Tracks for Egyptian fruit bats included in the field manipulation for testing the use of the communal roost as an information center hypothesis
Data files
Apr 26, 2024 version files 285.08 MB
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Field_Manipulation_Table.csv
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manipulations_trees_locations.csv
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README.md
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Syc_Manipulation_Dec2020_Filtered.sqlite
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Syc_Manipulation_July2020_Filtered.sqlite
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Syc_Manipulation_June2020_Filtered.sqlite
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Tags_manipulated_and_visiting.csv
May 22, 2024 version files 292.34 MB
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Description_table_movies.xlsx
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Field_Manipulation_Table.csv
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manipulations_trees_locations.csv
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README.md
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syc_exp_Dec20_2020-12-08light_42fps.mp4
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syc_exp_Dec20_2020-12-09light_42fps.mp4
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syc_exp_Dec20_2020-12-10light_42fps.mp4
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syc_exp_Dec20_2020-12-11light_42fps.mp4
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syc_exp_July20_2020-07-20light_42fps.mp4
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syc_exp_July20_2020-07-21light_42fps.mp4
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syc_exp_July20_2020-07-22light_42fps.mp4
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syc_exp_June20_2020-06-23light_42fps.mp4
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syc_exp_June20_2020-06-24light_42fps.mp4
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syc_exp_June20_2020-06-25light_42fps.mp4
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syc_exp_June20_2020-06-28light_42fps.mp4
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Syc_Manipulation_Dec2020_Filtered.sqlite
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Syc_Manipulation_July2020_Filtered.sqlite
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Syc_Manipulation_June2020_Filtered.sqlite
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Tags_manipulated_and_visiting.csv
Abstract
According to the Information Centre Hypothesis (ICH), colonial species use social information in roosts to locate ephemeral resources. Validating the ICH necessitates showing that uninformed individuals follow informed ones to the new resource. However, this following behavior may not be essential when individuals memorize the resources’ locations. For instance, Egyptian fruit bats forage on spatially predictable trees, but some bear fruit at unpredictable times. These circumstances suggest an alternative ICH pathway in which bats learn when fruits emerge from social cues in the roost but then use spatial memory to locate them without following conspecifics. Here, using a unique field manipulation and high-frequency tracking data, we test for this alternative pathway: We introduced bats smeared with the fruit odor of the unpredictably fruiting Ficus sycomorus trees to the roost, when they bore no fruits, and then tracked the movement of conspecifics exposed to the manipulated social cue. As predicted, bats visited the F. sycomorus trees with significantly higher probabilities than during routine foraging trips (of >200 bats). Our results show how the integration of spatial memory and social cues leads to efficient resource tracking and highlight the value of using large movement datasets and field experiments in behavioral ecology.
README: Tracks for Egyptian fruit bats included in the field manipulation for testing the use of the communal roost as an information center hypothesis
Movement tracks derived from the ATLAS reverse-GPS system for Egyptian fruit bats (Rousettus aegyptiacus) in the Hula Valley, Israel.
Description of the data
The tracks are of bats exposed to a manipulation in which some (n=14) were introduced to the communal cave-roost smeared with the fruit pulp of a Ficus sycomorus tree during the time the only two trees in the landscape bore no fruits. The reminder bats (n=57) were tracked but not manipulated with the fruit odors. Importantly, F. sycomorus is characterized by having unpredictable fruiting regimens in this region, which supports the hypothesis that the bats will use social information (the odor cue, shared publicly) to know when the fruits ripen but then navigate to the trees' locations owing to their advanced spatial memory capabilities, without following conspecifics (see Toledo et al. 2020).
The tracks provided here are meant to enable visualization of the movement of bats in the field manipulation and see that they visit the two target trees (location of the trees provided as well).
Tracks are divided into the three manipulation campaigns (different dates) and saved as SQLite files.
Definition of variables in the file "manipulations_trees_locations.csv"
Locations of Ficus sycomorus trees that the tracked bats are expected to visit following the manipulation:
X_ITM: X-coordinate of the location of Ficus sycomorus trees in the Israel Transverse Mercator (ITM) coordinate system (meters)
Y_ITM: Y-coordinate of the location of Ficus sycomorus trees in the Israel Transverse Mercator (ITM) (meters)
Lat_WGS84: Latitude of the trees in the World Geodetic System 1984 (WGS84) coordinate system
Long_WGS84: Longitude of the trees in the World Geodetic System 1984 (WGS84) coordinate system
Definition of variables in the bat tracks (.sqlite files)
TAG: Unique identifier to each tracked bat
TIME: Timestamp in Unix time format
X: X-coordinate of the bat's location in the Israel Transverse Mercator (ITM) coordinate system (meters)
Y: Y-coordinate of the bat's location in the Israel Transverse Mercator (ITM) coordinate system (meters)
FREQ: Temporal sampling frequency (secs)
NBS: Number of ATLAS base stations that received a radio signal from the bat at each recorded location (min 3 are required for trilateration)
VARX: Variance of the localization signal along the X-axis, part of the covariance matrix for location accuracy
VARY: Variance of the localization signal along the Y-axis, part of the covariance matrix for location accuracy
COVXY: Covariance between the X and Y localization signals, indicating the degree to which the two variables vary together
dateTime: Combined date and time for each recorded location formatted as YYYY-MM-DD HH:MM:SS.
date: Date for each recorded location, formatted as YYYY-MM-DD.
date_global: Represents the "night" period from 3 PM on the recorded date to 5 AM the following day (relevant for nocturnal activity)
Night: Identifier for unique nights tracked
distance: Distance traveled between consecutive recorded locations of the bat (meters)
dT: Time interval between consecutive locations
spd: Speed of the bat between consecutive locations (distance/dT)
stdVarXY: Standard deviation of the location variance (derived from the covariance matrix), used to filter out localizations with poor accuracy.
Lon: Longitude of the bat's location in the World Geodetic System 1984 (WGS84) coordinate system
Lat: Latitude of the bat's location in the World Geodetic System 1984 (WGS84) coordinate system
Definition of variables in the file "Tags_manipulated_and_visiting.csv"
The summary of the movement behaviors of the manipulated bats.
tag: Unique identifier to each bat that visited the focal tree of the manipulation (hence, visited="yes")
When?: date of visiting the tree
Cave origin: Roost of the tag. The manipulations were conducted in Zemer and Gershom
date_manipulation: Date of the manipulation for this tagged bat
Nights_after_manipulation: The number of nights between the manipulation and the bats' visit
n_trees_before_same night: The number of trees visited before visiting the focal tree during the night it visited it
n_trees_before_all_nights: The number of trees visited before visiting the focal tree during all nights between the manipulation and the date of visit
n_trees_after_night: The number of trees visited after visiting the focal tree during the same night
Explored_more_that_night: Assessment based on visualizing the tracks to determine whether the tag was particularly explorative during the night of visiting the focal tree
Description of MP4 movies and "Description_table_movies.xslx"
The MP4 files show a subset of the tags included in the manipulation for information transfer in roosts. For visual clarity, these include all bats that visited the focal trees and a representative sample of bats that did not. Each bat has a different color, but the colors are not bat-specific across movies. We show only dates when one or more bats visited one of the focal trees. Tagged bats did not visit the trees during the nights in between.
In each movie, the two main roost locations are marked with a triangle, and the location of the two Ficus sycomorus trees of the manipulation is in a red circle. Note that due to the relative size of the trees compared to the landscape scale, some tags appear to visit the southern tree but were visiting nearby it when looking closely. For more details, please map the raw tracks used for the movies and the Ficus trees’ locations, which are also supplied here.
For details on the specific tags included in the movie, please see the “description_table_movies” Excel file.
All movies were animated using the MoveVis library in R, with a CARTO basemap (Schwalb-Willmann, J.; Remelgado, R.; Safi, K.; Wegmann, M. (2020). moveVis: Animating movement trajectories in synchronicity with static or temporally dynamic environmental data in R. Methods Ecol Evol. 2020; 11: 664–669. https://doi.org/10.1111/2041-210X.13374.
Variables of the Excel file with the tags that were included in each movie:
movie_file: name of the file, with the date.
date_manipulation: The date when the manipulated bats were introduced to the caves (not the date of the movie)
tags_visited: The ID of the tags that visited the trees of the manipulation
experiment_category: Cateogy of bats - either manipulated (smeared with the odor of the F. sycomorus fruits), or naive (tracked in advance, but not smeared).
date_visiting: the dates the specific bat visited any of the manipulation trees
which_tree?: Either northern or southern trees (marked with a red circle)
cave origin: Which cave did the bat roost in, either Zemer a bit to the North or Gershom below Zemer (both marked as a black triangle)
night_visiting_after_manipulation: The night the focal bat visited the trees after the manipulation started
tag_color_movie: The color of the animated bat in each movie
Sharing/Access information
The main analyses and data of the manuscript can also be found on Zenodo and GitHub (see related links).
Methods
Movement tracks of Egyptian fruit bats (Rousettus aegyptiacus) that were exposed to a manipulation introducing an odor cue of a newly emerging fruit (Ficus sycomorus), by releasing bats smeared with fruit pulp into the cave-roost. The tracks were collected using the ATLAS reverse-GPS system (see Nathan et al. 2022, Toledo et al. 2020), in the Hula Valley, Israel. The provided tracks underwent basic filtering for localization errors (see Gupte et al. 2022, Lourie et al. 2021) but were not segmented to separate commutes.