Data from: Could adult or juvenile dispersal shape geographical parthenogenesis? Evidence from the facultatively parthenogenetic phasmid Megacrania batesii
Data files
May 14, 2025 version files 338.84 KB
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7_females_no_switching_publication.csv
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all_combined_2020_CO.csv
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all_combined_7females_updated.csv
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all_combined_co_2022.csv
16.54 KB
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all_combined_patch_a_c.csv
8.95 KB
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all_combined_patch_b_excluding_7females.csv
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dispersal_data_all_years_publication.csv
234.83 KB
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Individual_summary_publication.csv
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non_removal_patch_all_publication.csv
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README.md
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Abstract
Despite their individual reproductive flexibility, populations of many facultatively parthenogenetic animals vary in sex ratio and reproductive mode. Sex-specific dispersal could contribute to such spatial variation. We asked if sex-specific dispersal by adults or nymphs occurs in the facultatively parthenogenetic phasmid Megacrania batesii, which forms a geographical mosaic of mixed-sex (mostly sexually reproducing) and all-female (parthenogenetic) populations. If sex-specific dispersal contributes to sex-ratio variation in this species, we would expect to observe greater dispersal by females than by males. We carried out a mark-resighting field study over three years to investigate adult dispersal in mixed-sex and all-female populations. To better understand how males affect female behaviour, we also investigated pairing and mate-guarding. In addition, we investigated dispersal by hatchling nymphs in a semi-natural enclosure. Mean nightly movement distances did not differ between unpaired (single) females and males in the mixed-sex population. However, unpaired females moved further in mixed-sex than in all-female populations. Many adult females in the mixed-sex population continually carried guarding males on their dorsum. Pairs often remained together for multiple days, and few females or males were observed pairing with multiple partners. Paired females moved shorter distances than unpaired females, and such females’ movement increased following experimental removal of males. Hatchling nymphs rarely moved between plants. Our findings suggest that guarding males affect females’ movement patterns, but nymph and adult dispersal is unlikely to shape spatial variation in sex ratio in Megacrania batesii.
https://doi.org/10.5061/dryad.zkh1893jv
File: Individual_summary_publication.csv
Description: Individual summary table while excluding male removal experiment
Variables
- year: The year (y) in which field study conducted.
- pop_type: Whether the population is mixed-sex or all-female.
- ind_id: The unique individual ID of each focal individual (i.e., each individual that was marked).
- sex: The sex of the focal individual, represented as F for female and M for male.
- status: The pairing status, whether the individual is found 'paired' or 'unpaired' on each visit.
- Count: Total number of sightings for the focal individual including first observation. Individuals observed both paired and unpaired are listed twice, with the number of observations for each status shown in this column. Individuals observed both paired and unpaired are listed twice, with the number of observations for each status shown in this column.
- Mean_disp_dist: Mean nightly dispersal distance for each individual.
File: 7_females_no_switching_publication.csv
Description: Male removal experiment
Variables
- year: The year (y) in which field study conducted.
- date: Exact dates of annual visits to field sites.
- days: The sequence of visits to each site is recorded, with each day labelled sequentially as day 1, day 2, and so forth.
- time_interval: The time interval represents the number of nights between site checks. NA values are noted in this column for observation 1 and when an individual was not found.
- observed_times: This variable indicates how many times the focal individual has been resighted after marking (e.g. obs3 indicates that the individual is sighted for the third time). If an individual is not found on a specific day, it is recorded as NA.
- pop_type: Whether the population is mixed-sex or all-female.
- location: Codes representing the three study sites (based on Miller et al. 2024 American Naturalist).
- patch_type: Codes for host plant (Pandanus) patches at site CO.
- sex: The sex of the focal individual, represented as F for female and M for male.
- ind_id: The unique individual ID of each focal individual (i.e., each individual that was marked).
- paired_with: The individual ID of partner (guarding male or female being guarded). Individuals that are either found unpaired or not found at all on that observation day are recorded as NA.
- status:The pairing status, whether the individual is found 'paired' or 'unpaired' on each visit. Individuals not found at all are recorded as NA.
- plant_id: Unique ID for each host plant where a focal Megacrania batesii individual was found. If an individual is not found on a specific day, it is noted as NA.
- dist_cm: The distance travelled (in cm) since the last observation each time (i.e., the distance between the previous and current host-plant where the individual was found). If an individual was not found on a specific day or was encountered for the first time, it is noted as NA.
- nightly_dist:The nightly distance is calculated by dividing distance travelled by time interval (the number of nights between current and previous observation). If an individual was not found on a specific day or was encountered for the first time, it is noted as NA.
- replacement: Indicates whether the individual is paired with the same individual as it was in previous observation or different individual. If an individual is missing on a specific day, it is noted as NA.
- found_nf: Whether the individual is found or not found on each visit.
- male_manipulation: Whether the observation is made while males were removed from patch B at CO in 2021 ("males removed") or not ("no male removal").
File: dispersal_data_all_years_publication.csv
Description: Master data contains all three years of mark-resight studies
Variables
- year: The year (y) in which field study conducted.
- date :Exact dates of annual visits to field sites.
- days: The sequence of visits to each site, with each day labelled sequentially as day 1, day 2, and so forth.
- time_interval: The time interval represents the number of nights between observations of the focal individual. NAs are present in this column for observation 1 because newly marked individuals were observed for the first time.
- observed_times: This variable indicates how many times the focal individual has been resighted after marking (e.g. obs3 indicates that the individual is sighted for the third time). If an individual is not found on a specific day, it is recorded as NA.
- pop_type: Whether the population is mixed-sex or all-female.
- location: Codes representing the three study sites (based on Miller et al. 2024 American Naturalist).
- patch_type: Codes for host plant (Pandanus) patches at site CO. All study sites have NA except for CO.
- sex: The sex of the focal individual, represented as F for female and M for male.
- ind_id: The unique individual ID of each focal individual (i.e., each individual that was marked).
- paired_with: The individual ID of partner (guarding male or female being guarded). Individuals that are either found unpaired or not found at all on that observation day are recorded as NA.
- status: The pairing status, whether the individual is found 'paired' or 'unpaired' on each visit. Individuals not found at all are recorded as NA.
- plant_id: Unique ID for the host plant where a Megacrania batesii focal individual was found. We did not keep track of individual plants across years, and therefore assigned a new ID to each host plant each year. If an individual was not found on a specific day, the plant ID is noted as NA.
- dist_cm: The distance travelled (in cm) since the last observation each time (i.e., the distance between the previous and current host-plant where the individual was found). If an individual was not found on a specific day or was encountered for the first time, it is noted as NA.
- nightly_dist: The nightly distance is calculated by dividing distance travelled by time interval (the number of nights between current and previous observation). If an individual was not found on a specific day or was encountered for the first time, it is noted as NA.
- replacement: Indicates whether the individual is paired with the same individual as it was in previous observation or different individual. If an individual is missing on a specific day, it is noted as NA.
- found_nf: Whether the individual is found or not found on each visit. Last day of observation of 2021, when males were reintroduced to the patch B is NA. This is because resightings of these males were not included in the analyses.
- male_manipulation: Whether the observation is made while males were removed from patch B at CO in 2021 ("males removed") or not ("no male removal").
- exclude: Used to exclude rows with paired males in the ind_id column to avoid duplicates. Paired males are listed as partners in the "paired_with" column.
File: all_combined_7females_updated.csv
Description: Supplementary Figure S3
Variables
- date: Exact dates of annual visits to field sites.
- status: The pairing status, whether the individual is found 'paired' or 'unpaired' on each visit.
- sex: The sex of the focal individual, represented as F
- ind_id: The unique individual ID of each focal individual (i.e., each individual that was marked).
- paired_with: The individual ID of females whether they paired or unpaired. Any NAs represent females whose males were removed.
- patch: Codes for host plant (Pandanus) patches at site CO. B represents Middle patch CO in 2021
- plant_id: Unique ID for the host plant where a Megacrania batesii focal individual was found.
- lat: GPS coordinates of plants (Latitude).
- long: GPS coordinates of plants (Longitude).
- division :Connecting points to a line. Any NAs represent females that did not move and remained on the host plant.
- order: Points are connected based on order of points. Any NAs represent females that did not move and remained on the host plant.
- male_removal: Females status while paired represents "before", and while unpaired represents "after".
File: non_removal_patch_all_publication.csv
Description: Part of male removal experiment.
Variables
- year: The year (2021) in which field study conducted.
- date : Exact dates of annual visits to field sites.
- days: The sequence of visits to each site, with each day labelled sequentially as day 1, day 2, and so forth.
- time_interval: The time interval represents the number of nights between observations of the focal individual. NAs are present in this column for observation 1 because newly marked individuals were observed for the first time.
- observed_times: This variable indicates how many times the focal individual has been resighted after marking (e.g. obs3 indicates that the individual is sighted for the third time). If an individual is not found on a specific day, it is recorded as NA.
- pop_type: Whether the population is mixed-sex or all-female.
- location: Codes representing the three study sites (based on Miller et al. 2024 American Naturalist).
- patch_type: Codes for host plant (Pandanus) patches at site CO.
- sex: The sex of the focal individual, represented as F for female.
- ind_id: The unique individual ID of each focal individual (i.e., each individual that was marked).
- paired_with: The individual ID of partner (guarding male or female being guarded). Individuals that are either found unpaired or not found at all on that observation day are recorded as NA.
- status: The pairing status, whether the individual is found 'paired' or 'unpaired' on each visit. Individuals not found at all are recorded as NA.
- plant_id: Unique ID for the host plant where a Megacrania batesii focal individual was found. We did not keep track of individual plants across years, and therefore assigned a new ID to each host plant each year. If an individual was not found on a specific day, the plant ID is noted as NA.
- dist_cm: The distance travelled (in cm) since the last observation each time (i.e., the distance between the previous and current host-plant where the individual was found). If an individual was not found on a specific day or was encountered for the first time, it is noted as NA.
- nightly_dist: The nightly distance is calculated by dividing distance travelled by time interval (the number of nights between current and previous observation). If an individual was not found on a specific day or was encountered for the first time, it is noted as NA.
- replacement: Indicates whether the individual is paired with the same individual as it was in previous observation or different individual. If an individual is missing on a specific day or found unpaired, it is noted as NA.
- found_nf: Whether the individual is found or not found on each visit.
- male_manipulation: Patches where male removal did not occur.
- male_removal: Paired females in Southern and Northern patches before and including March 3, 2021 (when males were removed from the Middle patch) with nightly dispersal distances of those females after this date.
File: all_combined_2020_CO.csv
Description: Supplementary Figure S1
Variables
- date : Exact dates of annual visits to field sites.
- sex: The sex of the focal individual, represented as F for female and M for male.
- Individual code: The unique individual ID of each focal individual (i.e., each individual that was marked).
- Paired with : Individuals that are found unpaired on that observation day are recorded as NA.
- single/pairs: The pairing status, whether the individual is found 'paired' or 'unpaired' on each visit.
- Plant id : Unique ID for the host plant where a Megacrania batesii focal individual was found.
- lat: GPS coordinates of plants (Latitude).
- lon: GPS coordinates of plants (Longitude).
- DIVISION : Connecting points to a line. Any Nas represent females that did not move and remained on the host plant.
- ORDER: Connecting points to a line. Any Nas represent females that did not move and remained on the host plant.
File: all_combined_patch_a_c.csv
Description: Supplementary Figure S2
Variables
- date: Exact dates of annual visits to field sites.
- status: The pairing status, whether the individual is found 'paired' or 'unpaired' on each visit.
- sex: The sex of the focal individual, represented as F for female and M for male.
- ind_id: The unique individual ID of each focal individual (i.e., each individual that was marked).
- paired_with: The individual ID of partner (guarding male or female being guarded). Individuals that are found unpaired on that observation day are recorded as NA.
- patch: Codes for host plant (Pandanus) patches at site CO. A represents Southern patch while C represents Northern patch.
- plant_id: Unique ID for the host plant where a Megacrania batesii focal individual was found.
- lat: GPS coordinates of plants (Latitude).
- long: GPS coordinates of plants (Longitude).
- division : Connecting points to a line.
- order: Points are connected based on order of points.
File: all_combined_co_2022.csv
Description: Supplementary Figure S5
Variables
- date : Exact dates of annual visits to field sites.
- patch_type: Codes for host plant (Pandanus) patches at site CO. A represents Southern patch and B represents Middle patch CO in 2021
- sex: The sex of the focal individual, represented as F for female and M for male.
- ind_id: The unique individual ID of each focal individual (i.e., each individual that was marked).
- paired_with: The individual ID of partner (guarding male or female being guarded). Individuals that are found unpaired on that observation day are recorded as NA.
- plant_id: Unique ID for the host plant where a Megacrania batesii focal individual was found.
- lat: GPS coordinates of plants (Latitude).
- long: GPS coordinates of plants (Longitude).
- division : Connecting points to a line.
- order: Points are connected based on order of points.
- status: The pairing status, whether the individual is found 'paired' or 'unpaired' on each visit.
File: all_combined_patch_b_excluding_7females.csv
Description: Supplementary Figure S4
Variables
- date: Exact dates of annual visits to field sites.
- sex: The sex of the focal individual, represented as F
- ind_id: The unique individual ID of each focal individual (i.e., each individual that was marked).
- paired_with: The individual ID of partner (guarding male or female being guarded). Individuals that are found unpaired on that observation day are recorded as NA.
- patch: Codes for host plant (Pandanus) patches at site CO. B represents Middle patch in 2021. C represents Northern patch.
- plant_id: Unique ID for the host plant where a Megacrania batesii focal individual was found.
- lat: GPS coordinates of plants (Latitude).
- long: GPS coordinates of plants (Longitude).
- division : Connecting points to a line.
- order: Points are connected based on order of points.
- status: The pairing status, whether the individual is found 'paired' or 'unpaired' on each visit.
Access information
Other publicly accessible locations of the data:
- NA.
Data was derived from the following sources:
- NA.
Mark-resighting methodology
Within each population, we used a mark-resighting method to track movements of Megacrania batesii adults (and a few final-instar female nymphs). Individuals were marked on the first day of the study each year, and additional unmarked individuals were marked on subsequent days. Resighting data were collected either daily or every other day, starting on the 2nd or 3rd day of the study. Newly sighted individuals were marked with unique codes on their thorax and/or wings. using black permanent marker (Artline xylene-free permanent marker, Shachihata, Japan) in situ on their host plants, without handling or restraining them. Host plants on which Megacrania batesii individuals were marked or resighted were tagged with numbered plastic tags. Both males and females can spray a defensive fluid when disturbed (Cermak and Hasenpusch 2000; Jones and Bulbert 2020), which can complicate marking by depositing moisture on the thorax. If a spraying response occurred, we waited a few minutes and then attempted to write the same code on the forewings. When an individual was found at the base of a leaf, we gently tapped the tip of its abdomen to trigger it to crawl upwards to become accessible for marking. When marking male-female pairs, the male’s antennae sometimes blocked the female’s thorax. In such cases, the antennae were pushed to the side or the male was moved gently to the side or backwards to expose the female’s thorax.
In 2020, we conducted a mark-resighting study from 2nd to 14th February at CO and CB (only within the Benstonea monticola patch). At CO, we marked individuals on 2nd February, and then collected resighting data daily until 4th of February, and every second day thereafter until 14th of February. At population CB, we marked individuals on 3rd February, and then collected resighting data daily from 4th February, and every second day thereafter until 14th February. In addition to adult females, we also marked three final-instar female nymphs at CB. Almost no rain occurred during our mark-resighting study, and average maximum temperature was ~34.6ºC (Table S1-S3). In 2021, we conducted a mark-resighting study from 25th February to 8th March at CO and KB. At CO, we marked and resighted Megacrania batesii individuals in the same patch of P. tectorius plants as in 2020, as well as an adjacent patch (see Results). We marked individuals on 26th February, and then collected resighting data every other day until 8th March. At KB, we marked individuals on 26th February, and then collected resighting data every other day until 8th March. There was considerable rainfall during our mark-resighting study, and the average maximum temperature was ~30.5ºC (Table S1-S3). In 2022, we conducted a mark-resighting study from 22nd February to 4th March at CO and CB (only within the Pandanus tectorius patch). At CO, we marked individuals in the same two patches as in 2021 on 22nd February, and then collected resighting data every other day until 4th March. At CB, we marked individuals on 23rd February, and then collected resighting data every other day until 5th March. There was little rainfall during our field-study, and average maximum temperature was ~34.7 ºC (Table S1-S3).
Dispersal
To estimate dispersal rates, we quantified how far individuals moved between successive sightings. We checked for previously marked individuals on each plant (absence or presence) on each resighting day, measured the distance between the previous sighting location and new location, and recorded the identity and pairing state (unpaired or paired) of each marked individual. We collected the Global Positioning System (GPS) coordinates of each individual at its point of initial sighting or resighting using a Garmin eTrex 20x GPS. Because GPS coordinates are imprecise over small distances, we also measured the linear distance between plants using a tape-measure and use these measurements in analyses of dispersal distance. The “nightly dispersal” distance was calculated for each individual each time it was resighted as the distance between the previous and current location divided by the number of nights between the current sighting and the previous sighting (since Megacrania batesii are mostly active at night). The mean nightly dispersal distance for each individual was calculated as the sum of the nightly dispersal distances divided by the number of nights between the initial sighting/marking and the final resighting.
Male removal experiment
To further investigate the effect of male guarding on female dispersal, we removed males from a patch of host plants at CO on the 3rd of March 2021, thoroughly checking both during the day and at night and removing any males that we could find. Locations of all females that had been separated from guarding males were recorded daily until the 7th of March, and their nightly dispersals were measured. The removed males were kept in individual mesh cages in our field-laboratory, misted with water and provided fresh host plant leaves daily. The males were released in the same patch on 7th of March.
Dispersal of hatchlings
We observed dispersal of Megacrania batesii hatchling nymphs from 25th July to 28th August 2020 in a semi-natural enclosure set up inside a controlled-temperature room at UNSW Sydney. Hatchlings were obtained from eggs collected in the field between Cow Bay and Cape Tribulation, Queensland, in February 2020. Each day, newly hatched nymphs were sexed based on the morphology of the terminal abdominal sternites (see Miller et al. 2024a), marked individually with distinctive patterns of coloured dots using permanent marker (Sharpie, Australia), and released on Pandanus tectorius plants distributed on the floor of a controlled-temperature room (maintained at 25 ± 2°C and 60 ± 20% relative humidity; 12 hrs of cycle day/night with white and red lights). Six immature Pandanus plants (40 – 60 cm in height) were placed in the room, with one plant in each corner and two plants in the centre. Each morning, we recorded the locations of all hatchlings. Each nymph was monitored until it underwent its first molt, after which we were not able to track individuals because their individual markings were shed along with their exoskeletons. In total, we marked and released 55 hatchlings (39 females, 16 males), and observed each hatchling over 10 ± 2 days.