Resource manipulation reveals interactive phenotype-dependent foraging in free-ranging lizards
Data files
Jun 03, 2024 version files 648.71 KB
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cagebylizard_data.csv
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lizard_cage_visits_data.csv
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lizard_data.csv
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README.md
Abstract
Recent evidence suggests that individuals differ in foraging tactics and this variation is often linked to an individual’s behavioural type (BT). Yet, while foraging typically comprises a series of search and handling steps, empirical investigations have rarely considered BT-dependent effects across multiple stages of the foraging process, particularly in natural settings.
In our long-term sleepy lizard (Tiliqua rugosa) study system, individuals exhibit behavioural consistency in boldness (measured as an individual’s willingness to approach a novel food item in the presence of a threat) and aggressiveness (measured as an individual’s response to an ‘attack’ by a conspecific dummy). These BTs are only weakly correlated and have previously been shown to have interactive effects on lizard space use and movement, suggesting that they could also affect lizard foraging performance, particularly in their search behaviour for food.
To investigate how lizards’ BTs affect their foraging process in the wild, we supplemented food in 123 patches across a 120-ha study site with three food abundance treatments (high, low, and no-food-controls). Patches were replenished twice a week over the species’ entire spring activity season and feeding behaviours were quantified with camera traps at these patches. We tracked lizards using GPS to determine their home range (HR) size and repeatedly assayed their aggressiveness and boldness in designated assays.
We hypothesised that bolder lizards would be more efficient foragers while aggressive ones would be less attentive to the quality of foraging patches. We found an interactive BT effect on overall foraging performance. Individuals that were both bold and aggressive ate the highest number of food items from the foraging array. Further dissection of the foraging process showed that aggressive lizards in general ate the fewest food items in part because they visited foraging patches less regularly, and because they discriminated less between high and low-quality patches when revisiting them. Bolder lizards, in contrast, ate more tomatoes because they visited foraging patches more regularly, and ate a higher proportion of the available tomatoes at patches during visits.
Our study demonstrates that BTs can interact to affect different search and handling components of the foraging process, leading to within-population variation in foraging success. Given that individual differences in foraging and movement will influence social and ecological interactions, our results highlight the potential role of BT’s in shaping individual fitness strategies and population dynamics.
README: README: Dataset descriptions
Orr Spiegel & Marcus Michelangeli
2024-05-20
Below we describe three data sets that were used in the statistical analysis for the paper Resource manipulation reveals interactive phenotype-dependent foraging in free-ranging lizards published in Journal of Animal Ecology.
These datasets are used in the R script titled data_analysis_SleepyForaging which provides R code to reproduce the analysis.
The provided data is cleaned and collated from several raw datasets including GPS data of lizard tracks, camera trap observations, and lizard biometrics. If you would like any of the raw, unprocessed data please contact Orr Spiegel (orrspiegel@tauex.tau.ac.il) or Marcus Michelangeli (marcus.michelangeli@gmail.com).
Brief description of the study design and the type of data collected
We investigated how a lizard’s behavioral type (boldness and aggressiveness), as well as social and ecological factors, affected their foraging behaviour in the wild. We supplemented food (cherry tomatoes) in 123 patches that were evenly distributed across a 120-ha study site. Food patches contained one of three food abundance treatments (high quality = 9 tomatoes, low quality = 3 tomatoes, and no-food-controls). Patches were replenished twice a week over the species’ entire spring activity season. We quantified a lizards feeding behaviours (e.g. the number of tomatoes they ate, the duration of their visit to food patches) using footage from camera traps at each food patch. We also tracked lizards using GPS, allowing us to measure their search behaviours, home range size, and a proxy for their social interaction rate. We used habitat surveys to assess the ecological conditions surrounding both food patches and a lizards home range. Finally, we also repeatedly assayed each lizards aggressiveness and boldness behaviors in designated assays.
lizard_cage_visits_data
Each row in the data set corresponds to an observed visit by a lizard to a food patch (captured by camera traps at the food patch).
This dataset is used in the analysis of the following foraging metrics
- Time taken for a lizard to visit a patch following a tomato replenishment event (Time until patch discovery)
- Patch visit duration
- Number of available tomatoes eaten by a lizard during a patch visit
- Total number of tomatoes eaten by a lizard during the study
Columns with .s suffix (not listed here) are some these columns standardized (by subtracting the mean and dividing by the standard deviation).
Data.type | Description | |
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cage | character | Food patch ID |
treatment | numeric | Food patch treatment (0 = control, 3 = low, 9 = high) |
date | character | Date of observation |
LizardID_only | character | ID of visiting lizard |
distHRc | numeric | Distance of food patch from visting lizards home range centre (m) |
mon_days | integer | Number of days the food patch was monitored by camera traps |
prop_mon_days | numeric | Proportion of total experimental days that the food patch was monitored by camera traps |
VisitDurationIntMin | numeric | Duration of lizard visit to the food patch (seconds) |
AvailableTomatoes | numeric | Number of availble tomatoes at the food patch when the lizard visited |
TomatoesEaten | numeric | Number of tomatoes eaten by the lizard during the food patch visit (not rounded) |
RemainingTomatoes | numeric | Number of tomatoes remaining at the food patch after the lizards visit |
OtherLizardPresent | numeric | Binary outcome identifying whether another lizard was present at the food patch during the focal lizards visit (0 = no other lizard present, 1 = another lizard was present) |
SeedingEventNum | numeric | Replenishment event of tomatoes at the food patch (i.e. 1 = first time tomatoes were provided at the food patch, 2 = second tomato replenishment event) |
TmSncDplymntFirstVisLiz | numeric | Time taken for the lizard to visit the food patch since it was replenished with tomatoes (seconds) |
Tomatoes_Eaten_rounded | numeric | Number of tomatoes (rounded up) eaten by the lizard during the visit at the foraging patch |
patch_moistfood40 | numeric | Moist food score based on a 40m radius around the food patch (a rank between 1–5, 1 = lowest score, 5 = highest score) |
patch_refuge40 | numeric | Refuge quality score based on 40m radius around the food patch (a rank between 1–5, 1 = lowest score, 5 = highest score) |
LizHR95 | numeric | Lizard 95% home range size (hectres) |
avgrefuge40_rel | numeric | Moist food score based on a 40m radius from the central point of the visiting lizards 95% home range (average rank between 1–5 based on surveys taken throughout the season, 1 = lowest score, 5 = highest score) |
Boldness | numeric | Visiting lizards boldness score (Average rating between 1-10 across three trials; 1 = low boldness, 11 = high boldness) |
Aggression | numeric | Visiting lizards aggression score (Average rating between 1-10 across three trials; 1 = low aggression, 11 = high aggression) |
Sex | factor | Sex of the visiting lizard |
SVL | numeric | Snout-vent-length of the visiting lizard (cm) |
PHRmean.nz_iso95 | numeric | The average extent to which the visiting lizards HR was overlapped by the home range (utility distribution) of other lizards (i.e. PHR; higher values indicate greater overlap) |
num_cage95_filmed | integer | Number of food patches that were filmed by camera traps within the visiting lizards 95% home range |
cagebylizard_data
Each row in the data corresponds to a foraging patch and a summary of a lizard visting behaviour to that specific food patch.
This dataset is used in the analysis of the following foraging metrics
- How many times a lizard revisited a specific patch after its first visit to that patch (Patch revisitation rate)
Columns with .s suffix (not listed here) are some these columns standardized (by subtracting the mean and dividing by the standard deviation).
Data.type | Description | |
---|---|---|
cage | character | Food patch ID |
LizardID_only | character | Lizard identifier |
distHRc | numeric | Distance of food patch from visting lizards home range centre (m) |
treatment | numeric | Food patch treatment (0 = control, 3 = low, 9 = high) |
mon_days | integer | Number of days the food patch was monitored by camera traps |
prop_mon_days | numeric | Proportion of total experimental days that the food patch was monitored by camera traps |
n_visits_per_cage | integer | Number of visits this lizards made to this food patch |
n_unique_days_at_cage | integer | Number of unique days the lizard visited the food patch |
mean_visit_duration | numeric | The average duration of a lizards visit to the food patch (seconds) |
num_revisits | numeric | The number of times a lizard revisited the food patch after its first visit |
patch_moistfood40 | numeric | Moist food score based on a 40m radius around the food patch (a rank between 1–5, 1 = lowest score, 5 = highest score) |
patch_refuge40 | numeric | Refuge quality score based on 40m radius around the food patch (a rank between 1–5, 1 = lowest score, 5 = highest score) |
LizHR95 | numeric | Lizard 95% home range size (hectres) |
avgrefuge40_rel | numeric | Moist food score based on a 40m radius from the central point of the visiting lizards 95% home range (average rank between 1–5 based on surveys taken throughout the season, 1 = lowest score, 5 = highest score) |
Boldness | numeric | Lizard boldness score (Average rating between 1-10 across three trials; 1 = low boldness, 11 = high boldness) |
Aggression | numeric | Lizard aggression score (Average rating between 1-10 across three trials; 1 = low aggression, 11 = high aggression) |
Sex | factor | Lizard sex |
SVL | numeric | Lizard snout-vent-length (cm) |
PHRmean.nz_iso95 | numeric | The average extent to which the visiting lizards HR was overlapped by the home range (utility distribution) of other lizards (i.e. PHR; higher values indicate greater overlap) |
lizard_data
Each row in the data corresponds to a focal lizard and provides a summary of their foraging behaviour at food patches
This dataset is used in the analysis of the following foraging metrics
- A lizard’s home range size (hectres)
- The number of unique food patches visited by a lizard during the study
- Total number of food patches a lizard visited during the study
- Total number of tomatoes eaten by a lizard during the study
Columns with .s suffix (not listed here) are some these columns standardized (by subtracting the mean and dividing by the standard deviation).
Data.type | Description | |
---|---|---|
LizardID_only | integer | Lizard identifier |
n_visits | integer | Total number of food patch visits |
n_unique_visits | integer | Number of unique food patches visited |
mean_visit_duration | numeric | The average duration of a lizards visits to all food patches (seconds) |
mean_prop_tom_eaten | numeric | The average proportion of available tomatoes eaten by a lizard during a food patch visit |
LizHR95 | numeric | 95% home range size (hectres) |
num_control_cage95 | integer | Total number of control food patches within a lizards 95% home range |
num_med_cage95 | integer | Total number of low treatment food patches within a lizard 95% home range |
num_high_cage95 | integer | Total number of high treatment food patches within a lizard 95% home range |
num_control_cage95_filmed | integer | Number of control food patches within a lizards 95% home range that were monitored by camera traps |
num_med_cage95_filmed | integer | Number of low treatment food patches within a lizards 95% home range that were monitored by camera traps |
num_high_cage95_filmed | integer | Number of high treatment food patches within a lizards 95% home range that were monitored by camera traps |
num_cage95 | integer | Total number of food patches (all treatments) within a lizards 95% home range |
num_cage95_filmed | integer | Total number of food patches that were monitored by camera traps within a lizards 95% home range |
prop_cages95_filmed | numeric | Proportion of food patches within a lizards 95% home range that were monitored by camera traps during the study |
avgmoistfood40_rel | numeric | Moist food score based on a 40m radius from the central point of the visiting lizards 95% home range (average rank between 1–5 based on surveys taken throughout the season, 1 = lowest score, 5 = highest score) |
Boldness | numeric | Lizard boldness score (Average rating between 1-10 across three trials; 1 = low boldness, 11 = high boldness) |
Aggression | numeric | Lizard aggression score (Average rating between 1-10 across three trials; 1 = low aggression, 11 = high aggression) |
Sex | character | Lizard sex |
SVL | numeric | Lizard snout-vent-length (cm) |
PHRmean.nz_iso95 | numeric | The average extent to which the visiting lizards HR was overlapped by the home range (utility distribution) of other lizards (i.e. PHR; higher values indicate greater overlap) |
tot_tom_eaten_rounded | integer | Total number of tomatoes eaten by the lizard during the study (rounded up) |
Methods
The data included in this manusript combines several sources of information from our field site at Bundy Bore, Australia.
- The most central dataset for this paper is the lizard visit documentation, obtained by camera-traps recording in a time-lapse mode, the dataset is included here in a cleaned form, after removing irrelevant lines (e.g. non lizard visit) and colunms.
- Behavioral data with repeated assays on individual lizards. This data is included in the recent paper by Payne et al. (2021) Animal Behaviour; as well as in the dataset cited below.
- GPS tracking data for estimating Home Range (HR) size for focal lizards. This is used as a predictor in relevant models. HR . Information on the HR results is aviaible in the included dataset and a broader version that includs several years and not only this particualr one was included in Payne et al. (2022) Ecological Monographs
- Code for the modeling is included as well, see readme for more details.