Data from: Genetic and habitat complexity effects on unpredictability in escape behavior of a grasshopper species
Data files
Aug 21, 2025 version files 10.81 GB
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Raw_data.zip
10.81 GB
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README.md
4.37 KB
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Unpredictability_HeritabilityHabitat_Data_230710.txt
817.91 KB
Abstract
The debate surrounding the role of genetic and environmental factors in shaping behavior has a long tradition. However, their effects on complex behaviors such as unpredictability in anti-predator strategies remain poorly understood. Behaving unpredictably when escaping predators may increase the prey's chances of survival, especially when prey can rely on a complex habitat providing camouflage and shelter opportunities. We explored the effects of genetic and environmental influences on escape strategies of the steppe grasshopper Chorthippus dorsatus. Individuals from controlled breeding had been randomly assigned to one of two environmental complexity treatments during ontogeny. We then quantified escape behavior in a large cohort through burst experiments. Using a multivariate double-hierarchical animal model, we analyzed the effects of pedigree and environmental complexity on both inter- and intra-individual variance in three components of escape behavior: flight initiation distance (FID), jump distance, and jump angle. Habitat complexity affected average jump angle, but not the average FID or jump distance, nor unpredictability in any of the three traits. Pedigree relatedness accounted for 5-6% of the total variance in average FID and average jump distance and 7% of the variance in unpredictability in jump angle. Genetic correlations suggest a behavioral syndrome structure in escape strategies that involves FID (a potential indicator of boldness). Our study demonstrates that unpredictability in escape behavior has the potential to evolve by natural selection, as some of its components are heritable. Furthermore, we show that although habitat complexity represents a strong environmental treatment, its lasting effects during ontogeny on escape behavior are minimal.
Code
You can download the analysis code at https://doi.org/10.17605/OSF.IO/7PBVQ
Study
The study examined genetic and environmental influences on unpredictability in the escape behavior of Chorthippus dorsatus grasshoppers. Using a controlled breeding design, offspring were raised in either simple or complex habitats and tested for flight initiation distance (FID), jump distance, and jump angle. A multivariate double-hierarchical animal model revealed that habitat complexity influenced average jump angle but had no lasting effects on FID, jump distance, or unpredictability. Genetic factors accounted for 5-6% of the variance in average FID and jump distance and 7% in the unpredictability of jump angle. Genetic correlations indicated a behavioral syndrome involving FID. The findings suggest that unpredictability in escape behavior is heritable and may evolve through natural selection, while environmental complexity has limited long-term effects.
Description of the data and files
Unpredictability_HeritabilityHabitat_Data_230710.txt
Dataset with all observations of escape jumps of grasshoppers. See description of variables below.
Raw_data.zip
Folder containing all videos used in the analyses of escape responses. File names are the same as the variable [TrialID] in the data file Unpredictability_HeritabilityHabitat_Data_230710.txt
Description of variables
The dataset consists of a total of 9150 observations. Each line represents an escape jump.
- TrialID: refers to each observation.
- IndID: refers to the identification number of each individual.
- CageID: refers to the cage where an individual was raised. Hatchlings of an egg pod were raised in the same cage.
- DamID: refers to the mother identity (full-sibling families)
- SireID: refers to the father identity (half-sibling families)
- Treatment: refers to the type of cage that the individual was raised in. (S) for a simple white cage containing only food and water, (C) for an environmental complexity treatment, with climbing, hiding, color, and texture structures added to the cage, besides water and food.
- Sex: is coded as (M) for males and (F) for females.
- ColorMorph: indicates the color morph of that individual. (B) entirely brown individuals, (G) entirely green individuals, (BG) individuals that are brown dorsally and green on the laterals of the body, (GB) individuals that are green dorsally and brown on the laterals of the body.
- Weight: body weight, in grams. Measured at the end of the experimental session, after 10 jump escapes were recorded.
- JumpOrder: refers to the sequential number of jumps within the 10 trials of an individual.
- Cohort: due to housing capacity, offspring were hatched in 7 different cohorts. Each cohort lasted around 1.5 months - around 30 days for the developmental period from hatching of the eggs until final molt, plus the time taken to phenotype the escape responses of all individuals.
- Temperature: temperature in Celsius degrees in the experimental arena, where escape responses were recorded. Room temperature was controlled, with slight variation.
- DayTime: time of the day when escape behavior was phenotyped, coded as 24h with the minutes converted to decimals (for example: 1:30 pm = 13.5)
- PhenotypingDate: is the date when the experiment occurred (DD_MM_YY).
- DaysAfterMolt: number of days since the final molt. A proxy for the age of an individual after reaching maturity.
- PoorConditionYN: logical variable used to remove from the analysis individuals that lost hind legs or seemed ill during a phenotyping session. All observations containing 1 (yes) were removed from the analyses.
- FID: is the flight initiation distance in centimeters, defined as the minimum distance between the chaser and the grasshopper before the grasshopper jumped.
- JumpDistance: is the jump's length in centimeters, defined as the distance between the point where the jump started and where the grasshopper landed
- JumpAngle: is the angle of the jump direction in degrees in relation to the initial grasshopper body position. Straight jumps scored 0ᵒ, while negative values marked jumps to the left, and positive values jumps to the right.
The study aimed to determine whether unpredictability in escape behavior is heritable in steppe grasshoppers (Chorthippus dorsatus) and whether habitat complexity influences developmental plasticity in unpredictability. Grasshopper offspring were obtained through a half-sib full-sib breeding design using field-caught individuals from Jena, Germany. Males (N = 51) were mated with approximately five females each (N = 249 total), ensuring a balanced color morph representation. Offspring were raised in either simple (plain white) or complex (enriched with patterned surfaces and climbing structures) habitats to assess environmental effects. Escape behavior was measured in a controlled arena where individuals were exposed to a simulated predator approach. Flight initiation distance (FID), jump distance, and jump angle were recorded using Ethovision XT software.