Assessing the Flight Potential of the Four-Eyed Fir Bark Beetle Polygraphus proximus Blandford in Natural Conditions

Round 1

Reviewer 1 Report (New Reviewer)

Comments and Suggestions for Authors

Interesting manuscript that aimed to better understand the flight capacity of Polygraphus proximus in natural conditions. This beetle is considered an invasive species in Siberia’s fir forests. Investigating the flight potential of bark beetles help to better comprehend their dispersal and can help improve the monitoring tactics.

Major comment:

My main concern with this manuscript is the lack of repetitions for the experiment. The experiment was conducted in 2022, however, it failed due to fire damage. Then, the experiment was carried out in 2023 for 45 days (May 19 – July 3), with an intermediate inspection (June 14). The experiment was conducted once and in one location only. It seems the authors are using the trapping objects (located at different directions and distances) as experimental units and replicates. In stats this is called pseudoreplication. Sometimes pseudoreplication cannot be avoided due to either logistics or other constrains, especially in medicine. It is impossible to determine if the location had an influence in the dispersal/flight of P. proximus. It could be possible that in a different location, beetles could not fly 1,500m. It would be good if the authors can explain the limitations of their experiments (especially why they did not use more fields) and also explain how their results should be interpreted with extreme caution.

Additional comments:

Figure 3. Is this figure absolutely necessary? Basically, the authors are just saying that the diameter, length, and bark area of the trapping logs were evenly distributed (similar?) before using them in the experiment. The trapping logs did not have any significant effect on the beetle’s flight. This can be easily mentioned in the text and the figure can be submitted as supplementary material.

Figure 4. Same comment as above. What is the purpose of this graph? The authors are just showing that trapping logs were evenly used in the field during the experiment. This can also be submitted as supplementary material.

Both figures showed the authors carefully accounted for sources of variation. However, this can be easily explained in the M&M without long explanations. The authors can indicate the readers to check for additional information in the supplementary material. I believe it is more important to address the issue of lack of repetitions. I believe the authors spend too much “time” explaining why they did the things the way they did it and the most important aspect of the manuscript (the flight of P. proximus) is left a little bit behind.

Discussion

General comments:

L314-334: The authors already explained the criteria for choosing the study site. They even conducted statistical analyses to prove there was no influence of the trapping log sizes on their results. These three paragraphs are just repetitive of something that was already mentioned in the text and do not add anything new to the manuscript.

Minor comments:

L10-11: “However, its spread in secondary area is not yet complete” I do not think “secondary area” and “not yet complete” are the right terms. Do the authors mean that its potential dispersal/incursion into new areas is not fully understood?

L16: replace “from this point” with “from the release point”. This will provide clarity.

L19: replace “from the source of beetles” with “from the release point”. This is more accurate. The authors did not use “different” sources of beetles. All beetles came from infested slabs.

L39: The authors need to define what a “secondary area” is. This is a vague term that is open to interpretation by the readers. I still believe this is not the correct term. Perhaps explaining (in the text) what a “primary area” and “secondary area” mean would be helpful.

L43: “Secondary range”. Then, I ask, what is the primary range (fir forest only)? Same comment as above.

L46: “Secondary area”. Same comment as the two above.

L55-56: “…spreading into parts of the non-native area that are not already occupied by it.” This sounds confusing and somewhat redundant. Please consider using “spreading into new non-native areas”.

L57: “one way of assessing this”. Please consider using a different word instead of “this”. Perhaps one way to assess its dispersal potential? One way to assess its incursion into new areas?

L62: Add ) after long-distant.

L69: distance from their original point of take-off AND the mobility of individuals is not the same. By using the conjunction “OR” it sounds that one is more important than the other. Both are equally important. An insect can be a poor flyer or a really good flyer, which will impact the distance covered (from the point of take-off). Please use the “and” instead of “or”.

L94: Please consider “study site and experimental set up” rather than just “experimental procedure”.

L113: Use “×” instead of “x”. The first one is a symbol, the other one is just a letter.

L118: please consider using the following sentence which is clearer “…short logs of Siberian fir trees with no signs of bark beetle attacks nor galleries were used as trapping objects”.

L123: “were” instead of “was”

L128: “on April 4, 2023” instead of “at April 4, 2023”

L132: “eight slabs” instead of “8 slabs”. Numbers are used if they are followed by a unit of measurement. Slab is not a unit of measurement. In this case, the actual word “eight” should be used.

L133: “Then” instead of “once there”

L134: “at the bottom” instead of “in the bottom”. Please include what the actual ambient temperature is. I would think ambient temperature is 25C, however, I do not believe that is the case for this study considering the geographic location of the study.

L149-150: “without unsuccessful and/or successful attacks”. I am sorry, this phrase is extremely confusing. The statement is contradictory. Please consider: “During the examination of the selected area in 2022, we only observed fir trees with ≤ 6-cm of diameter with few successful/unsuccessful attacks”. I believe this statement is a little bit clearer.

L170: “studies” instead “researches”

L212-213: “For each depended variable was created the set of models that included predictors from Table 1”. There seems to be an issue with the syntax of this sentence. I do not quite understand what is message the authors are trying to convey. Authors, please revise the accuracy of this sentence.

L215: “do not” instead of “don’t”

L248-250: “Unsuccessful attacks, indicated by an entry hole without a nuptial chamber, were observed at distances of 150(E), 750(N), and 1250(E) from the release point”

Perhaps it would be ideal to include some sort of symbol in Table 2 indicating the unsuccessful attacks. Combinations (cardinal point & distance) that do not show any values indicate that there were no attacks whatsoever to those trapping logs.

L250-253: “…26 cases, representing 35.1% of the total (Table 3)”. Please double check the math. In Table 3, I only count 11 traps out of 36 used, which represents 30.5%. Unless the authors mean 26 cases (of trapping logs) out of 72 used. This represents 36.1%.

Figure 5. This is a very interesting and very crowded graph. What does the circle in the right mean? Wind direction? There is no reference at all in the figure caption about this part of the graph.

L262: “Number of nuptial chambers…) delete “the”

L269-270: “Non-target species were found in single instances on trapping logs that were left after an unsuccessful experiment in 2022 and were damage by the fire”

I don’t understand the purpose of the above statement. The authors already mentioned the experiment failed due to fire. Did the authors use “any remaining data from 2022”. It does not look like it. I believe the 2022 data is inconsequential and the authors should only be focused on data from the actual experiment in 2023.

L285-286: “influence on dependent variables” instead of “influence to depended variables”

Figure 6. This is the core of the manuscript. The figure depicts the relationship between the numbers of pairs and pairs per dm-2 with the distance from the release point. Easy to interpret and concise. Well done!

L304: “The correlation between real and predicted ps value “was” instead of “is”

L335: Are the authors referring Figure 6A?

L343-352: This is a very good paragraph, and it is the core of the manuscript. I would suggest starting the discussion with this paragraph.

L376: delete “during their conduct”.

L382: There is no Table 5 in the manuscript. Please either include or delete statement.

L415: “frontalis” not “frontais”

L401-412: Good paragraph. Just as a comment: Although we know that bark and ambrosia beetles use pheromones and ethanol, respectively, to locate new host; not using attractants/lures allow the beetles to disperse passively, which is biologically more meaningful, because you have isolated the attraction source. It is possible that once the beetles detect an “odor”, they would/could be encouraged to fly further and longer.

L484-485: “We observed that the experimentally confirmed maximum flight distance of P. proximus is 1500 m”.

The statement above seems kind of abrupt. The authors already stated in lines 454-456 that the beetle can fly up to 1,500 m because that’s the maximum distance from the release point in the experiment.

I would suggest a slight modification that it is more aligned with the results obtained. “We observed P. proximus can fly up to 1,500 m. However, our model estimated that the potential flight range of P. proximus is approximately 3,000 to 5,000 m”

References

References must be double-check for consistency

According to MDPI Editorial office, scientific journals should be written in its entirety. References #4, #13, #32, #53, #71, and #73 used the abbreviation form. Please address this issue.

L696: “Ips” instead of “Lps”

Comments on the Quality of English Language

Minor issues with the text that are easy to fix. I have pointed out some of them.

Author Response

Dear colleague,

We appreciate Your review. Thank You very much for Your time and efforts. Below we are try to answer to Your comments.

Author Response File: Author Response.pdf

Reviewer 2 Report (New Reviewer)

Comments and Suggestions for Authors

will be sent as an attached file 

Comments for author File: Comments.pdf

Comments on the Quality of English Language

will be sent as an attached file

Author Response

Dear colleague,

We appreciate Your review. Thank You very much for Your time and efforts. Below we are try to answer to Your comments.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report (New Reviewer)

Comments and Suggestions for Authors

Overall, the authors improved the manuscript. Just some minor revisions required.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

Author Response

Dear colleague, 

All of Your commentaries have been utilized in the new version of manuscript. 

Thank You very much, 

Authors. 

Reviewer 2 Report (New Reviewer)

Comments and Suggestions for Authors

After reading the text for the second time, I am convinced that it is an interesting and important research work. However, some fundamental problems remain. The English needs a thorough review by someone proficient in the language. The corrections I propose are only examples of unclear wording, and in many cases, I can only infer the authors' intent.

Another fundamental issue is the motivation for the research. The author mainly attributes this to management of the beetle, but there is no justification or real foundation for this. The biological research itself is a sufficient justification for the study. The authors might consider focusing only on that.

Below are some examples of text that require corrections and clarifications:

line 35 change to 'other wood borers'
line 48 suggest to omit 'but this species has not yet occupied the entire range of Abies even within Russia'
line 54  please supply an example of for emergency action that should be taken. This is really needed since monitoring seems to be a major motivation of the research.  
line 58-59  unclear sentence. Please consider this one 'The development of such models for regressive invasive bark beetle and borer species is essential'
line 62  what do you mean by 'communities' ?
 line 69 omit 'and borer'  or write other wood borers
line 76 change 'dead fir' to 'killed fir' or 'colonized fir'
line 103 omit 'imago'

line 106, change 'the amount of food'  to 'host tree abundance'  
line 107, change to other borers

line 111  change to 'The experiment plot'
Lines 112 from 'In its native' to line 118 [43]….. This text is not normally a part of M&M. if required put it in the Introduction, or omit it  
lines 121-123, the last sentence, better place it in the Introduction  
line 125 Bark beetles do not actively migrate long distances. Please correct. Thus, this should not be included among the criteria
line 134 please change to 'source of the insects'
lines 140-140  change 'was cut into sawn pieces' to  'divided to several pieces'  
lines 146-8 the statement is not clear
line 154 what does the citation mean ?
line 185 put the citation after 'studies' or at the end of the sentence
line  203  please correct 'westerly winds' also in other places along the text
line 212, change 'experiment' to 'activity related to the beetle flight period'
line 221 change 'trapping' to 'trap'
line 225 change 'on' to 'in'
line 371  Change 'Bark beetle host searches'  to 'Bark beetle search for host'
lines  372-4  the sentence 'This is further compounded by the fact that flight direction may 373 vary'  is not clear  
line 374 change 'pheromone' to 'a pheromone source'
lines 379-381 Change 'The representation of the young generation by stages from larvae to adults' to ' the age structure of the immature stages'
line 381 specify 'bark beetles'
line 384 confusing sentence, rewording is required  
lines 386-387 please change the sentence. Your results suggest that only small proportion eventually colonized the trap logs. However, the number of beetles that were attracted to the logs is unknown!
line 400-402 I suggest to erase the sentence. it does not contribute to the presented idea.  
lines 406-408 I think I understand what the authors mean by that,  but rewording is badly needed
lines 412-413 the sentence is confusing, and the motivation to include the information is not clear
lines 417-418 the objective is not to maximize the flight. Please correct the sentence and the idea as it is presented
line 425 as mentioned earlier, the term 'borers' is not clear enough,  please be more specific
lines 438-9  the sentence 'as their actual flight range coincided with the maximum distance of food items from the release point'  is misleading. maybe instead of 'coincided' write 'influenced'  
line 448-9 'to the different conditions in which the insects were located' please correct the language  
line 470 I got the impression that there is only one main experiment  

Comments on the Quality of English Language

Please see above comments.

Author Response

Major changes (and all about the borers):

line 54  please supply an example of for emergency action that should be taken. This is really needed since monitoring seems to be a major motivation of the research.  

Some data have been added to the text (l. 67 and 83). For better understanding of our intention I should show the context of the added citations:

We model the following scenario: (1) an invader has been found; (2) the timing of invasion is unknown; (3) species characteristics, such as dispersal distance, are unknown; ... These are realistic conditions that will occur for most new invaders. Because of the conditions 2 and 3, we do not know how far the invader has spread (DOI: 10.1111/j.1472-4642.2010.00653.x).

Effective surveillance tools (e.g., traps) are crucial for detecting and delimiting newly established populations when they are still small, thereby minimizing the cost of eradication as well as the probability of failure. ... When such pheromones are used as attractants for surveillance, it is virtually impossible for reproductively viable populations to persist for long periods at subdetectable levels if the traps are spaced at distances near males’ typical dispersal range... (DOI 10.1146/annurev-ento-010715-023809).

Host plant destruction was unsuccessful for eradication of emerald ash borer (Agrilus planipennis), in large part because of rapid spread and ineffective methods for delimiting populations (48), but has been a component of successful eradication programs targeting the Asian longhorned beetle (43) (DOI 10.1146/annurev-ento-010715-023809).

line 62  what do you mean by 'communities'?

This term have been clarified (l. 73 and 75).

Lines 112 from 'In its native' to line 118 [43]….. This text is not normally a part of M&M. If required put it in the Introduction, or omit it  

The composition of text have been changed according to Your comment (paragraphs from l. 51 and 133).

lines 121-123, the last sentence, better place it in the Introduction  

As previous comment (l. 113–116 and 136–138).

line 125 Bark beetles do not actively migrate long distances. Please correct. Thus, this should not be included among the criteria

Ips sexdentatus beetles can fly up to 4 km (DOI 10.1051/forest:19910405). Flight distance of Dendroctonus valens reached to 35 km (DOI 10.1007/s10531-004-0697-9). Wind-dispersed Ips typographus beetles can migrate even across English channel (DOI 10.1007/s10340-024-01763-4). Of course, all the species are bigger than P. proximus and, presumably, have got the better flight capacity, but usage of this criteria looks like reasonable precaution.

line 154 what does the citation mean?

This is a link to a source that describes the method for calculating the population characteristics of bark beetles.

line 185 put the citation after 'studies' or at the end of the sentence

Corrected (l. 202).

line 381 specify 'bark beetles' 

‘Bark beetles’ have been changed to ‘scolytine beetles’ (like, e.g., in 10.1016/B978-0-12-417156-5.00001-0) (l. 393).

lines 386-387 please change the sentence. Your results suggest that only small proportion eventually colonized the trap logs. However, the number of beetles that were attracted to the logs is unknown!

I tried to change the sentence to show that the number of recaptured bark beetles is the result of calculations (l. 408–412).

line 400-402 I suggest to erase the sentence. it does not contribute to the presented idea.  

This sentence has been deleted.

lines 417-418 the objective is not to maximize the flight. Please correct the sentence and the idea as it is presented

I hope, this correction (l. 428–432) make the idea more clear.

line 35 change to 'other wood borers'; line 69 omit 'and borer'  or write other wood borers; line 107, change to other borers; line 425 as mentioned earlier, the term 'borers' is not clear enough, please be more specific

Throughout the text the term ‘borer’ now have been used either as a part of term ‘bark beetles and wood borers’ (e.g., DOI 10.1007/978-3-319-24744-1_18) or as a part of common name ‘Emerald ash borer’. The definition of the term ‘bark beetles and wood borers’ (l. 36) is given according to (DOI 10.1525/bio.2010.60.11.5).

Unclear sentences:

line 58-59  unclear sentence. Please consider this one 'The development of such models for regressive invasive bark beetle and borer species is essential'

The sentence has been revised (l. 68-69).

lines 146-8 the statement is not clear

The sentence has been revised (l. 160-161).

lines  372-4  the sentence 'This is further compounded by the fact that flight direction may 373 vary'  is not clear  

The sentence has been revised (l. 386-387).

line 384 confusing sentence, rewording is required

The sentence has been revised (l. 394-400). 

lines 406-408 I think I understand what the authors mean by that,  but rewording is badly needed

The sentence has been revised (l. 422-424).

lines 412-413 the sentence is confusing, and the motivation to include the information is not clear

The sentence has been revised (l. 429-431). The information is crucial for understanding that the observed restriction of beetle flight range in previous studies is often a consequence of experimental limitations, as beetles are capable of flying over much greater distances.

line 448-9 'to the different conditions in which the insects were located' please correct the language  

The sentence has been revised (l. 465-469).

line 470 I got the impression that there is only one main experiment  

The sentence has been revised (l. 490-492).

lines 438-9  the sentence 'as their actual flight range coincided with the maximum distance of food items from the release point'  is misleading. maybe instead of 'coincided' write 'influenced'

The sentence has been revised (l. 455-458).  

Small text changes:

line 48 suggest to omit 'but this species has not yet occupied the entire range of Abies even within Russia'

Omitted.

line 76 change 'dead fir' to 'killed fir' or 'colonized fir'

Changed (l. 90-91.).

line 103 omit 'imago'

Omitted.

line 106, change 'the amount of food'  to 'host tree abundance'  

In the context of both bark beetle’s biology and this experiment more suitable term is, in my opinion, ‘food availability’ (l. 128), like in [Bark Beetles: Biology and Ecology of Native and Invasive Species, p. 20; DOI 10.1016/B978-0-12-417156-5.00001-0]. In fact, in our experiment and, sometimes, in real conditions, bark beetles can colonize objects that are no longer a tree.

line 111  change to 'The experiment plot'

Changed (l. 132). Revised and changed all.

line 134 please change to 'source of the insects'

Changed (l. 148).

lines 140-140  change 'was cut into sawn pieces' to  'divided to several pieces'  

Changed (l. 155).  

line  203  please correct 'westerly winds' also in other places along the text

Changed (l. 216, 378).

line 212, change 'experiment' to 'activity related to the beetle flight period'

Changed (l. 228).

line 221 change 'trapping' to 'trap'

Changed (l. 233). Revised and changed all.

line 225 change 'on' to 'in'

Changed (l. 237).

line 371  Change 'Bark beetle host searches'  to 'Bark beetle search for host'

Changed (l. 384).

line 374 change 'pheromone' to 'a pheromone source'

Changed (l. 387).

lines 379-381 Change 'The representation of the young generation by stages from larvae to adults' to ' the age structure of the immature stages'

Changed (l. 393).

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Review of forests-2993615

 

Assessing flight potential of the four-eyed fir bark beetle Polygraphus proximus (Blandford) in natural conditions

by Denis A. Demidko*, Sergey S. Kulakov, Anton A. Efremenko, Nikita S. Babichev, Alexey P. Barchenkov and Pavel 4 V. Mikhailov*

The study deals with an invasive bark beetle species with a high potential of spreading in Russian and European Forests and causing damage in conifer trees. From this point of view I find the study suitable for publication, but there are some methodological questions which should be answered in order to the study being „publishable“. Now it is on the edge of rejection/major revision, I think.

My main concerns are:

-AIC model selection – I think the authors used in the wrong way, see my comments to Table 5 and l. 222-228 below

-Experiment 1 was destroyed by floods and vandalism so the explanatory value of this experiment is in doubt (although I understand that it is a pitty, I would be upset too)

-Experiment 1 (steppe) and Experiment (2) had gained different values of beetle infestation which could be caused simply by a source of beetles in the vicinity of Experiment 2. Although authors state that no population of P.proximus was present, but the results presented in the manuscript contradicts this. For example, on l. 100-105 the authors state that a distance of 2km is needed without the beetle to set up the experimental plots, but their theoretical (?) calculations show that distance of cca 5000 meters is possible?

-The statistical models in Table 5 are doubtful, I think. The authors just compared the effect of distance of logs on different aspects of beetle phenology or abundance (f,b,fs and bs are explained on l.212-221 which is annoying - explanation should be listed in the table) which is a bit weird. The number of beetle galleries is dependent on the number of beetles and the status of the logs (shaded, thick phloem, moisture…), not just the distance. See my comment to l. 351-353 below.

Fig.3 is very nice, although based on meteo data of a 30 km distance from the plots (l.188). Year of the study should added to the plots (or to the description of figures).

Questions and comments to the authors:

l.11-12: “However, its spread in secondary area is not yet complete. “ - what do you mean by that? How would you asses that the spread in secondary area is „complete“? I suggest to remove or clarify this sentence.

l.18: „nest“? I think the proper term is „gallery“.

l.22-23: so a flight distance of 1500 m was established, but what about the 4,919 m or the 2,965m? This was calculated based on confidence intervals? In methods you say that you choosed sites wih at least 2000 meters which not enough, obviously (2000m vs 2965m)?

l.22-23: the english writing style for numbers should use commas separating thousands

27: I suggest to include the scientific name Polygraphus proximus

l.32: missing t in “anropogenic”

l.81-83: suddenly the Agrilus planipennis is discussed but I think this comparison is better suited for the Discussion section

l.95: tree size must be a factor because the beetles require phloem to be thick in order to feed?

l.121: is it possible to include some photos of your experiment sites and logs and slabs?

Fig.1: can you insert a small map where exactly in Russia or in the globe this research has been carried out?

l.173: “nest” is used for social insects, please check throughout the manuscript

l.203: “fierl” – mistake here

Tab.1: You should add explanations to columns – tables should be self explanatory without checking what is “S” or “Cdir” in the main text

Table 1: is this related to “experiment 1” or both? Are these models the same as in Table 5? In Table 5 there is no S or Cdir?

l.236-239: I am not familiar with these calculations – what is “a”, what is “e”, what is “b” etc? Based on this formula you calculate Fig.5 for 6000 meters? The beetles have some energy resources after overwintering for example, and that is the main factor how far the beetles can fly. Or they can be transported by wind, but I do not exactly understand how do you calculated these theoretical distances. Is this make sense if you do not know the condition of the beetle and the weather?

Table 2: I would prefer to see a boxplot – easier to interpret

l.261-265: I see your point in vandalism and flooding, but the experiment is very hard to interpret now – this is one of my main concern regarding this manuscript. It is mostly based on one experiment (experiment 2)

Fig.3: change azbuka to latin font

Table 5: AIC number should be interpreted - the lower is the number, the better is the model – but your lowest number is the fourth model (-67.80). Also, explain dependent variables in notes below the table. And l.222-228: – so how many models have you created? One for each dependent variable? In that case I don’t think AIC makes sense – you should compare only models from the same dataset but if you change the dependent variable each time you have different number of data points? Than AIC is not suitable probably.

My understanding of the AIC model selection is that for example you have your first model with f (number of nests/galleries) as the dependent variable and you test different set of predictors (distance, DBH of logs, length, temperature…) in separate models. In this case AIC makes sense.

See Burnham, K.P., Anderson, D.R. & Huyvaert, K.P. AIC model selection and multimodel inference in behavioral ecology: some background, observations, and comparisons. Behav Ecol Sociobiol 65, 23–35 (2011). https://doi.org/10.1007/s00265-010-1029-6, for example.

In your case, you just compared different dependent variables (f, b) with the same predictor which is distance – I see no point of selecting the best model, because the “best” model is each one for each particular variable. Therefore I suggest to make the whole methods and results section more clear.

l.337-343: the meteo station was quite far away, 30 km, if you will continue with your research it is better to have local ministations

l.351-353: if the size was so variable, that should as an additional predictor variable into models in tab.4

l.403-409: one reason for differences between Experiment 1 (steppe) and Experiment 2 (forest) is that one is a steppe and the second one is a forest – which you ruled out? It could simply happen that the beetles are not from your logs, but from elswhere – but I agree that fig.3 would explain this to some extent.

Fig.5 – see my comments to l.236-239

Reviewer 2 Report

Comments and Suggestions for Authors

The paper deals with an important issue, and the experiments appear to have been correctly programmed. Unfortunately, for various reasons some of them could not be fully completed, and as a consequence the results appear to be in part incomplete. The effort by the authors to anyway supply some useful information is evident, and in general it appears to have been relativeòly successful, even though some of the data in the discussion appear to be quite trivial, others, like the effect of the wind, seem to be uncertain. Anyway, these data can be useful in the management of the invasion of this pest of the fir trees.

One major problem is the presence of the Russian captions in all the graph!!! It seems to be impossible to understand how the authors did not realize such an error! Needless to say, all the graphs MUST be in English and not in cyrillic!!!

line 32: anthropogenic

line 36 and following: the year of publication of the species must be added to the author’s name the first time they are cited.

FIGURES. ALL FIGURES MUST HAVE ENGLISH CAPTIONS, NOT RUSSIAN!!!!!

line 236. all parameters are specified, excepting “a”. This should be explained as well.

density is sometimes indicated as nest per dm^-2 and sometimes as nest per dm²

The results have been influenced by several unexpected problems occurred during the experiments; they are extensively discussed, but perhaps a shorter discussion with a more synthetic approach would help in better understanding the various aspects.

Reviewer 3 Report

Comments and Suggestions for Authors

This paper estimates the flight distance of the bark beetle Polygraphus proximus in a field. All beetles nested in trapping logs were supposed to disperse from placed slabs, though the beetles were not marked before their dispersal. First of all, the emergence of the beetles from placed slabs was not confirmed. The low number of catches in Experiment 1 was explained by unfavorable weather conditions for beetle flight, though there are many other possibilities. Generally, direct estimation of beetle flight distance is difficult due to the low recapture rate. Authors should carefully interpret and discuss the obtained results without making questionable assumptions.

 

L115-117

What is the source of these slabs? What kind of infected trees were used to make them? Two experiments were conducted in different years. The tree species, the location where trees were collected, and how beetle infection was confirmed should be described for each year.

 

L127

Authors should clearly describe how many slabs were transported to the laboratory for each year of experiments.

 

L162-164, L189-191

The number of emerged beetles per unit bark area was estimated as 7.2 and 9.7. This value is expected to vary among slabs; therefore, the variance should also be described.

 

Figure 2-5

Axis labels should be described in English.

 

L171-173

The absence of beetles at the end of the experiment does not indicate beetle flight, as the presence of beetles was not confirmed before the experiment.

 

L185-187

I couldn't understand why the authors can exclude the possibility that beetles flew into the plot from outside.

 

L222-223

Authors assumed the random deviation of the dependent variable by a cardinal orientation by treating it as random intercepts. Therefore, the increase in AIC of the model by the inclusion of these random intercepts doesn't suggest an insignificant effect of a cardinal orientation. If you want to test the effect of the variable, you should include that variable as a fixed term.

 

L236-

What do the parameters y, a, and b represent in this equation?

 

L241-245, Table 2

I presume that this analysis aimed to demonstrate that the size of placed logs did not differ among different cardinal directions. The small number of beetles cannot be attributed to the impossibility of the analysis. Table 2 does not aid readers in understanding the result. This table should directly present the outcome of the test.

 

L250-253

Authors assumed that there were beetles inside the slabs at the start of the experiment and confirmed that no beetles remained at the end of the experiment (L171-173). Assuming that no beetles flew during the term of the experiment, where did they go?

 

L261-263

These should be described in tables in the same way as Experiment 2.

 

Table 5

R-squared doesn't take a negative value.

 

L328-330

Low recapture rate is common for this kind of study. Authors should carefully interpret and discuss all the obtained results without making questionable assumptions.

 

L333-334

Another possibility is that beetles emerged from the slabs, but no beetles flew to the logs. How can you dismiss this possibility?

 

L334-335

This study lose credibility due to this description.

 

L338-340

Though 65.7 is higher than 57.5, it is doubtful whether this difference causes a difference in beetle flight activity. The intended meaning of "influence of the forest stand" is unclear.

 

Figure 5

This should be described in Results section.