Effect of Aphid Foraging on the Intensity of Photosynthesis and Transpiration of Selected Crop Plants in Its Early Stages of Growing

Round 1

Reviewer 1 Report

In this study, the authors investigated the biotic pressure of three aphid species foraging on three different plant species. To evaluate the impact of the aphid colony on plant status, two important parameters were considered: photosynthetic activity and transpiration. In my opinion, the evaluation of the effects of aphid foraging on the plant should be better investigated and described. The effect of an aphid colony on the plant photosynthetic activity and transpiration strongly depends on the aphid mortality and on the offspring produced during the experimental period. To understand the real effect of an aphid colony on plants, it should be opportune to record the total number of aphids, that is, considering not only the initial aphids, but also the progeny at the 5, 10 and 15 days from the beginning of the experiment. Aphids could also cause several injuries to host plants, such as chlorosis and leaf crumbling, for example, affecting overall plant health. However, the authors measure only “youngest, fully developed, randomly selected leaves”, without giving any information on the health of the plant. All this information could be useful to the readers in understanding the real impact of aphid colonies on plants.

Introduction. The introduction seems to me weak, out of focus, and not very articulate. For example, the influence of aphids (or in general of many phytophagous insects) in reducing the intensity of photosynthesis is only briefly mentioned (lines 65-71), although it is the focus of the study. In addition, the cited literature should also be detailed. For example, is it enough to write that "the effect of phytophages foraging on plants has not been completely identified" (lines 58-59) without adding anything else? I think that is opportune to discuss the findings of these authors and explain why their results are ambigous. These aspects could be better described in the Introduction and discussed in the Conclusion, in accordance of discordance with the results presented in the present study.

Lines 38-40: farming technologies are not the focus of the manuscript. This paragraph, as others in the introduction, adds nothing to the manuscript.

Lines 52-55: please introduce these results.

Lines 59-61: please introduce these results.

Lines 72-77: in this paragraph I would have expected to find a description of the present experiment in light of the bibliography on the subject. Why were these aphids used? Why were these plants used? What are the possible impacts of this study on the continuing demand for food?

Line 83: winter wheat.

Materials and Methods. The sample sizes of the experiments are not indicated in the materials and methods. As trivial as it may seem to the authors, knowing if an experiment was carried out on 1, 5, 10 or 20 plants makes a lot of difference. The authors repor of 5 repeated measurements on each plant (or leaf), which are by no means experimental replicates. If no other details are given, my idea is that the results refer to experiments conducted on only one plant for each experimental group. I recommend the authors clarify this point or add other experimental replicates if the experiments are based on data from a single plant, species, or treatment.

Lines 93-99: If I correctly understand, the three species of aphid were reared in the same chamber type but located in three different places, that is, the experiments were conducted in three different places. Please describe this section better. It is also more important to report the origin (year of capture and host plant) and mass rearing conditions (temperature, humidity, and host plant) rather than the faculty where the aphids come from.

Lines 101-102: were all three plant species in the 4-6 leaf stage 4 weeks after germination?  

Line 108: what are the “experimental objects”?

Line 121: What are the experimental factors? Maybe the aphids?

Lines 123-126 (Statistical analysis): this part should be rewritten, I don't understand which type of test was used for which kind of data. I advise authors to be precise in describing the tests and use the appropriate scientific rigor. I also think that the choice of a particular glm must be detailed.

Results. Why were the three species of aphids first analyzed together and then separately for photosynthesis and transpiration? The authors actually present and analyze the same data twice, and it does not sound correct to me. Wouldn't it be better to use a single model with different factors, such as aphid species, days, and initial density? And obviously considering all possible interactions. The authors could then make a model selection and present the results correctly. In general, I find that all the analyses presented in the manuscript are not detailed enough or even inaccurate. I would advise the authors to clarify this point, adding the samples size at least in the captions of the figures.

Lines 140-145: these two sentences seem more suitable for a student thesis than for a scientific article.

Table 1: Degrees of freedom are missing for all correlations presented in table 1. The results of the correlations should also be presented in the text.

Line 149: I'm sorry, but I don't understand the meaning of this sentence.

Table 2: if I correctly understand, the results presented in tab 2 refer to the differences between plant without aphids vs plant with aphids (for each combination). A linear model and 5 glms were then performed, pooling the data of the three aphid and plant species (which I do not find correct). Assuming it makes sense not to consider the differences between species, wouldn't it have been more correct to use a t-test (or a non-parametric variant of it) since the authors are comparing a single variable with two levels? In my opinion, the authors should use only one model, evaluate the significance of a predictor, decide what type of multiple comparison performs and then move to evaluating individual differences. This consideration extends to all the analyses presented in the manuscript.

Table 3, table 4: if I have interpreted the text correctly, the same results were analyzed again, but keeping the species distinct.

Discussion. Before evaluating this section, I think the authors should clarify the materials and methods (sample sizes) and data analyses.

 

Author Response

Dear Editor

We thank the reviewers for their generous comments on the manuscript and their comments. Proposed changes and suggestions have been accepted and implemented as far as possible.

Thank you for your consideration

Sincerely Yours

Mariusz Nietupski

Author Response File: Author Response.pdf

Reviewer 2 Report

1. In Materials and Methods: the plant species and cultivars of pea, winter wheat and winter oilseed rape were selected for their suitability as host plants, but the different cultivar with different resistance and susceptible level to aphid, please provide some description for the background of the test plants aphid -resistance or susceptible level .     

2. The data were only superficially analysis the effect of the number of aphids and feeding period on the intensity of photosynthesis and transpiration in the host plant, but do not clarify the interaction between the nutrient robbing by aphid with photosynthesis intensity , and interaction between the nutrient robbing by aphid with the plant's own need for nutrition and reproductive growth. Therefore, a deeply statistic analysis need to do compare the different treatments (aphids) with control (no-aphid), and also separate the plant growth stage, maybe find some interesting results.

3. In the discussion need to some description to answer the aim addressed in the introduction,  deducing the significance of the research.

4. Some suggestion in details :

In Figure 3,6,7,8, the data missing SE ;

Line 83, should be “winter wheat” 

Author Response

Dear Editor

We thank the reviewers for their generous comments on the manuscript and their comments. Proposed changes and suggestions have been accepted and implemented as far as possible.

Thank you for your consideration

Sincerely Yours

Mariusz Nietupski

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

I find the introduction of this new version of the manuscript much improved.

Important information has also been added to the materials and methods. However, I do not understand why the newly hatched aphids were removed (please explain). In line with what was written in the introduction, I would have liked much more to understand how the evolution of aphid colonies (starting from different numbers) influences the parameters measured for the three species.

Lines 209-213: “This coefficient identifies …..” please remove this sentence.

I also find that the results of this new version of the manuscript are much improved. However, I would have preferred a one model to be used for each species vith days and initial density as main factors. With a single analysis by species, the interaction between the two factors could have been discussed (see Figure 4 for A. pisum and figure 5 for R. padi).

Also in this version, ignoring my recommendations, the authors do not provide any information on the health of the plant. Please explain.

 The discussion/conclusion is in line with the results.

Author Response

We have included the responses to the reviewer's comments in the attached word file.

Author Response File: Author Response.docx

Reviewer 2 Report

The author focus on evaluation the intensity of photosynthesis and transpiration in plants, but to which extent for the effect of foraging by aphids is very important, without the results, the research could not answer the question by the topic. 

Author Response

We have included the responses to the reviewer's comments in the attached word file.

Author Response File: Author Response.docx