Data from: Extended and cumulative effects of experimentally induced intergroup conflict in a cooperatively breeding mammal

Morris-Drake, Amy 1 ; Linden, Jennifer1; Kern, Julie2; Radford, Andrew1

Published Jan 05, 2026 on Dryad. https://doi.org/10.5061/dryad.98sf7m0k4

Data files

Jan 05, 2026 version files 124.86 KB

ProcB_datasets_for_dryad.xlsx

118.63 KB
README.md

6.23 KB

Abstract

Conflict between rival groups is rife in nature. Whilst recent work has begun exploring the behavioural consequences of this intergroup conflict, studies have primarily considered just the 1–2 hours immediately after single interactions with rivals or their cues. Using a habituated population of wild dwarf mongooses (Helogale parvula), we conducted week-long manipulations to investigate longer-term impacts of intergroup conflict. Compared to a single presentation of control herbivore faeces, one rival-group faecal presentation (simulating a territorial intrusion) resulted in more within-group grooming the following day, beyond the likely period of conflict-induced stress. Repeated presentations of outsider cues led to further changes in baseline behaviour by the end of the week: compared to control weeks, mongooses spent less time foraging, foraged closer to their groupmates and exhibited more pronounced inter-individual grooming differences, even when there had been no recent simulated intrusion. Moreover, there was more baseline territorial scent-marking and a higher likelihood of group fissioning in intrusion weeks. Consequently, individuals gained less body mass at the end of weeks with repeated simulated intrusions. Our experimental findings provide evidence for longer-term, extended and cumulative effects of an elevated intergroup threat, which may lead to fitness consequences and underpin this powerful selective pressure.

Dataset DOI: 10.5061/dryad.98sf7m0k4

Description of the data and file structure

The experiment had two treatments (control and intrusion), each one-week long, that were conducted on each of the seven habituated dwarf mongoose groups on the Dwarf Mongoose Research Project.

To assess behavioural changes the day after exposure to a single rival-group intrusion and after repeated intrusions, we conducted observations on Days 2 and 6 of each treatment week.

Data from the experiment was used to analyse the extended and cumulative effects of intergroup conflict in dwarf mongooses.

Files and variables

File: ProcB_datasets_for_dryad.xlsx

Description and variables: Below are descriptions of the data that were used in our analyses (provided in the order that they appear in the manuscript).

Day 2 proportion time grooming - the first tab of the Excel document includes data for analysis of the response variable: proportion of time grooming on day 2 (prop_day_gr in Excel spreadsheet). This was calculated by taking the total time that each individual spent grooming (min)/the total time available for grooming (min). Predictor variables in the analysis included: treatment (control, rival), dominance status of the individual (dominant, subordinate), and sex (male, female).

Day 6 proportion time grooming - the second tab of the Excel document includes data for analysis of the response variable: proportion of time grooming on day 6 (prop_day_gr in Excel spreadsheet). This was calculated in the same way and contained the same predictor variables as on Day 2.

Day 2 grooming rate - this tab in the document contains data for analysis of the response variable: grooming rate on Day 2. This was analysed in a model where the response variable was the counts of grooming interactions that each individual was involved in (Gr_freq in the Excel spreadsheet). Duration (min) was added as an offset term to account for differences in the time available for grooming. The same predictor variables were included in the model as those in the proportion analyses above: treatment, dominance, and sex.

Day 6 grooming rate - this tab contains data for analysis of the response variable: grooming rate on Day 6. This was analysed in the same way as that on Day 2 (see above) with the same predictor variables.

Day 2 grooming duration - this tab contains data for analysis of the response variable: mean grooming bout duration per individual. This was log transformed (Av_gr_dur_log) and analysed in a model with the predictor variables: treatment, dominance, and sex.

Day 6 grooming duration - this tab contains the same data as above, but for Day 6.

Day 2 sentinel - this tab contains data for analysis of whether a sentinel was present when a scan sample was conducted (yes/no). Predictor variables in this model include: treatment (control, rival), habitat (open, medium, dense), wind (still, light breeze) and group size (number of individuals in the group).

Day 6 sentinel - this tab contains the same data as above, but for Day 6.

Day 2 Nearest neighbour - this tab contains data for analysis of nearest-neighbour distances (m) at the individual level. Distances were square-root transformed (NN_distance_sqrt) and analysed in a model with the predictor variables: treatment, dominance, and sex.

Day 6 Nearest neighbour - this tab contains the same data as above, but for Day 6.

Day 2 Adult body mass - this tab contains data for analysis of the body mass changes (grams) of adult individuals during the morning foraging session on Day 2 (DIFFERENCE). Predictor variables in this model included: treatment, dominance, and sex.

Day 6 Adult body mass - this tab contains the same data as above, but for Day 6.

Day 2 Pup body mass - this tab contains data for analysis of the body mass changes (grams) of independently foraging pups over the morning foraging session on Day 2 (DIFFERENCE). Predictor variables in this model included: treatment and sex. Dominance status was not included as it is not assigned until adulthood.

Day 6 Pup body mass - this tab contains the same data as above, with the exception that the pup body mass data was square-root transformed (SQRT) for this analysis of Day 6 data.

Day 2-6 Adult body mass - this tab contains the data for analysis of the difference in body mass change (Diff_adult_weights) of adults between Day 2 and Day 6 for each treatment week. Treatment was included as a predictor variable (control/rival).

Day 2-6 Pup body mass - this tab contains the same data but for the body mass changes of pups (Diff_pup_weights) between Day 2 and Day 6. Treatment was included as a predictor variable (control/rival).

Foraging, latrine, group splits - this tab contains data for analysis of group-level events. By monitoring groups over the course of a whole trial week, we could also gain sufficient data to consider treatment effects on relatively sporadic group-level behaviours. We analysed the proportion of scan samples in which the group was foraging (number of scan samples where the group was foraging/total number of scan samples; Day2_prop_foraging_control, Day2_prop_foraging_rival, Day6_prop_foraging_control, Day6_prop_foraging_rival). We also analysed the proportion of time latrining (total time latrining/total time available for latrining; proportion_time_latrine_control, proportion_time_latrine_rival) and the rate of group splits (total number of group splits/total time available for group splitting; Grp_split_rate_control, Grp_split_rate_rival).

Code/software

For group-level analyses (foraging activity, latrining, group fissions), we ran Wilcoxon signed-rank tests in SPSS 24 (IBM Corp, 2016) and used exact tests to generate p-values. When multiple factors and repeated sampling from the same groups and individuals needed to be taken into consideration, we conducted linear mixed models (LMMs) or generalized linear mixedmodels (GLMMs) in RStudio 3.6.2 (R Core Team, 2019) using the packages lme4 and glmmTMB.