Data from: Stalk-eyed flies carrying a driving X chromosome compensate by increasing fight intensity
Data files
Sep 12, 2024 version files 137.75 KB
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Editorial_1.XLSX
129 KB
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README.md
8.75 KB
Abstract
Exaggerated ornaments provide opportunities for understanding how selection can operate at different levels to shape the evolution of a trait. While these features aid their bearer in attracting mates or fending off competitors, they can also be costly and influenced by the environment and genetic variation. Eyestalks of the stalk-eyed fly, Teleopsis dalmanni, are of interest because eyestalk length is the target of both intra-and intersexual selection and is also reduced by loci on a highly-diverged sex ratio X chromosome (XSR), a meiotic driver accounting for up to 30% of wild X chromosomes. Male stalk-eyed flies fight to control access to females and over food using a combination of low intensity displays and high intensity physical fights. We staged, filmed and scored contests among eyespan-matched male pairs to evaluate whether X chromosome type impacts the behavior and outcome of aggressive interactions. While our results broadly match expectations from previous studies, we find that XSR males used more high intensity behaviors than males carrying a non-driving, standard X chromosome (XST), in particular when their eyestalks were of similar size or smaller than their opponents. Additionally, we find that when XSR males use high intensity behaviors they win more bouts than when they use low intensity behaviors. Taken together these results suggest that XSR impacts male aggressive behavior to compensate for the shorter eyestalks of XSR males, and may help to explain how this selfish chromosome is maintained.
https://doi.org/10.5061/dryad.79cnp5j51
Description of the data and file structure
We staged, filmed and scored contests among eyespan-matched pairs of stalk-eyed fly males to evaluate whether X chromosome type impacts the behavior and outcome of aggressive interactions. Males were genotyped for the presence of a meiotic drive X chromosome after scoring.
Files and variables
File: Editorial_1.XLSX
Description of the data table columns
Variable | Description |
---|---|
Trial type | Standardized opponent trials involved an outbred male fighting an inbred competitor; Outbred pair trials involved two outbred males fighting each other |
Focal Male | ID of first male |
Opponent Male | ID of opponent |
Any bout | Y if any aggressive interactions occurred, N if not |
Focal Eyespan | eyespan in mm (Focal) |
Focal Body | body length in mm (Focal) |
Focal Thorax | thorax width in mm (Focal) |
Opp Eyespan | eyespan in mm (Opponent) |
Opp Body Length | body length in mm (Opponent) |
Opp Thorax | thorax width in mm (Opponent) |
Focal X | X chromosome type, ST = XST, SR = XSR (Focal) |
Opp X | X chromosome type, ST = XST, SR = XSR (Opponent) |
Num Bouts | Number of aggressive contests within 10 minute trial, NA if none scored |
Total bout length (s) | Total duration of aggressive contests (s) |
First bout length (s) | Duration of the first aggressive contest (s) |
Last bout length (s) | Duration of the last aggressive contest (s) |
Focal Initiate | Number of times the male initiated an aggressive contest (Focal) |
Focal Approach | Number of times the male performed the approach behavior (Focal) |
Focal Line up | Number of times the male performed the line-up behavior (Focal) |
Focal Flex and Extend | Number of times the male performed the flex and extend behavior (Focal) |
Focal Jump Attack | Number of times the male performed the jump attack behavior (Focal) |
Focal Attack/Lunge | Number of times the male performed the attack/lunge behavior (Focal) |
Focal Tussle | Number of times the male performed the tussle behavior (Focal) |
Focal Away | Number of times the male performed the away behavior (Focal) |
Focal Pursue | Number of times the male performed the pursue behavior (Focal) |
Focal Retreat | Number of times the male performed the retreat behavior (Focal) |
Focal Escalation | Number of times the male transitioned from low to high intensity behavior (Focal) |
Focal Descalation | Number of times the male transitioned from high to low intensity behavior (Focal) |
Opp Initiate | Number of times the male initiated an aggressive contest (Opponent) |
Opp Approach | Number of times the male performed the approach behavior (Opponent) |
Opp Line up | Number of times the male performed the line-up behavior (Opponent) |
Opp Flex and Extend | Number of times the male performed the flex and extend behavior (Opponent) |
Opp Jump Attack | Number of times the male performed the jump attack behavior (Opponent) |
Opp Attack/Lunge | Number of times the male performed the attack/lunge behavior (Opponent) |
Opp Tussle | Number of times the male performed the tussle behavior (Opponent) |
Opp Away | Number of times the male performed the away behavior (Opponent) |
Opp Pursue | Number of times the male performed the pursue behavior (Opponent) |
Opp Retreat | Number of times the male performed the retreat behavior (Opponent) |
Opp Escalation | Number of times the male transitioned from low to high intensity behavior (Opponent) |
Opp Descalation | Number of times the male transitioned from high to low intensity behavior (Opponent) |
Focal Wins | Number of aggressive contests won by the focal male |
Focal Loss | Number of aggressive contests lost by the focal male |
Draw | Number of aggressive contests drawn |
Following previous studies of fighting in stalk-eyed flies (Panhuis and Wilkinson 1999; Egge et al. 2011; Bubak et al. 2014), we quantified male aggressive behavior in two sets of trials conducted either at SUNY Geneseo (outbred pair trials) or the University of Maryland, College Park (standardized opponent trials). We conducted trials with outbred and inbred flies as opponents to confirm that the results were robust to the opponents’ genetic background. Sexually mature males at least four weeks post-eclosion were anesthetized using carbon dioxide, eyespan and body length were measured from video-captured images to the nearest 0.01 mm using ImageJ. All trials were conducted in transparent plastic arenas (10 x 3.5 x 6 cm) lined with moist blotting paper and initially divided into three sections by opaque plastic barriers. Each male was placed into an outer compartment of the arena and fasted 20-24 h. At the beginning of the trial, a piece of agar gel made with corn juice was placed into the center compartment as a food resource and the barriers were removed. Trials were video recorded for ten minutes. Scoring of each video was done blind to genotype. Occurrence of aggressive behaviors performed by each fly in each trial were scored from video recordings following a published ethogram. Within a trial, we defined fighting “bouts” to begin once either fly performed an aggressive behavior and end when the flies were more than a body length apart or not facing each other for 3 s without exhibiting any aggressive behavior. A male was scored as losing a bout if he moved away from his opponent at the end of a bout either slowly (away) or quickly (retreat) and his opponent did not. A mutual away or retreat was considered a tied bout. Most trials involved multiple bouts. Aggressive behaviors were categorized as either high intensity (HI) behaviors that involved physical contact (tussle, attack/lunge, jump attack) or low intensity (LI) behaviors that involved males mutually displaying their eyestalks in close proximity (approach, flex, and extend, line-up eyestalks). Escalations were tallied for each individual as a transition from a LI to a HI behavior with no other behaviors or the start or end of a bout separating them. Similarly, de-escalations were defined as a transition from HI to LI behavior. Males were collected immediately after each trial for DNA extraction and genotyping for X chromosome type (XSR or XST) using polymerase chain reaction (PCR) to amplify either of two markers (Table S1) that each predict drive phenotype in this population with 95% accuracy.