Does Handling for Public Talks in Zoos Affect the Behaviour of Captive Mexican Red-Kneed Spiders Brachypelma hamorii?

Round 1

Reviewer 1 Report

The aim of the study was to investigate whether handling affected the 24-hour activity and enclosure usage of three Mexican red-kneed spiders. I think this is a paper with very well-done research in a much-needed taxa. It is also well written and easy to follow. The discussion of the results is good and provides ideas for further research, especially with the objective to improve the individuals’ life in captivity.

I just have a few comments/suggestions:

L26: I would use as keywords only words that do not already appear on the title of the paper.

L47-48: not all zoos use ZIMS, so perhaps the number of institutions is bigger. I would change ‘approximately’ for ‘at least’ or instead add something like this: ‘approximately 140 institutions according to ZIMS [12]’.

L98: add the scientific name of the locust used for feeding.

L125: I would include the ethogram on the main text instead of on the appendix. It is a key element of your research, and it should be given more importance.

Figures 1 and 2: add in the graphs the significant differences on H days compared to NH days.

L251: I believe that after results comes a , instead of a .

L277-279: how did the keepers selected the spiders? Based on what? It might be personal observations, but I would include it in the text.

Acknowledgements: this section is done on the first person singular (I), but the paper is written by several authors. Either the name of the author that is giving these acknowledgements needs to be clarified or the section should be done on the first person plural (we).

Author Response

Dear reviewer 1,

Thank you for taking the time to read our manuscript and leave your comments, which were all well received. Please see the attachment for our responses to your comments.

Many thanks

Author Response File: Author Response.pdf

Reviewer 2 Report

I read this manuscript with great interest. I think it is a novel and necessary approach to study the captive invertebrates and it might work as a baseline for further studies on this research line,which is very necessary.  Unfortunately, I think that, although interesting, the paper has several flaws which should be corrected. Given that I consider these issues should be fixed in a first instance, I will focus mostly on methodological details, which in my concept are the main issues I found on this paper.

Introduction. I consider the introduction is well written and structured. However, it has several flaws, for example some names like “Theraphosidae” are written in italics, which is strange for me, since italics is only limited to some taxonomical categories such as genus or species. In addition, I think some hypotheses should be more clearly explained or developed. For example, authores mention stress is measured similarly on these spiders when compared to vertebrates, but I think more references should be used to support this claim, so the main hypothesis gets stronger and the main question can be developed more clearly.  

Methods: My main concern with the paper is the low number of individuals. It is not very clear why they use only three individuals, is there a limitation for accessing a higher number of specimens?  In addition, more information about the individuals is needed, are they mature or subadult female? In table 1, it is described that studied individuals are female, but in the text it is not specified. What is the feeding regime for the studied specimens, what are the main offered prey before records and how often? This should be specified as feeding might affect the occurrence of certain behaviors. Since the activity is strongly influenced by photoperiod, this should be specified in the methods section. It is not very clear to me, what is the reason for recording specimens between  15-15.30hs, was it to evaluate the effect of handling the spider? I think an interesting approach would be to compare for example, what happens between spiders frequently handled vs those with are not frequently handled. A different approach would be to compare the frequency of these behaviors against wild populations.

I’m not statistician, but I’m not sure if it is appropriate to apply methods such as GLM, given this data has a lot of pseudoreplications, as the same animals were observed multiple times.  In addition, I’m not sure if the most corrected choice is to use the spider ID as a fixed effect, instead I would use a GLMM or GEE using the individual as a random effect (See Pekár & Brabec, 2018) . For a new version, I strongly suggest that authors use instead descriptive statistics given the low number of specimens. Otherwise, please consider use valid statistical analyses for small samples such as bootstrap. If authors want to ensure a valid statistical analyses, more individuals should be used.

I strongly suggest these authors to read and cite studies regarding to behavioral repertories in arachnids. There are several papers in some groups like harvestmen, scorpions, and even whip-spiders and ricinuleids which might work as a reference. 

Results could be significantly improved by incorporating the suggested statistical analyses. Again, please consider to change statistical analyses.

Discussion. I think this section should be written only after the introduction and methods be structured again.

Author Response

Dear Reviewer 2,

Thank you for taking the time to read our manuscript and leave your comments, all of which have been carefully considered. Please see the attachment for our responses.

Many thanks

Author Response File: Author Response.pdf

Reviewer 3 Report

I would like to commend the authors on tackling a subject that is much needed in zoo animal welfare. The manuscript is well written and clear to follow and the results have been interpreted fairly and critically. The work provides an interesting and through-provoking start in this field.

Some thoughts by way of improvement are below:

The introduction tackles the subject but is a little brief and more could be made of the recent work by authors such as

Browning, H., & Veit, W. (2020). Improving invertebrate welfare. Animal Sentience, 5(29), 4. 

and

Carere, C., & Mather, J. (Eds.). (2019). The welfare of invertebrate animals (Vol. 18). Springer.

and in particular on the topic of individuality which applies well to this study

Mather, J. A., & Carere, C. (2019). Consider the individual: personality and welfare in invertebrates. In The Welfare of Invertebrate Animals (pp. 229-245). Springer, Cham.

 

In the methods the behavioural data has been stated to have run from Jan- Mar 2020 though in Appendix A2 there are dates from Dec 2019, please clarify this.

Line 99 how were the spiders lifted from the enclosure?

 

2.1 data analysis the GLM with limb interaction has not been included- please detail this. Line 152 only includes the measures locomotion, object interaction and time under cover.

What was the sampling interval for S1 and S2, only S3 has been mentioned as a change to half the data collection samples.

In Appendix A2 the spiders have been handled in different ways during the sessions (palm/trousers), it would have been nice to have seen this factor incorporated into your model or referred to in the discussion as this is potentially likely to have affected the behavioural measures made.

Additionally, some days have been recorded consecutively, time since handling would also have been a good factor to consider in the model.

How was enclosure use measured and was the difference in cover size included in analysis? 

Line 169 What was the direction of difference in enclosure use when locusts were present.

Figure 1 graph legend is covered and under cover- what is the difference here, should one not be not covered?

probabilities either = or are < please don't use both symbols together (ie line 167).

Could limb interaction occur under covered areas and not be counted - could this account for the reduction in limb interaction between S1 and the other spiders?

Author Response

Dear Reviewer 3,

Thank you for taking the time to read our manuscript and leave your comments, all of which have been carefully considered. Please see the attachment for our responses.

Many thanks

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Dear authors, 

In this new version, I find some disconnection between the introduction, the methods, the results and the discussion. It is not clear yet why if the aim of this paper is to describe the activity rhythm and the relationship with stress level, the relationship between both topics is so short.  In addition, from the introduction I understand that staying in the burrow is a way to measure the stress in spiders, but spiders have a marked nocturnal activity and many species do not leave the burrow while hunting, so it would be important to clarify this point.

In consequence, I suggest to follow a new structure where they mention clearly the aims of this paper.

My general comments to improve the papers are:

• If the aim is to assess the activity rhythm, this should be clearly stated in the introduction. If that’s the case, the relationship between both aspects should be developed in detail. The only mention I can find to the relationship between activity rhythm and stress level are some brief mentions in reptiles and fishes but it is extremely vague, I strongly suggest to describe in detail this relationship, given it is the main core of this paper.
• Some behaviors are used as a way to measure stress in spiders. It would be important to correlate some of these behaviors with physiological measurements of stress in other arthropods, so selected variables will be justified in a better way.
• I suggest to move the table A to methods section. Again, if the table is supported by other studies it would be interesting to include references.
• In methods section I would discriminate in three sections. 1) Ethogram building, 2) daily activity and 3) Stress level and activity. That would make the reading easier to follow. According to this, please consider to place the ethogram in the results section.
• Although the authors use tests for repeated samples, I think that given the small number of studied individuals and very extensive number of records per specimen, I would limit the study to descriptive statistics or would try an approach using for example tests for small samples such as the bootstrap and would compare the confidence intervals for example.
• It would be interesting for example if authors compare the different behaviors, particularly those related to stress during the day vs night. Otherwise, the measurement of the daily activity loses relevance. If spiders are more active during the night, probably differences will be more evident at this time period.
• In the results section, I would split it following the same structure I suggested for methods. In addition, I do not know if it is good to split the information per individual. Please consider to present all the information together if some test such as the bootstrap is made. Otherwise please explain the differences observed in some behaviors (i.e. figs 3 and 4) for the S3 compared to the other individuals.

         The sections for limb interaction and object interaction seem a bit out           of context, probably because these are not explained in detail. I think             this section would benefit a lot if it is organized.

• The discussion is also a bit confusing, again, if the objectives are clear enough, I think it would have a focus. For example, although activity is described in detail, it is barely mentioned in the discussion. In addition, I suggest to rewrite this section after reanalyzing the data. Given the extremely low number of individuals, please be careful with the conclusions, given the low number of individuals, these might be highly speculative and I would clarify that most of the conclusions should be verified with a higher number of individuals.

Once these corrections be applied I consider the paper could be published. I do not feel qualified to evaluate the language since I'm not native english speaker. 

Reviewer 3 Report

I am happy all comments have been addressed