Effects of Temperature on Life-History Traits of Paralipsa gularis (Zeller) (Lepidoptera: Pyralidae), a Newly Emerged Maize Pest from the Border Areas Between China and Southeast Asian Countries

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Starting at the 209 line and further the p-value described as equal to zero.  It should be equal to some positive value or more or less than some value lower than 1 and higher than 0.

Table. 1 contains data that is similar to those in Figure 1: Larval duration/Pupa mass/Adult longevity, but not divided by sex. These data are meaningless, because it is not representing real developmental features (especially for Pupa mass). These indices will be highly depended on the sex ratio and shifted strongly with prevalence of one sex over the other.

The sex ratio is not specified for any temperature condition or adult/pupa stage. This index is important for interpretation of the data.

In Figure 1, it’d be good to mark statistically significant differences.

Table 4. There is very strange level of developmental threshold for the females at the second instar and for both sexes at the 5^th instar: threshold temperatures are higher than 18 °C the temperature at which survival rate of the individuals was higher 80% in compare with previous instar. It is illogical. Maybe there is some excess of observed data at the 18°C that shifts the trend line at the greater angle therefore makes the threshold temperature higher than expected. The graphics of developmental rate with trend line would be more illustrative because it is showing how well the observed values lie along the trend line.

Table 5. the benefits of this table is not clear. The equations with calculated coefficients are given in the text, the levels of determination are shown, and the data of average development at different stages are in the previous tables. It seems to be enough.

Author Response

Starting at the 209 line and further the p-value described as equal to zero. It should be equal to some positive value or more or less than some value lower than 1 and higher than 0.

Response: Accepted. We have revised all “p = 0.000” to “ p < 0.001” in the manuscript. Thanks.

 

Table. 1 contains data that is similar to those in Figure 1: Larval duration/Pupa mass/Adult longevity, but not divided by sex. These data are meaningless, because it is not representing real developmental features (especially for Pupa mass). These indices will be highly depended on the sex ratio and shifted strongly with prevalence of one sex over the other.

Response: Revised. We sincerely thank the reviewer for this insightful comment. Table 1 presents the developmental durations of all stages of Paralipsa gularis (Zeller), including individuals that did not successfully reach adulthood. For example, if a larva dies during the fifth instar, its data are included in the calculation of the fourth-instar developmental duration but excluded from that of the fifth instar. The same principle applies to the calculation of other indicators. Additionally, temperature significantly influences the variation in instar duration of P. gularis, as shown in Table 1. Given that developmental duration, pupal weight, and other indicators may vary depending on sex ratio, we further analyzed these parameters separately for males and females at each developmental stage. Therefore, we consider Table 1 and Figure 1 to be necessary. However, to avoid redundancy, we have re-designated Table 1 as Table S1.

 

The sex ratio is not specified for any temperature condition or adult/pupa stage. This index is important for interpretation of the data.

Response: Accepted. We have revised the sex ratios at various temperatures in Table S1. Thanks.

 

In Figure 1, it’d be good to mark statistically significant differences.

Response: Accepted. We have added the significance analysis to Figure 1.

 

Table 4. There is very strange level of developmental threshold for the females at the second instar and for both sexes at the 5th instar: threshold temperatures are higher than 18 °C the temperature at which survival rate of the individuals was higher 80% in compare with previous instar. It is illogical. Maybe there is some excess of observed data at the 18°C that shifts the trend line at the greater angle therefore makes the threshold temperature higher than expected. The graphics of developmental rate with trend line would be more illustrative because it is showing how well the observed values lie along the trend line.

Response: Revised. Thank you very much for your valuable comments. As you mentioned, the developmental threshold temperatures for second instar females and both sexes at the 5th instar are slightly higher than 18°C; this may be due to some excess of observed data at 18°C and 33°C. Therefore, we have included a trend graph showing how the developmental rate varies with temperature (Figure 6).

 

Table 5. the benefits of this table is not clear. The equations with calculated coefficients are given in the text, the levels of determination are shown, and the data of average development at different stages are in the previous tables. It seems to be enough.

Response: Accepted. We have deleted Table 5. Thanks.

Reviewer 2 Report

Comments and Suggestions for Authors

Reviewer’s Comments on the Manuscript “Effects of Temperature on Life-History Traits of Paralipsa gularis (Zeller), a Newly Emerged Maize Pest from the Border Areas between China and Southeast Asian Countries” submitted to Insect

This manuscript reports a lab rearing experiment of a maize pest in China, which provide some insight for our understanding and benefit future pest control practice. However, the present form of this manuscript cannot be accepted for publication in Insects. The recommendation is Major Revision.

In the title and abstract, please add “(Lepidoptera: Pyralidae)” to indicate the taxonomic group of this pest, this is very important for more general readers to grasp the basic information of it.

Please choose other keywords to avoid duplication from title.

The background states that P. gularis has “evolved” into a field pest, but the manuscript does not provide evidence of genetic or physiological adaptation. The term “shifted” or “expanded its ecological niche” would be more accurate unless evolutionary change is demonstrated.

The first paragraph of introduction is confusing, at least comparing to the title. P. gularis is now commonly found in many provinces across China, but in the title the authors stated that this pest is newly emerged on the border area with SE Asia. This may mislead the readers (including me) to believe the pest is about to enter China as an invasive species. Please take care of the basic logic in the narration.

The introduction mentions climate warming as a driver of range expansion, but the authors must keep in mind that climate warming does not necessarily cause range expansion of all lepidopterous insects. Some suffered from contraction too. In addition, using butterflies as examples are not suitable in this context, as most of them are not even pest potential, which shows different respond to climate warming. One more point, it would be proper to use climate change rather than climate warming.

Line 123 under ‘Insects’, for Pu’er, it is inappropriate to use ‘city’. It is a municipality. Actually, this administrative level should be Prefecture.

Lines 126-127: “round plastic container (3000 ml)” sounds confusing. The word ‘round’ means a 2D circle shape. Is this container spherical or cylindrical? Please choose the proper word.

Line 132: ‘the mouth of the tube’ should be ‘the opening of the tube’.

Line 133: what shape of the ‘plastic container (25 ml)’? Petri dish? Please check and correct throughout the text. And what is ‘an appropriate amount’, please be clear here although a citation is given. Making the methodology specific facilitates others to replicate your research.

Section 2.2 has a very long paragraph, please break it into several with each one focusing on one step of the experiment. This will make the article more readable.

The study includes a wide temperature range (15-35 °C), but the justification for choosing these specific intervals (e.g., based on local climate data or historical records) is not provided. Adding such justification would strengthen the ecological relevance.

Lines 145-146: The statement that “the larvae were fed an artificial diet… replaced every 2-3 days” is vague. Diet freshness and potential microbial growth could affect development, especially at higher temperatures. Please specify how diet quality was controlled.

Lines 172-176: What are these formulae for? Please indicate the function of each one in the text.

Line 183: SPSS is a commercial analytical tool, please provide your registered license number.

Table 3: The authors report that no mating occurred at any temperature (which is rather strange), this is confusing as there are offsprings for the authors to complete the research?? Please check if there are any errors.

Result presentation issues: (1) Table 1 is overly dense and difficult to interpret. Please consider reformat it to enhance it legibility. (2) All figures are too small with poor legibility, please enlarge the figure plates to make them clearer. (3) There are zillions of data in the text, which make it very hard to grasp the key findings, please consider visualise those data into charts.

Discussion:

The most critical issue—complete failure of mating—is mentioned only briefly in the discussion (lines 410-420) and is not adequately explored. The authors speculate about environmental factors but do not propose specific follow-up experiments or acknowledge that this failure invalidates key life table parameters. This is a major omission.

The discussion claims that “all P. gularis adults were unmated, and the eggs they produced were infertile” but then continues to compare fecundity and R₀ across temperatures as if these values were meaningful. This is internally inconsistent. The authors should either reanalyze the data without the life table parameters or redesign the study to achieve mating.

The discussion would benefit from a more critical evaluation of whether the laboratory conditions (e.g., individual rearing, container size, absence of host plant volatiles) suppressed natural mating behavior. This is essential for interpreting the study’s relevance to field populations.

The authors cite several studies on temperature effects in other insects but do not discuss why P. gularis failed to mate while similar species under comparable conditions did mate. This comparison would strengthen the discussion.

Comments on the Quality of English Language

Please invite a native English speaker to facilitate the writing to enhance the readability of this manuscript. Especially, the logic of narration must be taken care of.

Author Response

Thank you very much for taking the time to review this manuscript. Following are our point-by-point responses to the comments or suggestions.

In the title and abstract, please add “(Lepidoptera: Pyralidae)” to indicate the taxonomic group of this pest, this is very important for more general readers to grasp the basic information of it.

Response: Revised. We have added “(Lepidoptera: Pyralidae)” to the title and abstract (Line 3, Line 30). Thanks.

 

Please choose other keywords to avoid duplication from title.

Response: Revised. We have replaced “development duration,” “life table,” and “fecundity” with “biology,” “two-sex life table,” and “demographic parameters” (Lines 53-54). Thanks.

 

The background states that P. gularis has “evolved” into a field pest, but the manuscript does not provide evidence of genetic or physiological adaptation. The term “shifted” or “expanded its ecological niche” would be more accurate unless evolutionary change is demonstrated.

Response: Revised. We have changed “evolved” to “shifted” (Line 19). Thanks.

 

The first paragraph of introduction is confusing, at least comparing to the title. P. gularis is now commonly found in many provinces across China, but in the title the authors stated that this pest is newly emerged on the border area with SE Asia. This may mislead the readers (including me) to believe the pest is about to enter China as an invasive species. Please take care of the basic logic in the narration.

Response: Revised. We have revised the basic logic in the manuscript (Lines 59-63). Previously, it was stated that Paralipsa gularis (Zeller) was distributed across Europe, North America, and multiple provinces in China and was a storage pest that damages stored crops. In recent years, however, its damage patterns in the border areas between China and Southeast Asian Countries have shifted from storage to field crops. Thanks.

 

The introduction mentions climate warming as a driver of range expansion, but the authors must keep in mind that climate warming does not necessarily cause range expansion of all lepidopterous insects. Some suffered from contraction too. In addition, using butterflies as examples are not suitable in this context, as most of them are not even pest potential, which shows different respond to climate warming. One more point, it would be proper to use climate change rather than climate warming.

Response: Thank you for the suggestion. We have removed the references to butterflies as examples and changed climate warming to climate change (Lines 78-91).

 

Line 123 under ‘Insects’, for Pu’er, it is inappropriate to use ‘city’. It is a municipality. Actually, this administrative level should be Prefecture.

Response: Accepted. We have changed “city” to “Prefecture” (Line 122). Thanks.

 

Lines 126-127: “round plastic container (3000 ml)” sounds confusing. The word ‘round’ means a 2D circle shape. Is this container spherical or cylindrical? Please choose the proper word.

Response: Accepted. We have changed “round” to “cylindrical” (Lines 126-127). Thanks.

 

Line 132: ‘the mouth of the tube’ should be ‘the opening of the tube’.

Response: Accepted. We have changed “mouth” to “opening” (Line 131). Thanks.

 

Line 133: what shape of the ‘plastic container (25 ml)’? Petri dish? Please check and correct throughout the text. And what is ‘an appropriate amount’, please be clear here although a citation is given. Making the methodology specific facilitates others to replicate your research.

Response: Revised. We have changed “plastic container (25 ml)” to “cylindrical plastic containers (25 ml)” (Line 132) and added the amount of artificial diet. “The hatched larvae were placed individually in cylindrical plastic containers (25 ml) equipped with a square artificial diet (approximately 1.5 cm in length, width, and height)” (Lines 131-133). Thanks.

 

Section 2.2 has a very long paragraph, please break it into several with each one focusing on one step of the experiment. This will make the article more readable.

Response: Thank you for the suggestion. We have divided this paragraph into three sections: larva, pupa, and adult (Lines 137-169).

 

The study includes a wide temperature range (15-35 °C), but the justification for choosing these specific intervals (e.g., based on local climate data or historical records) is not provided. Adding such justification would strengthen the ecological relevance.

Response: Thank you for the suggestion. We have added the justification in the manuscript (Lines 139-140). We determined the temperature range based on the field occurrence patterns of P. gularis and local temperature data. P. gularis primarily occurs during the maize ear stage in summer, though it is also found in maize fields in winter. Furthermore, the average annual minimum temperature in Yunnan, China, is >13°C, and the average annual maximum temperature is <30°C; in recent years, temperatures have shown an upward trend. Therefore, we selected a broad temperature range of 15–35°C to assess the impact of temperature on P. gularis.

 

Lines 145-146: The statement that “the larvae were fed an artificial diet replaced every 2-3 days” is vague. Diet freshness and potential microbial growth could affect development, especially at higher temperatures. Please specify how diet quality was controlled.

Response: Revised. We assessed the freshness of the artificial diet by checking for signs of mold, spoilage, or dehydration. We have included this information in the revised manuscript (Lines 147-149). During the experiment, no signs of mold were observed in the artificial diet after 2–3 days. However, when left unchanged for extended periods under high temperatures, the artificial diet tended to dehydrate and dry out, making it difficult for young larvae to consume. After 2–3 days, the artificial diet had not yet dried out. Therefore, we replaced the artificial feed every 2–3 days.

 

Lines 172-176: What are these formulae for? Please indicate the function of each one in the text.

Response: Revised. These formulas are used to calculate the developmental threshold temperatures, effective accumulated temperatures, and their standard deviations. We have explained this in the manuscript (Lines 174-175).

 

Line 183: SPSS is a commercial analytical tool, please provide your registered license number.

Response: Revised. We updated our data analysis software and reanalyzed the data using Python 3.14 (Line 187).

 

Table 3: The authors report that no mating occurred at any temperature (which is rather strange), this is confusing as there are offsprings for the authors to complete the research?? Please check if there are any errors.

Response: Revised. We deleted it and discussed this in the Discussion section (Lines 407-437).

 

Result presentation issues: (1) Table 1 is overly dense and difficult to interpret. Please consider reformat it to enhance it legibility. (2) All figures are too small with poor legibility, please enlarge the figure plates to make them clearer. (3) There are zillions of data in the text, which make it very hard to grasp the key findings, please consider visualise those data into charts.

Response: Revised. We have revised Table 1 to Table S1, converted Table 2 into Figure 3, removed Table 5, added Figure 6, and enlarged all figures. Thanks.

 

Discussion:

The most critical issue—complete failure of mating—is mentioned only briefly in the discussion (lines 410-420) and is not adequately explored. The authors speculate about environmental factors but do not propose specific follow-up experiments or acknowledge that this failure invalidates key life table parameters. This is a major omission.

Response: Thank you very much for your comments. We acknowledge that the P. gularis in the experiment were unmated. Under these conditions, the life table parameters differ from those obtained under mated conditions and should be used for reference only (Lines 401-406). We also discuss the factors affecting mating and the follow-up experiments to be conducted in the manuscript (Lines 407-437).

 

The discussion claims that “all P. gularis adults were unmated, and the eggs they produced were infertile” but then continues to compare fecundity and R0 across temperatures as if these values were meaningful. This is internally inconsistent. The authors should either reanalyze the data without the life table parameters or redesign the study to achieve mating.

Response: Thank you very much for your comments. This study investigated the effects of temperature on the growth, development, and reproduction of P. gularis. The results indicated that developmental duration, survival rates, and pupal weight at various life stages were significantly influenced by temperature; however, the adults remained unmated. This may be due to the influence of other environmental factors and requires further investigation. We have discussed this in the Discussion section (Lines 407-437). We have also presented life table parameters such as R₀, r, and λ for unmated adults to provide a reference for future research.

 

The discussion would benefit from a more critical evaluation of whether the laboratory conditions (e.g., individual rearing, container size, absence of host plant volatiles) suppressed natural mating behavior. This is essential for interpreting the study’s relevance to field populations.

Response: Thank you for the suggestion. We have already added factors affecting mating behavior to the Discussion section (Lines 407-437).

 

The authors cite several studies on temperature effects in other insects but do not discuss why P. gularis failed to mate while similar species under comparable conditions did mate. This comparison would strengthen the discussion.

Response: Revised. We have already discussed in detail why P. gularis failed to mate in the Discussion section (Lines 407-437).

 

Supplementary instruction

We have revised the manuscript in review mode: (1) revised the manuscript to improve its readability, narrative logic, and logical flow, and (2) removed and added relevant references.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

Figure 6. The pointers in the Figure6 better to be smaller and you can make someone of them hollow or devide the Figure into 5 graphs as in others to prevent overlapping.  The legend would look better in the caption. And the fonts preferably to reduce to one.

Please indicate the sex ratio for different developmental stages (at least for the pupa and imago).

Author Response

Thank you very much for taking the time to review this manuscript. Following are our point-by-point responses to the comments or suggestions.

Figure 6. The pointers in the Figure6 better to be smaller and you can make someone of them hollow or devide the Figure into 5 graphs as in others to prevent overlapping. The legend would look better in the caption. And the fonts preferably to reduce to one.

Response: Revised. Thank you for the suggestion. We have revised Figure 6 into five graphs in the manuscript.

Please indicate the sex ratio for different developmental stages (at least for the pupa and imago).

Response: Revised. We have added the sex ratio at different temperatures in the caption of Figure 1. “Number of females/males in the figure: 54/41 (18 °C); 59/36 (20 °C); 115/101 (23 °C); 106/101 (25 °C); 112/111 (28 °C); 77/90 (30 °C); 2/10 (33 °C)” (Lines 259-261). Thanks.

Reviewer 2 Report

Comments and Suggestions for Authors

The revised manuscript addressed all questions raised in the first round, I have no further questions and concerns for this version. It can be accepted for publication in my opinion.

Author Response

Thank you very much for taking the time to review this manuscript.