Effect of Short-Term High-Temperature Stimuli on the Functional Response of Trichopria drosophilae (Matsumura)
Round 1
Reviewer 1 Report
Review on
Effect of short-term high temperature stimuli on the functional response of Trichopria drosophilae (Matsumura)
The manuscript describes a study on parasitism response of the pupal parasitoid Trichopria drosophilae exposed to different host and parasitoid densities at increasing temperature regimes (23°C to 35°C). The aim was to characterize the functional responses of this species under these conditions. Trichopria drosophilae is studied worldwide as one potential biocontrol candidate of the fruit pest Drosophila suzukii, which causes tremendous damage especially in areas where the pest is invasive.
In principle, the study is well conducted and data are analysed adequately. Nevertheless, I think the manuscript needs to be rewritten in a sense that the aim and outcome of the laboratory study is placed more in focus and the results should not be too much over-interpreted. For instance, it is not clear for me to come to the final result, that T. drosophilae can be considered as a “good natural enemy for the control of D. suzukii” (Line 31, Line 362) or showed “good parasitic ability” (Line 16, Line 357) because neither a clear definition is given what is considered as “good”, sufficient or efficient to control D. suzukii nor a comparison to other potential biocontrol agents. Because this is laboratory study, we cannot expect to obtain data that allow to evaluate the real biocontrol potential of the parasitoid.
Abstract: please revise, especially Lines 29 to 32 with more focus on the results of this laboratory study. What are the conclusions on the temperature stimulation for the parasitism capacity of this species? In the introduction (Line 126 -128) it is said, that the study was conducted to optimize the mass rearing process of the parasitoid. So you may refer to this as a conclusion in the abstract.
Introduction:
Line 37: (Diptera: Drosophilidae)
Line 43: add “in China” – the listed fruits are of concern mainly in China, in other parts of the world, especially berries (raspberries, blueberries) and cherries are the main infested crop.
Line 45 to 80: I think this part can be kept shorter. The subject of this paper is not the pest status and management of D. suzukii, which has already been covered in several publications that can be cited here, but the parasitism behaviour of one particular parasitoid. There exists already the publication [14] on the functional response of T. drosophilae and it should be stated here in the introduction what is the additional question of the present study and why also the factors temperature (stimulation) and interference between parasitoids are worthwhile to be studied.
Line 78: replace “superior natural geographic conditions” by “highly diverse natural geographic conditions”
Line 80: is there a reference which supports the statement, that “Trichopria drosophilae is one of the most effective parasitic wasps”?
Line 96: please check that the cited reference [12] is really appropriate to support the statement made Line 94 and 95.
Line 101-104: who is developing this simulation model? Do the authors develop this model and was the described laboratory study conducted to provide data for this model?
Line 117: what do you mean with temperature “stimuli” – only a short-term exposure to various temperatures before the exposure to hosts or various temperature regime during the host exposure and parasitization behaviour? – this is also not clear in the description of Material & Methods (see comment below). Please clarify.
Line 118: “treatment time” = “handling time”?
Line 126 to 128: “The purpose of this study was to effectively raise T. drosophilae…” – does this mean that you can use the results of this study to optimize the rearing and application process? – If yes, could you outline in the discussion section, how the obtained results can contribute to this process in detail?
Material and Methods
Line 138: is the cited reference [20] supportive for the statement? Please check.
Line 145: is the cited reference [22] supportive for the statement? Please check.
Line 160: is the cited reference [23] appropriate for the statement? Please check.
Line 151: could you define “second instar pupae”?
Line 151: replace “heads” by “fly pupae” or “hosts” or “host pupae”
Line 153: T. drosophilae wasps were used 24 h after emergence + 12 h “stimulation”. Do they possess their full egg load at that time? Is it comparable for the different temperature treatments?
Line 156/157: it is not clear for me, if parasitoids were exposed only for “12 h of stimulation” and then returned to standard temperature (23°C) for the parasitism experiment or whether they were exposed to the different temperatures also after stimulation for 12 h and subsequently for 24 h for parasitism experiment. Please clarify. The same for Line 169-171
Line 169: replace “hornets” with “wasps”
Line 160 and Line 175: did you include also a control without parasitoid exposure to evaluate general mortality of fly pupae?
Results:
Line 220: control temperature – what is considered as control temperature, 23°C? And why this temperature?
Line 221: again: how you define “temperature stimulation”?
Line 268: “one pair” instead of “1 pair”
Line 270ff: “two pairs” instead of “2 pairs” , “three pairs”, “five pairs”
Discussion:
Line 302/303: what do you mean with “the number of hosts attached”?
Line 307: please check suitability of reference [36] – I understand that knowledge on functional response of a parasitoid may be used to improve mass rearing – can you explain why and can you give examples here?
Line 309/311: I think you should compare your results also with the study of [14]: Kacar G, Wang X-G, Biondi A, Daane KM (2017) Linear functional response by two pupal Drosophila parasitoids foraging within single or multiple patch environments. PLoS ONE 12(8): e0183525. These authors found a linear (typ I) functional response of T. drosophilae at 23°C.
Line 313: Leptopilina japonica instead of Trichopria drosophilae?
Line 314: I don’t understand what you want to say with this sentence and the cited study is related to a predatory species and not to a parasitoid. The same is true for the statements made in Line 321 to 323.
Line 332 to 335: so what would be your conclusion now regarding the right temperature for the mass-rearing derived from your results?
Line 336: replace “self-disturbance” by “interference” of Trichopria drosophilae
Line 347: please check if [44] is the appropriate reference here and if yes, please explain.
Line 348/349: please check wording of the sentence, seems not to be correct.
Line 357 – 363: please revise conclusion, as mentioned before:
For instance, it is not clear for me to come to the final result, that T. drosophilae can be considered as a “good natural enemy for the control of D. suzukii” (Line 31, Line 362) or showed “good parasitic ability” (Line 16, Line 357) because neither a clear definition is given what is considered as “good”, sufficient or efficient to control D. suzukii nor a comparison to other potential biocontrol agents. Because this is laboratory study, we cannot expect to obtain data that allow to evaluate the real biocontrol potential of the parasitoid.
In general, the English Language is appropriate. Please check carefully, if all sentences are complete, also the references. Sometime the wording seems to be too complicated and sentences should be shortened. Grammar should also be checked carefully.
Please check also whether particular terms are used throughout the manuscript and not replaced by other new ones (for instance interference should be used and not "self-disturbance".
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
In this work, the authors study the effect of short-term high temperatures and conspecific interference on the functional response of Trichropia drosophilae. The above is in order to evaluate the potential of this parasitoid for the control of Drosophila suzukii, and also for the subsequent development of a host-parasitoid population dynamics simulation model.
The work contains relevant information and a contribution to the biological control of D. suzukii. However, there are several inconsistencies that it is essential to correct, especially in relation to the statistical analysis. There are also some passages of the text that are unclear and it is recommended that the text be reviewed by an English native speaker. Therefore, it is essential to make modifications before the work can be published.
Below are several relevant comments:
Line 3 (title): Scientific names must be in italics
Lines 59-61: This information requires a citation
Line 67: There is no point in repeating this information that is already in the table. The correct thing is to refer to "oviposition habit", not "oviposition method"
Line 78: This is ambiguous. What exactly does "superior natural geographic conditions" mean?
Line 118: It is not clear what is being called "treatment time". The interaction time between the parasitoid and host?
Line 126: The stated objective is not consistent with what is presented in the work. This work deals with functional response analysis. The methodology never addresses the issue of field releases.
Line 176: The statistical software or language used for the different analyzes is not mentioned. It is essential that authors include this information. It is also convenient to mention the non-linear estimation method of the parameters that was used.
Line 185: Enkegaard states (from Juliano, 1993) that a negative P1 coefficient determines a type II functional response and a positive one a type III functional response. However, at no time is it stated that a non-significant parameter indicates a type I functional response. This claim has no support, at least in what Enkegaard mentioned. Authors should support this claim about the type I functional response, or delete it from the text.
Line 196: The most widely used term in the literature is "handling time". Authors should use this term for clarity.
Table 1: In accordance with what is mentioned in the methodology, the relevant criterion for deciding whether it is a type II or III functional response is the significance of the P1 parameter. However, in this table, although the values of P1 and the sign of the coefficient are shown, the significance test of the parameter P1 is not presented, which turns out to be the most relevant information. On the other hand, with the standard error, it is not possible to know if the parameter was significant or not. Authors should include the significance test specifically for the parameter P1.
Table 1: R2 as a fit criterion only makes sense when working with linear least squares. In the case of nonlinear least-squares, it makes no sense to interpret R2 as a measure of fit.
This column should therefore be removed. In the case of the nonlinear models presented here, you could use AIC, BIC, or pseudo-R2 as fit measures.
Line 223: You assess the quality of fit according to how close the value of R2 is to 1, but you do not perform a significance test for R2, as erroneously mentioned here.
Line 229: The R2 is NOT the correlation coefficient. The correct name is coefficient of determination. These are two different parameters.
Line 230: R2 as a fit criterion only makes sense when working with linear least squares. In the case of nonlinear least-squares, it makes no sense to interpret R2 as a measure of fit. In the case of the nonlinear models presented here, you could use AIC, BIC, or pseudo-R2 as fit measures.
Line 231: This statement involves several errors:
1-As mentioned before, R2 is the coefficient of determination, not of correlation.
2-R2 does not measure correlation. It is a measure of the proportion of the variance in the dependent variable that is explained by the independent variable.
3-Since the parameters were adjusted by non-linear regression, it does not make sense to interpret R2.
Table 2: R2 as a fit criterion only makes sense when working with linear least squares. In the case of nonlinear least-squares, it makes no sense to interpret R2 as a measure of fit.
This column should therefore be removed. In the case of the nonlinear models presented here, you could use AIC, BIC, or pseudo-R2 as fit measures.
Line 237: What is presented in Figure 2 disagrees with this value.
Figure 2 (Model for 33°C): This model is not suitable. It shows a poor fit for the observed data.
Figure 2: (Model for 35°C): This model is not suitable. It shows a poor fit for the observed data.
Lines 247-251: This sentence simply repeats what is shown in Figure 2, without providing relevant observations or analysis.
Line 255: What was the statistical analysis performed for this comparison? ANOVA? It is not mentioned anywhere in the methodology. It must be mentioned.
Table 3: R2 as a fit criterion only makes sense when working with linear least squares. In the case of nonlinear least-squares, it makes no sense to interpret R2 as a measure of fit.
This column should therefore be removed. In the case of the nonlinear models presented here, you could use AIC, BIC, or pseudo-R2 as fit measures.
Table 3 footnote: As mentioned here, you used ANOVA and LSD multiple comparison tests. This should be mentioned in the methodology in the statistical analysis section. Additionally, it should be mentioned whether tests for normality of the residuals and homogeneity of variances were carried out, to validate the assumptions of the ANOVA.
Lines 276-282: What was the statistical analysis performed for this comparison? ANOVA? It is not mentioned anywhere in the methodology. It must be mentioned.
Line 286:There is no point in repeating this information that is already in the table.
Additional comments are included in the attachment
Comments for author File: Comments.pdf
Various writing and syntax errors are observed throughout the text. Some parts are not clear. It is important that the authors have the work reviewed by an English native speaker
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 2 Report
I consider that the text improved remarkably. The authors took pains to analyze each suggestion and make the corresponding modifications, or justify why they did not accept some recommendation. The presentation and description of the statistical aspects are now much better. I consider that the text can be accepted for publication with two minor corrections included in the PDF file.
Comments for author File: Comments.pdf
Minor editing of English language required
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
