Data from: Size-dependent behavioral and antennal responses to doses of (+)-isopinocamphone and 1,8-cineole mixed with pheromone: a potential host selection strategy in female Ips typographus L.
Data files
Oct 28, 2025 version files 15.84 KB
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Data_females_ips_typographus.7z
8.48 KB
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README.md
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Abstract
Context:
Ips typographus, a major pest of Norway spruce (Picea abies) in Europe, is experiencing more frequent outbreaks due to climate change. These outbreaks involve shifts in population dynamics and phenotypic traits, influencing beetle responses to olfactory cues from stressed host trees.
Aims:
The study examines the size-dependent behavioral and antennal responses of female I. typographus to two host selection–deciding volatiles with contrasting ecological roles: 1,8-cineole, which inhibits attraction to unsuitable trees, and (+)-isopinocamphone, a pheromone synergist. Size-linked morphological and olfactory adaptations may influence females' ability to select suitable host trees for reproduction.
Methods:
In field trap experiments conducted in 2019 and 2022, the body size of I. typographus females caught in response to different doses of (+)-isopinocamphone or 1,8-cineole in combination with pheromone was compared. Female Ips typographus were sorted based on body length, the size of the antennal club was measured, and size-dependent antennal responses to these volatiles were analyzed using electroantennography.
Results:
Larger females were more attracted to (+)-isopinocamphone in combination with pheromone in the field, showed stronger antennal detection, and had proportionally larger antennal clubs than smaller females. In contrast, smaller females were less repelled by 1,8-cineole added to pheromone, but, in contradiction, antennally detected it more strongly than larger females despite having smaller antennal clubs.
Conclusion: The total body length significantly influences semiochemical detection in I. typographus females. (+)-isopinocamphone was detected more effectively by larger females, implying an advantage in the selection of suitable host trees. In contrast, the discrepancy between behavioral and antennal responses to 1,8-cineole in smaller females suggests involvement of not only peripheral detection but also central nervous processing of olfactory signals driving behavior. This adaptation may enable smaller females to reduce competition with large ones by selecting less suitable trees. These findings provide new insights into the ecological relationship between beetle morphology and olfactory cues, with implications for tree–bark beetle interactions.
Dataset DOI: 10.5061/dryad.rxwdbrvn1
Description of the data and file structure
Size-dependent behavioral and antennal responses to doses of (+)-isopinocamphone and 1,8-cineole mixed with pheromone: a potential host selection strategy in female Ips typographus L.
Description of the data and file structure
Read the instructions step-by-step:
The trapping experiments were conducted in 2019 and 2022 at the Forest CZU property in Kostelec nad Černými lesy, Czech Republic. The experiments took place in a mature, 100-year-old Norway spruce forest, a natural habitat for I. typographus, located at 600 m above sea level. In 2019, the experiment was conducted at coordinates (49°56′02″N, 14°52′21″E), while the 2022 experiment took place at (49°55′57″N, 14°55′13″E). Both experiments were conducted during the same time frame: June 3 to July 28 of each year. In both the 2019 and 2022 experiments, traps were set up approximately 30 m from the forest edge in a 2-year-old clearing. The average temperature was 2019 16 °C (June), 18 °C (July), and 2022 17 °C (June), 19 °C (July). They were arranged in a row, with a minimum distance of 15 m between each trap, and were installed on wooden poles 1.5 m above the ground.
In 2019, seven cross-vane Ecotraps (Fytofarm, Slovak Republic) were used for collecting data for this experiment: three traps were baited with three different doses (low, medium, high) of 1,8-cineole or (+)-isopinocamphone, respectively, in combination with the synthetic pheromone. One trap was baited with pheromone alone and served as a control (for bait composition). To minimize positional bias, the positions of the tested baits among these seven traps were changed seven times according to a randomization scheme. (see the original article for more details).
measure for body size length: millimeter (mm)
measure for antennal club in length and width: micrometer (μm)
µg= microgram and/or ng= nanogram
mg= milligram
Low (L), Medium (M), High (H)= treatment doses of 1,8-cineole or (+)-isopinocamphone) and control (pheromone= 2-Methyl-3-buten-2-ol and Cis-verbenol) in milligram per day (mg/day). Nominal doses (see the original article for more details).
L: 0.1 mg/day + control
M: 1 mg/day + control
H: 10 mg/day + control
Control: 10:1 (2-Methyl-3-buten-2-ol : Cis-verbenol) mg/day
Dose–response tests were conducted using an aggregation pheromone in a 10:1 ratio of 2-methyl-3-buten-2-ol (MB) to cis-verbenol (cV).
1,8-cineole doses: 0.001 µg, 0.01 µg, 0.1 µg, 1 µg, 10 µg, 100 µg, and 1000 µg.
(+)-isopinocamphone doses: 0.001 µg, 0.01 µg, 0.1 µg, 1 µg, 10 µg, 100 µg, and 1000 µg.
General instructions:
Step 1: Download the file named: Data_females_ips_typographus.7z
Step 2: Extract files;
Here, the files were named as:
- Field data_bodysize_It
- Sma_Regression
- EAG_analysis_dose responses
# the end.
Files and variables
File: Data_females_ips_typographus.7z
Description: software, code and file name
The software used was R version 4.3.1 / RStudio 2024.04.2. The code is possible to be accessed in section "Files". The file name: code files_field and laboratory experiment with I. typographus females.txt
Brief description: the code is presented in txt. format. The file also is dived in step-by-step, 1. Field data_bodysize_It, 2. Sma_Regression and 3. EAG_analysis_dose responses, as explained in this readme.
Therefore, following the README description and file code information is needed. Below is presented a description regarding to the file name: code files_field and laboratory experiment with I. typographus females
data folder: 1. Field data_bodysize_It
The folder contains the dose-response field experiments conducted in 2019 and 2022, with the compounds and years named as follows. Insects were collected and measured for body size length in millimeters.
cine.2019.csv
cine.2022.csv
ipc.2019.csv
ipc.2022.csv
where is ipc = (+)-isopinocamphone; cine= 1,8-cineole followed by respective experiment year
#Step 3: below are listed files save as .csv extension (same legend as above)
1.Ph = Pheromone alone (control)
2.Ph.H = Pheromone + oxygenated monoterpenes at high dose
3.Ph.M = Pheromone + oxygenated monoterpenes at medium dose
4.Ph.L = Pheromone + oxygenated monoterpenes at low dose
#Step 4: Follow the respective R script for folder for further instruction.
# the End.
Data folder: 2. Sma_regression
Analysis of female I. typographus antennal measurements (measured for antennal club in length and width in micrometer
SMA= (Standardised) Major Axis Estimation.
Step 1: Open the data from the folder: Sma Regression
Step 2: open the csv file called: "SMA.1"
The data presented here represent the log-transformed measurements of the antennal club's length and width, expressed in micrometers
SMA.1 legend: Group: small and large represent the body size of females Ips typographus
Log.leng: represents the measurement of antennal club length;
Log.wid: represents the measurement of antennal club width
Step 3: Follow the respective R script for (2) Sma_Regression for further instruction.
# the End.
##########################################
Data folder: 3.EAG_analysis_dose responses
Data from small and large of females Ips typographus
EAG= electroantennography analysis
Step 1: Open the data from the folder: 3.EAG analysis_dose responses
#Each folder from "EAG analysis_dose responses" provided (+)-isopinocamphone, 1,8-cineole or Pheromone from females of Ips typographus L. 1758).
#Two group were tested: larger than 4.80 mm (n= 10) versus smaller than 4.70 mm. The size was selected based on field experiment results.
Dose-response labels each from files, (+)-isopinocamphone, 1,8-cineole or Pheromone:
Dose–response tests were conducted using an aggregation pheromone in a 10:1 ratio of 2-methyl-3-buten-2-ol (MB) to cis-verbenol (cV).
µg= microgram
ng= nanogram
1,8-cineole doses: 0.001 µg, 0.01 µg, 0.1 µg, 1 µg, 10 µg, 100 µg, and 1000 µg.
(+)-isopinocamphone doses: 0.001 µg (or 1ng), 0.01 µg (or 10ng), 0.1 µg (100 ng), 1 µg, 10 µg, 100 µg, and 1000 µg (or 1 mg).
#eag.1ng
#eag.10ng
#eag.100ng
#eag.1ug
#eag.10ug
#eag.100ug
#eag.1mg
#Step 2: open the csv accordingly: (+)-isopinocamphone, 1,8-cineole or Pheromone
#Both files mentioned above have the same columns and labels as follows:
#id= number of beetles tested
#eag = stimulated dose response obtained, here IPC_eag = (+)-isopinocamphone, Cine_eag = 1,8-cineole or Phero_eag = Pheromone.
#group.eag = size category small or large.
#Step 3: Follow the respective R script for EAG_analysis_dose responses for further instructions.
# the End.
1) Study Location and years:
The experimental areas: Norway spruce forest, the natural habitat of Ips typographus, at 600 m a.s.l. within the Forest CZU property, Kostelec nad Černými lesy, Czech Republic.
- 2019 site: Coordinates 49°56′02″N, 14°52′21″E.
- 2022 site: Coordinates 49°55′57″N, 14°55′13″E.
2) Time Frame and field experiments:
- Experiments ran from June 3 to July 28 in both 2019 and 2022.
2.1 Trap Type:
- Cross-vane Ecotraps (Fytofarm, Slovak Republic) were used for the experiments.
2.2 Trap Placement:
- Traps were positioned 15 meters apart, 1.5 meters above the ground, and approximately 30 meters from the forest edge.
2.3 Experimental Design (2019):
Seven traps were used.
- Six traps were baited with a pheromone and three different doses (low, medium, high) of either 1,8-cineole or (+)-isopinocamphone.
- One control trap was baited with pheromone alone.
2.4 Experimental Design (2022):
Two experimental blocks were established:
- One block tested 1,8-cineole dose.
- The second block tested (+)-isopinocamphone dose.
- Each block included a pheromone control trap to ensure reliable comparisons.
- Experimental setup are detailed in Moliterno et al. (2023).
Field effects of oxygenated monoterpenes and estragole combined with pheromone on attraction of Ips typographus and its natural enemies. Front. For. Glob. Change 6:1292581. doi: 10.3389/ffgc.2023.1292581
2.5 Morphological Measurements i. Insects
- Study Subject: Ips typographus (F0 generation) emerged from naturally infested Norway spruce logs (n = 12; ~50 x 28 cm).
- **Logs: **Tree logs were collected in Kostelec nad Černými Lesy during June–July 2024.
- Selection Criteria: Only female insects (~3 days old) were selected after sex sorting for further measurements and experiments.
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Size Groups Considered:
- Large-sized females: Body length ≥ 4.80 mm (n = 30).
- Small-sized females: Body length ≤ 4.70 mm (n = 30).
ii. Dose-Responses to Pheromones, 1,8-Cineole, and (+)-Isopinocamphone in Laboratory Experiments
- Subjects Tested: Only female insects.
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Size Groups:
- Large-sized females: Body length ≥ 4.80 mm (n = 10).
- Small-sized females: Body length ≤ 4.70 mm (n = 10).
- Exclusion: The analysis did not include damaged insects (broken or missing elytra).
2.6 Statistical Analysis
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Preliminary Tests:
- Data normality and variance homogeneity were assessed using the Shapiro-Wilk test and Levene’s test.
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Dependent and Independent Variables:
- Dependent Variable: Body length.
- Independent Variable: Doses of tested compounds.
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Comparative Analysis:
- Generalized Linear Model (GLM).
- The model employed a Gamma distribution with a log link function.
- Post hoc comparisons were conducted with the Tukey test, followed by a multiplicity correction using the Bonferroni method.
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Isometric vs. Allometric Relationships:
- Assessed via the Standardized Major Axis (SMA) method for antennal clubs of large and small females;
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Electroantennography Analysis:
- Compared responses of large and small females (n = 10 each) using the exact Wilcoxon rank-sum test;
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Software and alpha value:
- Analyses were performed in RStudio (version 4.1.1).
- Significance level (α) was set at 0.05.
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Additional Information:
- For further details, please refer to the related article.