PCLM-D-25-00040

The amplitude, duration, and timing of a heatwave can alter parasite fitness depending on the baseline temperature.

PLOS Climate

Dear Dr. McCartan,

Thank you for submitting your manuscript to PLOS Climate. After careful consideration, we feel that it has merit but does not fully meet PLOS Climate’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

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Although the manuscript reports interesting data, however, many comments have need raised by the reviewers. Therefore, authors should revise their manuscript by addressing clearly the reviewers comments and answering their questions.

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Please submit your revised manuscript by Apr 17 2025 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at climate@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pclm/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

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Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

We look forward to receiving your revised manuscript.

Kind regards,

Noureddine Benkeblia, Dr. Sci., Dr. Agr.

Academic Editor

PLOS Climate

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Additional Editor Comments (if provided):

he manuscript presents interesting data, however, many pints need to be clarified and reviewers' comments should be addressed.

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. Does this manuscript meet PLOS Climate’s publication criteria ? Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe methodologically and ethically rigorous research with conclusions that are appropriately drawn based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: I don't know

Reviewer #2: Yes

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3. Have the authors made all data underlying the findings in their manuscript fully available (please refer to the Data Availability Statement at the start of the manuscript PDF file)?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception. The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #2: No

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4. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS Climate does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

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5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: I have reviewed the manuscript titled "The amplitude, duration, and timing of a heatwave can alter parasite fitness depending on the baseline temperature." The manuscript presents a well-designed and comprehensive study on the effects of heatwave attributes (amplitude, duration, and timing) on parasite fitness in the Daphnia magna-Ordospora colligata host-parasite system. It offers valuable insights into how these extreme temperature events can influence host-parasite dynamics. The study highlights the complexity of heatwave impacts on disease dynamics and emphasizes the importance of considering multiple heatwave attributes and their interactions.

However, I have several concerns before consider to accept for publication:

Introduction: Important literatures related to this paper have not been included for other host-parasite systems, the effects of heatwaves, baseline temperature, amplitude, duration, and timing would strengthen the argument (doi: 10.1146/annurev-ento-041520-074454; 10.1127/entomologia/2022/1410; 10.1111/gcb.12654; 10.1007/s10340-022-01574-5;).

Methods: How were the baseline temperatures (14°C, 17°C, 20°C, and 23°C) chosen? How were the heatwave amplitudes (+3°C and +6°C) determined?

Explaining the use of elastic net regression and bootstrapping in more detail would help readers unfamiliar with these techniques. A brief justification for choosing these methods over more traditional approaches (e.g., GLMMs) would be beneficial.

Results: Figure 2 and 3, the error bars and regression curves could be differentiated by different thickness, making the elements that you want to emphasize the importance thicker to improve the clarity.

The descriptions of results are not clear enough. It has not clearly demonstrated the general effects of baseline temperature, timing, amplitude and duration, and their interactions one by one. It is a bit difficult for readers to get a clear image for the results both from the figures and the corresponding text. Consider adding a summary table or figure that directly compares the outcomes for infection prevalence and parasite proliferation across the different experimental conditions (timing, amplitude, duration, baseline temperature).

Discussion: a deeper discussion of host immune responses, parasite thermal tolerance, and host-parasite coevolutionary dynamics would be beneficial. It would be helpful to discuss how these findings might apply to other host-parasite systems to expand the general ecological and evolutionary implications.

References: Some recent studies on heatwaves and disease dynamics could be included to strengthen the introduction and discussion.

Reviewer #2: Overall Assessment:

This study explores the effects of heatwave attributes—amplitude, duration, and timing—on the fitness of the parasite Ordospora colligata in the Daphnia magna host system under different baseline temperatures. The research is timely and contributes significantly to understanding how climate-induced extreme temperature variations impact host-parasite dynamics. The manuscript is well-structured, methodologically sound, and presents insightful findings. However, there are areas that require clarification, refinement, and further discussion to improve the overall impact and clarity of the study.

Areas for Improvement and Recommendations

1. Title and Abstract Improvements

• The title, while informative, could be made more engaging. Consider:

o "Impact of heatwave amplitude, duration, and timing on parasite fitness at different baseline temperatures"

• In the abstract, clarify the ecological and practical relevance of findings beyond just Daphnia-Ordospora. How do these results inform predictions for other host-parasite systems in a warming world?

• The sentence "Furthermore, the presence of complex two- and three-way interactions both with parasite prevalence and proliferation highlight the nuanced and context-dependent nature of heatwave impacts."

Consider simplifying this for better readability. For example:

o "Our results reveal complex interactions between heatwave attributes and baseline temperature, emphasizing that heatwaves have highly context-dependent effects on parasite prevalence and proliferation."

2. Introduction: Expanding the Conceptual Framework

• While the introduction effectively sets the stage, some additional literature could be referenced regarding:

o The ecological consequences of temperature variability on multi-host parasite systems.

o How heatwave-induced stress affects immune responses in ectothermic hosts.

o Existing predictive models of parasite fitness under climate change (e.g., dynamic disease forecasting models).

• The introduction predominantly discusses temperature effects on parasite fitness but could better integrate host physiological responses, particularly regarding immune suppression or resilience under fluctuating conditions.

3. Methodology: Clarifications and Justifications

• Experimental Design:

o The rationale behind choosing specific baseline temperatures (14, 17, 20, and 23°C) could be further justified. Are these reflective of typical environmental conditions for Daphnia magna?

o How do these temperatures compare to real-world climate projections?

• Parasite Fitness Measurement:

o Infection burden is quantified via spore cluster counts, but how was the variability across replicates controlled? Were there individual host variations in spore susceptibility?

o Provide justification for defining infection success as presence/absence rather than using a more continuous metric.

• Statistical Models:

o The manuscript employs elastic net regression for model selection, which is appropriate given multicollinearity concerns. However, additional details on how feature importance was calculated and interpreted should be provided.

o The reasoning behind using bootstrapping (50,000 iterations) for model stability could be briefly explained. Was this number chosen empirically?

o It would be helpful to discuss any limitations of the statistical approaches used.

4. Results: Enhancing Data Presentation

• The figures and tables are well-constructed, but some additional clarifications could improve readability:

o Figure 2 and 3: Consider adding summary takeaways in the captions to guide interpretation.

o Table 1 & 2: Instead of just presenting coefficients, a brief note explaining how to interpret effect sizes would be helpful.

o Given the complexity of interactions, a visual model or pathway diagram illustrating the relationships between heatwave characteristics and parasite fitness could improve clarity.

5. Discussion

• The discussion provides a thorough interpretation of findings but could be more concise. Consider summarizing key takeaways or a concluding paragraph.

• Real-World Implications:

o How do these results translate to natural ecosystems where heatwaves are unpredictable?

o Could they inform disease forecasting models or conservation strategies for species vulnerable to heat stress?

• Comparison to Other Studies:

o Some comparisons are made to previous work (e.g., Kunze et al. 2022), but further exploration of whether similar trends occur in other parasite taxa would strengthen the manuscript.

• Limitations and Future Directions:

o The study primarily focuses on Ordospora colligata in Daphnia magna. How generalizable are the findings to other host-parasite systems?

o Would incorporating additional host immune response variables improve predictive accuracy?

6. Minor Stylistic and Formatting Suggestions

• Ensure consistent formatting of in-text citations (some appear as numerical, while others use author-date format).

• Some sentences are long and could be split for readability (e.g., in the results section).

• The phrase "Not all heatwaves result in the same outcome in parasite fitness" is repeated in multiple sections. Consider rewording for variety.

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For information about this choice, including consent withdrawal, please see our Privacy Policy .

Reviewer #1: No

Reviewer #2: Yes:  Sokame, Bonoukpoe Mawuko

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Impact of heatwave amplitude, duration, and timing on parasite fitness at different baseline temperatures.

PCLM-D-25-00040R1

Dear Dr. McCartan,

We are pleased to inform you that your manuscript 'Impact of heatwave amplitude, duration, and timing on parasite fitness at different baseline temperatures.' has been provisionally accepted for publication in PLOS Climate.

Before your manuscript can be formally accepted you will need to complete some formatting changes, which you will receive in a follow-up email from a member of our team. 

Please note that your manuscript will not be scheduled for publication until you have made the required changes, so a swift response is appreciated.

IMPORTANT: The editorial review process is now complete. PLOS will only permit corrections to spelling, formatting or significant scientific errors from this point onwards. Requests for major changes, or any which affect the scientific understanding of your work, will cause delays to the publication date of your manuscript.

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Thank you again for supporting Open Access publishing; we are looking forward to publishing your work in PLOS Climate.

Best regards,

Noureddine Benkeblia, Dr. Sci., Dr. Agr.

Academic Editor

PLOS Climate

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Additional Editor Comments (if provided):

Reviewer Comments (if any, and for reference):

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

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2. Does this manuscript meet PLOS Climate’s publication criteria ? Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe methodologically and ethically rigorous research with conclusions that are appropriately drawn based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

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3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available (please refer to the Data Availability Statement at the start of the manuscript PDF file)?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception. The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: (No Response)

Reviewer #2: Yes

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5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS Climate does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #2: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: I have no more comments.

Reviewer #2: The manuscript has significantly improved and addressed most of the key points raised.

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7. PLOS authors have the option to publish the peer review history of their article (what does this mean? ). If published, this will include your full peer review and any attached files.

Do you want your identity to be public for this peer review? If you choose “no”, your identity will remain anonymous but your review may still be made public.

For information about this choice, including consent withdrawal, please see our Privacy Policy .

Reviewer #1: No

Reviewer #2: No

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