The Impact of Predation of Laricobius nigrinus (Coleoptera: Derodontidae) on Adelges tsugae (Hemiptera: Adelgidae) and Tsuga canadensis (Pinales: Pinaceae) Tree Health

Round 1

Reviewer 1 Report

 

The authors provide the predation of Laricobius nigrinus on HWA populations and demonstrated a positive effect to hemlock tree health at the branch level. I agree with the authors as these sources of information will be useful for future research on this little-studied group around the world.

However, I only have a few minor suggestions regarding the references, which are highlighted in yellow in the attached pdf.

Secondly, I will recommend the author to add some filed photographs and also give the detail photographs of both the pest and predator in the revised file.

Comments for author File: Comments.pdf

Author Response

Thank you for viewing our manuscript. I have addressed your suggestions regarding the references and have updated the manuscript. 

Thank you for your recommendation for adding some field photographs, however, we believe that there are numerous images of both Laricobius nigrinus and hemlock woolly adelgid in the literature and on the internet that the reader can easily access. 

Reviewer 2 Report

My serious concern is that this paper exists on Ln, ofcourse they study the impact on something else. But what is the significance of studying Ln impact on one sps after the other. the authors have to justify the significance of this study. 

Impact of the introduced predator, Laricobius nigrinus, on ovisacs of the 2 overwintering generation of hemlock woolly adelgid in the eastern United States 3 Carrie S. Jubba,*, Ariel R. Hemingera,1, Albert E. Mayfield IIIb , Joseph S. Elkintonc 4 , Gregory J. Wigginsd,2, Jerome F. Grantd , Jeffrey A. Lombardoc,3, Thomas J. McAvoya 5 , Ryan S. Crandallc and Scott M. Saloma

https://www.sciencedirect.com/science/article/pii/S1049964419308205

 

The authors also need to shrink certain portions of the abstract, intro, discussion, they some how dont seem to nail it

Figures schemes could be useful.....need a scheme that will discuss what is the mechanims, atleast the speculated one. 

If the authors can highlight confidently the novelty of this work, then the manuscript can be considered

 

Author Response

Q1. Thank you for your suggestions and presenting your concerns of the manuscript. This manuscript demonstrates that by using a predatory biological control agent of an invasive insect pest, such as HWA, it could help protect the plant host, in this case the eastern hemlock, by decreasing the HWA population. The paper you cite by Jubb et al., does demonstrate that Ln does decrease the sistens generation of HWA, but it does not focus on how that affects the eastern hemlock host. This manuscript takes it one step further and focuses on the tritrophic relationship between the predator (Ln), the prey (HWA), and the plant host (eastern hemlock). Other papers looking at the effects of Ln on HWA have tried to assess hemlock tree health using the USDA Forest Service Forest Inventory and Analysis crown condition categories, but they don’t look into tree physiology and they are not as in depth. 

Q2. I have shortened the abstract and removed some unnecessary information in the introduction. A sentence was added in the introduction to enhance the reasoning behind the study. The discussion addressed the results and by limiting the discussion further it would weaken the standing of the paper, therefore the discussion was not shortened.

Q3. I am unsure about your meaning to adding figure schemes. I have added a figure to better explain the field site set up.

Reviewer 3 Report

In this MS, the topic is interesting. While there are many shortcomings, which were following as:

Q1 M&M: 2.1: Not cleat about the treatment setup. e.g., Four 1-m branches were selected from each tree. One branch with HWA populations < 1 adelgid per cm on current-year shoot growth was assigned as the negativecontrol treatment (Con). Three branches with HWA densities >1 adelgid/cm on current year growth were randomly assigned one of the following treatments: No L. nigrinus(NL), four L. nigrinus (L4), and eight L. nigrinus (L8). From the 1-m branches, two 20 – 30 cm

branchlets from each branch were marked with green twist ties and were assigned either experiment 1 or experiment 2. Once treatments and branchlets were assigned, branches were tapped approximately ten times with a wooden dowel to dislodge any predators of HWA that were present. Describe it with a picture will make it clearer.

Q2 The picture format should be uniform. e.g., In picture 2, the letter which present significance difference or no significance difference showed be added.

Q3 Three-line table showed by used in the MS, please replace it. Eg. Table 4.

Q4 More discussion should be used to explain why the changes of tree physiology occured after using biological agent.

Q5 The content in the conclusion need more Specific description.

Author Response

Thank you for reviewing and providing suggestions for our manuscript. My responses to your questions are below:

Q1 To address your question I have created a diagram (new Fig. 1) showing how an individual tree was set up. This should clarify the different treatment groups and how the study was set up. 

Q2 I have added the letters NS (no significance) to figures where there is no significance among treatments. This helps make it easier for viewing. 

Q3 I have recreated Table 4 and have made sure all captions of the rest of the tables and figures are intact and not separated by page breaks. 

Q4 After looking at the other reviewer comments I have limited the amount of material to add in the discussion, due to some concern over the discussion length. In the discussion I have mentioned that by feeding on HWA and decreasing the pest population, L. nigrinus, may have reduced the amount of stress from the HWA feeding which then led to an increase in the photosynthetic rate, transpiration rate, and stomatal conductance in June.  

Q5 For the conclusion I have edited the sentence about final HWA density so that it focuses on how it would affect tree health instead of sounding like it was a result. I hope this addresses your comment, it was unclear. 

Reviewer 4 Report

Comments to the Author 
The manuscript explores Laricobius nigrinus as biological control agent against Adelges tsugae predation and its impact on the Eastern hemlock tree health. The information is really interesting. There are several comments to be addressed before publication.

Detailed comments as following. 

Title=
Predation Impact of Laricobius nigrinus (Coleoptera: 2 Derodontidae) on Adelges tsugae (Hemiptera: Adelgidae) and 3 Tsuga canadensis (Pinales: Pinaceae) Tree Health---------------Plz. Check is it ok?

The authorities and common names, for all the scientific names should be incorporated at first mentioning.

In the table 1, can author add tree age, height, and irrigation method, these are very important parameters should be addressed.

In Table 2 sampling date for several month are missing. Please incorporate.

In Figures, the significance level (letters) for some sections are present but several are missing above the bars This should be addressed and inserted.

Author Response

Q1: Thank you for your review of this manuscript. I have viewed the title and I do not see the numbering that you see in the title. It may be dependent on the device that was used to view the manuscript. 

Q2: I have checked the manuscript and updated it so that it has the authorities and common names for all species that are mentioned for the first time, except in the abstract. I looked in the guidelines and there are no requirements on whether the authorities and common names should be used in the abstract, so I did not add them due to the 200 word limit. 

Q3: That would have been great data to collect, unfortunately those data were not collected. In regards to irrigation method, all trees were in a forested area where the trees were not maintained. 

Q4: For Table 2, sampling only occurred in June, July, and October. That is why there are no sampling dates for the rest of the months. 

Q5:  I have added the letters NS (no significance) to figures where there is no significance among treatments. This helps make it easier for viewing.

 

Round 2

Reviewer 3 Report

All my issues have been solved.

Author Response

Thank you for taking the time to review this manuscript! 

Reviewer 4 Report

Dear author, it will be better to add the letters NS either significant or not significant to figures. This will help to make it easier for viewing.

Thanks

Author Response

Thank you for reviewing this manuscript. Based on your suggestion regarding the figures, I have already added NS (not significant) to Fig 2B and Fig2C. Fig 2A did have significant differences among treatments so letters were used to indicate significant differences. For Fig 3 there were significant differences among treatments, so NS was not used for that particular figure. For Fig 4A, B, and C, there were significant differences among treatments for the June analysis, but there were not significant differences among treatments for the July and October analyses. Therefore, NS was added above the graphs which did not have significant differences among treatments. I hope this addresses your comment.