DOI: 10.5061/dryad.8cz8w9gzs
title: Data from: Dietary tryptophan affects group behavior in a social bird

description: The amino acid tryptophan (Trp) is precursor of the neurotransmitter
 serotonin. Trp supplementation or other forms of serotonergic enhancement
 generally promote pro-social behavior, decreasing aggression and also
 feeding in different animals. However, past research has been conducted in
 confined spaces, and there is little work in naturalistic conditions where
 animals move and associate more freely. We gave a Trp-enriched diet to a
 free-flying flock of common waxbills (Estrilda astrild) in semi-natural
 conditions, and monitored group foraging, aggressions during feeding and
 the social network. Contrary to expectations, aggressiveness and feeding
 increased during Trp supplementation. Consistent with the prediction of
 increased social associations, foraging groups became larger and
 individuals joined more foraging groups, but these changes appear driven
 by increased appetite during Trp treatment. Also, the mean strength of
 associations in the social network did not change. Overall, Trp
 supplementation affected group behavior in this free-flying flock, but
 mostly in directions unanticipated based on research conducted in small
 spaces. To harmonize our results with those found in small confined
 spaces, we hypothesise that free-flying birds have energetic requirements
 not experienced in lab-housed individuals, which may impact social
 behaviour and responses to Trp.
description: # Data from 'Dietary tryptophan affects group behavior in a social
 bird' (Saldanha et al. 2024, Behavioral Ecology). Created in March
 2024 by Beatriz C. Saldanha
 ([beatriz.saldanha@cibio.up.pt](mailto:beatriz.saldanha@cibio.up.pt)).
 GENERAL INFORMATION 1. Title: Data from: Dietary tryptophan affects group
 behavior in a social bird 2. Authors: Beatriz C. Saldanha 1,2, Patrícia
 Beltrão 1,2, Ana Cristina R. Gomes 1,2,3, Marta C. Soares 1,2,4, Gonçalo
 C. Cardoso 1,2 & Sandra Trigo 1,2 1CIBIO, Centro de Investigação em
 Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Campus
 de Vairão, Universidade do Porto, 4485-661 Vairão, Portugal 2BIOPOLIS
 Program in Genomics, Biodiversity and Land Planning, CIBIO, Campus de
 Vairão, 4485-661 Vairão, Portugal 3Department of Zoology, Stockholm
 University, Svante Arrhenius väg 18B, Stockholm 10691, Sweden 4MARE -
 Centro de Ciências do Mar e do Ambiente, ARNET -Rede de Investigação
 Aquática, Departamento de Paisagem, Universidade de Évora, Ambiente e
 Ordenamento, Rua Romão Ramalho 59,7000-671 Évora, Portugal 3. Data
 collection: 2021 4. Funding sources: PTDC/BIA-COM/2644/2020 (doi:
 10.54499/PTDC/BIA-COM/2644/2020), DL57/2016/CP1440/CT0019,
 DL57/2016/CP1440/CT0011, FEDER funds under COMPETE 2020 (CEEC
 Individual–2021.01458.CEECIND/CP1668/CT0003, doi:
 10.54499/2021.01458.CEECIND/CP1668/CT0003), FCT CEEC IND5ed (doi:
 10.54499/2022.03732.ceecind/cp1730/ct0009), FCT CEEC
 2022.07867.CEECIND/CP1730/CT0005
 (doi.org/10.54499/2022.07867.CEECIND/CP1730/CT0005), SFRH/BD/129002/2017
 and SFRH/BD/148392/2019 from FCT with European Union funds. 5. Citation
 for this dataset: Saldanha, Beltrão, Gomes, Soares, Cardoso & Trigo
 (2024), Data from: Dietary tryptophan affects group behavior in a social
 bird, Dryad, Dataset ## FILE OVERVIEW 1. Description of datasets Datasets
 for the 10 metrics computed in the research article and used to obtain
 bootstrap distributions in experimental and control treatments. 2. File
 List: File ‘aggression_rate.txt’ Description: Aggression rate at the
 feeders per minute. Data used in Figure 1a. File ‘steepeness.txt’
 Description: Steepness of the dominance hierarchy. Data used in Figure 1b.
 File ‘group_size.txt’ Description: Foraging group size. Data used in
 Figure 2a. File ‘N_groups_day.txt’ Description: Number of foraging groups
 per day. Data used in Figure 2b. File ‘time_groups.txt’ Description: Mean
 time at the feeding area per foraging group (in minutes). Data used in
 Figure 2c. File ‘N_individuals_day.txt’ Description: Number of foraging
 groups an individual was present per day. Data used in Figure 2d. File
 ‘time_individuals.txt’ Description: Mean time an individual spent at the
 feeders per foraging group (in seconds). Data used in Figure 2e. File
 ‘strength_associations.txt’ Description: Strength association values
 between every dyad of individuals. Data used in Figure 3. METHODOLOGICAL
 INFORMATION Data was recorded through a radio-frequency identification
 (RFID) system (Dorset ID, The Netherlands), present at the feeding area of
 the mesocosm, which monitored the attendance of common waxbills by reading
 the passive integrated transponder (PIT) tag, that each and every bird had
 on a leg ring. Aggressive displacements were computed with the function
 available in Beltrão et al. 2021 (doi: 10.1016/j.anbehav.2021.09.011),
 which also provides the code for this work. INFORMATION FOR:
 ‘aggression_rate.txt’ 1. The file has two variables: (1) Treatment and (2)
 aggression_rate (per minute per individual). 2. The column
 "Treatment" has 4 categories: * control_before, tryptophan, and
 control_after, corresponding to the two control treatments and tryptophan
 treatment. * In addition, controls_together is the combined pair of
 control treatments that preceded and followed tryptophan treatment, in
 order to compute the bootstrap distribution that will be used for
 comparison with each treatment. 3. The column “aggression_rate” has
 aggression rates per minute, with each line referring to a different
 individual in a given treatment. INFORMATION FOR: ‘steepness.txt’ 1. The
 file has three variables: (1) Treatment and (2) Winner (3) Loser. No
 respective units since it is a count. 2. The column "Treatment"
 has 4 categories: * control_before, tryptophan, and control_after,
 corresponding to the two control treatments and tryptophan treatment. * In
 addition, controls_together is the combined pair of control treatments
 that preceded and followed tryptophan treatment, in order to compute the
 bootstrap distribution that will be used for comparison with each
 treatment. 3. Each line represents a displacement event at a feeder
 between 2 individuals (i.e., columns "Winner" and
 "Loser"). 4. For these data was used the function
 "estimate_uncertainty_by_repeatability" (from the aniDom
 package), procuding parametric bootstrapped replicates, contrarily to the
 remaining behavioural variables, which are used to compute the
 non-parametric bootstrap distributions. INFORMATION FOR: ‘group_size.txt’
 1. The file has two variables: (1) Treatment and (2) group_size. No
 respective units since it is a count. 2. The column "Treatment"
 has 4 categories: * control_before, tryptophan, and control_after,
 corresponding to the two control treatments and tryptophan treatment. * In
 addition, controls_together is the combined pair of control treatments
 that preceded and followed tryptophan treatment, in order to compute the
 bootstrap distribution that will be used for comparison with each
 treatment. 3. The column “group_size” has the number of individuals in a
 foraging group, with each line referring to a different foraging group in
 a given treatment. INFORMATION FOR: ‘N_groups_day.txt’ 1. The file has two
 variables: (1) Treatment and (2) N_groups_day (per day). 2. The column
 "Treatment" has 4 categories: * control_before, tryptophan, and
 control_after, corresponding to the two control treatments and tryptophan
 treatment. * In addition, controls_together is the combined pair of
 control treatments that preceded and followed tryptophan treatment, in
 order to compute the bootstrap distribution that will be used for
 comparison with each treatment. 3. The column “N_groups_day” has the
 number of foraging groups per day, with each line referring to a different
 day in a given treatment. INFORMATION FOR: ‘time_groups.txt’ 1. The file
 has two variables: (1) Treatment and (2) time_groups (in minutes). 2. The
 column "Treatment" has 4 categories: * control_before,
 tryptophan, and control_after, corresponding to the two control treatments
 and tryptophan treatment. * In addition, controls_together is the combined
 pair of control treatments that preceded and followed tryptophan
 treatment, in order to compute the bootstrap distribution that will be
 used for comparison with each treatment. 3. The column “time_groups” has
 the time (minutes) a foraging group spent at the feeding area, with each
 line referring to a different foraging group in a given treatment.
 INFORMATION FOR: ‘N_individuals_day.txt’ 1. The file has two variables:
 (1) Treatment and (2) N_individual_day (per day). 2. The column
 "Treatment" has 4 categories: * control_before, tryptophan, and
 control_after, corresponding to the two control treatments and tryptophan
 treatment. * In addition, controls_together is the combined pair of
 control treatments that preceded and followed tryptophan treatment, in
 order to compute the bootstrap distribution that will be used for
 comparison with each treatment. 3. The column “N_individuals_day” has the
 mean number of foraging groups in which each individual was present, with
 each line referring to a different day in a given treatment. INFORMATION
 FOR: ‘time_individuals.txt’ 1. The file has two variables: (1) Treatment
 and (2) time_individuals (in seconds). 2. The column "Treatment"
 has 4 categories: * control_before, tryptophan, and control_after,
 corresponding to the two control treatments and tryptophan treatment. * In
 addition, controls_together is the combined pair of control treatments
 that preceded and followed tryptophan treatment, in order to compute the
 bootstrap distribution that will be used for comparison with each
 treatment. 3. The column “time_individuals” has the mean time (seconds) an
 individual spent at the feeders per foraging group, with each line
 referring to a different individual in a given treatment. INFORMATION FOR:
 ‘strength_associations.txt’ 1. The file has two variables: (1) Treatment
 and (2) strength_associations. No respective units since it is a rate. 2.
 The variable "Treatment" has 3 categories: * control_before,
 tryptophan, and control_after, each categorie corresponding to a control
 or tryptophan treatment. 3. The column “strength_associations” has the
 strength of association between 2 individuals, with each line referring to
 a different dyad in a given treatment. 4. Using the data for each
 treatment, we computed 1000 bootstrapped replicates, and for each
 replicate computed the mean strength of association (Figure 3a), the
 network entropy (Figure 3b), and the coefficient of variation of the
 strengths of association (Figure 3c).