subordinate behavior (Sub) assays. In the OF and SC, the number of times entering each zone of the tank, and the time spent in each zone of the tank, was scored using BORIS. In the Dom and Sub assays, the number of approaches, displacements, approaches received, and submissions were scored using Solomon Coder (https://solomon.andraspeter.com/). The R package compete was used to calculate the directional consistency index (DCI) for the Dom and Sub assays, for patterns of approaching and displacing. This package was also used to calculate the dominance index David’s Score. The code was adjusted so that the calculation took both approaches and displacements into account when calculating dominance. Water-borne cortisol was collected after the behavior assays and quantified using enzyme-linked immunosorbent assays.

Curley, J. P. (2016). Compete: Analyzing competitive interaction data: R package version 0.1.

Friard, O., & Gamba, M. (2016). BORIS: a free, versatile open-source event-logging software for video/audio coding and live observations. Methods in Ecology and Evolution, 7(11), 1325–1330.

Schneider, C. A., Rasband, W. S., & Eliceiri, K. W. (2012). NIH Image to ImageJ: 25 years of image analysis. Nature Methods9(7), 671–675. doi:10.1038/nmeth.2089

Usage notes

Excel files

Funding

W.M. Keck Science Department*