An Evaluation of Light-Emitting Diode (LED) Traps at Capturing Phlebotomine Sand Flies (Diptera: Psychodidae) in a Livestock Area in Brazil

Are phlebotomine sand flies (Diptera: Psychodidae) really attracted to UV-light sources?

Phlebotomine sand flies are the sole confirmed vector of leishmaniosis, a group of endemic and re-emerging diseases in southern European countries such as Spain. Light traps are the major surveillance method currently being employed. Nevertheless, color light attraction by sand flies remains mostly unknown. Following prior research, the effect of UV-LED light sources, and its synergic effect with different color lights has been evaluated employing a modified Flebocollect (FC) light trap model. Results suggest that female Phlebotomus perniciosus sand flies are more attracted to a FC trap lured with the combination of blue and UV LED light sources than commercial CDC (Center for Disease Control and prevention) traps (Bonferroni post-hoc test; p < 0.08; blue/UV mean = 0.50; CDC mean = 0.13), while the combination of red and UV modified-traps excel in capturing Sergentomyia minuta sand flies (Bonferroni post-hoc test; p < 0.04; blue/UV mean = 1.19; CDC mean = 0.66). However, based on our prior studies, incorporating UV light sources into sand fly traps does not seem to enhance their attractiveness, as it has not resulted in higher capture rates. These findings contribute to understanding how sand flies' vision and light color detection is. Further research is recommended to standardize trap construction procedures and explore variations in different endemic regions according to different sand fly species.

Field comparison of broad-spectrum white LED-baited traps with narrow-spectrum green LED-baited traps in the capture of Anopheles mosquitoes (Diptera: Culicidae)

Light-Emitting Diodes (LEDs) have been effective light sources in attracting Anopheles mosquitoes, but the broad-spectrum white light, even with a wide-ranging application in lighting, have not been evaluated yet. In this study, the white light was field evaluated against the green one in the light trapping of anopheline mosquitoes by using two non-suction Silva traps and two CDC-type suction light traps. Anopheline mosquitoes were captured for two 21-night periods of collecting (2022 and 2023). In the first period, two LEDs were used per Silva trap, but three were used in the second one to increase the luminance/illuminance at traps. A CDC-type suction light trap equipped with an incandescent lamp was used in 2022 and a CDC-type suction light trap equipped with a 6 V-white light (higher luminance/illuminance) in 2023. A total of eight species and 3,289 specimens were captured in both periods. The most frequent species were Anopheles triannulatus s.l., An. goeldii, An. evansae and An. argyritarsis. In 2022, white LEDs were less attractive to anopheline mosquitoes than the other light sources, but without statistical difference among treatments (F = 2.703; P = 0.0752; df = 2). In 2023, even with an increased luminance/illuminance at traps, no statistical difference was found between the two LED-baited Silva traps (F = 6.690; P = 0.0024; df = 2), but rather between the 6 V-white-baited CDC-type suction light trap and green-baited Silva traps. Due to some drawbacks and the lower abundance of individuals caught by using white LEDs, the narrow-banded green LEDs is preferable to white ones for attracting anophelines.

Field evaluation of a new suction light trap for the capture of phlebotomine sand flies (Diptera: Psychodidae: Phlebotominae), vectors of leishmaniasis

Phlebotomine sand flies are crepuscular and nocturnal small dipteran insects in the family Psychodidae. Several disease agents, including Leishmania parasites, are transmitted to humans and other vertebrate hosts by the bite of an infected female sand fly. As part of leishmaniasis surveillance programs, light traps have been routinely used in sand fly collections. In this context, new trapping devices are always being required to improve vector monitoring. Here, the efficiency of a new suction light trap, named Silva suction trap or SS trap, was field evaluated in collecting sand flies. Two SS traps, one with green (520 nm, 15,000 mcd) and the other with white (wide spectrum, 18,000 mcd) LEDs, and one CDC-type trap were deployed in a rural forested environment. A total of 4686 phlebotomine sand flies were captured. The most frequent species were females of the Ps. Chagasi series (77.8%) followed by males of Ps. wellcomei (11.6%), Nyssomyia whitmani (3.3%), and Bichromomyia flaviscutellata (2.4%). The CDC-type light trap collected 101.9 ± 20.89 sand flies and 14 species, followed by the white-baited SS trap (87.78 ± 16.36, 14), and the green-baited SS trap (70.61 ± 14.75, 15), but there were no statistically significant differences among traps. A discussion on the considerable advantages of the use of SS traps over CDC traps is included. In this study, the Silva suction trap proved to be efficient and can be an alternative to CDC traps for monitoring adult phlebotomine sand fly populations.

The evening crepuscular host-seeking activity of Anopheles mosquitoes in northeast Brazil

Studies on the timing of anopheline host-seeking are important for understanding mosquito ecology, behaviors, and possible role in disease transmission. To study the evening crepuscular host-seeking activity of anophelines and the effects of moonlight, anopheline mosquitoes were collected with light traps settled in a livestock area in the Brazilian Cerrado region. Traps (Silva traps) were placed next to animal enclosures at 1.5 m asl. The research was divided in 2 experiments: the first experiment (12 nights) comprised 2 trapping periods, one from 6 PM to 7 PM and one from 7 PM to 6 AM, and the second experiment (16 evenings) divided in three 20-min intervals based on the 3 twilight phases (civil: 6-6:20 PM; nautical: 6:20-6:40 PM; and astronomical: 6:40-7 PM). A total of 2,815 anopheline mosquitoes and 9 species were found. The main species were Anopheles triannulatus s.l., An. argyritarsis, An. goeldii, and An. evanse. Host-seeking mosquitoes were more frequently active during the first hour after sunset, with a significant peak in the second 20-min interval. After that, a decrease in the number of individuals was observed from the astronomical twilight onwards. Moonlight did not affect the evening flight activity of anophelines. By using LED-based passive light traps, the evening arrival time of anophelines at blood-feeding sites was demonstrated, and it may be a key time window for malaria vector control interventions.

Light-emitting diodes as visual attractants to phlebotomine sand flies (Diptera: Psychodidae): A mini-review

Phlebotomine sand flies are responsible for the transmission of different pathogens, including flagellate protozoan of the genus Leishmania. To locate a vertebrate host, females use chemical cues called kairomones, which are also used by males and females to locate carbohydrate sources of food. In addition to these chemical cues, visual cues (such as light and color) can play a key role in determining host location. In this way, incandescent white light is widely used to capture these insects in the field, being more recently replaced by light-emitting diode (LEDs) technology, which can be used with different colors. In this review, we summarize the main results of the use of LEDs as attractants for sand flies. Considering the different LEDs colors, blue and green are responsible for catching the highest number of sand fly species, especially for field trials conducted in New World countries. The intensity of light colors is an important factor to be considered, but so far little explored. In general, the use of LEDs can be considered as a feasible tool for the improvement of light traps. Future research is required to assert the contribution of different colors individually, in different combinations and intensities, as well as the possible synergistic effect of LEDs in association with attractive compounds in the behavior of sand flies.

Can Potted Plants Catch Mosquitoes? Applying Rare-Earth Luminescent Materials and Plant Energy to the Development of Innovative Mosquito-Trapping Potted Plants

Due to the global warming crisis, the spread of various infectious diseases is worsening, with mosquito-borne contagious diseases posing a significant threat. While many residential and public spaces contain plants, often for greening the environment and improving mental and physical well-being, the carbon dioxide released by these plants produces ideal habitats for mosquitoes. Considering the quality of life of urban residents and the development of health-related products simultaneously is an important topic. This study used diverse complementary techniques, such as energy-storing rare-earth luminescent materials, sustainable power generation using plant energy, blue light-emitting diodes, and environmentally friendly fermentation formula, to develop planting products with potential mosquito control functionality. The prototype design for this mosquito-trapping potted plant has been patented. The aim of this paper is to discuss the design principles adopted to improve the defects of existing mosquito-trapping designs, the green energy materials and techniques employed, the architecture configuration of the product prototype, and the test results. By integrating green materials and technology, the prototype can be self-powered without being plugged in to yield conspicuous energy savings. The results showed that the developed multi-function products, combined with the concept of energy sustainability, can improve global public health as well as individuals' physical and mental health.

Color preference of Sergentomyia minuta (Diptera: Phlebotominae) determined using Flebocollect Do It Yourself light traps based on LED technology

Whether phlebotomine sand flies show a preference for different light colors remains controversial. As light-capture methods are widely used to study sand flies, knowing the visual stimuli they respond to could help the design of novel control tools to prevent their attraction to hosts. We have detected a significant preference of male Sergentomyia minuta for green and red light sources. Accordingly, male S. minuta were 2.16 and 2.01 times more likely to be lured by Flebocollect model traps with green and red diode-lights, respectively, than the commercial CDC traps. Flebocollect traps are homemade light traps developed through citizen science. Dipterans are widely considered unable to distinguish the color red so this finding was unexpected. To our knowledge, this is the first description of a color preference in a species of the genus Sergentomyia. Our research also confirms the great potential of Flebocollect light traps for use in medical entomology studies.

Use of light emitting diodes (LEDs) are effective and useful for sand fly ecoepidemiology studies in an Amazonian environment

One strategy to identify transmission foci is based on vector monitoring, and efficient methods are important for vector control. Our study evaluated different light sources (red, green, ultraviolet, blue, and incandescent light) to capture sand fly in Porto Velho, Brazil. We also evaluated Leishmania and blood meal sources in females. A total of 1,943 individuals were identified in 45 species level-taxa, with Trichophoromyia ubiquitalis (Mangabeira) (n=364), Nyssomyia antunesi (n=241), Bichromomyia flaviscutellata (Mangabeira) (n=222), and Psychodopygus davisi (Root) (n=148) being the most abundant. Incandescent light captured most individuals (n=589), followed by blue (n=471), green (n=452), ultraviolet (n=281) and red (n=150). No significant difference was observed between the species composition and lights (PERMANOVA: Pseudo F = 1.29, p = 0.14, NMDS: Stress 0.18). The Shannon and Simpson indices demonstrated a high diversity captured using all lights. Our data demonstrated that LEDs are alternative devices for sand fly capture, with blue and green LEDs presenting similar results to incandescent light. 53 pools were analyzed, only one pool was positive for kDNA and hsp70 targets [Nyssomyia fraihai (Martins, Falão & Silva)] and identified as Endotrypanum spp., suggesting that other trypanosomatids may circulate in the locality. Choloepus hoffmanni (two-toed sloth) Peters, Homo sapiens Linnaeus, Proechimys gardneri (Gardner's spiny rat) Da Silva, and Tamandua tetradactyla (lesser anteater) (Linnaeus) were blood meal sources identified in females, increasing the knowledge about sources used by these insects.

LED Colour Trap for Aedes aegypti Control

BACKGROUND

Aedes aegypti mosquitoes transmit dengue, zika, and chikungunya viruses, neglected diseases that are considered global health challenges. Due to the lack of antiviral drugs and vaccines for these illnesses, vector control with chemical insecticides is the principal strategy for preventing their spread. However, vector populations are becoming increasingly resistant to insecticides, and the development of other control measures is, therefore, imperative.

METHODS

A new insect trap (IT) was used to control Aedes aegypti. A specific light-emitting diode (LED) served as the attractant based on specific wavelength ranges (450-495, 500-550 and 570-600 nm). The IT utilized insect-attracting and killing mechanisms that included a black capture box, a suction-producing mechanism, an electric shock device and a nylon cloth device that held surviving mosquitoes, which died due to starvation. Capture assays of twenty non-feeding females inside a cage were performed in triplicate using different LED intensities. A commercial trap (ultraviolet lamp attractant and suction system) was used as a positive control.

RESULTS

Capture assays of A. aegypti with different intensities and LED combinations showed that the tricolored trap captured 100% of the females, followed by the Green LED 8 set, which captured 91%; in comparison, commercial traps captured approximately 25% of the insects. Although there were no significant differences between the experimental groups, the tricolored trap probably will capture more mosquito females considering the vision variation in individual females.

CONCLUSION

We herein present a green technology-based IT that is effective, safe and successful for reducing mosquito populations, thereby preventing mosquito-borne disease spread.

Comparison of sand fly trapping approaches for vector surveillance of Leishmania and Bartonella species in ecologically distinct, endemic regions of Peru

BACKGROUND

In Peru, the information regarding sand fly vectors of leishmaniasis and bartonellosis in the Amazon region is limited. In this study, we carried out sand fly collections in Peruvian lowland and highland jungle areas using different trap type configurations and screened them for Leishmania and Bartonella DNA.

METHODOLOGY/PRINCIPAL FINDINGS

Phlebotomine sand flies were collected in Peruvian Amazon jungle and inter Andean regions using CDC light trap, UV and color LED traps, Mosquito Magnet trap, BG Sentinel trap, and a Shannon trap placed outside the houses. Leishmania spp. screening was performed by kDNA PCR and confirmed by a nested cytochrome B gene (cytB) PCR. Bartonella spp. screening was performed by ITS PCR and confirmed by citrate synthase gene (gltA). The PCR amplicons were sequenced to identify Leishmania and Bartonella species. UV and Blue LED traps collected the highest average number of sand flies per hour in low jungle; UV, Mosquito Magnet and Shannon traps in high jungle; and Mosquito Magnet in inter Andean region. Leishmania guyanensis in Lutzomyia carrerai carrerai and L. naiffi in Lu. hirsuta hirsuta were identified based on cytB sequencing. Bartonella spp. related to Bartonella bacilliformis in Lu. whitmani, Lu. nevesi, Lu. hirsuta hirsuta and Lu. sherlocki, and a Bartonella sp. related to Candidatus B. rondoniensis in Lu. nevesi and Lu. maranonensis were identified based on gltA gene sequencing.

CONCLUSIONS/SIGNIFICANCE

UV, Blue LED, Mosquito Magnet and Shannon traps were more efficient than the BG-Sentinel, Green, and Red LED traps. This is the first report of L. naiffi and of two genotypes of Bartonella spp. related to B. bacilliformis and Candidatus B. rondoniensis infecting sand fly species from the Amazon region in Peru.

Lutzomyia longipalpis, Gone with the Wind and Other Variables

Lutzomyia longipalpis (Lutz & Neiva) is the main vector of Leishmania infantum (Nicolle) in America, associated in turn with the current spread and urbanization of American visceral leishmaniasis (AVL). The vector distribution in AVL foci shows a spatial-temporal clustering despite the different epidemiological contexts. The factors associated with the macroscale distribution of Lu. longipalpis as a landscape stratification are discussed in the framework of the process of their adaptation to anthropized environments. On the other hand, the fact that Lu. longipalpis is clustered in only a few hot spots or critical sites suggests that microscale approaches that describe the trap surrounding environment and the availability of refuges and food sources are better at explaining the uneven distribution of this vector, and should contribute, together with macroscale variables, to design operational control strategies. With regard to temporal distribution and climatic or vegetation data obtained by remote sensing as variables to explain and forecast the abundance of Lu. longipalpis, it is necessary to take into account the time lags in relation to the life cycle of the vector, the difference between the level of daily activity and actual abundance, and the differences in critical variables and thresholds according to the region or season. In conclusion, this review shows that it is feasible to characterize the distribution of Lu. longipalpis at focus level and within it to identify the main critical sites, proposing a sequential cost-effectivity strategy for urban AVL surveillance and control.

Artificial light and biting flies: the parallel development of attractive light traps and unattractive domestic lights

Light trapping is an important tool for monitoring insect populations. This is especially true for biting Diptera, where light traps play a crucial role in disease surveillance by tracking the presence and abundance of vector species. Physiological and behavioural data have been instrumental in identifying factors that influence dipteran phototaxis and have spurred the development of more effective light traps. However, the development of less attractive domestic lights has received comparatively little interest but could be important for reducing interactions between humans and vector insects, with consequences for reducing disease transmission. Here, we discuss how dipteran eyes respond to light and the factors influencing positive phototaxis, and conclude by identifying key areas for further research. In addition, we include a synthesis of attractive and unattractive wavelengths for a number of vector species. A more comprehensive understanding of how Diptera perceive and respond to light would allow for more efficient vector sampling as well as potentially limiting the risk posed by domestic lighting.

Phlebotomines (Diptera: Psychodidae) and Mosquitoes (Diptera: Culicidae) Surrounding an Environmental Protection Zone in the Metropolitan Region of Natal: Use of Light-Emitting Diode (LED) Bulbs in Entomological Surveillance

Entomological surveillance is very important for parasite and arbovirus vector control programs. Light traps with incandescent bulbs are used to attract insects and analyze the factors that contribute to the occurrence of species surrounding an environmental protection zone. Phlebotomine and mosquito abundance and their diversity were analyzed. Captures occurred monthly using six CDC light traps with two incandescent bulbs, two blue and two red LED lights. A total of 2211 phlebotomines of seven species and 4486 mosquitoes belonging to 20 taxa were captured. Different phlebotomine and mosquito species were found in the forest and peridomestic environments, with a predominance of the sand fly Evandromyia walkeri (Newstead) and the mosquito Coquillettidia venezuelensis (Theobald). There was a significant difference in the abundance of sand flies captured with the three bulbs tested, the blue bulb being the most efficient. The Shannon-Wiener diversity index showed that the trap equipped with a red LED light obtained a higher value than that of the blue LED and incandescent bulb. Analyses showed that the potential vectors and non-vectors of the two groups circulate between the forest and the peridomestic environment, suggesting an adaptation process of species to the altered environment. An incandescent light bulb can be substituted by an LED bulb, without compromising the sensitivity of the method. A blue LED is indicated for the abundant capture of mosquitoes and sand flies, while a red LED obtains a better result in terms of species diversity per capture.

Influence of Moonlight on Male Mating Aggregations of Nyssomyia whitmani, a Vector of American Cutaneous Leishmaniasis in Brazil

Nyssomyia whitmani (Antunes & Coutinho) is the sandfly vector of causative agents of American cutaneous leishmaniasis in South and Central America. It is widely spread throughout Brazil, in a close association with domestic animals. Almost nothing is known about male mating aggregations in N. whitmani, let alone the influence of moonlight on this behavior. Thus, the influence of moonlight on male N. whitmani aggregations was investigated by using non-attractant suction traps deployed in chicken cages under full moon and new moon nights. In this 18-night study, 2,160 specimens and seven species were collected. The most frequent species was N. whitmani accounting for 91.48% of the total sample. The abundance of males of N. whitmani was significantly higher in the presence than in the absence of moon. The sex ratio on new moon nights was 1:1 (M:F) and on full moon nights was male-biased (1.7:1). Based on this study, an influence of moonlight on male mating aggregations of N. whitmani was verified. The extent of this influence on increasing sandfly aggregation at hosts, the moonlight influence on the early flight activity of male sandflies and the use of chickens as aggregation sites for males of N. whitmani, are all discussed.

Exploiting the Synergistic Effect of Kairomones and Light-Emitting Diodes on the Attraction of Phlebotomine Sand Flies to Light Traps in Brazil

The synergistic effect of light-emitting diodes (LEDs) and kairomones on the attraction of sand flies to light traps was evaluated. Octenol and lactic acid were used as chemical attractants. Green LEDs and the incandescent lamps were used as light attractants. Five CDC-type light traps with the respective combination of attractants (incandescent lamp, incandescent lamp + chemical attractant, green LED, green LED + chemical attractant, and chemical attractant alone [without light]) were set between 18:00 and 06:00 following a Latin square design. A total of 6,536 sand flies and 16 species were collected. The most frequent species collected was Lutzomyia longipalpis (Lutz & Neiva, 1912) (Diptera, Psychodidae) accounting for 43.21% of all individuals. Order of success (mean, SD) of lactic acid attractant fly capture was as follows: LED + lactic acid (36.83 ± 4.74), LED alone (34.87 ± 4.61), incandescent lamp + lactic acid (22.80 ± 3.19), incandescent lamp alone (12.67 ± 2.03), and lactic acid (0.46 ± 0.13). Order of success of octenol attractant fly capture was as follows: LED + octenol (37.23 ± 5.61), LED alone (35.77 ± 5.69), incandescent lamp + octenol (18.63 ± 3.28), incandescent lamp alone (14.67 ± 2.86), and octenol alone (1.80 ± 0.65). With exception of lactic acid + incandescent light, chemical synergists played no part in significantly increasing light trap capture of phlebotomine sand flies. However, the use of LEDs, with or without such attractants, provided significantly higher capture compared to the incandescent lamp with or without such chemicals, showing that LEDs are suitable and efficient light sources for surveillance and monitoring of phlebotomine sand flies in Brazil.

Evaluation of an ultraviolet LED trap for catching Anopheles and Culex mosquitoes in south-eastern Tanzania

BACKGROUND

Improved surveillance techniques are required to accelerate efforts against major arthropod-borne diseases such as malaria, dengue, filariasis, Zika and yellow-fever. Light-emitting diodes (LEDs) are increasingly used in mosquito traps because they improve energy efficiency and battery longevity relative to incandescent bulbs. This study evaluated the efficacy of a new ultraviolet LED trap (Mosclean) against standard mosquito collection methods.

METHODS

The study was conducted in controlled semi-field settings and in field conditions in rural south-eastern Tanzania. The Mosclean trap was compared to commonly used techniques, namely CDC-light traps, human landing catches (HLCs), BG-Sentinel traps and Suna traps.

RESULTS

When simultaneously placed inside the same semi-field chamber, the Mosclean trap caught twice as many Anopheles arabiensis as the CDC-light trap, and equal numbers to HLCs. Similar results were obtained when traps were tested individually in the chambers. Under field settings, Mosclean traps caught equal numbers of An. arabiensis and twice as many Culex mosquitoes as CDC-light traps. It was also better at trapping malaria vectors compared to both Suna and BG-Sentinel traps, and was more efficient in collecting mosquitoes indoors than outdoors. The majority of An. arabiensis females caught by Mosclean traps were parous (63.6%) and inseminated (89.8%). In comparison, the females caught by CDC-light traps were 43.9% parous and 92.8% inseminated.

CONCLUSIONS

The UV LED trap (Mosclean trap) was efficacious for sampling Anopheles and Culex mosquitoes. Its efficacy was comparable to and in some instances better than traps commonly used for vector surveillance. The Mosclean trap was more productive in sampling mosquitoes indoors compared to outdoors. The trap can be used indoors near human-occupied nets, or outdoors, in which case additional CO2 improves catches. We conclude that this trap may have potential for mosquito surveillance. However, we recommend additional field tests to validate these findings in multiple settings and to assess the potential of LEDs to attract non-target organisms, especially outdoors.

Field performance of a low cost, simple-to-build, non-motorized light-emitting diode (LED) trap for capturing adult Anopheles mosquitoes (Diptera: Culicidae)

In this paper, a non-powered trap equipped with light-emitting diodes (LEDs) designed for capturing small night-flying insects was field-evaluated for sampling anopheline mosquitoes. This new light trap, referred to as the Silva trap, was compared with the Centers for Disease Control and Prevention (CDC) miniature light trap in a livestock area in northeastern Brazil. Light traps were operated from 18:00 to 06:00 between July and August 2018, over a 12-night period. A total of 3124 specimens and eight species were collected. Anopheles (Nyssorhynchus) argyritarsis was the prevalent species, followed by A. (Nys) triannulatus s.l., A. (Nys) goeldii, A. (Nys) evansae, A. (Nys) rangeli, A. (Nys) galvaoi, A. (Nys) darlingi and A. (Nys) albitarsis s.l. The total number of anopheline mosquitoes captured with the Silva trap was higher than the number of individuals captured with the CDC light trap, but no significant difference between the two trapping methods was found. Concerning the damaged specimens, the Silva trap damaged significantly less mosquitoes than the CDC light trap. According to these results, the Silva trap has acceptable performance in being an efficient tool for sampling anopheline mosquitoes, mainly in comparison with the CDC light trap. The Silva trap has a number of advantages over other trapping devices that collect questing mosquitoes and these advantages are pointed out and discussed.

Centers for Disease Control-type light traps equipped with high-intensity light-emitting diodes as light sources for monitoring Anopheles mosquitoes

In this study the phototactic response of anopheline mosquitoes to different luminous intensity light-emitting diodes (LEDs) was investigated. Centers for Disease Control-type light traps were changed by replacement of the incandescent lamps by 5 mm round type green (520 nm) and blue (470 nm) LEDs of different luminous intensities: green-LED traps with luminous intensities of 10,000, 15,000 and 20,000 millicandela (mcd) and the blue-LED traps with luminous intensities of 4000, 12,000 and 15,000 mcd. Our data showed that increasing luminous intensity has an effect on the attraction of anopheline mosquitoes to light traps, highlighting the importance of taking LEDs and light sources of high luminous intensity into account when using light-trap collections in monitoring populations of Anopheles species.

The effect of luminous intensity on the attraction of phlebotomine sand flies to light traps

To improve the efficiency of light traps in collecting phlebotomine sand flies, the potential effects of luminous intensity on the attraction of these insects to traps were evaluated. Sand flies were collected with Hooper Pugedo (HP) light traps fitted with 5-mm light-emitting diodes (LED) bulbs: green (520 nm wavelength-10,000, 15,000 and 20,000 millicandela (mcd) and blue (470 nm-4,000, 12,000 and 15,000 mcd). A total of 3,264 sand flies comprising 13 species were collected. The collected species were Lutzomyia longipalpis (Lutz & Neiva) (Diptera: Psychodidae) (52.48%), Evandromyia evandroi (Costa Lima & Antunes, 1939) (Diptera: Psychodidae) (32.90%) and Micropygomyia goiana (Martins, Falcão, & Silva) (Diptera: Psychodidae) (9.76%). An increase in luminous intensity of the LEDs increased the size of the sand fly catch. The lower luminous intensity of green (10,000 mcd) attracted an average of 13.7 ± 2.8 sand flies/trap per night and the other luminous intensities accounted for a mean of 24.1 ± 4.0 (15,000 mcd) and 28.2 ± 5.0 (20,000 mcd) sand flies/trap per night. Regarding the blue wavelength, the lower luminous intensity (4,000 mcd) attracted an average of 27.4 ± 4.1 sand flies/trap per night, followed by 12,000 mcd (37.6 ± 8.7) and 15,000 mcd (40.5 ± 7.3). Based on our data, the luminous intensity of light traps should be considered when developing light traps for monitoring or controlling phlebotomine sand flies.

Light-Emitting Diode (LED) Traps Improve the Light-Trapping of Anopheline Mosquitoes

Numerous advantages over the standard incandescent lamp favor the use of light-emitting diodes (LEDs) as an alternative and inexpensive light source for sampling medically important insects in surveillance studies. Previously published studies examined the response of mosquitoes to different wavelengths, but data on anopheline mosquito LED attraction are limited. Center for Disease Control and Prevention-type light traps were modified by replacing the standard incandescent lamp with 5-mm LEDs, one emitting at 520 nm (green) and the other at 470 nm (blue). To test the influence of moon luminosity on LED catches, the experiments were conducted during the four lunar phases during each month of the study period. A total of 1,845 specimens representing eight anopheline species were collected. Anopheles (Nyssorhynchus) evansae (35.2%) was the most frequently collected, followed by An. (Nys.) triannulatus (21.9%), An. (Nys.) goeldii (12.9%), and An. (Nys.) argyritarsis (11.5%). The green LED was the most attractive light source, accounting for 43.3% of the individuals collected, followed by the blue (31.8%) and control (24.9%) lights. The LED traps were significantly more attractive than the control, independent of the lunar phase. Light trapping of anopheline mosquitoes was more efficient when the standard incandescent lamp was replaced with LEDs, regardless of the moon phase. The efficiency of LEDs improves light trapping results, and it is suggested that the use of LEDs as an attractant for anopheline mosquitoes should be taken into consideration when sampling anopheline mosquitoes.