Reduced Soil Moisture Decreases Nectar Sugar Resources Offered to Pollinators in the Popular White Mustard (Brassica alba L.) Crop: Experimental Evidence from Poland

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The manuscript is coherent, well-structured, and presents an investigation into the effects of drought stress on flowering dynamics, nectar production, and pollinator visitation in Brassica alba cv. Palma. The experimental design is clearly described, with a strong emphasis on methodological transparency and ecological relevance. The topic addressed - drought stress in agriculture and its impact on pollinators - is both timely and highly significant in the context of global climate change and sustainable crop production.

The study offers valuable insights into how environmental stressors can alter plant–pollinator interactions and potentially affect crop yields. The inclusion of phenological, physiological, and ecological data adds considerable depth. While the manuscript requires only minor revisions—particularly in the expansion of pollinator-specific discussion and clarification of certain methodological details—it remains a solid contribution to the field. Overall, it is a well-written and relevant study with high potential for publication.

Lines 101-102: It should be 'we observed the blooming phenology and the number of developed flowers per individual plant' instead of ' we observed its blooming phenology and the number of developed flowers 101 per individual plant '.

Methods

Lines 110-113: unnecessary information. Data on the use of this species in agriculture has already been included in the Introduction section. Information on the composition of the seeds does not contribute anything to this section

Lines 193-199: Were the assessments made in similar weather conditions or different? This will affect the number of visits to the flowers. Observations over 3 days may not be sufficient to capture the full variability (e.g. weather effects). Was care taken to measure under different atmospheric conditions?

No information on the randomization of plot layout. Whether plots were randomly distributed in space (which prevents the “field position” effect) or all plots from the same experimental group were together.

Section 2.6. The division of pollinators is too general and insufficient, especially in the context of potential differences in pollination efficiency and sensitivity to environmental stress.

Results

Figure 2 and 3: statistically significant differences (P < 0.05) between w ich GROUPS are marked with different letters?

Figure 4: Y axis title?

Discussion

The discussion is very well argued and shows the Authors' understanding of the complexity of drought in the context of plant-pollinator relationships. It requires minor improvements

The discussion is based on the assumption that the decrease in insect visits worsens pollination, but there is no direct data on yield. It should be highlighted that the impact on pollination and yield requires further research (more emphasis).

There is no data on the efficiency of pollination by different groups – for example, bumblebees often visit more flowers and transfer more pollen than honeybees.

Lines 429-448: Is the honey bee the primary pollinator of white mustard? Not necessarily. Although Apis mellifera frequently visits white mustard and other Brassicaceae crops, several studies suggest that bumblebees (Bombus spp.) and even some solitary bee species may play a significant role in the pollination of annual Brassicaceae crops. Bumblebees tend to be more active under cooler and more challenging weather conditions. Under drought conditions, honey bees may reduce their foraging activity due to lower nectar rewards, whereas bumblebees may continue to forage, albeit at a reduced level. If field data do not indicate a significant decline in bumblebee abundance, this should be emphasized, as they may serve as key stabilizers of pollination under environmental stress.

Author Response

My co-authors and I have prepared the corrected version of the manuscript (Submission ID Sustainability-3705080 "Drought reduces nectar sugar resources offered to pollinators in the popular white mustard (Brassicaalba L.) annual crop: experimental evidence from Poland".

We would like to express our deep thanks to three Reviewer’s for the kind words, time spent to reviewing the article, and  their valuable comments that make our ms better and, we hope, suitable to publish in the Sustainability journal.

We have followed their notes step-by-step. Considering major comments of the Reviewers, we proved the description of Material and Methods (the ommited detals were completed). We wiwdrown the Fig. 5 as contributing nothing to the interpretation of the results.

We have changed the ms title, as suggested by Rev 1 and Rev 3. Now it is „Reduced soil moisture decreases nectar sugar resources offered to pollinators in the popular white mustard (Brassica alba L.) crop: experimental evidence from Poland”.

We also verified the Discussion in relation to the particular insect visitor groups behavior and their frequency. Accordingly, relevant references have been added. We hope our data on insect visitors are easier to follow now and the discussion is more reliable.   

We have corrected also all the minor issues indicated for improvement, i.e. completed omitted details or removed unnecessary phrases.

The English language of article has been also corrected.

We hope that our ms reaches a standard acceptable for publication in the Sustainability journal.

Please find our detailed response to all Reviewer’ comments.

Bożena Denisow and co-authors

Rev. 1

Comment 1. The manuscript is coherent, well-structured, and presents an investigation into the effects of drought stress on flowering dynamics, nectar production, and pollinator visitation in Brassica alba cv. Palma. The experimental design is clearly described, with a strong emphasis on methodological transparency and ecological relevance. The topic addressed - drought stress in agriculture and its impact on pollinators - is both timely and highly significant in the context of global climate change and sustainable crop production.

The study offers valuable insights into how environmental stressors can alter plant–pollinator interactions and potentially affect crop yields. The inclusion of phenological, physiological, and ecological data adds considerable depth. While the manuscript requires only minor revisions—particularly in the expansion of pollinator-specific discussion and clarification of certain methodological details—it remains a solid contribution to the field. Overall, it is a well-written and relevant study with high potential for publication.

We would like to express our deep thanks for the kind words and time spent to reviewing our article, and  we hope we adressed your valuable comments properly. 

Comment 2.  Lines 101-102: It should be 'we observed the blooming phenology and the number of developed flowers per individual plant' instead of ' we observed its blooming phenology and the number of developed flowers 101 per individual plant '.

Corrected

Methods

Comment 3.  Lines 110-113: unnecessary information. Data on the use of this species in agriculture has already been included in the Introduction section. Information on the composition of the seeds does not contribute anything to this section

Corrected, The information was removed.

Comment 4. Lines 193-199: Were the assessments made in similar weather conditions or different? This will affect the number of visits to the flowers. Observations over 3 days may not be sufficient to capture the full variability (e.g. weather effects). Was care taken to measure under different atmospheric conditions?

In fact, we only condacted these  observation for three days. So in this manuscript the interpretation applies to the indicated period. We used previously described and applied methods, e.g. Dmitruk, M., et al., (2022). Plants enhancing urban pollinators: Nectar rather than pollen attracts pollinators of Cotoneaster species. Urban Forestry & Urban Greening, 74, 127651.

The observation of insect visitors was made during the weather condition suitable for  insect visitors foragings. We did not observe the pollinators in various weather conditions, therefore the influence of atmospheric factors on the composition of entomofauna was not taken into account in our survay. Relevant information was added to the text „ Insect visitors monitoring was carried out in weather condition suitable for their activ-ity, i.e. no rain, no wind or light wind (<35 km/h), cloud cover <40%, air temperature 23–27 °C.

Comment 5. No information on the randomization of plot layout. Whether plots were randomly distributed in space (which prevents the “field position” effect) or all plots from the same experimental group were together.

Yes, the experiment was conducted in accordance  with the principles of experimentation .  The information on randomn plots distribution  was added.

Comment 6. Section 2.6. The division of pollinators is too general and insufficient, especially in the context of potential differences in pollination efficiency and sensitivity to environmental stress.

In this study we did not determine the insect efficiency in the pollination proces. No experiments on the number of pollen grains transfer on the pollinator body or the number of pollen grains deposited on the stigma were made. We followed the methods of Masierowska, M.; Piętka, 2014; Dmitruk et al., 2022, therefore the insects were only clasified to the following taxonomic groups: Apis mellifera, Bombus spp., other Hymenoptera, Diptera, and Lepidoptera. In ‘other Hymenoptera’ group solitary bees are included . These insects are indicated as efficient pollinators in white mustard, therefore we expanded the discussion.

We are aware that our data on the  impact on soil moisture levels on total floral resources availability and their influence on insect visitors behaviour have to be treeated as preliminary, therefore we unerlined it as our study limitation (in the Discussion section).

Results

Comment 7. Figure 2 and 3: statistically significant differences (P < 0.05) between w ich GROUPS are marked with different letters?

Thank you very much for this remark. It shouldn't happen. We added the ommited information: Fig 2 (treatment x year effect is shown);  

Fig. 3  a-c treatment x year effect is shown

Figure 4: Y axis title?

We added the description of the Y axis;

We added the ommited information on statistical differences between means:  A-C between treatments, a-c treatment x year effect.

Discussion

Comment 8. The discussion is very well argued and shows the Authors' understanding of the complexity of drought in the context of plant-pollinator relationships. It requires minor improvements

Thank you for noticing our efforts to interpret the results in accordance with the methods used and the results obtained.

Comment 9. The discussion is based on the assumption that the decrease in insect visits worsens pollination, but there is no direct data on yield. It should be highlighted that the impact on pollination and yield requires further research (more emphasis).

There is no data on the efficiency of pollination by different groups – for example, bumblebees often visit more flowers and transfer more pollen than honeybees.

 

In general, we are aware of the study limitation regarding the insect visitor data. Please note the name of the 2.6. section „Flower attractiveness to insect visitors ‘ . We did not use the term ‘pollinators’ because the effectiveness of insects was not experimentally determined (data on the pollen loads  transferred on their body or the pollen load deposited on the stigma were not collected).

We have now added this information in the context of the limitations of our experiment.

Comment 10. Lines 429-448: Is the honey bee the primary pollinator of white mustard? Not necessarily. Although Apis mellifera frequently visits white mustard and other Brassicaceae crops, several studies suggest that bumblebees (Bombus spp.) and even some solitary bee species may play a significant role in the pollination of annual Brassicaceae crops. Bumblebees tend to be more active under cooler and more challenging weather conditions. Under drought conditions, honey bees may reduce their foraging activity due to lower nectar rewards, whereas bumblebees may continue to forage, albeit at a reduced level. If field data do not indicate a significant decline in bumblebee abundance, this should be emphasized, as they may serve as key stabilizers of pollination under environmental stress.

We absolutely agree. Therefore, we add more information and slightly re-build the discussion. First, we have added the information that honey bee can be overrepresented in our field because, the apiary was present in a nearby area. Second, we added the info. on possible role of solitary bees and bumble bees in effective pollination of white mustard, considering their suginfficance as key stabilizers of pollination under environemntal stress conditions. Relevant literaturę have been added  to the References.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have conducted an interesting  study examining the effects of drought stress on white mustard nectar production and pollinator visitation, which addresses an important aspect of climate change impacts on plant-pollinator interactions. However, the manuscript requires significant revision before it can be considered for publication.

Major comment

1. The authors used chemicals to control flea beetles and rape beetles but failed to specify which types of pesticides were applied. Additionally, the authors did not address the potential effects of pesticide application on pollinator visitation rates. Previous studies (e.g., Paulo et al., 2019; Edivani et al., 2023; Das et al., 2024) have demonstrated that pesticide application significantly reduces pollinator visitation rates, which represents a critical confounding factor that should have been considered in this study.
2. I question the direct correlation established between drought-induced changes in nectar composition and pollinator visitation rates. While nectar serves as an important reward, it is not the primary attractant for pollinators. Pollinators are initially attracted by floral volatiles volatile organic compounds (VOCs) that serve as infochemical signaling resource availability and quality. The authors did not investigate how drought affected floral VOC profiles, which is a critical omission since these chemical signals are the primary drivers of pollinator attraction and foraging decisions.

Without data on VOC changes under drought stress, it is problematic to directly correlate nectar composition with visitation rates. Nectar primarily functions as a reward that influences foraging behavior after initial attraction, rather than as the primary attractant itself. Additionally, the authors only examined total sugar content in nectar but did not analyze the specific sugar composition (sucrose, glucose, fructose ratios), which is known to influence pollinator preferences and foraging efficiency.

The relationship between nectar composition and pollinator visitation is more complex than presented. While nectar quality may affect pollinator survival, colony fitness, and community richness over time, its direct influence on short-term visitation rates is mediated by multiple factors including floral display, VOC emissions, and environmental context.

3. The experimental design is misleading regarding the treatment structure. The authors describe three treatments: control, irrigation and drought stress which creates confusion about what constitutes the baseline condition. A proper drought stress experiment should have only two main treatment categories: well-watered (control) and drought-stressed plants.

I suggest the authors should have implemented a more robust experimental design with a clear control treatment (well-watered plants maintained at optimal soil moisture) and multiple drought stress treatments with different water stress intensities. For example, they could have used treatments based on soil water holding capacity such as:

1. Control: 80-100% field capacity (well-watered)
2. Moderate drought: 50-60% field capacity
3. Severe drought: 30-40% field capacity
4. Extreme drought: 20-30% field capacity

This approach would provide a more comprehensive understanding of how different drought intensities affect nectar production and pollinator visitation, rather than using an ambiguous three-treatment design.

4. Figure 5 lacks critical information about the experimental context. The figure shows insect visitation data by taxonomic group, but it fails to specify which treatment these data represent. Given that the study includes multiple treatments (control, irrigation, and drought stress) and was conducted over multiple years, this omission is a significant flaw in data presentation.
5. Figure 6: The presentation of insect visitation data as raw numbers is scientifically inadequate and does not constitute proper analysis of visitation rates. The data shows absolute numbers rather than standardized visitation rates (e.g., visits per flower per hour, visits per unit time per treatment area). Without knowing the observation duration, flower density, or sampling effort for each treatment, these numbers are not comparable. The authors need to perform appropriate statistical modeling (e.g., generalized linear mixed models with Poisson or negative binomial distribution) to account for count data and repeated measures. The data should be standardized by observation time, number of flowers available, or plot area to generate meaningful visitation rates.
6. The stated objectives do not align with the actual experimental design and methodology described in the study. The authors claim their objective was to test how the variability in soil water holding capacity affects flowering and nectar production, which implies a gradient or multiple levels of water stress. However, the experimental design appears to include only discrete treatment categories rather than a true gradient of soil water capacities.

Other minor comments

1. I suggest to remove “annual crop” from the title, since mustard is already known to be annual
2. In the abstract line 18: nectar production is a function of soil moisture levels. This statement is too absolute. Should be nectar production is influenced by or depends on etc.
3. Figure 1&5. Lettering should be above the error bars.
4. Line 355: “a decrease in the floral display size” authors do not present any flower pictures, or any data regarding flowering size. Need to present data to support this argument.
5. Line 32: the informal tone (There is no doubt) is not appropriate for scientific writing.

Comments on the Quality of English Language

English language can be improved 

Author Response

My co-authors and I have prepared the corrected version of the manuscript (Submission ID Sustainability-3705080 "Drought reduces nectar sugar resources offered to pollinators in the popular white mustard (Brassicaalba L.) annual crop: experimental evidence from Poland".

We would like to express our deep thanks to three Reviewer’s for the kind words, time spent to reviewing the article, and  their valuable comments that make our ms better and, we hope, suitable to publish in the Sustainability journal.

We have followed their notes step-by-step. Considering major comments of the Reviewers, we proved the description of Material and Methods (the ommited detals were completed). We wiwdrown the Fig. 5 as contributing nothing to the interpretation of the results.

We have changed the ms title, as suggested by Rev 1 and Rev 3. Now it is „Reduced soil moisture decreases nectar sugar resources offered to pollinators in the popular white mustard (Brassica alba L.) crop: experimental evidence from Poland”.

We also verified the Discussion in relation to the particular insect visitor groups behavior and their frequency. Accordingly, relevant references have been added. We hope our data on insect visitors are easier to follow now and the discussion is more reliable.   

We have corrected also all the minor issues indicated for improvement, i.e. completed omitted details or removed unnecessary phrases.

The English language of article has been also corrected.

We hope that our ms reaches a standard acceptable for publication in the Sustainability journal.

Please find our detailed response to all Reviewer’ comments.

Bożena Denisow and co-authors

Rev 2

Comment 1. The authors have conducted an interesting  study examining the effects of drought stress on white mustard nectar production and pollinator visitation, which addresses an important aspect of climate change impacts on plant-pollinator interactions. However, the manuscript requires significant revision before it can be considered for publ1.cation.

We would like to express our deep thanks for the kind words and time spent to reviewing our article, and  we hope we adressed your valuable comments properly. 

 

Major comment

Comment 2. The authors used chemicals to control flea beetles and rape beetles but failed to specify which types of pesticides were applied. Additionally, the authors did not address the potential effects of pesticide application on pollinator visitation rates. Previous studies (e.g., Paulo et al., 2019; Edivani et al., 2023; Das et al., 2024) have demonstrated that pesticide application significantly reduces pollinator visitation rates, which represents a critical confounding factor that should have been considered in this study.

Thank ypu very much for this remark. We have added the information on the type of pesticides used. All  activities related to chemical applications  were carried out strictly in accordance with the recommendations.

Pesticides spraying was made after sunset minimizing potential risks to pollinators (cessation of their activity). Moreover, the insect visitor observations were conducted 4-5 days after pesticides application.

Comment 3. I question the direct correlation established between drought-induced changes in nectar composition and pollinator visitation rates. While nectar serves as an important reward, it is not the primary attractant for pollinators. Pollinators are initially attracted by floral volatiles volatile organic compounds (VOCs) that serve as infochemical signaling resource availability and quality. The authors did not investigate how drought affected floral VOC profiles, which is a critical omission since these chemical signals are the primary drivers of pollinator attraction and foraging decisions.

Without data on VOC changes under drought stress, it is problematic to directly correlate nectar composition with visitation rates. Nectar primarily functions as a reward that influences foraging behavior after initial attraction, rather than as the primary attractant itself. Additionally, the authors only examined total sugar content in nectar but did not analyze the specific sugar composition (sucrose, glucose, fructose ratios), which is known to influence pollinator preferences and foraging efficiency.

The relationship between nectar composition and pollinator visitation is more complex than presented. While nectar quality may affect pollinator survival, colony fitness, and community richness over time, its direct influence on short-term visitation rates is mediated by multiple factors including floral display, VOC emissions, and environmental context.

Thank you very much for this comment. Please note that the complexity of floral attractions for visiting insects is indicated in the Discussion section (Ls 439-442; ms version 1). However, to be more precise and following the suggestions above, we have expanded and clarified the discussion. Also, we added more specific information considering the study limitation.

Comment 4. The experimental design is misleading regarding the treatment structure. The authors describe three treatments: control, irrigation and drought stress which creates confusion about what constitutes the baseline condition. A proper drought stress experiment should have only two main treatment categories: well-watered (control) and drought-stressed plants.

I suggest the authors should have implemented a more robust experimental design with a clear control treatment (well-watered plants maintained at optimal soil moisture) and multiple drought stress treatments with different water stress intensities. For example, they could have used treatments based on soil water holding capacity such as:

 

Control: 80-100% field capacity (well-watered)

Moderate drought: 50-60% field capacity

Severe drought: 30-40% field capacity

Extreme drought: 20-30% field capacity

This approach would provide a more comprehensive understanding of how different drought intensities affect nectar production and pollinator visitation, rather than using an ambiguous three-treatment design.

Thank you very much for all the above suggestions. However, our experiment has been designed as presented and described in details in the Material and Methods section. We can use your suggestions in the future.

Comment 5. Figure 5 lacks critical information about the experimental context. The figure shows insect visitation data by taxonomic group, but it fails to specify which treatment these data represent. Given that the study includes multiple treatments (control, irrigation, and drought stress) and was conducted over multiple years, this omission is a significant flaw in data presentation.

We have decided to withdrow Fig. 5.

Comment 6. Figure 6: The presentation of insect visitation data as raw numbers is scientifically inadequate and does not constitute proper analysis of visitation rates. The data shows absolute numbers rather than standardized visitation rates (e.g., visits per flower per hour, visits per unit time per treatment area). Without knowing the observation duration, flower density, or sampling effort for each treatment, these numbers are not comparable. The authors need to perform appropriate statistical modeling (e.g., generalized linear mixed models with Poisson or negative binomial distribution) to account for count data and repeated measures. The data should be standardized by observation time, number of flowers available, or plot area to generate meaningful visitation rates.

We appreciate the suggestion to analyse visitation data using generalized linear mixed models (GLMMs). However, the aim of the present study was to compare the relative frequencies and group structure of insect visitors across treatments, rather than to model absolute visitation rates. To this end, we applied non-parametric and chi-square tests to assess differences in visitation distribution among taxa and treatments. We acknowledge that a more advanced statistical approach could provide additional insights and allow for a deeper interpretation of the data. However, in this study, we focused on basic analyses that address the core questions related to independence and distributional consistency. A more detailed analysis using statistical modelling is planned for a separate publication.

Our data used in statiatical comparisons of particular insect groups distribution between treatemens were standardized, which directly results from the methods used. For each treatement, the observations were carried out on plots of the same size, the numer of plots was the same, observations were carried out at the same day-time hours,  and lasted the same amount of time (census of observation). We procedurę of insect visitor observations was described in details in the section 2.6. Flower attractiveness to insect visitors

Comment 7. The stated objectives do not align with the actual experimental design and methodology described in the study. The authors claim their objective was to test how the variability in soil water holding capacity affects flowering and nectar production, which implies a gradient or multiple levels of water stress. However, the experimental design appears to include only discrete treatment categories rather than a true gradient of soil water capacities.

The term ‘soil water capasity ‘was changed for ‘soil moisture’, which was also suggested by other Reviwers. The information on soil moisture for each treatement preformed was added to the Figures description. We hope that additional information will make the interpretation of our results more reliable and reflect the reality of the experiment.

Comment 8. Other minor comments

I suggest to remove “annual crop” from the title, since mustard is already known to be annual

Corrected

In the abstract line 18: nectar production is a function of soil moisture levels. This statement is too absolute. Should be nectar production is influenced by or depends on etc.

Figure 1&5. Lettering should be above the error bars.

The letters position has been changed.

Line 355: “a decrease in the floral display size” authors do not present any flower pictures, or any data regarding flowering size. Need to present data to support this argument.

 

Thank you for this remark. We do not measured flower size.  In fact our data refers to the numer of developed flowers (as presented in Fig. 2), therefore the phrase was changed. 

Line 32: the informal tone (There is no doubt) is not appropriate for scientific writing.

We changed the phrase for more formal – „In recent decades”

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript presents a specific assessment testing how the variability in soil water holding capacity (better to say actual soil moisture status) affects flowering and nectar production in field-cultivated white mustard. This field-based experimental work on a key crop species under climate-related stress is valuable and timely.

The title is descriptive, though it does not accurately reflect the soil-related content of the manuscript.

The abstract is well-structured and clearly summarizes the study’s background, objectives, key findings, and implications, though it could be clearer in indicating the limitations (e.g., focus on one cultivar, short duration) of the study.

The introduction thoroughly establishes the relevance of studying plant-pollinator interactions under drought stress, with an appropriate review of existing literature. This section is well-contextualized within climate change and pollination services. What I missed from the end of the chapter is the clear statement of objectives and maybe some hypotheses. I found a minor inconsistency in the nomenclature (e.g., switching between Sinapis alba and Brassica alba). I recommend using consistent botanical nomenclature throughout the text.

The Materials and Methods section provides detailed and transparent methodology that would enable replication for each subsection. The experimental design is robust, including appropriate controls and treatments, though I do not consider the use of the term ‘drought’ proper. The description of the determination of the soil moisture measurements is not correct. The sample sizes for nectar collection are not clear. I highly recommend revising the whole text to ensure a consistent and coherent use of terms for soil moisture content.

The results are logically presented and well-illustrated with figures and tables. Statistical significance is clearly communicated. Nevertheless, I cannot see the clear, quantified linkage between water availability (actual soil moisture status) and changes in flowering and nectar production. The soil moisture data are missing.

The Discussion section demonstrates a strong understanding of the broader ecological and agricultural context, though some impacts (e.g., predicting socio-economic) are speculative. The results are interpreted with reference to the existing literature, and here the limitations are acknowledged.

The conclusions are appropriate and justified by the data. Referring to the ‘soil moisture levels’ is much better than in the Materials and Methods section, though quantified data are missing. The practical applications (e.g., breeding programs, water management) are emphasized.

I indicated some remarks in sticky notes in the manuscript.

Comments for author File: Comments.pdf

Author Response

My co-authors and I have prepared the corrected version of the manuscript (Submission ID Sustainability-3705080 "Drought reduces nectar sugar resources offered to pollinators in the popular white mustard (Brassicaalba L.) annual crop: experimental evidence from Poland".

We would like to express our deep thanks to three Reviewer’s for the kind words, time spent to reviewing the article, and  their valuable comments that make our ms better and, we hope, suitable to publish in the Sustainability journal.

We have followed their notes step-by-step. Considering major comments of the Reviewers, we proved the description of Material and Methods (the ommited detals were completed). We wiwdrown the Fig. 5 as contributing nothing to the interpretation of the results.

We have changed the ms title, as suggested by Rev 1 and Rev 3. Now it is „Reduced soil moisture decreases nectar sugar resources offered to pollinators in the popular white mustard (Brassica alba L.) crop: experimental evidence from Poland”.

We also verified the Discussion in relation to the particular insect visitor groups behavior and their frequency. Accordingly, relevant references have been added. We hope our data on insect visitors are easier to follow now and the discussion is more reliable.   

We have corrected also all the minor issues indicated for improvement, i.e. completed omitted details or removed unnecessary phrases.

The English language of article has been also corrected.

We hope that our ms reaches a standard acceptable for publication in the Sustainability journal.

Please find our detailed response to all Reviewer’ comments.

Bożena Denisow and co-authors

REV 3

Comment 1. The manuscript presents a specific assessment testing how the variability in soil water holding capacity (better to say actual soil moisture status) affects flowering and nectar production in field-cultivated white mustard. This field-based experimental work on a key crop species under climate-related stress is valuable and timely.

We would like to express our deep thanks for the kind words and time spent to reviewing our article, and  we hope we adressed your valuable comments properly. 

Comment 2. The title is descriptive, though it does not accurately reflect the soil-related content of the manuscript.

We have changed the ms title for:

Reduced soil moisture decreases nectar sugar resources offered to pollinators in the popular white mustard (Brassica alba L.) crop: experimental evidence from Poland

Comment 3. The abstract is well-structured and clearly summarizes the study’s background, objectives, key findings, and implications, though it could be clearer in indicating the limitations (e.g., focus on one cultivar, short duration) of the study.

The information on the study years was added. Also we underlined that the study focused on one cultivar.

Comment 4. The introduction thoroughly establishes the relevance of studying plant-pollinator interactions under drought stress, with an appropriate review of existing literature. This section is well-contextualized within climate change and pollination services. What I missed from the end of the chapter is the clear statement of objectives and maybe some hypotheses.

We added a hypothesis; We hypothesized that reduced soil moisture levels lead to the reduction of sugar food resources available to pollinators and adversely affect pollinator activity.

Comment 5. I found a minor inconsistency in the nomenclature (e.g., switching between Sinapis alba and Brassica alba). I recommend using consistent botanical nomenclature throughout the text.

Thank you for this remark. The botanical nomenclature has been clarified throughout the text.

Comment 6. The Materials and Methods section provides detailed and transparent methodology that would enable replication for each subsection. The experimental design is robust, including appropriate controls and treatments, though I do not consider the use of the term ‘drought’ proper. The description of the determination of the soil moisture measurements is not correct. The sample sizes for nectar collection are not clear. I highly recommend revising the whole text to ensure a consistent and coherent use of terms for soil moisture content.

We have looked through entire text. The term ‘soil moisture’ is now used across the whole text. Aslo , we tried to clarify the sample size for necatr collection procedure.

The experimental treatements has been clarified in the section  2.2. Experimental set-up and protocols

‘The experiment involved three treatments: (i) – control (= ambient precipitation); (ii) irrigation  – ambient precipitation + 30 mm of water added (3 x 10 l/m2); (iii) reduced soil moisture (hereafter drought) – no watering and elimination of rainwater with a tunnel made of transparent polyethylene foil.’

We tried to describe the procedure for nectar collection more precisly.

Comment 7. The results are logically presented and well-illustrated with figures and tables. Statistical significance is clearly communicated. Nevertheless, I cannot see the clear, quantified linkage between water availability (actual soil moisture status) and changes in flowering and nectar production. The soil moisture data are missing.

In the section 2.3. Soil moisture levels, we described soil moisture levels for particular treatements in particular years.

We have added the data on soil moisture available for particular treatements to the descriptions of all Figures.

Comment 8. The Discussion section demonstrates a strong understanding of the broader ecological and agricultural context, though some impacts (e.g., predicting socio-economic) are speculative. The results are interpreted with reference to the existing literature, and here the limitations are acknowledged.

We have withdrawn the phrase about possible indirect influence of drought scenarios on  socio-economic outcomes.

Comment 9. The conclusions are appropriate and justified by the data. Referring to the ‘soil moisture levels’ is much better than in the Materials and Methods section, though quantified data are missing. The practical applications (e.g., breeding programs, water management) are emphasized.

We tried to unify the nomenclature and used ‘soil moisture levels’ phrase throughout the text

Comment 10. I indicated some remarks in sticky notes in the manuscript.

We took all the comments inserted in the pdf file into account and made the necessary changes.

 

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

I appreciate the effort the authors have made in revising the manuscript. Many of my initial concerns have been addressed. The quality of the manuscript has improved, and can be considered for sustainbility.