Review of Predator Emitted Volatile Organic Compounds and Their Potential for Predator Detection in New Zealand Forests

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This review focused on the volatile organic compounds (VOCs) emitted by the bodies and secretions of introduced mammalian predators in New Zealand forests and different VOCs detection techniques. This topic is interesting and important to contribute to advancements in biosecurity and pest control in forests. This work have been conducted detailed analysis but some minor problems need to be addressed.

1. It is suggested to introduce the role of VOCs in biosecurity and pest control in forests.

Comments on the Quality of English Language

This review focused on the volatile organic compounds (VOCs) emitted by the bodies and secretions of introduced mammalian predators in New Zealand forests and different VOCs detection techniques. This topic is interesting and important to contribute to advancements in biosecurity and pest control in forests. This work have been conducted detailed analysis but some minor problems need to be addressed before acceptance.

1. It is suggested to introduce the role of VOCs in biosecurity and pest control in forests.

2. The error should be corrected in paper, such as, line 28, 225, 245, 304, 309, 358, 371, 436, 453, 480, and 492.

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

In general, the work provides a good opportunity to gather vital information about how VOCs are related to predators in New Zealand. However, I believe there are some important details that lower the quality of the manuscript:

1. In line 129, "Mus. Spicilegus," this is not the correct way to write a scientific name. In general, throughout the text, there are many misspellings of scientific names, which is a serious issue and must be corrected.

2. In Table 3, the unit and what it expresses are not clear. This is because the tables are not mentioned during the text. However, the unit of measurement should be much better explained, and the meaning of the obtained values clarified.

As general comments that should be taken into consideration:

1. I notice that the paper aims to report on the VOCs of certain animals, but throughout the manuscript, there is constant reference to high or elevated values. For instance, in line 339, it is mentioned that the abundance was high, indicating a 16%. High in comparison to what? What was the concentration? What was the abundance of other compounds in the chromatogram? As mentioned earlier, it is important to define these values. In general terms, VOCs can induce or shape different behaviors in animals depending on their concentration.

2. Therefore, considering the previous point, this review becomes too simplistic by not incorporating more quantitative values through GC analysis. I strongly suggest reviewing the literature used for ranges of values and the activities associated with these values in these animals or closely related ones (family or genus).

3. When describing the techniques, particularly chromatography, a very general concept of the technique is presented, which is widely known to all. Is it necessary to include it in such detail? I mean, would it be better to restructure that section and attempt to provide more depth to the review by discussing, for example, the quantification of these compounds or at least their relative abundances.

These suggestions aim to enhance the depth and quality of the review, providing a more comprehensive understanding of the VOCs in the studied animals.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This review briefly canvasses the current dominant methods to detect invasive mammalian predators in New Zealand forests. It proposes an alternative through the detection of species-specific volatile organic compounds (VOCs) by an ‘electronic nose’, either directly or by overflight of a drone. The authors ably review the VOCs emitted by the target species – mice, rats, mustelids, and possums – with useful summary tables. However, Table 6 is an anomaly reporting VOCs of the Brown Antechinus which is a marsupial in Dasyuromorphia and so remotely related to the Brushtail Possum in the Diprotodontia. Thus, this table and the accompanying paragraph are irrelevant. The authors arrive at a useful summary of commonalities between the target species and then progress to potential methodology, particularly about the detection apparatus. The conclusion argues for the potential of the use of VOCs but offers no proof of concept in this or another jurisdiction. Furthermore, the review could be improved with a cost/benefit analysis of the competing technologies, viz camera trapping, environmental DNA and species-specific VOC detection. There is also some comment on ambient VOCs that may confuse detection, but this could be more convincing with data from New Zealand forests.

The review is generally well-written, and the tables and figures are instructive. However, I suggest several errors are corrected as follows.

Line 21: New Zealand has many ecosystems (the plural is correctly used later in the text)

Line 23: native bat. (Not terrestrial?)

Line 23-25: Subject verb – this is not a sentence.

Line 27: ecosystems

Line 30: fauna [5]. This error needs to be corrected throughout the text.

Line 40: forest ecosystems

Line 55-57: This technology is more advanced through remote access if a network is available and AI-driven image recognition which greatly eliminates skilled labour.

Line 58: exploring predators?

Line 124: estrus for consistency and use of simplified American English.

Line 128: Mus spicilegus

Line 129: Mus domesticus

Line 139> These are not found

Line 144: It? What is the subject?

Line 164: It? What is the subject?

Line 173: Mus not Mus.

Line 202: concentration significantly increases

Line 208: Scientific study

Line 219: simulating experiments? Simulations?

Line 281: sources of odours.

Line 307: sex-attraction

Line 313: sources of odours.

Line 336: 150 different what?

Line 349: from glands.

Line 364: Brown Antechinus has no relevance.

Line 380: A variety

Line 418: they face

Comments on the Quality of English Language

See above

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

I appreciate the response to the comments; the paper has undoubtedly improved significantly. I have no further comments