PONE-D-19-24380

Influence of light availability and soil productivity on insect herbivory on bilberry (Vaccinium myrtillus L.) leaves following mammalian herbivory

PLOS ONE

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Reviewer #1: Yes

Reviewer #2: Yes

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Reviewer #1: No

Reviewer #2: Yes

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Reviewer #1: No

Reviewer #2: Yes

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Reviewer #2: Yes

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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: A review of a manuscript entitled “Influence of light availability and soil productivity on insect herbivory on bilberry (Vaccinium myrtillus L.) leaves following mammalian herbivory” for PLoS ONE (PONE-D-19-24380)

General comments

In this study, the authors aimed to evaluate whether the palatability of bilberry leaves (Vaccinium myrtillus) to insect herbivores is influenced by light availability, by soil productivity and by previous herbivory by mammals. A set of generalized linear models were used to test these three variables using a robust sample design. However, the results and discussion are dense, with many figures to look at and re-analyzes being described in the results and discussion. All of this part of data re-analysis to find the best model is part of the methods and I think it should not appear in the results. By reading the methods, the reader expects to see such analyzes and imagines such figures, but during the results the reader finds new analyzes being made based on the previous results. That does not seem appropriate to me here. These should all be described in the methods (or in supplementary documents) and the main results should be presented. This brings me to another issue. besides the text being dense in number of results, there are too many figures (14). In my opinion some tables and figures could be added as supplementary documents (e.g. Table 1, Figures 2, 3, 6, 8, and some ‘re-analyzed’ figures). This ‘cleaning’ of the paper (i.e. reduction in the amount of results by focusing on the main ones) are my main suggestions, since the study deals with an interesting topic and the results are promising. Minor suggestions are outlined below.

Specific comments (L: lines)

L 73-75: I suggest not leaving a sentence “alone” in the text. Please, add it to a paragraph.

L 189-190: What is the criterion used to establish these categories? Distribution of data? There is a much greater amplitude in the intermediate category than in the others.

L 474: Beware, the package itself shows nothing.

I could not access the data via DOI.

Reviewer #2: - The paper claims that bilberry palability by insects following mammalian herbivory is affected by leaf nutrient concentration and that this response is intensified by shade levels.

- The claims are properly placed in the context of previous literature but the readability of the introduction can be improved. Please see comments below.

- The analyses performed support their claims. However, figure 8 regarding the correlation between insect and mammalian herbivory must be improved. The analyses show a significant correlation but for some reason that’s not clear when looking at the figure.

- Information on protocols and analyses seems to be complete.

- The paper could be published provided that the authors improve some aspects (please see comments below).

- Raw data is not included, it would be useful to include it.

- Details of the methodology are sufficient.

- Yes, the manuscript is well organized and written clearly.

Comments

Line 54: There is no connection between the previous paragraph and the paragraph starting in this line. There is a phrase missing introducing this new hypothesis. How are connected the constitutive defense and the optimal defense (OD).

Line 60: Similarly as above, the carbon:nutrient balance (CNB) hypothesis comes out of the blue. Could you please introduce with an explanatory phrase on how this hypothesis is connected with the previous one?

Line 140 to 152: Probably it would be easier for the reader if you integrate this information in the text of the introduction to connect your own hypothesis with the one in the literature.

Line 218: Which are the productivity classes? They have not been introduced so far.

Figure 4a: The scales are so different between insect herbivory and mammalian herbivory that it is difficult to see the trend of the effect of shade on mammalian herbivory. Please separate these two figures. Why in the statistics of figure 4 (lines 303 to 310) there is a report of F and P values of years 2013 and 2014? What about year 2015? Please include missing information.

Why mammals feeding on low soil productivity levels?. Also, there was something going on in 2013: -High mammalian herbivory in quadrats with high shade levels than at quadrats with low shade levels. - there was no difference in mammalian herbivory between the three soil productivity classes. While for the other years a higher mammalian herbivory was registered for low soil productivity. Could you comment on that ?

Figure 6. Please explain briefly in the figure title what you mean with “standardized mammalian herbivory”.

Figure 8. Why an R2 value is not presented in the figure. Please include it. Can you please explain in the figure legend what you mean by “adjusted” R2. The correlation does not seem very strong when the shade variable is taken away…Especially taking into account that the Y axis goes only 35%. It should be 100%.

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Reviewer #1: No

Reviewer #2: No

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Influence of light availability and soil productivity on insect herbivory on bilberry (Vaccinium myrtillus L.) leaves following mammalian herbivory

PONE-D-19-24380R1

Dear Dr. Schrijvers-Gonlag,

We are pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it complies with all outstanding technical requirements.

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With kind regards,

Livia Maria Silva Ataide

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

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. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #2: Yes

**********

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?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). 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: Yes

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

PLOS ONE 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: Second assessment of the manuscript entitled “Influence of light availability and soil productivity on insect herbivory on bilberry (Vaccinium myrtillus L.) leaves following mammalian herbivory” for Plos One (PONE-D-19-24380R1)

Main comments

In this paper, the authors aimed to assess whether bilberry leaf palatability to insects is affected by light availability, soil productivity, and previous mammalian herbivory. They used a set of generalized linear mixed and additive models to test three main predictions about bilberry leaf palatability using a robust sample design. In my first assessment, I found the results and discussion very dense, with many figures to look at and many re-analyzes being described in both results and discussion. In this new version, I recognize the effort made by the authors to make the text shorter and more objective. I have no new suggestions to make. Therefore, I have a favorable opinion on the publication of this study that deals with an interesting research topic. This paper will be a good piece of work honoring the memory of Professor Harry P. Andreassen.

Reviewer #2: I have already considered that the first version of the manuscript contained an interesting research question, valuable data and a correct statistical analysis. However, there were problems with readability and with the clarity of some of the figures. The new version of the manuscript is much clearer and more enjoyable to read. It was a wise decision to put some of the figures and data as supplementary material. The authors did answer and clarify the questions I had from the previous version.

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If you choose “no”, your identity will remain anonymous but your review may still be made public.

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Reviewer #1: Yes: Pedro Giovâni da Silva

Reviewer #2: Yes: Karen Muñoz Cárdenas