DOI: 10.5061/dryad.866t1g24s
title: Data from: Ecological and behavioral determinants of sex-biased predation of katydid prey by a bat predator

description: Studying the factors leading to sex-biased predation is crucial to better
 understand natural selection, sexual selection, and evolution of
 mate-finding. A comprehensive understanding of these factors requires
 building a mechanistic link between the processes and the patterns. Using
 a case-study of sex-biased predation by a bat, Megaderma spasma, on a
 katydid, Mecopoda, we investigated ecological and behavioral factors
 driving male-biased predation in the breeding season, and female-biased
 predation in the non-breeding season. First, we compared the prey sex
 ratio with the predation pattern in the wild. The relative availability of
 the sexes does not explain male-biased predation on Mecopoda in the
 breeding season; whereas in the non-breeding season, very few males are
 available, potentially leading to female-biased predation. Next, we
 predicted that signaling, being a male-specific behavior, increases their
 predation risk in the breeding season, potentially exacerbated by
 movement, if they also engage in searching. Risk may be lower for females
 in the breeding season since they do not call, and the risk of movement
 for mate-finding may not be higher than for males. Predation risk
 associated with signaling and searching were compared between the sexes
 using enclosure experiments, and prevalence of their risky behaviors
 examined using field observations. The results show that males perform
 high-risk behaviors, such as calling and flight, with a high prevalence.
 Although flight is equally risky for both sexes, females rarely fly. Males
 thus use a high-risk call-and-fly mate-finding strategy, placing them at
 higher risk of predation relative to females in the breeding season.
description: # Data from: Ecological and behavioral determinants of sex-biased
 predation of katydid prey by a bat predator *Saha, K., & Balakrishnan,
 R. (in press). Ecological and behavioural determinants of sex-biased
 predation of katydid prey by a bat predator, Behavioral Ecology.* Dataset
 DOI: [10.5061/dryad.866t1g24s](https://doi.org/10.5061/dryad.866t1g24s) ##
 Authors Kasturi Saha^1*^, Rohini Balakrishnan^1^ *^1.^* *Centre for
 Ecological Sciences, Indian Institute of Science, Bengaluru, Karnataka,
 India 560012* \* *Corresponding author* Kasturi Saha:
 [kasturisahaks@gmail.com](mailto:kasturisahaks@gmail.com),
 [http://orcid.org/0000-0002-7149-9035](http://orcid.org/0000-0002-7149-9035) Rohini Balakrishnan: [brohini@iisc.ac.in](mailto:brohini@iisc.ac.in), [http://orcid.org/0000-0003-0935-3884](http://orcid.org/0000-0003-0935-3884) ## Date and Location where the data was collected December 2018 – March 2020; Mala village, Udupi district, Karnataka, India (13°13’31’’, 75°05’25”) ## Description of the data and file structure This repository contains the data and the code supporting the analysis used in the investigation of ecological and behavioral factors driving sex-biased predation of the katydid prey genus *Mecopoda* by a bat predator *Megaderma spasma. Mecopoda* spp. males are consumed more than females in the breeding season, but females are consumed more in the non-breeding season. We compared this with the availability of the males and females across seasons in the wild, which indicated male-biased predation. Next, we compared the predation risk associated with their mate-finding behaviors in enclosure experiments and examined the prevalence of their risky behaviors using field observations. The results show that males perform high-risk behaviors, such as calling and flight, with a high prevalence. Although flight is equally risky for both sexes, females rarely fly. Note: NA = data not available ### Files and variables #### File: prey_sex_ratio_(availability)_raw_data.csv **Description:** sex ratio of prey katydids representing the availability of the male and female katydids in the wild, measured as the number of adult males and females recorded during field sampling. ##### Variables * month: month in which prey katydid availability was sampled. * week: week number of prey katydid availability sampling. * date: date of prey katydid availability sampling in dd-mm-yyyy format. * place: name of the locality or area where sampling was conducted. * site: site ID. * UTM_coordinate_east: easting value (in meters) indicating the site’s position in the longitude direction, measured east of the central meridian of the UTM zone 43N. * UTM_coordinate_north: northing value (in meters) indicating the site’s position in the latitude direction, measured north of the equator in UTM Zone 43N. * site_selection: whether the site selection was done manually or by random. * male: number of katydid males found in that site. * female: number of katydid females found in that site. #### File: culled_prey_remain_(predation)_raw_data.csv **Description:** culled prey remains collected from bat roosts indicating predation, measured by number of forewing remains of male and female katydids. ##### Variables * month: month in which katydid culled remains were collected from bat roosts. * week: week number corresponding to the collection of katydid culled remains. * date: date of katydid culled remains collection in dd-mm-yy format. * roost_name: bat roost ID. * male_forewing: number of male culled remains i.e., forewings of male katydids found in the bat roost. * female_forewing: number of female culled remains i.e., forewings of female katydids found in the bat roost. #### File: prey_availability_and_predation_weekly_data.csv **Description:** prey availability and predation data aggregated and organized on a weekly basis. ##### Variables * season: season for the week; either breeding or non-breeding season of the katydid. * week: week number within the season, breeding season comprised 16 weeks (with availability data missing on week 1), and nonbreeding season comprised 8 weeks. * sites_availability: number of sites sampled for prey availability during that week. * male_availability: total number of male katydids recorded across all sampled sites that week. * female_availability : total number of female katydids recorded across all sampled sites that week. * bat_roosts: number of bat roosts inspected for culled katydid wing remains (predation) during that week. * male_predation: total number of male wing remains found in the bat roosts that week. * female_predation: total number of female wing remains found in the bat roosts that week. #### File: prey_availability_and_predation_monthly_data.csv **Description:** prey availability and predation data aggregated and organized on a monthly basis. ##### Variables * season: season for the month; either breeding or non-breeding season of the katydid. * month: month of sampling. * number_of_sites: number of sites sampled for prey availability during that month. * male_availability: total number of male katydids recorded across all sampled sites that month. * female_availability: total number of female katydids recorded across all sampled sites that month. * total_availability: total number of katydids recorded across all sampled sites that month. * number_of_roosts: number of bat roosts inspected for culled katydid wing remains (predation) during that month. * male_predation: total number of male wing remains found in the bat roosts that month. * female_predation: total number of female wing remains found in the bat roosts that month. * total_predation: total number of katydid wing remains found in the bat roosts that month. #### File: behavioral_experiment_data.csv **Description:** dataset from a controlled bat-katydid enclosure experiment examining bat responses to katydid males and females engaged in mate-finding behavior (calling, walking, and flying). ##### Variables * date: date of experiment in dd-mm-yyyy format. * day: day number of experiment, with day 1 indicating the day after capturing the bat. * time: time of experiment. * bat_id: ID of the captured bat. * prey_sex: sex of the prey katydid. * treatment_category: the behavioral state of the katydid which were divided into three categories for ease of analysis i.e., (1) signalling, (2) searching by walk, and (3) searching by flight.  * treatment: the sex-associated treatment applied within the three treatment categories mentioned above. signalling was a male-specific treatment, whereas searching by walk and searching by flight applied to both males and females, as well as female phonotaxis i.e., female walk/flight while the male call was being played from a speaker. * bat_approach: bat response to the treatment in binary format, whether the bat flew towards the prey katydid. * capture: bat response to the treatment in binary format, whether or not the bat successfully caught and fed on the prey. * flight_duration_in_seconds: duration of prey katydid flight in seconds. * inducing_prey_behaviour: indicates whether the prey behavior was self-induced or induced by the human observer by tapping with a stick of blowing wind through a pipe. #### File: prevalance_of_risky_behavior_data.csv **Description:** focal observation data of katydid individuals examining the prevalence of risky behaviors (call, flight) in the wild. ##### Variables * date: date of focal behavioral sampling of prey katydids in dd-mm-yy format. * sex: sex of the katydid. * duration_of_observation_in_minutes: duration of focal observation of katydid behavior. * flight: number of times the katydid took flight. * call: number of times the (male) katydid called for more than 3 minutes. #### File: katydid_analysis_script.R **Description:** R script to reproduce the statistical analysis and figures. ## Code/software All analyses were carried out in the R Statistical Software (version 4.5.1; R Core Team 2025) using the packages lme4 (version 1.1.37), sjPlot (version 2.9.0), and ggplot2 (version 3.5.2). File "katydid_analysis_script.R" can be used to reproduce the statistical analysis and figures.