Data and code from: Host plant nutrition drives fitness outcomes in the cactus specialist Drosophila mettleri
Data files
May 28, 2026 version files 69.19 KB
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cactus_plates.xlsx
6.16 KB
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Dev_assay.xlsx
15.38 KB
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ExQ_Sum.xlsx
5.91 KB
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metSag_scripts.R
16.79 KB
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Pilot_assay.xlsx
22.36 KB
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README.md
2.59 KB
Abstract
Organisms must navigate complex interactions with host plants, microbial communities, and environmental cues to ensure their survival and reproductive success when adapting to novel environments. Due to their ecological constraints, host plant specialists can be used to study how these interactions affect fitness due to their ecological constraints. In specialist species, such as cactophilic Drosophila, it remains unclear how feeding behavior, substrate composition, and microbial interactions collectively shape fitness outcomes. We examined the effects of laboratory media (cornmeal vs. banana) differing in their base diet and cactus-derived additives (dried Saguaro powder, exudate from rotting Saguaro, soil soaked by rotting Saguaro) on fitness in Drosophila mettleri, a columnar cactus specialist that breeds in Saguaro cactus (Carnegiea gigantea) in the Sonoran Desert. Cactus supplements often reduced survival from egg to pupa, but increased survival from pupa to adult, resulting in stage-specific tradeoffs shaping egg-to-adult fitness. Results show interactions between food substrate and cactus treatment: cactus supplementation reduced survival on banana media but increased survival on cornmeal-based diets. Feeding rate and overall amount of media consumed did not differ among treatments, indicating that differences in survival and fitness may depend on the broader nutritional environment and developmental stage. This suggests that studying host specialization should include multiple life stages.
Dataset DOI: 10.5061/dryad.x3ffbg7z6
Description of the data and file structure
We obtained fitness data from rearing Drosophila mettleri on two diets (cornmeal and banana) and 4 treatments each: control, exudate (collected from decomposing Saguaro tissue), powder (created by roasting decomposing Saguaro tissue - donated), and soil (collected from below decomposing Saguaro tissue)
Data files
cactus_plates.xlsx: Contains variables and data from the plate assay that was used to assess microbial community on the 4 treatments.
- Plate: Type of agar plate used. YPD refers to yeast peptone dextrose, BHI refers to Brain Heart Infusion, LB refers to Luria Broth, and MH refers to Meuller Hinton.
- Treatment: The type of treatment planned
- Number of Colonies: The resulting number of microbial colonies
- Total Area (mm2): The total area of all the microbial colonies
- Average Size (mm2): The average size of each microbial colony
- %Area: The total area of microbial colonies as a percentage cover of the full plate
Dev_assay.xlsx: Contains results of nutritional fitness assay
- Food: Type of base diet used, either banana or cornmeal
- cactus: Type of treatment added to the base diet
- fly_group: Group of D. mettleri adults on the specific food and cactus combination
- day: Adults were flipped onto new food every 24 hours. Refers to a specific day, adults from the specific fly group were in that vial.
- eggs: Number of eggs laid
- pupae: Number of pupae
- adults: Number of adults
ExQ_Sum.xlsx: Contains results of excreta quantification assay
- Sex: The sex of D. mettleri adults
- Food: The base diet and treatment
- mean_response: Mean amount of food eaten
- se_response: Standard error in the amount of food eaten
- CI: Confidence interval in the amount of food eaten
metSag_scripts.R: R scripts of all analyses run
Pilot_assay.xlsx: Contains results of pilot fitness assay
- Food: Type of base diet used, either banana or cornmeal
- cactus: Type of treatment added to base diet.
- fly_group: Group of D. mettleri adults on the specific food and cactus combination
- day: Adults were flipped onto new food every 24 hours. Refers to a specific day, adults from the specific fly group were in that vial.
- eggs: Number of eggs laid
- pupae: Number of pupae
- adults: Number of adults
Code/software
All analyses were done in R Environment for Statistical Computing R 4.4.2 (2024-10-31).