Data from: Differences in parasite infection status and behavior between a clonal fish and her sexually reproducing heterospecifics
Data files
May 06, 2026 version files 74.85 KB
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README.md
4.30 KB
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texas2022_all_20260421.csv
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Texas2022_analysis_submission_20260421.Rmd
54.16 KB
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texas2022_parasite_20260421.csv
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Abstract
Parasites impose strong selective pressures on animals, influencing traits from behavior to reproductive strategies. In particular, parasite-mediated selection has been proposed as a major driver of sexual reproduction, as genetic recombination can generate variation that facilitates rapid evolutionary responses to parasites. Accordingly, asexual vertebrates are predicted to be more susceptible to parasites, yet some persist over longer than expected evolutionary timescales. The Amazon molly (Poecilia formosa) is a gynogenetic, clonal fish that occurs sympatrically with its sexual parental species, including the Sailfin molly (P. latipinna). Here, we investigate the link between behavioral differences and parasite infection in wild-caught Amazon and Sailfin mollies across two populations. Fish were exposed to a simulated predator attack, and space-use behavior was quantified as time spent in open versus sheltered areas. We subsequently determined their infection status and parasite load via dissection. We found that Amazons and Sailfins differed in their qualitative, but not quantitative, resistance to parasites. Amazons had worse qualitative resistance (i.e., were more likely to be infected with at least one parasite) and spent more time in the open, riskier portion of the arena. However, consistent with previous studies, Amazons and Sailfins did not differ in quantitative resistance (i.e., parasite load). Parasite prevalence and load differed between our two collection sites, suggesting an important role for environmental context. These results suggest that there is a correlation between behavior and parasite exposure in Amazons, while immune or physiological traits may allow them to limit parasite loads once infected. While the scope of this study makes it difficult to tell whether increased risk-taking behavior leads to parasite exposure or vice versa, our results still highlight important differences between sexual and asexual species in parasite-laden environments.
Dataset DOI: 10.5061/dryad.jsxksn0r9
Description of the data and file structure
This README describes the columns and format of the data used in our analysis. This observational experiment was designed to test whether fish behavior was affected by parasite load and whether those patterns differed between species. Fish were collected by Kirsten Sheehy and Jon Aguiñaga. They also conducted the behavioral trials. Behavioral data and fish lengths were extracted from videos and photos by Nishika Raghavan and Kirsten Sheehy. Parasite data were collected by Dr. Jessica Stephenson, Dr. Mary Janecka, Charlie Walsh, and Kareen Wali.
Authors listed on the manuscript have made major contributions to at least two out of the following categories: ideation, funding, data collection, analysis, writeup of manuscript, and editing manuscript. Authors on this manuscript include Kirsten Sheehy, Dr. Jon Aguiñaga, Dr. Jessica Stephenson, and Dr. Mary Janecka.
All authors (Kirsten Sheehy, Dr. Jon Aguiñaga, Dr. Jessica Stephenson, and Dr. Mary Janecka) and contributors (Nishika Raghavan, Charlie Walsh, and Kareen Wali) to this dataset and manuscript have consented to the CC0 waiver.
NAs in the texas2022_parasite_20260421.csv reflect missing data (i.e., not available). There are 2 NAs for sex and 10 for standard.length. For sex, these are due to clerical errors--the specimen label either did not include sex or was illegible. For standard length, some of the fish that were dissected for the parasite counts were not assigned a unique ID, and were therefore unable to be linked with the photos used to measure standard length.
Files and variables
File: Texas2022_analysis_submission_20260421.Rmd
Description: R Markdown used for analysis and the generation of figures.
File: texas2022_parasite_20260421.csv
Description: Data used for the parasite-only analysis.
Variables
- site.id: Fish were collected from one of two sites: Brownsville or Weslaco.
- species: This is the species name of the fish being observed. It is either "latipinna" or "formosa".
- sex: There are both male and female P. latipinna in this dataset. There are only females of the P. formosa. Sex was determined by the presence/absence of a gonopodium. Sex was recorded as either M or F in the data.
- standard.length: Standard length is from the mouth of the fish to the caudal peduncle (in centimeters).
- totalpara: Sum of total parasites on that fish (trematodes and unknown).
File: texas2022_all_20260421.csv
Description: Data used for the behavioral analysis. Includes parasite data.
Variables
- fish.id: Each fish that went through behavioral trials got a unique ID based on the species and the order in which the fish were processed (e.g., PF-05 is the 5th Poecilia formosa measured). For the parasite data, some fish did not get a unique ID, or their labels were no longer legible. These fish were then just named after their species (e.g., P. formosa).
- trial.id: The first or second trial that a fish went through.
- site.id: Fish were collected from one of two sites: Brownsville or Weslaco.
- species: This is the species name of the fish being observed ("P. latipinna" or "P. formosa").
- sex: There are both male and female P. latipinna in this dataset. There are only females of the P. formosa. Sex was determined by the presence/absence of a gonopodium. Sex was recorded as either M or F in the data.
- totalpara: Sum of total parasites on that fish (trematodes and unknown).
- standard.length: Standard length is from the mouth of the fish to the caudal peduncle (in centimeters).
- total.time.open.after: Total amount of time in seconds that a fish spends in the open half of the arena after the startle stimulus.
- prop.open: Proportion of time a fish spends in the open half of the arena over the whole trial.
- prop.open.b4: Proportion of time that a fish spends in the open half of the arena prior to the startle stimulus.
- prop.open.after: Proportion of time that a fish spends in the open half of the arena after the startle stimulus.