Light-Emitting Diodes (LED): A Promising Street Light System to Reduce the Attraction to Light of Insects
Round 1
Reviewer 1 Report
The revised manuscript is considerably improved. I just suggest adding the references I recommended last time (especially Justice and Justice (2016) and Longcore et al. (2015)) into the Introduction with extended commentary – to show what is already known about the research area. Also, I still think that a short note about attraction of aquatic insects to the LED light (Ditrich and Cihak (20174) should be added into the Introduction.
Author Response
Author's Reply to the Review Report (Reviewer 1):
Reviewer: The revised manuscript is considerably improved. I just suggest adding the references I recommended last time (especially Justice and Justice (2016) and Longcore et al. (2015)) into the Introduction with extended commentary – to show what is already known about the research area. Also, I still think that a short note about attraction of aquatic insects to the LED light (Ditrich and Cihak (20174) should be added into the Introduction.
Authors: Done, please see new lines 38 and 52-54.
Reviewer 2 Report
The manuscript entitled “Light-Emitting Diodes (LED): a promising street light system to reduce the attraction to light of insects” is an important contribution on the use of LED technology in street lighting. In fact, LEDs have innumerable advantages over conventional streetlights. In the introduction, it would be interesting to add information about the impact of streetlights on the range and behavior of harmful insects (e.g., rove beetles of the genus Paederus – doi.org/10.1093/jme/tju006). As far as there is an effect of trap height on the captures, please, in the material and methods, give information about the heights in which the traps were installed. In the discussion, the light intensity is an important factor in attracting insects to light traps. There are studies with insect vectors demonstrating the effect of luminous intensity on the attraction of these insects (see, doi.org/10.1093/jme/tjx229).
Author Response
Author's Reply to the Review Report (Reviewer 2)
Reviewer: The manuscript entitled “Light-Emitting Diodes (LED): a promising street light system to reduce the attraction to light of insects” is an important contribution on the use of LED technology in street lighting. In fact, LEDs have innumerable advantages over conventional streetlights. In the introduction, it would be interesting to add information about the impact of streetlights on the range and behavior of harmful insects (e.g., rove beetles of the genus Paederus – doi.org/10.1093/jme/tju006).
Authors: Done, please see new lines 58-60.
Reviewer: As far as there is an effect of trap height on the captures, please, in the material and methods, give information about the heights in which the traps were installed.
Authors: Actually this information was already reported in the Methods section (“Sticky traps […] placed at 1.5 m above the ground), please see line 183.
Reviewer: In the discussion, the light intensity is an important factor in attracting insects to light traps.
Authors: In fact, the effect of intensity on the results of our study was thoroughly discussed in lines 334-365.
Reviewer: There are studies with insect vectors demonstrating the effect of luminous intensity on the attraction of these insects (see, doi.org/10.1093/jme/tjx229).
Authors: Mention to disease vectors and other harmful insects that can be attracted by light has been included in the manuscript (see also comment above on harmful insects). Please see new lines 49 (regarding light intensity) and lines 58-60 (regarding disease vectors).
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
The authors test the attraction of insects to different light sources (e.g. Mercury vapor and LED). Their study is commendable, however, I have several concerns about the paper as is currently written.
1) The authors gloss over the immense research that has been conducted already in the field of insect attraction to different light sources. See Langevelde's work, Donners' work, Holker's work, and Spoelstra's work. Owens and Lewis 2018 and Owens...& Seymoure 2020 are excellent reviews of this work, this literature needs to be further covered. You are not one of the first ones to do this work, much work has been done doing this research. If this manuscript was published as is, it would be very offensive to the many researchers in this field, so please cite the many appropriate studies.
2) During the discussion about the differences intensities and spectral distributions of light, the reader is left in the blind. You need to give more. Showing the emission spectra (preferably in photons) of the different light sources would be a good start. Seymoure et al 2019 and Seymoure 2018 would be good places for that information and need to be cited here. At the end of the day, what is important is that different insects have different spectral sensitivites and responses, this work needs to be reviewed and made clear, again, Donner's work is excellent.
3) The trapping approach needs to be further discussed in that you aren't biasis one light source over the other with the specific light traps. Light traps are similiar to Mercury Vapor, so how did you correct for that? Please discuss how there was not sampling bias. Furthermore, the sticky trap approach also has inherent bias and those traps were made specifically with aphid visual systems in mind. Thus they will be over sampling many hemiptera and under sampling many other insect groups, please discuss. Also, how far were the sticky traps from the light sources?
4) I am not sure that a X^2 test is the most appropriate. I think an ANOSIM would be much better. I don't think you can assume that insects are likely to go to each trap, so perhaps this needs to be further discussed.
5) I should have mentioned this sooner - much more is needed about the diversity of LED spectra and why you chose the 5000K bulb, which are not the most common LED bulbs used. Most LEDs are much warmer in temperature, meaning between 3000K and 4500K, please discuss this!
These are major concerns currently. I do think your study has many merits, but the manuscript currently needs to discern how this study helps with the large understanding that we already have and why only one LED source was used?
Author Response
The authors test the attraction of insects to different light sources (e.g. Mercury vapor and LED). Their study is commendable, however, I have several concerns about the paper as is currently written.
1) The authors gloss over the immense research that has been conducted already in the field of insect attraction to different light sources. See Langevelde's work, Donners' work, Holker's work, and Spoelstra's work. Owens and Lewis 2018 and Owens...& Seymoure 2020 are excellent reviews of this work, this literature needs to be further covered. You are not one of the first ones to do this work, much work has been done doing this research. If this manuscript was published as is, it would be very offensive to the many researchers in this field, so please cite the many appropriate studies.
Authors: Done
2) During the discussion about the differences intensities and spectral distributions of light, the reader is left in the blind. You need to give more. Showing the emission spectra (preferably in photons) of the different light sources would be a good start. Seymoure et al 2019 and Seymoure 2018 would be good places for that information and need to be cited here. At the end of the day, what is important is that different insects have different spectral sensitivites and responses, this work needs to be reviewed and made clear, again, Donner's work is excellent.
Authors: Done (see Table 1 and new references added).
3) The trapping approach needs to be further discussed in that you aren't biasis one light source over the other with the specific light traps. Light traps are similiar to Mercury Vapor, so how did you correct for that? Please discuss how there was not sampling bias.
Authors: Light traps are identical for all the light systems assessed. In fact, to test different lighting systems we used the same traps and we only changed the lamp of the trapping system. This has now been clarified in page 3. Regarding the possible sampling bias, please see page 3: “To avoid light competition between different lighting systems, we tested only one type of lighting system each night”. However, sampling bias emerge from the particular spectral sensitivity of the different insect groups, both in light and sticky traps (see Discussion section for a further discussion on this topic; see also comment below).
Furthermore, the sticky trap approach also has inherent bias and those traps were made specifically with aphid visual systems in mind. Thus they will be over sampling many hemiptera and under sampling many other insect groups, please discuss. Also, how far were the sticky traps from the light sources?
Authors: Since our sticky traps were made of a yellow-coloured material, insects with sensitivities within these wavelengths could be preferentially trapped compared with other groups. However, according to the most recent review on this topic (van der Kooi et al. 2021), some families of Hymenoptera and Lepidoptera are the most sensitive to yellow-orange lights. Although Hymenoptera were found with higher frequency than expected in sticky traps, Lepidoptera were found less than expected in the sticky traps thus our results still support the larger attraction in Lepidoptera. This discussion has now been included in the Discussion section (see lines 363-370).
4) I am not sure that a X^2 test is the most appropriate. I think an ANOSIM would be much better. I don't think you can assume that insects are likely to go to each trap, so perhaps this needs to be further discussed.
Authors: ANOSIM is typically used in Ecology to test if there is a statistical difference between the communities of two or more groups of samples. However, our aim was to test for differences in the relative frequency of capture of major groups of insects between light and sticky traps (see for instance Spafford and Lortie 2013). Therefore, we chose the chi-squared two-way test (this has now been clarified in the manuscript, please see page 4) which informs whether the sample significantly differs from the frequencies that we would expect if no difference among light attraction and captures in sticky traps exist.
Spafford, Ryan, Lortie, C.J. 2013. Sweeping beauty: Is grassland arthropod community composition effectively estimated by sweep netting? Ecology and Evolution, 3 DO - 10.1002/ece3.688
5) I should have mentioned this sooner - much more is needed about the diversity of LED spectra and why you chose the 5000K bulb, which are not the most common LED bulbs used. Most LEDs are much warmer in temperature, meaning between 3000K and 4500K, please discuss this!
Authors: We must have in mind that early LEDs have CCTs of 5000 K or more. The reason is because high-CCT white LEDs were more available, more efficient, and less expensive than lower-CCT versions during the technology’s early years. Therefore, although there were a few smaller-scale pilot studies and other installations involving products with CCT ≥ 5000 K in the first few years of LED outdoor lighting installations in U.S., the outdoor lighting experts finally converged around a warmer 4000 K when that technology became less expensive (by 2010). From then to 2016, most of municipalities and utilities favored 4000 K CCT products for LED street and roadway lighting applications. More recently, with continued improvement of the technology, a number of cities are now considering 3000 K and, in some cases, even lower CCTs (USDOE 2017). But our study was carried out between December 2012 and August 2013 and the LED technology available for outdoor lighting at that time was the one tested in our study. All this has now been clarified in the manuscript (please see lines 287-297).
Austrian Energy Agency. (2017). LED street lighting procurement and design guidelines. Available at: https://ec.europa.eu/research/participants/documents/downloadPublic?documentIds=080166e5b6d1cf07&appId=PPGMS
USDOE (2017). Street Light and Blue Light - Frequently Asked Questions, US Department of Energy; Office of Energy Efficiency and Renewable Energy.
These are major concerns currently. I do think your study has many merits, but the manuscript currently needs to discern how this study helps with the large understanding that we already have and why only one LED source was used?
Authors: We disagree with the reviewer. Taking into account only the quantity of the captures in light traps, we cannot infer the differential vulnerability among insect groups. Because differences in the number of catches among groups can be produce as a result of different abundance of the insect groups in the study area rather than the consequence of differential attraction to light. For this reason, in addition to light traps, we also captured insects using an alternative trapping method (i.e., sticky traps) in order to disentangle when there are truly light effects in the insect attraction levels. We have rewritten our aims in order to highlight this point at the end of the Introduction as well as in the Methods section (lines 164-174).
Submission Date
05 January 2021
Date of this review
25 Jan 2021 05:31:06
Final del formulario
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Author Response File: 
Author Response.docx
Reviewer 2 Report
Dear authors,
This paper presents data which is important for outdoor lighting practice. However, you present your data in a way which is totally incomprehensible for any lighting or ecological specialist involved in this field. Can you please add 'normal' tables or graphs showing differences in catches, next to statistical parameters.
Secondly, you've used very different light sources in your test, differing in spectrum and light output but also in light distribution. Your paper only mentions luminous flux and CCT. Please provide the spectra of the lights as well. More importantly, the LED source which you've used has a much lower flux. It is known that insect attraction scales with light output. So your conclusions about the relative effect of LEDs is unfounded. Its unclear which LED lamp type you've used, but several types which i see when i search for the description that you've given have a very different light intensity and luminance distribution when compared to a conventional lamp.
You also did not give any details about the construction of the light traps, to enable us to estimate whether that has any influence on the light output characteristics of the traps.
To summarize: you are showing comparisons which you can't make in a way nobody will understand.
Author Response
Dear authors,
This paper presents data which is important for outdoor lighting practice. However, you present your data in a way which is totally incomprehensible for any lighting or ecological specialist involved in this field. Can you please add 'normal' tables or graphs showing differences in catches, next to statistical parameters.
Authors: Absolute catches do not provide reliable information on differences among lighting systems if we do not take into account the confounding factors (i.e., moon phase, wind speed and direction, among others, see Table 2) affecting the quantity and richness of the captures. For this reason, we have modelled both species richness and number of insects in the catches (GLM models) including all these factors in order to assess whether, once these variables are considered, the effects of the lighting system in insect catches persist. See lines 182-188.
Secondly, you've used very different light sources in your test, differing in spectrum and light output but also in light distribution. Your paper only mentions luminous flux and CCT. Please provide the spectra of the lights as well. More importantly, the LED source which you've used has a much lower flux. It is known that insect attraction scales with light output. So your conclusions about the relative effect of LEDs is unfounded. Its unclear which LED lamp type you've used, but several types which i see when i search for the description that you've given have a very different light intensity and luminance distribution when compared to a conventional lamp.
Authors: As it is stated in the manuscript (please see lines 88-93), what we aimed was a similar usable light regardless of the luminous efficacy of the light systems. The reason is that we aimed to assess lighting systems that were equivalent in terms of light human perception. Because LED give off light in a very specific direction, they are more efficient and they can provide similar amount of usable light with lower luminous fluxes. We have clarified this issue in the text. We have now provided information on light spectra in Table 1 based on Wiens law (please see new addition in Table 1 legend) since the only information on light spectrum that we count on is derived from the technical specifications provided by the manufacturer of the different lighting systems.
You also did not give any details about the construction of the light traps, to enable us to estimate whether that has any influence on the light output characteristics of the traps.
Authors: Please, see page 3: “These traps consisted of two crossed plastic sheets of “plexiglass” within a shade lamp, a catch funnel, and a container filled with ethyl acetate-soaked plaster as a killing agent”. We have also added a new Figure 2 with a picture of the trap design.
To summarize: you are showing comparisons which you can't make in a way nobody will understand.
Authors: See also comment below regarding this same topic and further clarifications in Figure 2 and 3 captures).
Submission Date
05 January 2021
Date of this review
20 Jan 2021 15:55:32
Author Response File: Author Response.docx
Reviewer 3 Report
The manuscript entitled “Light-Emitting Diodes (LED): a promising street light system to reduce the attraction to light of insects” brings important and interesting issue - if the LED street lights could reduce a negative impact of urban light pollution, resp. reduce the number of insects attracted by a street lights.
The manuscript is generally good, with a clear outcome. However, I have several remarks that should be taken into account during the revision of the manuscript.
- Most important is an incomplete review of the main subject. There is almost 5 years old paper (Michael J. Justice, Teresa C. Justice "Attraction of Insects to Incandescent, Compact Fluorescent, Halogen, and Led Lamps in a Light Trap: Implications for Light Pollution and Urban Ecologies," Entomological News, 125(5), 315-326) that has to be added and (commented) into Introduction and the results compared in Discussion. Beside this, see (and add) also “Owens, ACS, Lewis, SM. The impact of artificial light at night on nocturnal insects: A review and synthesis. Ecol Evol. 2018; 8: 11337– 11358. https://doi.org/10.1002/ece3.4557” and references therein (e.g. Longcore Travis, Aldern Hannah L., Eggers John F., Flores Steve, Franco Lesly, Hirshfield-Yamanishi Eric, Petrinec Laina N., Yan Wilson A. and Barroso André M. 2015Tuning the white light spectrum of light emitting diode lamps to reduce attraction of nocturnal arthropodsPhil. Trans. R. Soc. B37020140125; http://doi.org/10.1098/rstb.2014.0125). Interesting may be also note that also aquatic insects are attracted to LED lights (Tomáš Ditrich & Petr Čihák (2017) Efficiency of subaquatic light traps, Aquatic Insects, 38:3, 171-184, https://doi.org/10.1080/01650424.2017.1359305).
- The figure 3 shows a difference among insect orders – however, I think more useful would be showing the different response of these insects to the different light source. I suggest replotting the graphs – similarly as is shown in fig. 2.
Concerning this graph, I did not get the results on l. 222 – 223. Are these results of χ2 comparison for all insect orders pooled, or what?
- There is a statement that “Compared to other traditional lighting systems, the insect attraction of LED is 5 to 8 times lower” in Conclusions (l. 296 – 297). But I didn’t find what is this statement based on.
- The English needs extended correction. Importantly I believe the word “abundance” is misused throughout the manuscript (l. 15; 113; 116; 125; 134 and so on) – it should be replaced by “quantity”; she light sources have shorter wavelengths (not smaller; l. 247); replace “produce” by “produced” (l. 259); change word order in l. 267 etc. – there are many mistakes in English.
According to my opinion, the Introduction has to be amended by the references mentioned above and the results has to compared with these, already published results. After this and language correction the manuscript could be published.
Author Response
The manuscript entitled “Light-Emitting Diodes (LED): a promising street light system to reduce the attraction to light of insects” brings important and interesting issue - if the LED street lights could reduce a negative impact of urban light pollution, resp. reduce the number of insects attracted by a street lights.
The manuscript is generally good, with a clear outcome. However, I have several remarks that should be taken into account during the revision of the manuscript.
- Most important is an incomplete review of the main subject. There is almost 5 years old paper (Michael J. Justice, Teresa C. Justice "Attraction of Insects to Incandescent, Compact Fluorescent, Halogen, and Led Lamps in a Light Trap: Implications for Light Pollution and Urban Ecologies," Entomological News, 125(5), 315-326) that has to be added and (commented) into Introduction and the results compared in Discussion. Beside this, see (and add) also “Owens, ACS, Lewis, SM. The impact of artificial light at night on nocturnal insects: A review and synthesis. Ecol Evol. 2018; 8: 11337– 11358. https://doi.org/10.1002/ece3.4557” and references therein (e.g. Longcore Travis, Aldern Hannah L., Eggers John F., Flores Steve, Franco Lesly, Hirshfield-Yamanishi Eric, Petrinec Laina N., Yan Wilson A. and Barroso André M. 2015Tuning the white light spectrum of light emitting diode lamps to reduce attraction of nocturnal arthropodsPhil. Trans. R. Soc. B37020140125; http://doi.org/10.1098/rstb.2014.0125). Interesting may be also note that also aquatic insects are attracted to LED lights (Tomáš Ditrich & Petr Čihák (2017) Efficiency of subaquatic light traps, Aquatic Insects, 38:3, 171-184, https://doi.org/10.1080/01650424.2017.1359305).
Authors: Done.
- The figure 3 shows a difference among insect orders – however, I think more useful would be showing the different response of these insects to the different light source. I suggest replotting the graphs – similarly as is shown in fig. 2.
Authors: The information requested by the reviewer is actually shown in Figure 2. In this figure we show the results from the GLM models which includes the variable type of “lighting system”. Please, see also comment below and new lines 189-192. What Figure 3 shows are the results from the chi-squared test: whether the observed values from the sample capture in light traps statistically differs from the expected captures collected with sticky traps. We have clarified this fact in the new version of the manuscript.
Concerning this graph, I did not get the results on l. 222 – 223. Are these results of χ2 comparison for all insect orders pooled, or what?
Authors: These results correspond to the coefficients derived from the GLM gaussian models. The lighting system effect is actually the coefficient for the lighting system variable in the GLM model. This has now been clarified in the new version of the manuscript.
There is a statement that “Compared to other traditional lighting systems, the insect attraction of LED is 5 to 8 times lower” in Conclusions (l. 296 – 297). But I didn’t find what is this statement based on.
Authors: Reviewer is right. We have removed this statement from the Conclusions section.
- The English needs extended correction. Importantly I believe the word “abundance” is misused throughout the manuscript (l. 15; 113; 116; 125; 134 and so on) – it should be replaced by “quantity”; she light sources have shorter wavelengths (not smaller; l. 247); replace “produce” by “produced” (l. 259); change word order in l. 267 etc. – there are many mistakes in English.
Authors: we have reviewed the language throughout the manuscript. In addition, we have removed the term “abundance” from the new version of the document and we have fixed all the language “bugs” identified by the reviewer.
According to my opinion, the Introduction has to be amended by the references mentioned above and the results has to compared with these, already published results. After this and language correction the manuscript could be published.
Authors: Done.
Submission Date
05 January 2021
Date of this review
25 Jan 2021 15:33:10
Author Response File: Author Response.docx
