DOI: 10.5061/dryad.p2ngf1w21
title: Radio telemetry reveals extensive dispersal capabilities of reintroduced Great Capricorn beetles (Cerambyx cerdo) in oak habitats at their Northern range limit

description: Amid accelerating global biodiversity loss, reintroducing and
 translocating endangered species have become pivotal conservation
 strategies. This study used radio telemetry to investigate the dispersal
 and movement patterns of the reintroduced Great Capricorn Beetle (Cerambyx
 cerdo) within Tromtö Nature Reserve, Sweden.We tracked 50 beetles (29
 females, 21 males) from 17 June 2022 to 17 July 2022, quantified their
 movements within the landscape, and recorded the distances moved across
 oak-rich areas at the northern edge of the species’ range. Female beetles
 were significantly larger and heavier than males, with longer antennae.
 The beetles were relocated an average of 9.5 times. Total movement
 distances ranged from 2.8 m to 822.2 m, with no significant association of
 movement distance or movement speed with sex, body size or mating status.
 We conclude that C. cerdo can reach oaks several hundred meters away and
 that dispersal distances were not associated with sex, body size or mating
 status. We recommend future studies employing more advanced telemetry
 techniques to refine our understanding of the species movement ecology and
 ensure successful reintroduction and survival.
description: <strong>Rearing and conservation programme at Nordens
 Ark</strong>   To
 address the urgent conservation need of the critically endangered
 <em>C. cerdo </em>in Sweden {Eide, 2020 #3407}, Nordens Ark
 initiated a pioneering breeding program in 2012, in collaboration with the
 County Administrative Boards of Kalmar and Blekinge, as part of
 Sweden's national species conservation action plan. The breeding
 stock was sourced from Halltorps Hage (coordinates 56.81N, 16.59E), the
 last natural stronghold of <em>C. cerdo</em> in Sweden, to
 minimise the impact on the wild population. Larvae were reared in
 controlled conditions within Petri dishes containing a custom-formulated
 substrate made from oak (Quercus spp.) shavings, providing optimal
 nutritional and environmental conditions. The larval stage lasted
 approximately two years, resembling the species' natural development
 cycle. During this time, larvae were monitored regularly for growth and
 development. Upon reaching pupation, individuals were closely observed
 during their transition to adulthood, typically in late summer. After
 emergence, adult beetles are overwintered in specialised refrigeration
 units set to temperatures that mimic natural winter conditions to ensure
 reproductive maturity. This overwintering process is critical for
 synchronising the reproductive cycle with natural environmental cues.
 Since 2017, Nordens Ark has released between 150 and 300 beetles annually
 into carefully selected protected areas in Sweden, including Björnö
 (coordinates 56.77N, 16.36E) and Tromtö (coordinates 56.16N, 15.49E),
 which provide habitats conducive to <em>C. cerdo</em> survival
 and reproduction. The selection of release sites was based on detailed
 habitat assessments, focusing on the availability of veteran oak trees and
 suitable microhabitats. Post-release monitoring is ongoing to assess the
 emergence of reintroduced <em>C. cerdo</em> from pupae and
 investigation of habitat utilisation. In captivity one-two days before
 release, 19 of the female beetles were mated, while 10 remained
 unmated.   
 <strong>Study area</strong>
   This study was conducted in Tromtö
 Nature Reserve, in Karlskrona municipality, Sweden (Fig. 1a,b). The
 reserve is characterised by a rich diversity of habitats, most notably
 featuring ancient and hollow oak (Quercus spp.) (Figure 1c), which are
 critical to the lifecycle of <em>C. cerdo</em> (Fig. 1c,d).
 The area is managed through a traditional grazing regime involving sheep
 and cattle, which helps maintain the open landscape and the health of
 veteran trees. A telemetry field study was conducted over five weeks, from
 June 16 to July 17, 2022.   
 <strong>Radio telemetry
 methods</strong>   The
 <em>C. cerdo</em> beetles used in this study originated from
 the Nordens Ark breeding program. We equipped 50 individuals (29 females,
 21 males) with NanoPin transmitters (model NTP-1, Lotek Wireless Inc.,
 Newmarket, Ontario, Canada). Each transmitter weighed 0.13 g with 11 mm
 length and 5 mm diameter dimensions, featuring a 12 cm flexible antenna
 (Fig. 1d). Transmitters were activated using a NanoTag activator (model
 NANOTAG IR ACT) and had an operational battery life of up to 30 days.
 Prior to release, we measured each beetle's body weight to the
 nearest 0.01 g using a Kern EMB series precision balance, and recorded
 body length, antenna length (to nearest mm), and pronotum width (to
 nearest 0.1 mm) using digital calipers. Beetles were equipped with radio
 transmitters on their pronotum using cyanoacrylate glue (Super Loctite
 Super Glue Original), with the transmittor antenna extending along the
 abdomen to minimise interference with movement. Beetles were released in
 five batches between 17 and 27 June 2022 (18 on June 17, 16 on June 20, 13
 on June 22, 4 on June 26, and 2 on June 27) onto 22 suitable ancient oak
 trees (Quercus spp.) within Tromtö Nature Reserve. Release trees were
 selected based on trunk size, sun exposure, and overall tree
 health.   We conducted daily
 tracking using a Biotracker receiver (model BIOTRACKER8 146-154 MHz) with
 a whip antenna (model SLA/FT-2). One person systematically searched Tromtö
 Nature Reserve and adjacent areas up to 3 km away. Each beetle was when
 searched for once per day during these searches. Beetle locations and
 activity were documented using Field Maps (Esri), which automatically
 recorded time, user, and coordinates for each observation.
description: # Radio telemetry reveals extensive dispersal capabilities of reintroduced
 Great Capricorn beetles (Cerambyx cerdo) in oak habitats at their Northern
 range limit ## Overview This repository contains the dataset and R script
 used in the analysis of movement and morphological traits of *Cerambyx
 cerdo* for the associated publication. The dataset includes tracked
 movement data and morphological measurements for each individual beetle.
 The R script provides a reproducible pipeline for data cleaning,
 statistical analysis, and figure generation. ## Files ### beetle\_data.csv
 ### Description: This dataset contains information on tracked movements
 and morphological characteristics of beetles. Each row corresponds to an
 individual beetle. #### Variables: * **Tag_ID** (Numeric): Unique
 identifier for each beetle. * **Sex** (Character): Biological sex of the
 beetle: * `M`: Male * `F`: Female * **Body_size** (Numeric): The length of
 the beetle's body in millimetres (mm). * **Antenna** (Numeric): The
 length of the beetle's antenna in millimetres (mm). * **Thorax**
 (Numeric): The width of the beetle's thorax in millimetres (mm). *
 **Weight** (Numeric): The body weight of the beetle in grams (g). *
 **total_distance** (Numeric): The total distance moved by the beetle
 during the tracking period (metres). * **first_observation** (Date): The
 beetle's first recorded observation date (`DD/MM/YYYY`). *
 **last_observation** (Date): The beetle's last recorded observation
 date (`DD/MM/YYYY`). * **tracking_days** (Numeric): The total number of
 days the beetle was tracked. * **movement_speed** (Numeric): Average
 movement speed (metres per day). * **Mating** (Character): Mating status
 of the beetle: * `Mated`: Beetle was mated. * `Not Mated`: Beetle was
 unmated. ### Franzen\_c\_cerdo\_ICDIV-24-0278.r #### Description: This R
 script includes the full analysis pipeline for the study. It processes the
 `beetle_data.csv` file, performs statistical analyses, and generates
 figures used in the publication. #### Key Features: 1. **Data Import and
 Preparation:** * Reads the `beetle_data.csv` file. * Renames and formats
 columns for consistency. * Handles missing values and performs data
 cleaning. 2. **Morphological Analysis:** * Calculates summary statistics
 (mean, SE) for traits like body size, antenna length, thorax width, and
 body weight. * Conducts Welch’s t-tests to compare male and female traits.
 3. **Movement Analysis:** * Computes movement metrics: total distance,
 tracking days, and movement speed. * Tests for differences in movement
 patterns by sex and mating status using Welch’s t-tests. * Fits linear
 models to assess relationships between movement and morphological traits.
 4. **Visualization:** * Generates high-quality figures showing: *
 Morphological differences by sex. * Total distance and movement speed by
 sex. * Relationships between body size and movement distance. * Saves
 figures as high-resolution PNG files. 5. **Statistical Tests:** * Uses
 ANOVA, linear models, and correlation analyses for hypothesis testing. *
 Outputs detailed statistical results for reproducibility. ####
 Dependencies: The script uses the following R packages: * `dplyr`,
 `ggplot2`, `readxl`, `car`, `gridExtra`, `broom`, `tidyr`. #### Execution
 Instructions: 1. Place `beetle_data.csv` in the same directory as the R
 script. 2. Open the R script in RStudio or another R environment. 3. Set
 the working directory to the file location. 4. Run the script line by line
 or execute the entire script to reproduce the analyses. ## Intended Use
 These files allow users to: * Reproduce the analyses presented in the
 manuscript. * Extend or modify the analysis for additional research. *
 Generate figures included in the publication. ## Citation If using this
 dataset or script, please cite the associated publication: ## Contact For
 further questions or issues regarding the data or script, please contact:
 **Markus Franzen**\ [markus.franzen@liu.se](mailto:markus.franzen@liu.se)